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There are three types of radio communication types: Simplex, Half-Duplex, and Full-Duplex. Each has its place in workplace communication. In Simplex Communication, data is sent in only one direction. In Half-Duplex Communication, data can only be sent from one device at a time. Once that device has finished sending its data, the other device may send data. In a Full-Duplex Communication, all devices on the network may transmit data at any time. Knowing the advantages and ideal applications of each can help make communication more efficient and also help choose the most cost-effective solution.

Intrinsic safety certification is a highly involved process that measures the energy risk in a specific device according to each component. CavCom‘s intrinsically safe products are built from the ground up and IS certified. We offer the protection workers need in inherently hazardous work locations. 

Manufacturers of products that are certified intrinsically safe must follow strict requirements for recordkeeping and documentation. Companies are inspected by the certifying body on a quarterly basis to ensure continued quality control and compliance. Manufacturers must also provide customers instructions for use of the product in hazardous locations. Lastly, products must be clearly marked with applicable intrinsic safety (IS) ratings. Following is an example of a permanent product label affixed to CavCom‘s intrinsically safe RadioGear® earsets. See key below to better understand IS classifications for North America. Please contact us if you have questions regarding IS certifications or if we can be of assistance.

*Product Intrinsic Safety Ratings

 Area Classifications

• Class I: Explosive Gas Atmospheres (flammable gases, flammable and combustible liquid-produced vapors)
• Class II: Explosive Dust Atmospheres (combustible dust)
• Class III: Ignitable Fibers/Flyings (easily ignitable fibers or materials producing combustible flyings)

Exposure Division

• Division 1: Where ignitable concentrations of flammable gases, vapors/liquids, combustible dust, or combustible fibers/flyings can exist all of the time or some of the time under normal operating conditions
• Division 2: Where ignitable concentrations of flammable gases, vapors/liquids or combustible dust are not likely to exist under normal operating conditions; where easily ignitable fibers are stored or handled but not manufactured/used

Hazard Group

• Group A: Acetylene
• Group B: Hydrogen
• Group C: Ethylene
• Group D: Propane
• Group E: Metal dust (Div 1 only)
• Group F: coal (carbonaceous) dust
• Group G: non-conductive dust such as flour, grain, wood, plastic, etc.

Temperature Class/Range

• Over a dozen temperature classifications; see "Temperature Range" for details on individual product specifications 

Few things are more frustrating than being unable to understand what others are saying. In a work environment, failing to comprehend important messages can result in severe consequences. Safety and productivity depend on workers' ability to collaborate, problem-solve, and react quickly to emergency situations. Obstacles including loud background noise, PPE such as respiratory and hearing protection, and isolated work locations can create special challenges to achieving effective 2-way communication.

Noise remains one of the most prevalent hazards in industry today. And noise creates challenges in the workplace well beyond its most basic threat to hearing health. Growing evidence suggests there may be a link between noise, hearing loss, and risk of occupational injury. And as demands on worker productivity become more complex, the need for efficient and effective communication is essential. Comprehending speech in the presence of loud background noise can be challenging at best, and at times nearly impossible. Here we review some of the basic principles affecting workers' ability to communicate and offer solutions for improving safety and productivity in your workplace.

Key factors affecting speech communication

• Speech-to-noise ratio (SNR). The most basic determining factor of speech detection (realizing someone is speaking) and speech intelligibility (understanding what is said) is the loudness of the speech compared to the background noise. The level of a speech signal must be significantly higher than the background noise for the message to be understood.
• Poor speech quality. If a talker is wearing a respirator or other head/face PPE, speech may be altered/garbled from the start. And shouting to be heard is not a solution. There is a physiologic limit to how loud and how long talkers can raise their voice. Shouted speech often sounds distorted, too.
• Environmental obstacles. When speaker and listener are separated by distance or other obstacles such as machinery, visual cues such as lip-reading and hand signals/gestures are missed. Under best circumstances, a spoken, even shouted message cannot be heard at 3 to 5 feet in high noise. Even if workers have the benefit of a 2-way radio, phone, or public announcement system, cranking up the volume to be heard over background noise results in distortion of the speech signal and adds to employee noise exposure.
• Inner ear distortion. Next, let's consider the ear itself. Simply making sounds louder doesn't render those sounds easier to understand. Sensory cells and nerve fibers in the inner ear work most effectively at low to moderate sound levels. At high sound levels, signals within the inner ear become distorted, and auditory function is diminished. Just as music can lose its quality if played through a stereo speaker at full volume, speech can become distorted when entering the ear at very high levels.
• Hearing loss. As if there weren't enough challenges to listening in noise, now add one of the most common problems experienced by adults: hearing loss. According to the National Institutes of Health, approximately 15 percent of American adults report some degree of hearing loss. There are many different types of hearing loss that can affect listeners in varying ways. Some people have trouble hearing even in quiet situations. Others get by fine in quiet, but experience significant difficulty distinguishing sounds, particularly speech, in the presence of competing background noise. A listener with hearing impairment is likely to say making sounds louder doesn't necessarily make them clearer or easier to understand and they have difficulty in crowds, restaurants, even in face to face speaking situations.
• Hearing protector complications. Finally, one more PPE obstacle for listeners in noisy environments: hearing protectors affect speech intelligibility, particularly for people with hearing impairment. Hearing protectors block out high pitched sounds (consonant speech sounds like s, f, th, sh, etc.) that are critical for speech discrimination, reducing the speech to mumbling or gibberish. For a worker with high frequency hearing loss (very common), wearing hearing protectors can exacerbate the high frequency deficit, and in turn, further impair speech intelligibility

Options for improving communication

If companies are concerned that noise may be interfering with 2-way communication for their workers, then a complete Communication Survey is warranted. Where possible, engineering noise controls should be considered as a first line of defense to reduce noise at its source. Other solutions to consider:

• Group communication systems. With new technologies emerging, there are now many options for group communication available. Companies can choose a wide range of technologies, from cell phones or simple short-range 2-way radios to complex multi-user systems capable of connecting many workers across wide areas.
• Personal communication devices. These specialty devices typically consist of a personal hearing protector (earplug or earmuff) that attenuates (blocks) the background noise in combination with a communication interface. Devices may be designed for one-way or two-way communication. Typically, a small speaker is imbedded in the earplug or earmuff to deliver the communication signal directly to the ear. For 2-way communication, microphone quality is important and personal preference can be a deciding factor: boom-style, bone-conduction, and CavCom‘s Talk Through Your Ears® in-ear mic technology are options. With any personal device, there are many factors to consider, including performance, comfort, and compatibility with other personal protective equipment. When it comes to communication effectiveness, there are three important features to consider:

Binaural (both ear) listening provides a significant advantage over monaural (one ear) listening. The human auditory system is clearly designed to work with input from both ears. The brain processes and compares signals from each ear for localization, understanding speech, and separating speech from background noise. As a result, signals such as radio transmissions do not need to be as loud if a listener is using both ears. The practical result of this phenomenon is that comfortable, and most importantly, SAFER volume settings are typically possible when using binaural systems compared to an earset with a monaural listening configuration.

Output-limiting promotes safer listening levels. Whether a worker has normal hearing or hearing loss, it is important that signals delivered to the ear do not add to a noise hazard on the job. When purchasing a communication headset for any employee, make sure the device has an electronic feature to limit outputs to safe levels. Again, a binaural listening also helps most users choose a lower, safer, listening level than would be possible with a monaural system.

Adequate seal of hearing protector ensures best results. Delivering audio communications directly to the ears at a safe but sufficient level can be strongly dependent on a suitable seal of the hearing protector. If the hearing protector is not sealed properly, then background noise leaks in and competes with the speech signal. Not only may the user be inadequately protected from background noise, but worse yet, may try to compensate by increasing the volume control on the communication device resulting in added noise exposure. Remember that the key to high-quality communication is an optimal speech-to-noise ratio. When a proper hearing protector seal is achieved, excessive background noise will not be competing with the desired speech signal.

• High-fidelity filtered hearing protectors. Consider providing a new technology that is generally referred to as uniform (or "flat") attenuation filtered hearing protectors. Uniform attenuation means the hearing protector or communication earset is specially designed to reduce sounds evenly across a broad frequency range. Combined with a moderate amount of noise reduction, this type of hearing protector preserves the frequency balance of sound. The result is that reduced sounds have roughly the same quality as the original sounds, only quieter. To learn more, check out this helpful previous article from our SoundBytes newsletter
  
  
  
• Individual review. Because job requirements vary and workers' hearing abilities differ, consider building job-specific protocols for hearing-critical jobs and individualized plans for any hearing-impaired workers. For more information on accommodations and safety considerations and preparedness for those with hearing loss, see this helpful previous article from our SoundBytes newsletter. 

To sum up, extreme noise and other obstacles can impair 2-way communication in your workplace. But with planning and ingenuity, employers can protect workers' hearing while promoting intelligible communications in a challenging environment.

If you would like to learn more about hearing loss and listening in noise, more resources are just a click away. 

Communication Survey: How are loud noise or other challenges such as use of respirators affecting 2-way communications in your workplace? Request a free copy of our Communication Survey. This simple tool will help you identify problem areas that may be compromising safety and productivity.

Downtime impact calculator: Ever wished you could place a price tag on how down-time in your operation affects your bottom line? The impact can be surprising and quickly demonstrates your return on investment for communication system upgrades. Request a free calculator. 

High-fidelity hearing protection: Read more and listen to an audio demonstration of CavCom‘s selection of high-fidelity filters to enhance speech communication in noisy situations.

Video/Audio Demonstration – Communicating in High Noise: View CavCom‘s quick demonstration videos for ideas on how to improve communication in your workplace. 

Contact CavCom for more information about improving your company's productivity, safety, and communication capabilities.

How many times have you seen employees break the seal of an earplug or earmuff because they can't communicate in the workplace? Individuals who are hard of hearing are often the worst offenders. Not only are these workers at risk of exposing themselves to hazardous noise, but communication typically isn't even improved. So what can we do to help?

According to the National Institutes of Health, approximately 17 percent of American adults report some degree of hearing loss. That's roughly 36 million people. Over 20 million Americans experience tinnitus, or annoying ringing in the ears. In noisy workplaces, individuals with hearing impairment face special challenges such as communicating with co-workers, detecting warning signals during emergencies, and working safely around motorized vehicles and heavy machinery. For people with severe hearing loss or hearing that is significantly worse in one ear, a common difficulty is localization. That is, the person may hear a sound, but not know which direction it's coming from...a real problem in situations where auditory alerts such as forklift back-up alarms are crucial to safety.

Another concern in noisy environments is that conventional hearing protectors may degrade speech audibility for hearing-impaired workers. Namely, conventional earplugs and earmuffs provide more sound reduction for high pitch sounds than lower pitches. In speech, vowel sounds (a, e, i, o, u) are fairly low in pitch, while consonants (such as k, s, t, f, sh, etc.) are higher pitched. For a worker with high frequency hearing loss (very common), wearing hearing protectors can exacerbate the high frequency deficit, and in turn, speech intelligibility is reduced. A common complaint for people with hearing loss is "I can hear you talking, I just can't understand what you're saying." Experiencing a hearing loss can be like reading a newspaper with holes in it. For those with high frequency hearing loss, missing out on the consonants of speech can leave the listener struggling to interpret vowel sounds that come across as mere mumbling or gibberish. Often listeners misinterpret consonant sounds; usually the brain tries to "fill in the blanks," sometimes arriving at inaccurate interpretations. Resulting miscommunications day to day can range from harmless to heartbreaking. In an industrial or first responder situation, miscommunications can affect job performance and efficiency, and can be dangerous, even deadly. The following is an example of how hearing loss (or loud background noise) can seriously affect speech communications on the job.

For these reasons, it is important for companies to consider ways to address the special needs of their hearing-impaired workers. Options to consider:

Develop visual cues: Where obstructed vision is not a problem, consider developing a system of hand signals or written text to clearly convey messages without relying on auditory communication. For emergency alerts, investigate alarm systems with flashing lights or vibrating pagers.

Create pre-coded messages: In advance, develop a predetermined set of short, predictable code words and key phrases for your most typical operations. Expected messages are typically easier to recognize than novel communications.

Improve the listening environment: There are two basic ways to improve an individual's ability to hear in noise: 1. increase the level of the speech or warning signal and 2. decrease the level of the background noise. Engineering controls in the workplace may help decrease noise at its source. The other part of the equation can be more difficult. For face-to-face communication, there is a physiologic limit to how loud and how long a speaker can shout to be heard. Cranking the volume of a PA system above loud background noise may help detection, but potentially adds to noise exposures for all workers in the area.

Utilize specialized hearing protectors: Another solution is to provide employees with specialized hearing protectors that block out background noise without compromising the speech or warning signal. Although these protectors are not hearing aids, by their design they often improve communication capabilities for all, including those with hearing loss. Options include:

Communication headsets/earsets: These systems consist of a standard hearing protector (earplug or earmuff) that attenuates or blocks the noise, in combination with a small speaker imbedded in the earplug or muff to deliver the communication signal directly to the ear. Systems may be designed for one-way or two-way communication. There are a variety of products in the marketplace with pros and cons to consider, including comfort and compatibility with other personal protective equipment. When it comes to communication effectiveness, there are two important features to look for:

1. Binaural (both ear) listening provides a significant advantage over monaural (one ear listening). Our auditory system is clearly designed to work with input from both ears. The brain processes and compares signals from each ear for localization, understanding speech, and separating speech from background noise. Most research studies agree that the more complex the signal, the more complex and loud the competing background noise, and when fewer visual cues are available, the binaural advantage is most robust. As a result, signals such as radio transmissions don't have to be as loud if a listener is using both ears. The practical result of this phenomenon is that volume settings typically don't need to be as high if using a binaural headset compared to one with a monaural listening configuration.

2. Output limiting promotes safer listening levels. Whether a worker has normal hearing or hearing loss, it is important that signals delivered to the ear do not add to a noise hazard on the job. When purchasing a communication headset for any employee, make sure the device has an electronic feature to limit outputs to safe levels. Again, a binaural listening feature allows most users to choose a lower, safer, listening level than would be possible with a monaural system.

Flat or uniform-attenuating hearing protectors: Special filters imbedded in these earplugs or earmuffs are designed to block out high and low frequency sounds nearly equally. Workers with high frequency hearing loss may find these filters helpful.

Level-dependent or non-linear devices: These hearing protectors block louder sounds such as gunfire, but still let in lower level sounds either through special filters or electronic circuitry. Electronics may even amplify quiet sounds, so it is important to choose only devices that limit amplification to safe levels. This type of device is especially helpful in intermittent noise environments where extended periods of quiet are common.

Hearing Aids: Some hearing-impaired workers own hearing aids and ask if they can wear them in noisy workplaces. It is important to remember that hearing aids amplify all sounds, speech as well as unwanted background noise. As a result, hearing aids typically should not be worn in loud noise environments. Even if turned off, hearing aids are not designed to be hearing protectors. OSHA has issued a letter of interpretation stating employees with hearing loss "cannot satisfy the requirement to wear hearing protection simply by turning off their hearing aids when working in a high noise area." (OSHA, 8/3/04). There is one more option to consider. In rare cases, it may be possible for a worker to wear hearing aids (volume set at a safe level) underneath earmuffs. One study showed improvements in speech intelligibility for this configuration, but warned that an audiologist would need to make the determination on a case-by-case basis and that employees should be monitored closely (Verbsky, 2004 - CAOHC Update).  A potential drawback with this option is the possibility of acoustic feedback (squealing) when a hearing aid is covered, making this option impractical in some cases.

Hearing conservation: Some companies mistakenly believe that it's too late to intervene if a worker's hearing abilities are "too far gone." But even individuals considered severely hearing impaired or "deaf" typically have some residual hearing. It's important to protect any remaining hearing the worker may have. For best practice suggestions, see OSHA's Safety and Health Information Bulletin 12-27-2005: Hearing Conservation for the Hearing-Impaired Worker

Individual review & accommodations: Because job requirements vary and workers' hearing abilities differ, consider developing job-specific protocols for hearing-critical jobs and individualized plans for your hearing-impaired workers. Emergency preparedness, alerting device options, and training accommodations are all important considerations. For best practice suggestions, see OSHA's Safety and Health Information Bulletin 07-22-2005: Innovative Workplace Safety Accommodations for Hearing-Impaired Workers. The U.S. Equal Employment Opportunity Commission (EEOC) provides technical guidance regarding workers with hearing loss under the ADA: Hearing Disabilities in the Workplace and the Americans with Disabilities Act, EEOC-NVTA-2014-1, 1-24-23.

If you would like to learn more about improving listening in noise, more resources are just a click away:

Communication demonstrations: Check out CavCom‘s video demonstrations of filtered hearing protectors and radio communications in high noise areas.

Contact CavCom for more information about improving your company's productivity, safety, and communication capabilities.

How a Shortage of PPE Impacts More than Health

In times of unbelievable scenarios and adversity driven by a global pandemic, the medical industry continues to innovate and respond to one crisis after another. Shortages of PPE (personal protective equipment), overflowing facilities, limited respirators, ICU capacity, and even staffing shortages are just some of the situations that are wreaking havoc across the nation. Amidst all that, the way thousands of medical professionals are adjusting to communicating is something that could drive change permanently.

No Shortage of PPE Problems in Healthcare

Within hospitals, physicians and nurses are facing shortages in PPE, driving organizations to alter protocol and adapt to what’s available in terms of safety. The N95 respirator shortage continues. In response, and under certain FDA guidance, for less critical situations, half mask ventilation is being used, a common style is called P100. This design, while designed to purify the air and protect against infectious, airborne materials, also constricts the mouth and the ability to hear the voice out of those respirators. This particular type of filtered mask respirator is likely the style that’s going to be used more for the day to day work of nurses and medical support staff. Communication is hampered when people wear half mask ventilation.

In more serious cases, PAPR (powered air-purifying respirators) respirators are being worn by critical care teams in healthcare settings. These respiratory protective devices are intensive by design, engineered to protect industrial and medical professionals from the most detrimental fumes and hazards. When you imagine a setting where the absolute most comprehensive protective device is necessary, this is the go-to style.

The product includes a helmet or hood with a motorized fan that blows air over the head and produces some noise inside the hood. That design minimizes difficulties caused by constricting the mouth or the voice, but because of the noise from the fan and because they have a hood over their face, it makes it difficult to hear and understand each other. These respirators are typically going to be used in regard to the higher-level cases of COVID-19 patient care. So when they have a patient who is coding and requires an intubation team, those medical professionals will be wearing PAPR respirators.

In more serious cases, PAPR (powered air-purifying respirators) respirators are being worn by critical care teams in healthcare settings. These respiratory protective devices are intensive by design, engineered to protect industrial and medical professionals from the most detrimental fumes and hazards. When you imagine a setting where the absolute most comprehensive protective device is necessary, this is the go-to style.

The product includes a helmet or hood with a motorized fan that blows air over the head and produces some noise inside the hood. That design minimizes difficulties caused by constricting the mouth or the voice, but because of the noise from the fan and because they have a hood over their face, it makes it difficult to hear and understand each other. These respirators are typically going to be used in regard to the higher-level cases of COVID-19 patient care. So when they have a patient who is coding and requires an intubation team, those medical professionals will be wearing PAPR respirators.

The Dangers of Miscommunication Between a Care Team

Communication in a hospital can literally translate to the difference between life and death. Clarity and continuity between medical professionals as they navigate new safety standards and adapt to different equipment are compromised each and every day.

For example, for a confirmed COVID-19 patient, the care team offers supportive care including supplemental oxygen, medication, and fluids akin to treating pneumonia or other severe lung conditions. The WHO tracking data show that one in six COVID-19 patients become seriously ill, requiring intensive treatment. The team might be comprised of roles including:

• Respiratory therapist
• Trauma specialist
• Circulating nurse
• Intubation specialist
• Anesthesiologist
• Laboratory personnel

Those who are bedside administering care are likely wearing PAPR respirators. Those who aren’t in direct contact with the patient might be wearing a P100 mask, perhaps it’s a documenting nurse, who's going to be outside of the room and that individual essentially needs to communicate with the nurses inside the room. In this critical scenario, one set of PPE is hindering hearing while the other is limiting speech and the entire team needs to communicate together with 100 percent certainty. You can imagine the outcome if communication is rendered ineffective or even impossible.

What's Working Right Now? 

We know the world will never be the same after this pandemic subsides. Every industry has now realized, in real-time, the gaps that exist between proper communication and required equipment. How to be innovative in the face of shortages and crises. How to simply maintain as the world shifts on its axis. Knowing how medical teams are adjusting to self-protection while facing equipment shortages means those same teams are altering communication practices for both hearing and speaking alike. CavCom product technology is helping bridge the gap in instances where communication is more crucial than ever — like hospitals.

And in these instances in healthcare settings, communication may be conducted between either a cell phone or a two-way radio. Cell phone users may be talking with their teams via some kind of a group chat, like Zoom, or some kind of an app where they can all communicate on their cell phones together. Two-way radios are also ideal communication tools that can vastly enhance comms between individuals and work teams. A variety of accessories are available for cell phones and two-way radios that further enhance the user’s ability to communicate clearly.

CavCom Phantom™ Lightweight Headsets have proved successful to facilitate that group chat-style communication with 2-way radios and cell phones with many styles of PPE, including PAPRs.  As the name implies, the lightweight design doesn’t add to or interfere with hooded PPE. The binaural design supports both ear listening which is optimal.

Another option is CavCom CellEarz™. This style offers a corded earset with the familiarity of a standard smartphone-style with the advanced technology to enhance clarity, the ability to listen, speak and be heard in high-noise environments like a chaotic emergency room.

If you could talk normally in high noise environments, what kind of a difference would that make? Take, for example, a steel mill with noise levels averaging 100 dBA or more. What if your daily PPE involves a respirator, face shield, helmet or protective suit?  Imagine the difference in radio communication if noise and respirators were no longer barriers to your ability to communicate. It is possible with Talk Through Your Ears®.

How Does It Work? 

In the simplest terms, Talk Through Your Ears® (TTYE) uses in-ear communications to bypass many of the problems associated with communicating in high noise environments. 

Unlike external communication technologies, like a throat mic or boom mic, TTYE uses an in-ear microphone. The microphone picks up whatever you say and transmits it via your radio. Sealing the ear is a hearing protector, so your communications don’t have to compete with environmental noise like you might be used to.  Mouth covered by a respirator? No problem – again, the microphone is in the ear canal, so no interference from a face mask or even SCBAs.

I know this might sound a bit too good to be true, but I assure you it isn’t. If background noise poses a challenge for radio communications for your team, TTYE might be just what your facility needs. 

Who Uses TTYE Technology? 

TTYE is well-suited to high noise manufacturing environments. 

Some examples include steel mills, paper mills, textile factories, chemical plants, and nuclear power plants. In each of these settings, there are employees struggling because they’re not outfitted with technology that both protects their hearing and enables them to hear and be heard. 

In addition to high noise, TTYE also excels in HazMat and other in-suit environments. With these PPE, the issue isn’t so much about noise, it’s about communicating while using a respirator. Instead of yelling, TTYE makes in-suit communications as clear as if you were speaking in person without a face-piece or mask on.

See it in action: 

Whether it’s an industrial workplace or an emergency response team, TTYE allows for in-suit communications via two-way radio. With it, you can communicate clearly in:

• Any suit
• Any radio
• Any respirator
• Any environment

Do You Need TTYE?

Knowing if you would benefit from TTYE is the same as asking, do you need to communicate in high noise environments?  Or does your HazMat team need to communicate? This technology makes it possible to communicate in any harsh environment. Ditch the yelling, hand signals, and the danger to personal safety with TTYE.

The NRR and other important indicators of hearing protector performance

Most countries have requirements for how hearing protectors are to be tested and labeled. The purpose is to provide a standardized method for rating products to help consumers compare protectors and choose the best product for your situation. But before we get into the details of hearing protector ratings, we feel it's important to stress that there are many factors other than noise reduction that determine which hearing protector will ultimately prove most effective in the real world. Many years' experience shows us that the "best" hearing protector is the one that is appropriate for the noise environment (not too much or too little noise reduction) AND the one that is worn correctly and consistently throughout the workday.

Regulatory matters

When OSHA promulgated its Hearing Conservation Amendment (29 CFR 1910.95) for general industry, it incorporated the existing Environmental Protection Agency (EPA) Noise Reduction Rating (NRR) system for assessing performance of hearing protectors. The EPA developed this laboratory-based system for quantifying noise reduction in the late 1970s and codified it in 40 CFR Part 211, Subpart B. Although numerous changes and improvements have been recommended over the years, the original NRR testing and labeling requirements are still in force today.

Soon after the Hearing Conservation Amendment went into effect, OSHA issued a controversial noise control guideline intended to clarify employer responsibilities for reducing noise given the new Amendment. This compliance directive, CPL 02-02-035, Appendix A, instructs companies to take into account certain factors such as hearing protection, shifts in hearing, cost of controls, etc. when comparing the relative effectiveness of hearing protectors and engineering and/or administrative controls. In this situation, OSHA instructs employers to "apply a safety factor of 50 percent" to the NRR. This directive does not apply to hearing protector requirements under the Hearing Conservation Amendment (OSHA 1910.95 Appendix B; Technical Manual Section III: Chapter 5, Appendix E. Noise Reduction Rating).

When MSHA introduced its latest Occupational Noise Exposure Standard in 1999, Part 62, it did not limit mining operators to use of the EPA's NRR system. Instead, MSHA took a much more flexible approach, allowing hearing protectors to be assessed according to "a scientifically accepted indicator of noise reduction value."

What is the NRR?

 The Noise Reduction Rating (NRR) is a laboratory-derived single-number rating designed to characterize a hearing protector's noise reduction capabilities. To quantify hearing protector performance, the EPA specifies laboratory test protocols that call for a trained experimenter to fit individual subjects with appropriately sized hearing protectors. Noise attenuation (reduction) values are calculated by comparing the subject's hearing threshold results with and without the hearing protector in accordance with ANSI Standard S3.19 test procedures. Test results are reported for individual octave band test frequencies 125-8000 Hz and then calculated into a single-number overall Noise Reduction Rating.

The NRR is intended to be used to estimate the amount of protection provided by the hearing protector. The EPA originally estimated that the level of noise entering a person's ear, when the hearing protector is well-fitted and worn as directed, is approximated by the difference between the environmental noise level and the NRR. Read further for lessons learned over the years about applying the NRR.

Hearing protector packaging labels must list the single-number NRR, product name, and manufacturer information (see example primary NRR label). A secondary label must also be included that provides further detail regarding the average amount of noise reduction across the required ANSI test frequencies (125 to 8000 Hz) and instructions on how to apply the NRR. example: EPA format for primary NRR label

Other Rating Systems

Although safety professionals in the United States are most familiar with the NRR, there are many different rating systems used in other parts of the world. As example, Canada allows a number of hearing protector ratings including a classification system that divides hearing protectors into Classes A, B or C, determined by how much noise reduction is provided in a specified laboratory setting (CSA Z94.2-14 Hearing Protection Devices). Class A hearing protectors offer the highest protection and may be used in 8-hour time-weighted average noise exposures up to 105 dBA; Class B protectors are rated for average noise exposures up to 95 dBA, and Class C up to 90 dBA. In addition, the suffix 'L' for "low frequency" is added to class A, B, or C when a hearing protector provides at least 20 dB of attenuation at 125 Hz.

How is the NRR used?

Following is a step by step summary of how to apply the laboratory-derived single-number NRR to determine compliance for hearing conservation purposes according to OSHA 191.95(j). Most people are surprised to learn that the NRR system was originally intended for use with broad-spectrum workplace noise readings. According to OSHA, however, employee time-weighted-average noise exposures must be calculated using an A-scale frequency setting on the sound measurement equipment (the A-scale is a weighted frequency setting more closely matched with human damage-risk criteria). To adapt the NRR to A-scale noise readings, a 7dB correction is required. The bottom line: if the employer collects A-scale noise information, but not C-scale, then 7 dB must be subtracted from the NRR to assess hearing protection for the workplace. The end goal of an NRR calculation is to ensure that the worker's protected noise exposure has been reduced to a "safe" level, in most cases considered 85 dBA TWA or below.

NRR METHOD

To estimate worker's protected noise exposure using the laboratory-derived Noise Reduction Rating (NRR):

1. Determine the employee's workplace noise exposure in dBA TWA*
2. Calculate the estimated noise reduction as follows:
o Start with the manufacturer's NRR for this hearing protector (NRR)
o Subtract 7 dB (if using A-weighted noise exposure values*)
o Divide in half to estimate "real world" performance (required if reviewing feasibility of engineering controls)
3. Subtract the noise reduction estimate from the employee's workplace noise exposure to approximate protected exposure (target 85 dBA TWA or below):

Workplace Noise Exposure* - [(NRR - 7)] = Estimated Protected Exposure

for HEARING CONSERVATION PROGRAM COMPLIANCE

Workplace Noise Exposure* - [(NRR - 7)/2] = Estimated Protected Exposure

for ENGINEERING NOISE CONTROL REVIEW

*Note: If workplace noise exposure readings are available in C-weighted form (dBC TWA), there is no need to deduct 7 dB when estimating protection using the product's NRR.

Example

 For a noise exposure of 95 dBA TWA and a hearing protector with NRR of 29:

95 – (29-7) = 73 dBA TWA estimated protected exposure (COMPLIANCE)

95 – [(29-7)/2] = 84 dBA TWA estimated protected exposure (ENGINEERING REVIEW)

In this example, both calculations are below the target of 85 dBA TWA

A Special Case: Dual Hearing Protection

Although most noise exposures encountered in industry today can be adequately addressed with a well-fitted earplug or earmuff, some exposures exceed the capabilities of traditional hearing protectors. When intensely loud noise cannot be controlled at the source, it may be necessary for workers to wear both earplugs and earmuffs at the same time, often referred to as "dual hearing protection" or "double hearing protection." The OSHA Technical Manual allows employers to add 5 dB for the second hearing protector. An example: if wearing an earplug with an NRR of 25 together with an earmuff (also with an NRR of 25), expect a combined NRR of 30. Keep in mind, however, that this rule of thumb is a general estimate.

Want to check out calculations for CavCom‘s hearing protectors or your own?

The Real World - Individual Fit Testing and the Personal Attenuation Rating (PAR)

First we reviewed methods for utilizing the NRR to estimate hearing protector performance. But now we need to point out that laboratory ratings have historically proved poor predictors of what happens in the real world. Hearing protector fit, training, and proper use vary greatly across individuals.

In 2008, an alliance between OSHA, NIOSH and the National Hearing Conservation Association identified a technology designed to establish individualized hearing protection attenuation ratings for each worker. This group of experts recognized the limitations to relying on laboratory conditions and group statistics to predict an individual user's hearing protector performance in the field. "The consequence of this approach is that an individual user may actually receive more but usually less attenuation than is stated on the hearing protector label." Based on their review of research and emerging trends and technologies, the Alliance identified Individual Fit Testing as a recommended best practice for hearing conservation programs. Individual fit testing of hearing protectors is similar in concept to fit testing for respirators. Preferred methods produce a single number overall estimate of real-world attenuation for each worker; this measure is generally referred to as a Personal Attenuation Rating or PAR.

We recommend you begin with the OSHA NRR calculation to help determine which types of hearing protectors will offer adequate reduction for your workplace noise exposures. However, to find out what is happening in the real world for each worker, conduct an Individual Fit Test to ensure that the chosen hearing protector is actually performing as intended. Similar to NRR calculations, the goal of the PAR calculation is to ensure the worker's protected noise exposure has been reduced to a "safe" level, in most cases considered 85 dBA TWA or below. The difference is that the PAR is specific to the worker, derived from individual testing, not laboratory estimates.

PAR METHOD

Estimate protected noise exposure using the worker's personal attenuation rating (PAR):

1. Determine the employee's workplace noise exposure in dBA TWA
2. Establish the employee's personal attenuation rating (PAR) from individual fit testing (no need for A-scale correction or "de-rating")
3. Subtract PAR from the employee's workplace noise exposure to approximate protected exposure:

Workplace Exposure - PAR = Estimated Protected Exposure
for HEARING CONSERVATION PROGRAM

Example

For a noise exposure of 95 dBA TWA and a hearing protector with PAR of 20:

95 – 20 = 75 dBA TWA estimated protected exposure
(COMPLIANCE and ENGINEERING REVIEW)

In this example, the real-world result is well below the target of 85 dBA TWA

Using different methods, you may arrive at different estimates for the same employee and same hearing protector based solely on calculation method. The NRR method might easily overestimate or even underestimate the hearing protector's ability to achieve the target protected goal of 85 dBA TWA. The PAR Method, however, is based on the worker's own field performance. PAR is a better indicator of that individual's protected noise exposure when the hearing protector is worn correctly and consistently throughout a work shift.

Noise Reduction Isn't Everything

Short answer is no. The FCC has indicated that their intention is to have the new standard at 6.25 kHz (digital) but have not provided a switchover date. If you're running radio communications on analog frequencies, you do not have to make the switch. And if you have great-working analog radios that meet your current communication needs, that's reason enough to stick with them until something changes.
However, if you are communicating via analog radio and experiencing issues communicating throughout your facility, common problems associated with analog radios simply go away after switching over to digital radio communications.

Benefits Digital Two-Way Radios Can Bring

RANGE: The top reason we see companies choose to go digital is that they're not getting complete coverage throughout their facility. Dead zones are an annoyance at best and potential danger at worst.
While digital transition won't solve all range issues for all facilities, countless times our customers have experienced complete elimination of dead zones just from moving from analog radio to digital. Ensuring everyone can communicate, regardless of location, is a big reason facilities choose to upgrade their radio comms.

CLARITY:. A lot of our customers work in high noise environments, and digital radios — all on their own — have excellent noise cancellation capabilities. If there are areas in your facility where radio communications are difficult to hear due to noise, swapping out your analog radios for digital ones can be a big help.

An upgrade to digital also brings a series of features that analog radios don't offer. These include calling features like text messaging, all call, and individual talk. Plus, digital radios have superior battery life over analog, which anyone who can't complete their shift without changing their radio battery can appreciate. Additionally, CavCom carries a complete line of radio accessories specifically designed to assist with radio comms in high noise. Suddenly, you're able to hear and be heard on the radio in areas where you used to be drowned out. It's a small change that can make a big improvement.

Top benefits a facility could see with the integration of digital communications are:

• Dead zone elimination
• Noise cancellation
• Modern calling features
• Extended battery life

With these potential benefits, it makes sense that some facilities aren't waiting for new FCC requirements to switch from analog to digital. Especially because the process can take place gradually.

The Push Toward Digital Two-Way Radios

After comparing analog vs digital, there's a chance you might be feeling a push toward making the switch.

First, I want you to know you're not alone.
Second, it's important to remember that if your analog radios are working for you and meeting the communication needs of your facility, there's no current regulation requiring you to move anything.
Third, I want you to know that if you do plan to eventually upgrade to digital, there are gradual ways to go about it.

Integrating Digital

The decision to switch to digital is something that can be implemented as quickly or slowly as you like. Some of our customers want to start receiving the benefits of digital two-way radios as quickly as possible and others want to remain on analog with the intent to go digital in the next few years. Either way they rely on us to help them navigate their process.
Some customers who choose to remain on analog but know that digital is in their future, choose replacement devices that are compatible with both digital and analog. This way, they can continue with their existing radio infrastructure while preparing for the future.

Partnering with CavCom

There are some great reasons why facilities are upgrading their radio infrastructure to support digital. By choosing to partner with CavCom, we can help you through the process. If you would like to explore upgrading radios in your facility, or you're simply looking for some advice tailor-made to your situation, connect with us. We can help you figure out a path to digital that isn't going to leave you dealing with a massive upset or unmanageable capital expense.
Our Process
We begin by checking on your FCC license and understanding your communication struggles as well as your short- and long-term communication goals. We can have a technical specialist conduct a demo and let you try our radios and communication solutions. We carry industrial digital radios that can be programmed in both digital and analog. These devices make great replacements for existing radios that eventually become obsolete. When you are ready to go digital, the radios can be set up to change to digital with literally a flip of a button. Your employees will still have those same radios, but their experience communicating will immediately improve.
Are you interested in learning about your options regarding integrating digital-capable radios into your facility? Get started by connecting with one of our sales representatives.

It is estimated that over 3 million American workers are injured on the job each year, resulting in incalculable human toll and billions in direct and indirect cost to the nation. Growing evidence suggests there may be a link between noise, hearing loss, and risk of occupational injury.

Many factors influence risk of accidents, including workplace conditions, PPE/safety equipment, and employee factors such as health and training. A collaborative team of researchers from Yale, Stanford, U. Michigan, and U. Washington have teamed up with industry to investigate the potential influence of workplace noise. The research group recently completed a large-scale analysis of records for approximately 9,000 manufacturing workers over a 6-year period. Among this group of workers, the researchers found that higher noise exposures were associated with higher risk of injuries, especially serious injuries. In addition, hearing impairment was linked to higher accident rates, particularly for those employees with a combination of high frequency hearing loss and tinnitus (ringing in the ears).

For more information and helpful resources for your hearing conservation program, see:

CavCom SoundBytes. Does Noise Increase the Risk of Accidents? 

CavCom SoundBytes. Special Considerations for Workers with Hearing Loss 

Cantley LF, Galusha D, Cullen MR, Dixon-Ernst C. Tessier-Sherman B, Slade MD, Rabinowitz PM, Neitzel RL. 2015. Does tinnitus, hearing asymmetry, or hearing loss predispose to occupational injury risk? International Journal of Audiology, 54 Suppl 1: S30-6.

Cantley LF, Galusha D, Cullen MR, Dixon-Ernst C, Rabinowitz PM, Neitzel RL. 2015. Association between ambient noise exposure, hearing acuity, and risk of acute occupational injury. Scandinavian Journal of Work & Environmental Health, 41(1): 75-83.

NIOSH Topic Page: Traumatic Occupational Injury. 

A new scientific report provides evidence for something companies have known for years. Hearing protection ratings, and de-ratings, are not helpful with the day-to-day success of a hearing conservation program. It's long been understood that the laboratory-based Noise Reduction Rating (NRR) does not accurately predict real-world performance of a hearing protector. But unfortunately, it's now clear that the numerous de-rating schemes developed over the years to compensate for NRR shortcomings aren't accurate either.

A new comprehensive analysis was recently published in the Journal of the Acoustical Society of America (JASA). Researchers from the National Institute for Occupational Safety and Health, the Department of Defense and others examined four real-world hearing protection attenuation studies. Results of Individual Fit Testing for workers were compared to product NRRs and various NRR de-rating schemes. The good news: individualized earplug fitting and training was shown to dramatically improve "real-world" protection for many workers. The not-so-good news was that NRR de-rating schemes failed to accurately predict real-world protection for the majority of workers tested. In many cases, real-world results far exceeded hearing protector performance predicted by NRR de-rating schemes. Because hearing protector fit testing systems are now readily available for use in the workplace, the authors concluded it is a better approach than relying on de-rating formulas.

NRR Ratings and De-Rating Schemes

Hearing protection devices provide a wide range of protection against noise depending on the design of the protector and the fit in the individual user's ear. When OSHA promulgated the Hearing Conservation Amendment for general industry in the early 1980s, it incorporated the Environmental Protection Agency's Noise Reduction Rating (NRR) as a way to help employers evaluate and compare expected performance of available hearing protectors. The NRR is a laboratory-derived estimate of the attenuation (sound reduction) expected from a hearing protector when it is fitted and worn as designed. Shortly after the Hearing Conservation Amendment went into effect, however, it became evident that the actual amount of attenuation achieved in the workplace often fell short of the laboratory-predicted NRR.

Since that time, regulatory and scientific groups have proposed a variety of schemes for adjusting hearing protector ratings in an attempt to better adapt NRR ratings to real-world performance. Some recommendations included cutting the NRR in half; others suggested a percent reduction according to the class of hearing protector. It's a commonly held misconception that OSHA, MSHA and other compliance authorities require that employers de-rate NRRs. Instead, companies should use the NRR calculation to help determine which types of hearing protectors will likely offer adequate reduction for workplace noise exposures. However, to find out what is happening in the real world for each worker, it is far more useful to conduct an Individual Fit Test to ensure that the chosen hearing protector is actually performing as intended. Read more about the NRR and other ratings here.

Real-World Measures

Individual Fit Test systems are designed to measure the noise reduction provided for an individual worker using their own hearing protector as it is routinely fit and worn. Although assessment equipment and procedures are not completely standardized, most fit test systems generate a Personal Attenuation Rating (PAR). Given the inability of laboratory ratings and de-rating schemes to accurately predict real world attenuation, PARs provide employers with beneficial information about fit and protection for each employee.

CavCom‘s experience mirrors the recent analysis published in JASA. Through Individual Fit Testing, we find our hearing protectors and earsets yield significantly higher actual protection via PARs than would be predicted by an NRR-based calculation, de-rated or not. In particular, custom-fitted hearing protectors are less susceptible to poor insertion, and generally provide more consistent and higher attenuation in the real world. Read more about Individual Fit Testing here.

The Bottom Line about NRR De-Rating Schemes

Stated simply, NRRs and de-rated NRRs do not accurately predict real-world performance of hearing protectors. For this reason, decisions regarding worker noise exposures and hearing protection are more accurate when based on real-world PAR values. Better information also helps companies tailor hearing protection to the work environment and avoid such pitfalls as overprotection. Overprotection is a situation where the worker receives more attenuation than necessary, leading to potential communication complications and safety concerns. Read more about overprotection here.

Lastly, it's important to remember that subjective considerations such as comfort and convenience are also key factors in hearing protector acceptance and wear time. It's often said, and is worth repeating, that the "best" hearing protector is the one that is worn correctly and consistently whenever the worker is exposed to hazardous noise. Read more about comfort here.

Contact Us

Not sure which hearing protectors are optimal for your workforce? Contact CavCom to discuss options and to learn more about how our innovative hearing protectors and communication earsets can improve safety and communication in your workplace.

Resources:

• Murphy, Gong, Karch, Federman and Schulz (2022). Personal attenuation ratings versus derated noise reduction ratings for hearing protection devices, The Journal of the Acoustical Society of America, 152 (2), 1074-1089. https://doi.org/10.1121/10.0013418.
• The Noise Reduction Rating (NRR), CavCom SoundBytes.
• Individual Fit Testing and Personal Attenuation Rating (PAR), CavCom SoundBytes.
• The Risk of Overprotection, CavCom SoundBytes.
• Improving In-Ear Comfort, CavCom SoundBytes.

The NRR and other important indicators of hearing protector performance

Most countries have requirements for how hearing protectors are to be tested and labeled. The purpose is to provide a standardized method for rating products to help consumers compare protectors and choose the best product for your situation. But before we get into the details of hearing protector ratings, we feel it's important to stress that there are many factors other than noise reduction that determine which hearing protector will ultimately prove most effective in the real world. Many years' experience shows us that the "best" hearing protector is the one that is appropriate for the noise environment (not too much or too little noise reduction) AND the one that is worn correctly and consistently throughout the workday.

Regulatory matters

When OSHA promulgated its Hearing Conservation Amendment (29 CFR 1910.95) for general industry, it incorporated the existing Environmental Protection Agency (EPA) Noise Reduction Rating (NRR) system for assessing performance of hearing protectors. The EPA developed this laboratory-based system for quantifying noise reduction in the late 1970s and codified it in 40 CFR Part 211, Subpart B. Although numerous changes and improvements have been recommended over the years, the original NRR testing and labeling requirements are still in force today.

Soon after the Hearing Conservation Amendment went into effect, OSHA issued a controversial noise control guideline intended to clarify employer responsibilities for reducing noise given the new Amendment. This compliance directive, CPL 02-02-035, Appendix A, instructs companies to take into account certain factors such as hearing protection, shifts in hearing, cost of controls, etc. when comparing the relative effectiveness of hearing protectors and engineering and/or administrative controls. In this situation, OSHA instructs employers to "apply a safety factor of 50 percent" to the NRR. This directive does not apply to hearing protector requirements under the Hearing Conservation Amendment (OSHA 1910.95 Appendix B; Technical Manual Section III: Chapter 5, Appendix E. Noise Reduction Rating).

When MSHA introduced its latest Occupational Noise Exposure Standard in 1999, Part 62, it did not limit mining operators to use of the EPA's NRR system. Instead, MSHA took a much more flexible approach, allowing hearing protectors to be assessed according to "a scientifically accepted indicator of noise reduction value."

What is the NRR?

 The Noise Reduction Rating (NRR) is a laboratory-derived single-number rating designed to characterize a hearing protector's noise reduction capabilities. To quantify hearing protector performance, the EPA specifies laboratory test protocols that call for a trained experimenter to fit individual subjects with appropriately sized hearing protectors. Noise attenuation (reduction) values are calculated by comparing the subject's hearing threshold results with and without the hearing protector in accordance with ANSI Standard S3.19 test procedures. Test results are reported for individual octave band test frequencies 125-8000 Hz and then calculated into a single-number overall Noise Reduction Rating.

The NRR is intended to be used to estimate the amount of protection provided by the hearing protector. The EPA originally estimated that the level of noise entering a person's ear, when the hearing protector is well-fitted and worn as directed, is approximated by the difference between the environmental noise level and the NRR. Read further for lessons learned over the years about applying the NRR.

Hearing protector packaging labels must list the single-number NRR, product name, and manufacturer information (see example primary NRR label). A secondary label must also be included that provides further detail regarding the average amount of noise reduction across the required ANSI test frequencies (125 to 8000 Hz) and instructions on how to apply the NRR. example: EPA format for primary NRR label

Other Rating Systems

Although safety professionals in the United States are most familiar with the NRR, there are many different rating systems used in other parts of the world. As example, Canada allows a number of hearing protector ratings including a classification system that divides hearing protectors into Classes A, B or C, determined by how much noise reduction is provided in a specified laboratory setting (CSA Z94.2-14 Hearing Protection Devices). Class A hearing protectors offer the highest protection and may be used in 8-hour time-weighted average noise exposures up to 105 dBA; Class B protectors are rated for average noise exposures up to 95 dBA, and Class C up to 90 dBA. In addition, the suffix 'L' for "low frequency" is added to class A, B, or C when a hearing protector provides at least 20 dB of attenuation at 125 Hz.

How is the NRR used?

Following is a step by step summary of how to apply the laboratory-derived single-number NRR to determine compliance for hearing conservation purposes according to OSHA 191.95(j). Most people are surprised to learn that the NRR system was originally intended for use with broad-spectrum workplace noise readings. According to OSHA, however, employee time-weighted-average noise exposures must be calculated using an A-scale frequency setting on the sound measurement equipment (the A-scale is a weighted frequency setting more closely matched with human damage-risk criteria). To adapt the NRR to A-scale noise readings, a 7dB correction is required. The bottom line: if the employer collects A-scale noise information, but not C-scale, then 7 dB must be subtracted from the NRR to assess hearing protection for the workplace. The end goal of an NRR calculation is to ensure that the worker's protected noise exposure has been reduced to a "safe" level, in most cases considered 85 dBA TWA or below.

NRR METHOD

To estimate worker's protected noise exposure using the laboratory-derived Noise Reduction Rating (NRR):

1. Determine the employee's workplace noise exposure in dBA TWA*
2. Calculate the estimated noise reduction as follows:
o Start with the manufacturer's NRR for this hearing protector (NRR)
o Subtract 7 dB (if using A-weighted noise exposure values*)
o Divide in half to estimate "real world" performance (required if reviewing feasibility of engineering controls)
3. Subtract the noise reduction estimate from the employee's workplace noise exposure to approximate protected exposure (target 85 dBA TWA or below):

Workplace Noise Exposure* - [(NRR - 7)] = Estimated Protected Exposure

for HEARING CONSERVATION PROGRAM COMPLIANCE

Workplace Noise Exposure* - [(NRR - 7)/2] = Estimated Protected Exposure

for ENGINEERING NOISE CONTROL REVIEW

*Note: If workplace noise exposure readings are available in C-weighted form (dBC TWA), there is no need to deduct 7 dB when estimating protection using the product's NRR.

Example

 For a noise exposure of 95 dBA TWA and a hearing protector with NRR of 29:

95 – (29-7) = 73 dBA TWA estimated protected exposure (COMPLIANCE)

95 – [(29-7)/2] = 84 dBA TWA estimated protected exposure (ENGINEERING REVIEW)

In this example, both calculations are below the target of 85 dBA TWA

A Special Case: Dual Hearing Protection

Although most noise exposures encountered in industry today can be adequately addressed with a well-fitted earplug or earmuff, some exposures exceed the capabilities of traditional hearing protectors. When intensely loud noise cannot be controlled at the source, it may be necessary for workers to wear both earplugs and earmuffs at the same time, often referred to as "dual hearing protection" or "double hearing protection." The OSHA Technical Manual allows employers to add 5 dB for the second hearing protector. An example: if wearing an earplug with an NRR of 25 together with an earmuff (also with an NRR of 25), expect a combined NRR of 30. Keep in mind, however, that this rule of thumb is a general estimate.

Want to check out calculations for CavCom‘s hearing protectors or your own?

The Real World - Individual Fit Testing and the Personal Attenuation Rating (PAR)

First we reviewed methods for utilizing the NRR to estimate hearing protector performance. But now we need to point out that laboratory ratings have historically proved poor predictors of what happens in the real world. Hearing protector fit, training, and proper use vary greatly across individuals.

In 2008, an alliance between OSHA, NIOSH and the National Hearing Conservation Association identified a technology designed to establish individualized hearing protection attenuation ratings for each worker. This group of experts recognized the limitations to relying on laboratory conditions and group statistics to predict an individual user's hearing protector performance in the field. "The consequence of this approach is that an individual user may actually receive more but usually less attenuation than is stated on the hearing protector label." Based on their review of research and emerging trends and technologies, the Alliance identified Individual Fit Testing as a recommended best practice for hearing conservation programs. Individual fit testing of hearing protectors is similar in concept to fit testing for respirators. Preferred methods produce a single number overall estimate of real-world attenuation for each worker; this measure is generally referred to as a Personal Attenuation Rating or PAR.

We recommend you begin with the OSHA NRR calculation to help determine which types of hearing protectors will offer adequate reduction for your workplace noise exposures. However, to find out what is happening in the real world for each worker, conduct an Individual Fit Test to ensure that the chosen hearing protector is actually performing as intended. Similar to NRR calculations, the goal of the PAR calculation is to ensure the worker's protected noise exposure has been reduced to a "safe" level, in most cases considered 85 dBA TWA or below. The difference is that the PAR is specific to the worker, derived from individual testing, not laboratory estimates.

PAR METHOD

Estimate protected noise exposure using the worker's personal attenuation rating (PAR):

1. Determine the employee's workplace noise exposure in dBA TWA
2. Establish the employee's personal attenuation rating (PAR) from individual fit testing (no need for A-scale correction or "de-rating")
3. Subtract PAR from the employee's workplace noise exposure to approximate protected exposure:

Workplace Exposure - PAR = Estimated Protected Exposure
for HEARING CONSERVATION PROGRAM

Example

For a noise exposure of 95 dBA TWA and a hearing protector with PAR of 20:

95 – 20 = 75 dBA TWA estimated protected exposure
(COMPLIANCE and ENGINEERING REVIEW)

In this example, the real-world result is well below the target of 85 dBA TWA

Using different methods, you may arrive at different estimates for the same employee and same hearing protector based solely on calculation method. The NRR method might easily overestimate or even underestimate the hearing protector's ability to achieve the target protected goal of 85 dBA TWA. The PAR Method, however, is based on the worker's own field performance. PAR is a better indicator of that individual's protected noise exposure when the hearing protector is worn correctly and consistently throughout a work shift.

Noise Reduction Isn't Everything

Despite best intentions, it's possible that your current hearing protectors are providing too much protection. When it comes to noise, not all environments are the same. New technologies for hearing protection devices (HPDs) are providing employers with more noise reduction options than ever before.

What is Overprotection?
Many companies mistakenly choose hearing protectors for their entire company based on one feature alone: The Noise Reduction Rating (NRR). Historically, conventional wisdom dictated that the more protection, the better, regardless of each employee's noise exposure, preference, and work requirements. It's long been known that too much noise exposure can cause permanent hearing loss. But now there is growing concern that too much noise attenuation (reduction) can be problematic, too.

According to OSHA, 80-90% of workplace noise exposures in general industry are under 95 dBA TWA. For these moderate noise environments, employees typically only need 10-15 dB of actual noise reduction to protect hearing. Overprotection occurs when a hearing protector reduces sounds to such low levels that it's difficult for the wearer to understand conversations and/or hear important sounds around them. An inability to communicate or detect warning signals can keep workers from performing their jobs safely and efficiently. Miscommunications or missed cues at best can lead to production errors and inefficiencies – at worst, accidents and injuries.

In the US, there is no formal recommendation for overprotection, but the National Institute for Occupational Safety and Health (NIOSH), has addressed the concern in various case studies and reports. In a 2005 hearing protector study, NIOSH stated: "Overprotection is a condition in which the worker receives more attenuation than necessary, and the worker's exposure is reduced to less than 70 dBA. Overprotection results in the reduction in verbal communication with other workers, the potential to miss safety signals, and reduced acoustic feedback from their machine or work process. Overprotected workers report being 'out of touch' with their environment or feeling isolated." The British Standards Institute and European Union jurisdictions recommend the ideal level of protection to be 70-80 dBA, while Canada promotes an ideal protected range of 75-80 dBA.

Identifying Overprotection in Your Workplace
In 2008, after a review of research and emerging trends/technologies, the Alliance of NIOSH, OSHA, and NHCA identified Individual Fit Testing as a recommended best practice for hearing conservation programs. Individual fit testing of hearing protectors is similar in concept to fit testing for respirators. Preferred methods produce a single number overall estimate of real-world attenuation, a Personal Attenuation Rating (PAR).

Conducting individual fit testing for your workers will help you better determine the actual amount of protection the employee is receiving with his/her HPD. And the results may be surprising. In a recent study of moderate noise exposures, 84% of workers were found to be using hearing protectors that provided too much noise reduction. Individuals were observed "self-adjusting" foam earplugs to create a poor fit (i.e. lower noise reduction) or worse, removing hearing protectors altogether in order to feel safer and in touch with their surroundings (Sayler et al. 2019).

Factors that Intensify Overprotection

Traditional HPDs Can Change Sound Quality. Comprehending speech in the presence of loud background noise and detecting subtle changes in the sound quality of machines or processes can be a challenge. Add a traditional hearing protector in the mix, and that challenge just got more difficult. As a general rule, most HPDs block out more high frequency (pitch) sounds than low frequencies. Workers wearing a traditional earplug or earmuff often say sounds are "boomy" or "bassy" because the treble is cut more than the bass. In addition, speech is "muffled" because the vowels (low frequency) come through more clearly than many consonants (high frequency). Often listeners misinterpret consonant sounds or the brain tries to "fill in the blanks," sometimes arriving at inaccurate interpretations. Resulting miscommunications day to day can range from humorous to frustrating or even dangerous.

Existing Hearing Loss. For a worker with high frequency hearing impairment, a common occurrence, wearing hearing protectors can exacerbate the high frequency deficit. Speech intelligibility is reduced even further. A common complaint for people with hearing loss is "I can hear you talking, I just can't understand what you're saying." Overprotection can place a hearing-impaired worker, and those around him or her, at greater risk of miscommunications.

Solutions to Reduce the Impact of Overprotection 

Know your noise levels and determine an appropriate amount of protection. An employee who moves in and out of noise frequently throughout a day may have very different hearing protection needs than a worker exposed to a consistent amount of noise throughout the shift. It may be advantageous to consider adjustable hearing protectors that provide maximum protection when in high noise but easily convert to less hearing protection for low noise areas – enhancing the ability to understand speech. Using tools such as CavCom‘s NRR calculator can help you determine a variety of protectors that provide sufficient protection for your moderate noise areas.

Enhance face-to-face communication with high fidelity hearing protectors. Consider providing a new technology generally referred to as uniform (or "flat") attenuation hearing protectors. Uniform attenuation means the HPD is specially designed to reduce sounds evenly across a broad frequency range. Combined with a moderate amount of noise reduction, this HPD preserves the frequency balance of sound. The result is that reduced sounds have roughly the same quality as the original sounds, only quieter. Since the attenuation (reduction) of sound is less at low frequencies than high frequencies, the result of wearing a high-fidelity uniform attenuation earplug or earmuff is that incoming sound is less distorted. When it comes to speech, high frequency consonants are attenuated less, reducing the chance for mumbled or muffled speech. And although these protectors are not hearing aids, by their design they typically improve communication capabilities for all, including those with hearing loss. Studies such as those by Giguere and Berger (2014, 2016) support these benefits for understanding speech.

Example: Compare high fidelity performance with traditional hearing protectors and older design vent/tube filters (both hearing protectors have an overall NRR of 19)

Verify with Individual Fit Testing. As we’ve demonstrated, your goal of balancing enough protection to guard against hearing loss, but not so much protection that the worker can’t hear important sounds in the environment, is not necessarily an easy task. So, remember that Individual Fit Testing is best practice for understanding the hearing protection attenuation for an individual worker using his/her own hearing protector as typically worn. And the best sign of success – workers are wearing their hearing protection correctly and consistently whenever they are exposed to noise.

Contact CavCom to learn more about our high fidelity filtered hearing protectors, individual fit testing, and other communication solutions for your hearing conservation program.

Resources/References:

• British Standards Institute (2016). Hearing protectors: recommendations for selection, use, care and maintenance. European harmonized standard BS EN 458.
• Canadian Standards Association (2019). CSA Z94.2-14 (R2019), Hearing Protection Devices - Performance, Selection, Care, And Use.
• Giguere, C and Berger, E (2014). Exploration of flat hearing protector attenuation and sound detection in noise. 168th Meeting of the Acoustical Society of America, The Journal of the Acoustical Society of America. 136(4):2165-2166.
• Giguere, C and Berger, E (2016). Speech recognition in noise under hearing protection: A computational study of the combined effects of hearing loss and hearing protector attenuation, International Journal of Audiology. 55(sup1): S30-S40.
• Individual Fit Testing for Hearing Protectors, CavCom SoundBytes.
• NIOSH (2005). Advanced Hearing Protector Study: General Motors Metal Fabricating Division – Flint, MI, 312-11a.
• The Noise Reduction Rating (NRR), CavCom SoundBytes.
• OSHA. Occupational Safety and Health Administration Technical Manual. Section III, Chapter 5, Noise.
• Sayler, S, Rabinowitz, P, et al. (2019). Hearing protector attenuation and noise exposure among metal manufacturing workers, Ear and Hearing. May-Jun 2019; 40(3): 680-689.
• Special Considerations for Workers with Hearing Loss, CavCom SoundBytes.

Noise measurement app photo credit: NIOSH/cdc.com

You provide hearing protection and training for your noise-exposed workers. But how do you know your efforts are truly effective? How can you be confident your workers are consistently and correctly wearing their hearing protectors, and getting the protection they really need?

To be truly successful, a hearing loss prevention program must emphasize employee education, buy-in, and self-motivation. That's why pro-active companies now include Individual Fit Testing as an integral part of any hearing conservation program. Individual Fit Testing is recognized by OSHA, NIOSH and prominent professional organizations as a best practice.

NRR vs. PAR

When OSHA promulgated its Hearing Conservation Amendment for general industry in the early 1980s, the new regulation incorporated the Environmental Protection Agency's noise reduction rating (NRR) for estimating hearing protector performance. The NRR is a laboratory-derived estimate of the attenuation (sound reduction) that can be expected from a hearing protector. Shortly after the Hearing Conservation Amendment went into effect, however, it became evident that the actual amount of attenuation achieved in the workplace often fell short of the laboratory predicted NRR.

In 2008, an alliance between OSHA, NIOSH and the National Hearing Conservation Association recognized a new technology designed to obtain individualized hearing protection attenuation ratings for each worker. This group of experts acknowledged the limitations of relying on laboratory conditions and group statistics to predict an individual user's hearing protector performance in the field: "The consequence of this approach is that an individual user may actually receive more but usually less attenuation than is stated on the hearing protector label."  Based on their review of research and emerging trends and technologies, the Alliance identified Individual Fit Testing as a recommended best practice for hearing conservation programs.

Individual fit testing of hearing protectors is similar in concept to fit testing for respirators. Preferred methods produce a single-number overall estimate of real-world attenuation for each worker; this measure is generally represented as a Personal Attenuation Rating or PAR. In our experience, hearing protection products that are custom fitted to individual workers are less susceptible to poor insertion, and generally perform better in the real world.

Example real-world data:

Data Sources

CavCom Customs: CavCom internal individual fit testing for over 700 industrial workers. Average PAR under everyday field conditions (tested with earplug fit as normally worn).
Flanged and Foam: Field testing of 390 steelworkers. Michael and Byrne (2002) "Current State of Insert-Type Hearing Protector Fit Testing." NHCA Spectrum, Vol. 19(1).

Basics of Popular Individual Fit Test Equipment and Protocols

At CavCom, we often receive inquiries from customers about Individual Fit Test technology and available products. Unfortunately, at the current time, there is little standardization in equipment and protocols. We have reviewed numerous commercially available systems, and have determined that "real ear at threshold" (REAT) methodology typically provides the best opportunity for personal interaction and effective fitting and education of individual employees. You may choose to purchase your own equipment for in-house programs or ask CavCom‘s CAOHC-certified and experienced technical staff to do the testing, fitting and training for you.

REAT (real ear at threshold)

 This type of Fit Test is a familiar protocol, very similar to a routine hearing test. The individual employee listens for tones presented via earcups or speakers. The amount of protection, PAR, is calculated by comparing threshold results for open/unoccluded ears (no earplugs) to results when the individual's own earplugs are in place. Therefore, if the employee's hearing protector is the wrong size, worn out/damaged, or fitted incorrectly, REAT can reveal the problem. The test procedure is generally quick and easy to understand, although listeners with significant hearing loss may have difficulty or be unable to complete the test. Any manufacturer's insert hearing protector can be tested with this method.

MIRE (microphone in real ear)

 In this type of test, a probe microphone is inserted into an earpiece or earplug placed in the user's earcanal, while test signals are presented via earcups or speaker. A calculated "pass/fail" or PAR is based on probe microphone measurements. This procedure requires use of a manufacturer-specific surrogate earplug with built-in microphone, or removal of core components of the worker's earplug to be replaced by the manufacturer's probe microphone apparatus. MIRE technology can only be used with the manufacturer's own earplugs and cannot provide a true "audit" of the worker's hearing protector as worn. The acoustic measure portion of the test does not require employee participation, but substantial attention to set-up/calibration of the microphone and speakers is imperative.

Why CavCom conducts Individual Fit Testing using REAT technology

• Universal: allows you to test any manufacturer's insert hearing protector
• Ability to audit real-world performance and fit: tests each employee's own earplug without modification, the actual earplug the way it is typically fit and worn each day
• Easy set-up: REAT is a "relative measure" that compares occluded vs. unoccluded results for each worker; does not rely on precise placement/calibration of speakers and microphone
• Gold standard: REAT is as familiar as an annual hearing test and follows the same basic ANSI test protocol used for NRR (laboratory) testing

Lastly, no matter what type of Individual Fit Test protocol you choose, remember that test results alone do nothing to bolster compliance. A trained and qualified health and safety professional must take time to review PAR results for accuracy, retest if needed, and refit, retrain, coach, or fit alternate hearing protectors. The goal is to achieve adequate noise reduction and instill a sense of self-reliance for each individual user. That's what hearing conservation is all about.

Assistance is a click away

To help you with hearing protector attenuation estimates for your workforce, we have created a quick and easy calculator for comparing NRR and PAR values for both single and dual hearing protector configurations. Contact CavCom to request our free hearing protection attenuation calculator  and to learn more about our   Individual Fit Testing services.

Research studies and real-world experience show when hearing protectors are not comfortable, workers avoid wearing them properly or consistently throughout the workday. And failing to use protectors correctly or taking them out during a workshift can dramatically reduce effectiveness.

Hearing protection and electronic earsets come in a variety of shapes, styles, sizes, materials, and noise reduction capabilities. With all of these choices, it can be difficult to decide which hearing protectors are best for your workers. Some safety managers mistakenly select a product based exclusively on the product's Noise Reduction Rating (NRR). Although the NRR must be sufficient to protect against workplace noise exposures, research shows that additional factors, such as the ability to communicate and convenience, comfort, and compatibility with other personal protective equipment are more important to predicting ultimate success.

The Importance of Comfort

Personal perceptions

Although personal preferences vary, we do know some basic realities about the role comfort plays in the selection and use of earsets and hearing protection devices (HPDs). In general, hearing protectors perceived to be softer, smoother, less cumbersome, and less restrictive are typically rated the most comfortable. Users may find the pressure of tight headbands or heaviness of earmuffs to be bothersome, especially when wearing them for long periods of time. For those workers using communication headsets, bulky boom-mics or heavy electronics can add to the burden. It's good to keep in mind that workers' first impressions can predict their long-term opinions about comfort of a given device. For summaries of general research relating to hearing protector comfort, see Davis (2008) and Byrne, et al. (2011).

Work Environment

Environmental factors also influence HPD comfort. In cold temperatures, many workers prefer earmuffs that are easy to use while wearing gloves and that provide some coverage of the outer ear for warmth. Conversely, ear plugs are generally preferred in hot environments. NIOSH researchers have found that heat and humidity increase significantly under earmuffs by asking volunteers to walk in an air-conditioned hallway for only 30 minutes (Davis and Shaw, 2011). Imagine the discomfort for workers performing a strenuous job during hot summer months during an 8- or 10-hour work shift.

PPE Compatibility

The use of other personal protective equipment (PPE) such as respirators, hard hats, and safety glasses, also can affect the comfort of HPDs. Earmuffs and communication headsets in particular may be considered more cumbersome and restrictive in combination with other headgear such as bump caps, hard hats, or blasting hoods--obvious drawbacks to comfort and use. An added concern is the possibility of PPE interference with the seal of the HPD, which is crucial to blocking dangerous noise.

Implications of Uncomfortable Hearing Protection

All too often we think of HPDs as a perceived nuisance that the worker "needs to get used to" or endure. But because we cannot monitor workers at all times, the individual's self-motivation is critical. Attitudes and beliefs about the hazards of noise and risk of hearing loss are important predictors of workers' correct and consistent use of hearing protectors, and so is comfort. Studies have shown that individuals report infrequent or even improper use when HPDs are uncomfortable (Morata, et al., 2001; Davis, 2008; Edelson, et al., 2009).

Implications of reduced wearing time of a properly fitted HPD can be significant. In order to fully achieve protection, an individual must wear an appropriate and well-fitted HPD for the entire noise exposure. Otherwise, the effective protection is significantly reduced. An example: A worker is fitted with a device with an NRR of 20 to sufficiently reduce noise in the workplace. If this employee wears the HPD only 75 percent of the workday, however, the effective NRR drops to approximately 10 dB. Wearing the device for only half of the work shift drops the effective NRR to a meager 5 dB (Berger, 2000). The result of an uncomfortable HPD can be reduced protection from noise and increased risk of noise-induced hearing loss.

Making Comfort a Priority

Although HPD comfort can be subjective and largely a personal choice, there are a few simple steps that can help improve HPD comfort in your workplace: 

• Lighten the load. Some workers experience medical problems and should avoid ear plug or insert-style hearing protectors (severe earwax buildup, fungal infection, ear surgeries, etc.). Some individuals just don't like to stick anything in their ears. Earmuffs can be the best choice for these employees. But for most of us, the smaller and lighter, the better. Offering multiple earplug and lightweight earmuff options where possible will help improve the likelihood of achieving a comfortable and acceptable HPD for each employee.
• Check for compatibility. Fitting workers with HPDs and training them in proper use is required. It is important to consider, too, that hearing protectors are rarely worn in isolation. In the real world, workers often use HPDs in conjunction with safety glasses, hard hats, respirators, and other safety gear. The HPD may seem comfortable and a good fit in isolation, but once combined with other protective equipment, the end result is not ideal. If comfort is diminished, the likelihood that the HPD will be worn throughout the work shift decreases as well. For these reasons, it's important to have your employees suit up with all of their gear when fitting a hearing protector.
• Conduct individual fit testing. We have known for a long time that laboratory measures of hearing protection attenuation, namely NRR values, do not accurately reflect the actual amount of protection achieved in the real world. In recent years, individual fit testing procedures for evaluating HPDs have been developed, similar in concept to fit testing for respirators. A single measure of protection is provided for each individual worker tested and is generally referred to as a Personal Attenuation Rating, or PAR. An alliance among OSHA, NIOSH, and the National Hearing Conservation Association has identified individual fit testing as a recommended best practice for hearing conservation programs (OSHA, NIOSH, NHCA Alliance, 2008). The alliance argues that when workers are involved in the fitting process, they will be more likely to achieve optimal fit, have a positive attitude about hearing loss prevention, and more likely to wear HPDs correctly and consistently at work.
• Schedule a trial. Even after the best fitting session possible, individuals won't really know how a hearing protector works until they try it. What seems a good choice of HPDs in your safety office or medical clinic may not hold true when the employee gets back to the job. And don't expect workers to simply "get used to" an uncomfortable hearing protector. Most studies show that comfort issues will arise within 30 minutes of using a hearing protector and that these first impressions can be good predictors of longer-term comfort. After fitting any new HPD, we recommend you check back with the user later in the workday to ensure results are as expected.

Since worker comfort and correct usage are key factors in HPD acceptance and wear time, CavCom now offers more options than ever before. In our experience, it doesn't matter how good the technology; if the earset or HPD is uncomfortable, the worker isn't going to wear it properly. It's often said and is worth repeating that the "best" hearing protector is the one that is worn correctly and consistently whenever the worker is exposed to hazardous noise.

Contact CavCom for more information about options for choosing the hearing protectors and electronic earsets that are right for your workforce.

References

• CavCom SoundBytes. The NRR: What's in a Number?
• CavCom SoundBytes. Custom Hearing Protection Solutions Promote Success.
• Berger EH (2000). Hearing protection devices. In: Berger EH, Royster LH, Royster JD, Driscoll DP, Layne M, editors. The Noise Manual, 5th Edition. Fairfax, VA: American Industrial Hygiene Association Press; 379-454.
• Byrne DC, Davis RR, Shaw PB, Specht BM, Holland AN (2011). Relationship between comfort and attenuation measurements for two types of earplugs. Noise Health, Mar-Apr; 13(51): 86-92.
• Davis RR and Shaw PB (2011). Heat and humidity buildup under earmuff-type hearing protectors. Noise Health, Mar-Apr; 13(51): 93-98.
• Davis RR (2008). What do we know about hearing protector comfort? Noise Health Jul-Sep; 10(40): 83-89.
• Edelson J, Neitzel R, Meischke H, Daniell W, Sheppard L, Stover B, Seixas N (2009). Predictors of hearing protection use in construction workers. Ann Occ Hyg, 53(6): 605-615.
• Morata TC, Fiorini AC, Fischer FM, Krieg EF, Gozzoli L, Colacioppo S (2001). Factors affecting the use of hearing protectors in a population of printing workers. Noise Health; 4:25-32
• Occupational Safety and Health Administration, National Institute for Occupational Safety and Health, and National Hearing Conservation Association Alliance (2008). Best Practice Bulletin: hearing protection-emerging trends: individual fit testing.

Disposable foam earplugs protect the wearer from noise exposure, this is undisputed. They are also the most common hearing protection provided by many industries around the world. In this time of disposable PPE and safety equipment, single-use foam hearing protection tends to become just another expense located on the plant floor budgetary sheet. However, disposables are not cheap when they are compared to custom or even reusable universal hearing protection. We are going to break that down here:

This is just a glimpse of the sustainability of custom hearing protection from an environmental and cost savings perspective. Achieving a circular economy focused on decreasing your global carbon footprint is challenging. Some initiatives are easily observable and remediation strategies can be designed and executed with clarity. Other areas prove more elusive in understanding the negative carbon footprint a specific course of action has on the environment. What if we told you that your company disposes of 48,000 items each year? More importantly, how would you react if the remedy to this waste was a simple decision that has a positive Return On Investment within as little as 2 years? The solution is a permanent end to the daily waste. The discarded items have a significant carbon footprint when the entire scope from creation to disposal is fully taken into consideration.

Every market is moving towards a sustainable circular economy and we have solutions to facilitate this noble endeavor. At CavCom, we want to learn from and help companies with bold initiatives. Try our EarzON® ROI Calculator and then contact us. We want to hear about the pain points in your hearing conservation program and the sustainability requirements your company is implementing. Learning is growing, let us grow with you. 

Let's talk about the real world. No matter how high the laboratory Noise Reduction Rating (NRR), your employees will not wear a hearing protector if it's not comfortable, convenient, compatible with other personal protective equipment, and allows effective communication in the workplace. Personalized custom technology is now readily available for both hearing protectors and communication earsets. Custom-made earpieces can help you overcome many of the toughest objections to traditional hearing protectors that come your way.

What exactly is a custom hearing protector?

A custom hearing protector is a laboratory-made set of earplugs or communication earpieces specially created for an individual user. First, impressions of the user's ears are taken with a soft putty-like impression material (see Steps 1 and 2). The ear impression is then sent to an earmold laboratory to custom-manufacture a set of earplugs or radio communication earsets designed to precisely fit that individual's outer ear and ear canal. The amount of noise reduction is determined primarily by the portion of the earplug that fits into the ear canal. Generally, the longer the canal section and the better the fit of this part of the earplug, the higher the attenuation or noise reduction. Be wary of moldable materials purported to create immediate earplugs by hand molding – these products often do not fit well or hold up with daily use.

Step 1: Taking an ear impression: a foam block is placed in the ear canal, then soft putty-like molding material is placed into the ear and allowed to harden.

Step 2: Once impression material is cured, the ear impression is removed and sent to a lab for manufacture.

Some labs manufacture the earplug by physically creating negative then positive molds from the ear impression which are hand-manipulated by a technician. CavCom custom products, however, are manufactured by state-of-the-art rapid prototyping (stereolithography) from a high resolution digital scanning process of the ear impression. Final custom earplugs are crafted from acrylic or silicone depending on user application and preference (See Step 3 examples). Laboratories using the hand-manipulated technique may not retain the impression for future use because the impression material has a limited "shelf life." CavCom‘s digital processing technology, however, has the capability to store electronic files indefinitely for ease in ordering exact replacements in the event of loss or need for a different custom product.

Step 3: Example final custom-manufactured earpieces.

What are the benefits of custom hearing protectors for the workplace?

• Fit for all: One clear advantage of custom hearing protection is that all sizes and shapes of ears can be accommodated, even when surgery, disease or injury has radically changed the characteristics of the outer ear.
• Consistent protection: Because custom earplugs go in the ear just one way and are designed to fit the individual's ear canal precisely, research studies show that actual protection in the real-world more closely matches laboratory-derived noise reduction predictions than other classes of earplugs.
• Durable, long-lasting: Unlike foam or even most premolded vinyl earplugs, customs are designed to survive for years. A set of custom earplugs can last many years due to the considerable strength and durability of materials. Digital storage of ear impressions allows remakes to be made without taking new ear impressions (new impressions may be needed to address any significant changes to a user's ear canals resulting from substantial weight change, injury, etc.).
• Hygienic: Work environments are often hot, dirty, dusty, greasy, or laden with hazardous or irritating chemicals. Unlike typical disposable protectors which must be rolled between the fingers, custom earplugs do not require compression. If properly made, they also will not absorb oil and dirt, and are washed easily with soap and water.
• Better for the environment: It can be startling to realize how many foam or other disposable-type earplugs are thrown away every day. For an average workforce, this may translate to literally tens of thousands of discarded earplugs annually! Using a custom product that lasts for years significantly decreases waste and conserves resources. Many clients tell us their clean-up time is reduced as well --- disposable earplugs often find their way to the floor and septic systems rather than the trash can.
• Personalized attention = motivation: Clearly, one of the major advantages of a custom-made product is the opportunity to boost motivation by individually addressing the employee's needs and concerns. CavCom engraves the user's name for added personalization.
• Cost effective: Many people are surprised to learn that custom hearing protectors can cost significantly less in the long run than disposable-type earplugs. To compare cost benefits for your facility, request CavCom‘s free Return on Investment Calculator.

What are the limitations of custom earplugs?

• Only as good as the ear impression: A custom-manufactured earpiece using the best laboratory technology is only as good as the quality of the original ear impression. It is critical that anyone taking ear impressions be well-trained and highly experienced.
• Learning curve: Because a custom hearing protector is so different from traditional earplugs, employees will need initial instruction on how to insert their new customs, as well as a little practice, too. The fact that the earplugs are custom-made to fit each ear, however, ensures that improper placement is obvious and quickly remedied.
• Not ideal with high employee turnover: Although custom earplugs will last for many years, the cost for purchasing them is incurred up-front when ear impressions are taken and earpieces manufactured. If a company has a history of high turnover in the workforce, employers may be reluctant to undertake this long-term investment.
• Not right for everyone: Despite all the advantages of custom earpieces, not everyone likes the feel of an earplug and some prefer an earmuff or foam product. In CavCom‘s experience, it's never beneficial to require all employees use a certain type of hearing protector. The most effective hearing conservation programs provide a variety of suitable protectors so employees can make their own choice based on job needs and personal preference.

How do we know a custom hearing protector is working?

No matter what hearing protection devices your employees use, it's important to monitor effectiveness via an ongoing hearing conservation program that includes noise exposure assessment/control, hearing protection selection, fitting and training, and annual education and audiometric testing. When assessing whether a hearing protector is suitable and doing its job, CavCom encourages Individual Fit Testing. Individual Fit Testing of hearing protectors is similar in concept to fit testing for respirators. Preferred methods produce a single overall estimate of real-world attenuation for each user (referred to as a Personal Attenuation Rating or PAR). Individual testing and PARs replace the need for clunky NRR derating schemes that may over- or under-estimate the amount of protection received by any given individual. And because custom hearing protectors are designed to precisely fit each user, research shows that real-world PAR ratings are closer to "best case" lab ratings than other types of earplugs.

At CavCom, we specialize in custom-manufactured products, offering program enhancements like insurance programs and a 90-day fit guarantee. We know that the very best hearing protector is the one a person likes and will wear willingly and consistently. Contact CavCom to discuss how custom earplugs and radio communication earsets can improve voluntary employee participation, reduce costs, and enhance the success of your overall hearing conservation program.

Few things are more frustrating than being unable to understand what others are saying. In a work environment, failing to comprehend important messages can result in severe consequences. Safety and productivity depend on workers' ability to collaborate, problem-solve, and react quickly to emergency situations. Obstacles including loud background noise, PPE such as respiratory and hearing protection, and isolated work locations can create special challenges to achieving effective 2-way communication.

Noise remains one of the most prevalent hazards in industry today. And noise creates challenges in the workplace well beyond its most basic threat to hearing health. Growing evidence suggests there may be a link between noise, hearing loss, and risk of occupational injury. And as demands on worker productivity become more complex, the need for efficient and effective communication is essential. Comprehending speech in the presence of loud background noise can be challenging at best, and at times nearly impossible. Here we review some of the basic principles affecting workers' ability to communicate and offer solutions for improving safety and productivity in your workplace.

Key factors affecting speech communication

• Speech-to-noise ratio (SNR). The most basic determining factor of speech detection (realizing someone is speaking) and speech intelligibility (understanding what is said) is the loudness of the speech compared to the background noise. The level of a speech signal must be significantly higher than the background noise for the message to be understood.
• Poor speech quality. If a talker is wearing a respirator or other head/face PPE, speech may be altered/garbled from the start. And shouting to be heard is not a solution. There is a physiologic limit to how loud and how long talkers can raise their voice. Shouted speech often sounds distorted, too.
• Environmental obstacles. When speaker and listener are separated by distance or other obstacles such as machinery, visual cues such as lip-reading and hand signals/gestures are missed. Under best circumstances, a spoken, even shouted message cannot be heard at 3 to 5 feet in high noise. Even if workers have the benefit of a 2-way radio, phone, or public announcement system, cranking up the volume to be heard over background noise results in distortion of the speech signal and adds to employee noise exposure.
• Inner ear distortion. Next, let's consider the ear itself. Simply making sounds louder doesn't render those sounds easier to understand. Sensory cells and nerve fibers in the inner ear work most effectively at low to moderate sound levels. At high sound levels, signals within the inner ear become distorted, and auditory function is diminished. Just as music can lose its quality if played through a stereo speaker at full volume, speech can become distorted when entering the ear at very high levels.
• Hearing loss. As if there weren't enough challenges to listening in noise, now add one of the most common problems experienced by adults: hearing loss. According to the National Institutes of Health, approximately 15 percent of American adults report some degree of hearing loss. There are many different types of hearing loss that can affect listeners in varying ways. Some people have trouble hearing even in quiet situations. Others get by fine in quiet, but experience significant difficulty distinguishing sounds, particularly speech, in the presence of competing background noise. A listener with hearing impairment is likely to say making sounds louder doesn't necessarily make them clearer or easier to understand and they have difficulty in crowds, restaurants, even in face to face speaking situations.
• Hearing protector complications. Finally, one more PPE obstacle for listeners in noisy environments: hearing protectors affect speech intelligibility, particularly for people with hearing impairment. Hearing protectors block out high pitched sounds (consonant speech sounds like s, f, th, sh, etc.) that are critical for speech discrimination, reducing the speech to mumbling or gibberish. For a worker with high frequency hearing loss (very common), wearing hearing protectors can exacerbate the high frequency deficit, and in turn, further impair speech intelligibility

Options for improving communication

If companies are concerned that noise may be interfering with 2-way communication for their workers, then a complete Communication Survey is warranted. Where possible, engineering noise controls should be considered as a first line of defense to reduce noise at its source. Other solutions to consider:

• Group communication systems. With new technologies emerging, there are now many options for group communication available. Companies can choose a wide range of technologies, from cell phones or simple short-range 2-way radios to complex multi-user systems capable of connecting many workers across wide areas.
• Personal communication devices. These specialty devices typically consist of a personal hearing protector (earplug or earmuff) that attenuates (blocks) the background noise in combination with a communication interface. Devices may be designed for one-way or two-way communication. Typically, a small speaker is imbedded in the earplug or earmuff to deliver the communication signal directly to the ear. For 2-way communication, microphone quality is important and personal preference can be a deciding factor: boom-style, bone-conduction, and CavCom‘s Talk Through Your Ears® in-ear mic technology are options. With any personal device, there are many factors to consider, including performance, comfort, and compatibility with other personal protective equipment. When it comes to communication effectiveness, there are three important features to consider:

Binaural (both ear) listening provides a significant advantage over monaural (one ear) listening. The human auditory system is clearly designed to work with input from both ears. The brain processes and compares signals from each ear for localization, understanding speech, and separating speech from background noise. As a result, signals such as radio transmissions do not need to be as loud if a listener is using both ears. The practical result of this phenomenon is that comfortable, and most importantly, SAFER volume settings are typically possible when using binaural systems compared to an earset with a monaural listening configuration.

Output-limiting promotes safer listening levels. Whether a worker has normal hearing or hearing loss, it is important that signals delivered to the ear do not add to a noise hazard on the job. When purchasing a communication headset for any employee, make sure the device has an electronic feature to limit outputs to safe levels. Again, a binaural listening also helps most users choose a lower, safer, listening level than would be possible with a monaural system.

Adequate seal of hearing protector ensures best results. Delivering audio communications directly to the ears at a safe but sufficient level can be strongly dependent on a suitable seal of the hearing protector. If the hearing protector is not sealed properly, then background noise leaks in and competes with the speech signal. Not only may the user be inadequately protected from background noise, but worse yet, may try to compensate by increasing the volume control on the communication device resulting in added noise exposure. Remember that the key to high-quality communication is an optimal speech-to-noise ratio. When a proper hearing protector seal is achieved, excessive background noise will not be competing with the desired speech signal.

• High-fidelity filtered hearing protectors. Consider providing a new technology that is generally referred to as uniform (or "flat") attenuation filtered hearing protectors. Uniform attenuation means the hearing protector or communication earset is specially designed to reduce sounds evenly across a broad frequency range. Combined with a moderate amount of noise reduction, this type of hearing protector preserves the frequency balance of sound. The result is that reduced sounds have roughly the same quality as the original sounds, only quieter. To learn more, check out this helpful previous article from our SoundBytes newsletter
  
  
  
• Individual review. Because job requirements vary and workers' hearing abilities differ, consider building job-specific protocols for hearing-critical jobs and individualized plans for any hearing-impaired workers. For more information on accommodations and safety considerations and preparedness for those with hearing loss, see this helpful previous article from our SoundBytes newsletter. 

To sum up, extreme noise and other obstacles can impair 2-way communication in your workplace. But with planning and ingenuity, employers can protect workers' hearing while promoting intelligible communications in a challenging environment.

If you would like to learn more about hearing loss and listening in noise, more resources are just a click away. 

Communication Survey: How are loud noise or other challenges such as use of respirators affecting 2-way communications in your workplace? Request a free copy of our Communication Survey. This simple tool will help you identify problem areas that may be compromising safety and productivity.

Downtime impact calculator: Ever wished you could place a price tag on how down-time in your operation affects your bottom line? The impact can be surprising and quickly demonstrates your return on investment for communication system upgrades. Request a free calculator. 

High-fidelity hearing protection: Read more and listen to an audio demonstration of CavCom‘s selection of high-fidelity filters to enhance speech communication in noisy situations.

Video/Audio Demonstration – Communicating in High Noise: View CavCom‘s quick demonstration videos for ideas on how to improve communication in your workplace. 

Contact CavCom for more information about improving your company's productivity, safety, and communication capabilities.

Many people don’t understand the proper roll-down technique to achieve a good seal of the ear to block out harmful noise. Others just don’t want to take the time, because they’re in and out of noise frequently during the workday. Some facilities provide pre-molded earplugs, but frequently we find workers end up with the wrong size and a poor fit. Even hearing protectors that are easy to understand and use, like earmuffs, can get worn out. We often see people using old earmuffs with bent headbands, flat cushions and cracked seals — not an effective way to protect against noise!

And unfortunately, all these day-to-day problems with hearing protectors can result in gradual changes in hearing. A shift in hearing means you need to refit, retrain, and follow up with that employee. Individual fit testing can help you meet all of these needs when you find hearing shifts — and it’s a great way to start off new hires right.

Common Problems with Hearing Protectors in the Workplace

Here are some of the common pitfalls we see with hearing protectors:

• One-size hearing protectors do not fit all
• Self-fitting can lead to incorrect size and poor fit
• Incorrect insertion/wearing of the protector
• Employee’s failure to replace the hearing protector when damaged or worn out
• Inconsistent use when employee not motivated to protect hearing
• Hearing protectors with too much or too little attenuation (noise reduction) for the work environment

How Fit Testing Can Help

CavCom’s fit testing service identifies how well a hearing protector is working for each individual. First, I perform a test with the worker’s ear unoccluded (no earplug), then I perform the occluded test (with the earplug in place). This back to back comparison allows us to determine the attenuation (noise reduction) for that particular hearing protector as worn by the employee.

For the occluded test, employees place their hearing protection just like they would normally wear it and then they receive the test. In my experience, it’s not uncommon for 50% of the individuals I test to first fail because they’re not inserting their hearing protection as the manufacturer intended. Next, I’ll actually place the hearing protector in the employee’s earcanal using the correct insertion technique. The occluded test is administered again and the majority of the time, the employee passes. And this is a great lesson to show how important it is to insert the earplug correctly. It’s really rewarding to see how fit testing can make the difference in motivating people to protect their hearing. 

Still, some employees will not pass the fit test even with better placement techniques. This can mean there’s an issue with the way that particular hearing protector fits the employee. They may require a different style or size earplug to accommodate the shape of their earcanal. This refitting can be done on the spot — with the retest documenting success.

A Successful Hearing Protection Program

Hearing protection fit testing is a great way to support your hearing conservation program. It’s common for me to meet people who’ve been working in the field for years and not placing their protectors properly. Until you really sit down with them and perform fit testing, the problem isn’t always obvious. Fit testing can be a real eye-opener. In the moment, it’s an opportunity to retrain them and show them the difference it makes right away. An intervention like that can make a huge difference. 

Another benefit of fit testing is that we provide documentation of the fit tests for the company’s record-keeping. This is good for you to document compliance and can help you make future decisions about which jobs or departments need more support in achieving adequate noise reduction. Here’s a sample of what our personal attenuation report looks like:

We understand that protecting employee hearing is your ultimate goal. That’s why we at CavCom want to support you and help facilities like yours protect employees. For more information, check out our resource library. 

Ready to get started? Request our NRR/PAR calculator that gives you the information you need to estimate noise reduction without having to deal with complex formulas. And contact us to arrange fit testing for your facility: 

Many people don’t understand the proper roll-down technique to achieve a good seal of the ear to block out harmful noise. Others just don’t want to take the time, because they’re in and out of noise frequently during the workday. Some facilities provide pre-molded earplugs, but frequently we find workers end up with the wrong size and a poor fit. Even hearing protectors that are easy to understand and use, like earmuffs, can get worn out. We often see people using old earmuffs with bent headbands, flat cushions and cracked seals — not an effective way to protect against noise!

And unfortunately, all these day-to-day problems with hearing protectors can result in gradual changes in hearing. A shift in hearing means you need to refit, retrain, and follow up with that employee. Individual fit testing can help you meet all of these needs when you find hearing shifts — and it’s a great way to start off new hires right.

Common Problems with Hearing Protectors in the Workplace

Here are some of the common pitfalls we see with hearing protectors:

• One-size hearing protectors do not fit all
• Self-fitting can lead to incorrect size and poor fit
• Incorrect insertion/wearing of the protector
• Employee’s failure to replace the hearing protector when damaged or worn out
• Inconsistent use when employee not motivated to protect hearing
• Hearing protectors with too much or too little attenuation (noise reduction) for the work environment

How Fit Testing Can Help

CavCom’s fit testing service identifies how well a hearing protector is working for each individual. First, I perform a test with the worker’s ear unoccluded (no earplug), then I perform the occluded test (with the earplug in place). This back to back comparison allows us to determine the attenuation (noise reduction) for that particular hearing protector as worn by the employee.

For the occluded test, employees place their hearing protection just like they would normally wear it and then they receive the test. In my experience, it’s not uncommon for 50% of the individuals I test to first fail because they’re not inserting their hearing protection as the manufacturer intended. Next, I’ll actually place the hearing protector in the employee’s earcanal using the correct insertion technique. The occluded test is administered again and the majority of the time, the employee passes. And this is a great lesson to show how important it is to insert the earplug correctly. It’s really rewarding to see how fit testing can make the difference in motivating people to protect their hearing. 

Still, some employees will not pass the fit test even with better placement techniques. This can mean there’s an issue with the way that particular hearing protector fits the employee. They may require a different style or size earplug to accommodate the shape of their earcanal. This refitting can be done on the spot — with the retest documenting success.

A Successful Hearing Protection Program

Hearing protection fit testing is a great way to support your hearing conservation program. It’s common for me to meet people who’ve been working in the field for years and not placing their protectors properly. Until you really sit down with them and perform fit testing, the problem isn’t always obvious. Fit testing can be a real eye-opener. In the moment, it’s an opportunity to retrain them and show them the difference it makes right away. An intervention like that can make a huge difference. 

Another benefit of fit testing is that we provide documentation of the fit tests for the company’s record-keeping. This is good for you to document compliance and can help you make future decisions about which jobs or departments need more support in achieving adequate noise reduction. Here’s a sample of what our personal attenuation report looks like:

We understand that protecting employee hearing is your ultimate goal. That’s why we at CavCom want to support you and help facilities like yours protect employees. For more information, check out our resource library. 

Ready to get started? Request our NRR/PAR calculator that gives you the information you need to estimate noise reduction without having to deal with complex formulas. And contact us to arrange fit testing for your facility: 

Recently CavCom has received questions from customers who are concerned about a significant hearing loss or standard threshold shift (STS) observed in only one ear. Is this common with occupational noise exposures? The answer is, well, not really. Single-ear hearing issues could be a warning sign.

First, let's be clear - no hearing loss is a good one. That said, a significant change in hearing in one ear (much more so in one ear than the other) is unusual. A high number of single-ear shifts in hearing among your workers is suspicious, especially if concentrated in one department or work group.

In most work environments, the ears are exposed to similar sound levels at the same time. Even if the noise appears to be coming from one side more often, most workers are moving their head/body throughout a day, and there isn't that much distance between our two ears after all. Most sound waves easily bend around the head to reach the other ear, especially in a reverberant environment. Although there is some discrepancy in the scientific literature, most well-controlled studies have shown hearing loss among noise-exposed workers to be fairly similar (symmetrical) between ears.

For these reasons, a significant difference between the ears indicates the need for special review and follow-up. Medical issues or injury to the head can cause one-sided hearing loss, ranging from mild to serious in nature. Some of the more common noise-related causes include:

• Impulse noise sources such as gunfire, explosions. Because of the high concentration of sound energy associated with gunfire or other impulse sounds (peaks may exceed 135 dB SPL), the sound pathway is often directional, and damage is concentrated on the nearer ear. Asymmetrical hearing loss in the nearer ear is well-documented for shooters (if rifle resting on shoulder for example) and for those exposed to other loud impulses.
• Poor fitting hearing protector or failure to use hearing protector in one ear. Ears come in different sizes and shapes, so each ear should be fit individually. Some users have more difficulty inserting an earplug correctly in one ear than the other. Worse yet, some workers mistakenly remove an earplug or one cup of an earmuff when experiencing trouble hearing in their surroundings. They may feel hearing protection makes it more difficult to hear their machine or people talking. This is often a misconception, but at the very least is a communication challenge in need of solving.
• Single-ear earphones or headsets. Because some headsets or earbuds exhibit uncontrolled outputs at high volume settings, it is possible that workers are receiving significant noise exposures from their communication devices. Another complication, listening with only one ear typically requires a higher volume level to achieve intelligibility. If the employee is wearing an unlimited headset or earbud in only one ear, or places a lapel speaker mic on one shoulder without adequate hearing protection, a single-ear shift in hearing may result.

Whenever a shift in hearing is noted, timely individual follow-up with that worker is essential. When patterns in hearing shifts are observed, an evaluation of the entire hearing conservation program is warranted. Best practices include:

• Professional review/referral. Medical/audiological evaluation should include a case-by-case evaluation to determine if an event/exposure in the workplace caused or contributed to the change in hearing and if medical follow-up is advised.
• Individual counseling/re-training. Take time to evaluate employee concerns or objections about using hearing protection. Address misconceptions and alleviate apprehensions about communicating safely in the workplace; provide solid communication solutions that meet needs of the job and complement other PPE. Employees should also be counseled about the potential effects of off-the-job noise exposure, such as hunting or recreational activities, and the need for protecting hearing at home as well as at work.
• Fit Testing. Individual fit testing of hearing protectors is a vital component of an effective hearing conservation program, not a luxury. Especially for those who have shown a shift in hearing, individual fit testing will provide insight into the amount of real-world protection received for that worker. Subtle differences in fit or insertion between the ears may be illuminated. Another major advantage is the opportunity to refit and retrain individual workers in real time, so they clearly see the result of proper fit and insertion of their own personal hearing protector.
• Specifications for communication headsets. In order to facilitate effective communication while at the same time protecting workers' hearing, communication headsets or earsets must be carefully vetted. Insist on the following key specifications to achieve your goals:
  • Effective hearing protection. Require devices that sufficiently attenuate or block workplace noise; a good seal of the ear canal is essential. For best results, look for a microphone and/or receiver integrated into the hearing protector so that signals are delivered directly to the ear while simultaneously blocking outside noise.
  • Binaural (both ear) listening. Binaural listening provides a significant advantage over monaural (one ear) listening. The human auditory system is designed to work most effectively with input from both ears. The brain processes and compares signals from each ear for localization, understanding speech, and separating speech from background noise. As a result, signals such as radio transmissions do not need to be as loud if a listener is using both ears. The practical result of this phenomenon is that comfortable, and most importantly, SAFER volume settings are possible if using a binaural earset compared to one with a single-ear listening configuration. Preferred listening levels are typically 3-6 dB lower when using both ears, a significant and important advantage of binaural devices.
  • Volume-limited outputs. Whether a worker is in low or high noise areas, it is important that signals delivered to the ear do not add to noise exposure on the job. When purchasing a communication headset for any employee, make sure the device has an electronic feature to limit outputs to safer levels. And again, a binaural listening configuration allows most users to choose a lower, safer, listening level than would be possible with a monaural system.

At CavCom, we are committed to customizing solutions for your most difficult listening challenges. Don't hesitate to contact us if we can be of assistance with your communication systems and your hearing conservation program. 

To learn more:

• Cavcom SoundBytes. Effective 2-way communication. 
• Cavcom SoundBytes. Non-occupational noise. 
• Cavcom SoundBytes. The NRR – What's in a number? 
• Dobie, Robert (2014). Does occupational noise cause asymmetric hearing loss? Ear & Hearing, Vol 35(5).
• Masterson et al. (2016). Asymmetrical hearing loss in cases of industrial noise exposure: a systematic review of the literature, Otology & Neurotology, Vol 37.

According to the U.S. Bureau of Labor Statistics, occupational hearing loss represents one-third of work-related illnesses reported annually in the manufacturing sector. In 2015, a total of nearly 17,000 cases of hearing loss were reported by private industries nationwide. OSHA recently issued a new interpretation regarding how to consider an employee's use of hearing protection when determining if a hearing loss is work-related.

As part of a hearing conservation program, companies conduct baseline and annual audiometric testing for their noise-exposed workers. Based on results, employers must record on the OSHA 300 Log any cases of work-related hearing loss that meet the following criterion:

1. Standard Threshold Shift (STS): an average change of 10 dB or more at 2000, 3000, and 4000 Hz in either ear compared to the baseline hearing test (age-adjustments allowed),

AND

2. Hearing Loss/Impairment: the employee's average hearing level at the same frequencies in the same ear is 25 dB HL or greater (regardless of employee's age).

It is important to remember that not all shifts in hearing are due to noise on the job. Medical concerns or non-occupational noise can also cause changes in hearing. For this reason, a professional case-by-case review is recommended. OSHA states that hearing loss work-relatedness must be determined according to specifications of section 1904.5. If an event/exposure in the workplace caused or contributed to the shift in hearing or "significantly aggravated" a previously existing hearing loss, then the case is considered recordable. OSHA's latest interpretation clarifies how to consider a worker's use of hearing protection as part of the review process.

"First, OSHA does allow the worker's use of hearing protection to be considered by an employer when making determinations of work relatedness. However, this should not be the sole criterion in such determinations, nor should the determination be reduced to an equation. Under OSHA's recordkeeping regulation, an employer must consider many factors when determining whether hearing loss is work-related, and such determinations must be made on a case-by-case basis." (OSHA, 2016)

For more information:

Overview:  Recording Occupational Hearing Loss on the OSHA 300 Log, by Susan Cooper, PhD, CAOHC Update, 2013. 

Regulations and Interpretations:

  Federal OSHA:

Regulation: 29 CFR, 1904.10. Recording criteria for cases involving occupational hearing loss. OSHA, 66 FR 6129, Jan. 19, 2001; 66 FR 52034, Oct. 12, 2001; 67 FR 44048, July, 1, 2002; 67 FR 77170, Dec. 17, 2002 

Interpretation Letters: 

OSHA (2003). Interpretation letter dated 5/8/03 from Richard E. Fairfax, Director, Directorate of Enforcement Programs to Linda Ballas, regarding audiogram baseline revision.

OSHA (2003). Interpretation letter dated 8/14/03 from Richard E. Fairfax, Director, Directorate of Enforcement Programs to Joan E. Piosa, regarding STS retests.

OSHA (2004). Interpretation letter dated 3/4/04 from Frank Frodyma, Acting Director, Directorate of Evaluation and Analysis, to Carl Sall, regarding timeframe for retests, line-outs, and application of 1904.10 to the construction industry.

OSHA (2005). Interpretation letter dated 9/9/05 from Richard E. Fairfax, Director, Directorate of Enforcement Programs to Laurie Wells, President of NHCA, regarding audiometric baseline revision.

OSHA (2007). Interpretation letter dated 8/29/07 from Keith Goddard, Director, Directorate of Evaluation and Analysis to Theresa Schulz, CAOHC Chair, regarding audiometric reviewer qualifications.

OSHA (2016). Interpretation letter dated 4/29/16 from Thomas Galassi, Director, Directorate of Enforcement Programs to Richard Stepkin, regarding consideration of hearing protection use in determining work-relatedness for purposes of recording occupational hearing loss on Form 300.

OrOSHA: Oregon Administrative Rules, Chapter 437, Division 1, Recordkeeping and Reporting, 437-001-0700 (11)(b): Occupational Hearing Loss Recording Criteria. 

WISHA: Washington Chapter WAC 296-27-01113 Recording criteria for cases involving occupational hearing loss. h

Professional Guidelines:

NHCA (2011). Guidelines for Recording Hearing Loss on the OSHA 300 Log, National Hearing Conservation Association, approved by the Executive Council on April 26, 2011. 

NHCA (2013). Guidelines for Audiometric Baseline Revision, National Hearing Conservation Association, approved by the Executive Council on February 20, 2013. 

Short answer is no. The FCC has indicated that their intention is to have the new standard at 6.25 kHz (digital) but have not provided a switchover date. If you're running radio communications on analog frequencies, you do not have to make the switch. And if you have great-working analog radios that meet your current communication needs, that's reason enough to stick with them until something changes.
However, if you are communicating via analog radio and experiencing issues communicating throughout your facility, common problems associated with analog radios simply go away after switching over to digital radio communications.

Benefits Digital Two-Way Radios Can Bring

RANGE: The top reason we see companies choose to go digital is that they're not getting complete coverage throughout their facility. Dead zones are an annoyance at best and potential danger at worst.
While digital transition won't solve all range issues for all facilities, countless times our customers have experienced complete elimination of dead zones just from moving from analog radio to digital. Ensuring everyone can communicate, regardless of location, is a big reason facilities choose to upgrade their radio comms.

CLARITY:. A lot of our customers work in high noise environments, and digital radios — all on their own — have excellent noise cancellation capabilities. If there are areas in your facility where radio communications are difficult to hear due to noise, swapping out your analog radios for digital ones can be a big help.

An upgrade to digital also brings a series of features that analog radios don't offer. These include calling features like text messaging, all call, and individual talk. Plus, digital radios have superior battery life over analog, which anyone who can't complete their shift without changing their radio battery can appreciate. Additionally, CavCom carries a complete line of radio accessories specifically designed to assist with radio comms in high noise. Suddenly, you're able to hear and be heard on the radio in areas where you used to be drowned out. It's a small change that can make a big improvement.

Top benefits a facility could see with the integration of digital communications are:

• Dead zone elimination
• Noise cancellation
• Modern calling features
• Extended battery life

With these potential benefits, it makes sense that some facilities aren't waiting for new FCC requirements to switch from analog to digital. Especially because the process can take place gradually.

The Push Toward Digital Two-Way Radios

After comparing analog vs digital, there's a chance you might be feeling a push toward making the switch.

First, I want you to know you're not alone.
Second, it's important to remember that if your analog radios are working for you and meeting the communication needs of your facility, there's no current regulation requiring you to move anything.
Third, I want you to know that if you do plan to eventually upgrade to digital, there are gradual ways to go about it.

Integrating Digital

The decision to switch to digital is something that can be implemented as quickly or slowly as you like. Some of our customers want to start receiving the benefits of digital two-way radios as quickly as possible and others want to remain on analog with the intent to go digital in the next few years. Either way they rely on us to help them navigate their process.
Some customers who choose to remain on analog but know that digital is in their future, choose replacement devices that are compatible with both digital and analog. This way, they can continue with their existing radio infrastructure while preparing for the future.

Partnering with CavCom

There are some great reasons why facilities are upgrading their radio infrastructure to support digital. By choosing to partner with CavCom, we can help you through the process. If you would like to explore upgrading radios in your facility, or you're simply looking for some advice tailor-made to your situation, connect with us. We can help you figure out a path to digital that isn't going to leave you dealing with a massive upset or unmanageable capital expense.
Our Process
We begin by checking on your FCC license and understanding your communication struggles as well as your short- and long-term communication goals. We can have a technical specialist conduct a demo and let you try our radios and communication solutions. We carry industrial digital radios that can be programmed in both digital and analog. These devices make great replacements for existing radios that eventually become obsolete. When you are ready to go digital, the radios can be set up to change to digital with literally a flip of a button. Your employees will still have those same radios, but their experience communicating will immediately improve.
Are you interested in learning about your options regarding integrating digital-capable radios into your facility? Get started by connecting with one of our sales representatives.

Through its Total Worker Health® (TWH) Program, the National Institute for Occupational Safety and Health (NIOSH) recommends an integrated approach to addressing the safety and health of workers. While protecting hearing on the job is essential, NIOSH recommends addressing noise risks outside of work as well.

Because exposure to hazardous noise is common in daily life, not just in the workplace, it is important to raise awareness and encourage healthy hearing habits outside of work. The TWH Program advocates for a comprehensive approach to improve overall health and well-being both on and off the job. NIOSH's new Hearing Health Solutions document focuses on promoting better hearing health and reducing the risks associated with noise exposure at work and at play. Recommendations are included for workers, employers, and hearing healthcare providers.

To learn more:

• Themann CL, Morata T, and Afanuh S (2019). Using Total Worker Health® Concepts to Address Hearing Health, NIOSH Publication 2019-155 
• Non-Occupational Noise: Quantifying Noise Exposures, SoundBytes 
• Guidance for Recreational Firearm Noise, SoundBytes 
• Helping Musicians Protect Their Hearing, SoundBytes 

Despite long-standing regulations requiring hearing conservation programs for noisy workplaces, there are no universally-accepted methods for evaluating program effectiveness. The National Institute for Occupational Safety and Health (NIOSH) recently funded a study of hearing loss prevention programs and announced tools for companies to evaluate their own programs.

In 2017, researchers from NIOSH, the University of Michigan, the University of Washington and Yale University studied hearing conservation programs at 14 facilities across the U.S. operated by a single manufacturing company. The research team conducted focus groups, interviews, anonymous surveys, noise dosimetry, walk-throughs, and an analysis of hearing test and noise data for each workplace.

The research group found that most facilities had a strong management commitment to hearing loss prevention as well as personal commitment among individual workers. However, few sites showed the same commitment to protecting hearing off the job. Based on the results of their research, the team created two self-evaluation tools, a checklist and a calculator that allows companies to estimate the cost of their hearing loss prevention efforts. In this study, the average annual cost was $295 per employee.

Both tools are available at the NIOSH hearing loss prevention website and a special webpage at the University of Washington. 

In 2009, the National Institute for Occupational Safety and Health (NIOSH) began an ambitious program to develop and maintain a national surveillance system for tracking hearing loss among occupational workers. The Occupational Hearing Loss (OHL) Surveillance Project uses a novel approach for data collection by partnering with audiometric service providers and other outside parties to collect worker audiograms. To date, NIOSH has partnered with 18 data providers and collected 9 million hearing tests for noise-exposed workers.

Project director Elizabeth Masterson, PhD, CPH, COHC explains the program: "To prevent more workers from losing their hearing, we need to know the size of the problem, identify the workers most at risk, and monitor trends in worker hearing loss for improvement." The OHL Project is longitudinal by design, continuing to collect hearing tests and recruit new data providers on an ongoing basis. An initial analysis of the OHL database revealed that 18% of noise-exposed workers had some form of hearing loss (results outside the normal range of hearing). Not unexpected, the prevalence of hearing loss was higher, 24% or more, within the Mining, Construction and Manufacturing industries. An analysis of significant changes (shifts) in hearing showed that 6% of workers sampled from the database had experienced a significant change in hearing, an OSHA Standard Threshold Shift (STS, age-adjusted). The number climbed to 14% for the group if STS age-adjustments were not considered. Higher still was the rate of shifts in hearing according to a more conservative NIOSH-recommended criterion: 20% of workers.

For more information on procedures, statistics, publications, and data provider partnerships, visit the OHL Surveillance Project website. Additional references:

Masterson, et al. (2014). Prevalence of workers with shifts in hearing by industry: a comparison of OSHA and NIOSH hearing shift criteria. Journal of Occupational & Environmental Medicine, 56(4), 446-455. 

Masterson, et al. (2013). Prevalence of hearing loss in the United States by industry. American Journal of Industrial Medicine, 56(6), 670-681. 

The hazardous effects of noise are well known, and most companies now have active hearing conservation programs to protect their workers. Less understood are the effects of "ototoxicants" (ear poisons). These chemicals or compounds can cause hearing loss, tinnitus and balance problems, sometimes accelerated when combined with noise exposures. OSHA and the National Institute for Occupational Health (NIOSH) have recently published a new safety and health bulletin on this important topic.

Chemical ototoxicity (meaning poisonous to the ear) first came to the attention of researchers in the 1970s and 80s; however, comprehensive studies and clear conclusions about the hazards are still in the making. Certain chemical substances are ototoxic when airborne, ingested, or absorbed through the skin. Some ototoxicants affect the inner ear in the same manner as noise; others target the balance center in the inner ear or "higher" parts of the auditory system such as the auditory nerve, cortex, and brainstem centers.

Not only can ototoxic agents cause temporary or permanent damage to the auditory system independently, they can also interact with noise to accelerate the risk of hearing loss. In occupational settings, because noise is often present where chemical exposures occur, it can be difficult to separate the degree of hazard from each agent.

Some of the occupational compounds implicated as being ototoxic:

• Solvents such as carbon disulfide, n-hexane, toluene, styrene, xylene, ethylbenzene
• Asphyxiants such as carbon monoxide, hydrogen cyanide, and tobacco smoke
• Metals such as mercury, lead and organic tin compounds
• Nitriles
• Certain pharmaceuticals

Jobs where ototoxicants may be present (and can often combine with noise exposures):

• Painting
• Printing
• Manufacturing of metal, leather, chemical, petroleum, paper and many other products
• Construction
• Firefighting
• Mining
• Utilities
• Fueling vehicles and aircraft
• Pesticide spraying
• Shipbuilding

Currently there are no regulations requiring monitoring of a worker's hearing due to occupational exposure to ototoxic chemicals. However, appropriate use of a respirator and/or skin protection can protect against chemical exposures, while effective hearing protection can protect against noise. Proactive companies are beginning to take into account special cases of chemical exposures in the workplace, including audiometric testing to monitor hearing levels.

To learn more, check out these helpful resources:

• OSHA, NIOSH (2018). Preventing Hearing Loss Caused by Chemical (Ototoxicity) and Noise Exposure. Safety and Health Information Bulletin 03-08-2018; NIOSH Publication No. 2018-124. 
• Estill, Rice, Morata and Bhattacharya (2017). Noise and neurotoxic chemical exposure relationship to workplace traumatic injuries: a review. Journal of Safety Research, 60, 35-42. 
• The National Research Council (2014). Review of Styrene Assessment In the National Toxicology Program, National Academies Press. 
• OSHA (2013). OSHA Technical Manual, Section III: Chapter 5, II. G. Noise and Solvent Interactions (Updated 08/15/2013). 
• Themann C, Suter A, Stephenson M (2013). National Research Agenda for the Prevention of Occupational Hearing Loss—Part 1. Semin Hear; 34(03): 145-207 
• European Agency for Safety and Health at Work (2009). Combined exposure to noise and ototoxic substances (literature review). 

Millions of workplace injuries occur every year in the U.S. resulting in 5,000 fatalities annually. Noise in the workplace can damage hearing, and neurotoxic chemical exposures can affect central nervous system functions including hearing and balance. In collaboration with the University of Cincinnati, the National Institute for Occupational Safety and Health (NIOSH) recently conducted a thorough review of available scientific evidence to determine if there is an association between exposure to noise or neurotoxins and injury.

The report summarizes results of 41 published research studies of noise exposure, hearing loss, and neurotoxic chemical (solvent) exposure. Some researchers studied workplace accidents while others reported on accidents outside of work and health outcomes such as sick days, decreased cognitive ability, and disability retirement. In general, higher exposures to noise were associated with injury and negative health outcomes, although the relationship was not well understood. Solvent exposures were also linked to accidents and other health outcomes such as balance disorders. Some of the strongest relationships were found among workers with hearing loss and the rate of accidents, injuries, and disability retirement.

To learn more:

• Estill, Rice, Morata and Bhattacharya (2017). Noise and neurotoxic chemical exposure relationship to workplace traumatic injuries: a review. Journal of Safety Research, 60, 35-42.
• CavCom, SoundBytes. Accident Risk and Noise
• CavCom, SoundBytes. Special Considerations for Workers with Hearing Loss
  (photo source: cdc.gov)

In 2013, OSHA launched the Temporary Worker Initiative (TWI), a project to help prevent work-related injuries and illnesses among temporary workers. The TWI's most recent safety bulletins focus on Respiratory Protection and Noise Exposure.

Temporary and contract workers are believed to have increased risk of work-related injury and illness. OSHA created the Temporary Worker Initiative (TWI) due to multiple reports of temporary workers suffering serious or fatal injuries, some in their first days on the job. For the purposes of TWI's recommended practices, "temporary workers" includes those supplied to a host employer and paid by a staffing agency, whether or not the job is actually temporary. It is OSHA's position that the staffing agency and its customer (host employer) are joint employers of temporary workers and, therefore, both are responsible for providing and maintaining a safe and healthy work environment.

In 2018, OSHA published two new TWI bulletins addressing temporary worker health and safety:

• Bulletin 8. Respiratory Protection: provides guidance for the protection of temporary workers exposed to airborne contaminants under OSHA's general industry and maritime standards. Both staffing agency and host are jointly responsible that workers wear respirators, but the two entities may agree in advance to a division of responsibilities. The host employer will usually have the primary responsibility for evaluating exposure levels, implementing and maintaining engineering, administrative, and work practice controls, providing an appropriate respirator, and maintaining a respiratory protection program in accordance with OSHA requirements. The staffing agency should also ensure its employees are protected, including being aware of respiratory hazards to which employees may be exposed and the customer's protective measures including any requirements for respiratory protection at the host employer's worksite.
• Bulletin 9. Noise Exposure and Hearing Conservation: this bulletin provides guidance for protecting temporary workers exposed to hazardous noise levels. Again, both staffing agency and host are jointly responsible for protecting workers against noise but may agree in advance to a division of responsibilities. The host employer will typically have primary responsibility for determining noise exposure levels, implementing and maintaining engineering/administrative controls, providing appropriate hearing protection, and maintaining a hearing conservation program. The staffing agency should also make sure individuals are protected by informing temporary employees of the noise hazards they may encounter, and ensuring as far as possible, that workers are adequately protected, including wearing hearing protection.

For more information:

• OSHA Temporary Worker Initiative main page
• OSHA TWI Bulletin No. 8: Respiratory Protection, OSHA 3952-06, 2018 
• OSHA TWI Bulletin No. 9: Noise Exposure and Hearing Conservation, OSHA 3953-06, 2018 
• NIOSH/OSHA Joint Statement on Recommended Practices – Protecting Temporary Workers, HHS (NIOSH) Publication Number 2014-139; OSHA – 3735, 2014 
• OSHA Interpretation Letter – Minimum exposure for inclusion in the hearing conservation program (HCP); removal criteria, Richard Fairfax, Directorate of Enforcement Programs, February 13, 2004.  

For many students, summer break is spent earning money for college, a car, and other personal items. But teens and parents beware, job-related injury rates are high for young workers. Limited job experience and training can put young people at increased risk.

Teen workers have higher rates of work-related injuries than their older, more experienced counterparts. Young people often work on a part-time or temporary basis, and may not receive adequate safety training and oversight. Some experts point out that middle and high school workers also may not have the physical strength and cognitive maturity needed to perform certain job duties. To help address this problem, the U.S. Public Health Service developed a Healthy People objective to reduce rates of work-related injuries among young people aged 15-19.

To learn more and to access helpful training resources, see:

• NIOSH Topic Page: Young Worker Safety. 
• OSHA Topic Page: Safe Work for Young Workers. 

In 2016, the National Institute for Occupational Safety and Health (NIOSH) launched a new online resource database. This searchable archive serves as a compendium of federal regulations and consensus standards related to all types of Personal Protective Equipment (PPE).

NIOSH's National Personal Protective Technology Laboratory developed the PPE-INFO database in collaboration with key partners including the International Safety Equipment Association, OSHA, MSHA, and members of the PPE Conformity Assessment Working Group. The database is comprised of standards and regulations published by U.S. Government Agencies and consensus standards organizations such as ANSI and ISO.

The goal of the project is to provide employers and workers with reliable information about occupational PPE in the United States. Future plans call for expanding the database to include international standards, conformity assessments standards, and a list of products that conform to these standards.

For more information:

NIOSH Announcement, Science Blog, May 2016 

PPE-INFO database 

It is estimated that over 3 million American workers are injured on the job each year, resulting in incalculable human toll and billions in direct and indirect cost to the nation. Growing evidence suggests there may be a link between noise, hearing loss, and risk of occupational injury.

Many factors influence risk of accidents, including workplace conditions, PPE/safety equipment, and employee factors such as health and training. A collaborative team of researchers from Yale, Stanford, U. Michigan, and U. Washington have teamed up with industry to investigate the potential influence of workplace noise. The research group recently completed a large-scale analysis of records for approximately 9,000 manufacturing workers over a 6-year period. Among this group of workers, the researchers found that higher noise exposures were associated with higher risk of injuries, especially serious injuries. In addition, hearing impairment was linked to higher accident rates, particularly for those employees with a combination of high frequency hearing loss and tinnitus (ringing in the ears).

For more information and helpful resources for your hearing conservation program, see:

CavCom SoundBytes. Does Noise Increase the Risk of Accidents? 

CavCom SoundBytes. Special Considerations for Workers with Hearing Loss 

Cantley LF, Galusha D, Cullen MR, Dixon-Ernst C. Tessier-Sherman B, Slade MD, Rabinowitz PM, Neitzel RL. 2015. Does tinnitus, hearing asymmetry, or hearing loss predispose to occupational injury risk? International Journal of Audiology, 54 Suppl 1: S30-6.

Cantley LF, Galusha D, Cullen MR, Dixon-Ernst C, Rabinowitz PM, Neitzel RL. 2015. Association between ambient noise exposure, hearing acuity, and risk of acute occupational injury. Scandinavian Journal of Work & Environmental Health, 41(1): 75-83.

NIOSH Topic Page: Traumatic Occupational Injury. 

Loud noise is one of the most common and pervasive hazards in industry today. The risk of hearing loss due to excessive noise is well known and has long been studied. But other risks from noise have not been so clear. Is excess noise also to blame for accidents in the workplace? Are all workers at higher risk, or perhaps just those individuals who are hard of hearing?

Identifying Listening Challenges

In recent years, there has been growing concern that noise in the workplace may increase a worker’s risk of occupational injury. Many accident investigations now include consideration of any possible noise interference with the detection of warning signals, moving vehicles, or speech communications. The National Institute for Occupational Safety and Health (NIOSH) maintains a central index of investigation data that includes NIOSH reports and data available from state programs. This Fatality Assessment and Control Evaluation (FACE) Program tracks details of the conditions and series of events that led to a deadly incident, including information about workplace noise and hearing status when available.

For most listeners, the level of a speech signal must be significantly higher than background noise in order to be intelligible (understandable). In industry, achieving an adequate signal-to-noise ratio can be a challenge in many work areas. There is a physiologic limit to how loud and how long talkers can raise their voice, or shout, to be heard. Simply making sounds louder through amplification may not make those sounds easier to understand. At high sound levels (typically over 85 dB), signals within the inner ear become distorted and auditory function can be diminished. Just as music can lose its quality if played through a stereo speaker on full volume, speech and other acoustic signals become distorted when entering the ear at very high levels. Worse yet, cranking up the volume on a traditional radio or PA system may actually add to workers’ noise exposures. 

As if there weren’t enough challenges to listening in noise, of special concern is when a worker is hard of hearing. There are many types and severities of hearing loss. Some people have difficulty hearing at all times, even in quiet situations. Others get by fine in quiet, but experience significant trouble distinguishing sounds, particularly speech, in the presence of competing background noise. Through interviews with noise-exposed and hearing-impaired workers and their supervisors, a team of researchers at The National Institute for Occupational Safety and Health (NIOSH) took an early step toward identifying job safety concerns (Morata et al, 2005). On the whole, the research team found workers and managers in agreement about reduced ability to hear important sounds in a noisy workplace. In particular, concerns were expressed about impaired capacity to monitor equipment, detect warning sounds, and understand speech. Especially for workers with hearing loss, there was the added worry that hearing protection devices can exacerbate listening difficulties. Some workers even commented that working in noise with a hearing loss was stressful and tiring, more potential risk factors for workplace mishaps.

Is There a Link to Accidents?

First and foremost, it is important to point out that drawing clear conclusions about “cause-effect” relationships is not easy. Historically, research has looked for associations, or links, between various risk factors and accidents. In addition, in the real world, research is often limited by unavailable or insufficient data on workplace noise levels and worker hearing status. One group of Canadian researchers (see studies listed under team leaders Girard and Picard in our References section below) has been able to systematically test the connection between noise and accidents by analyzing registry information available from the Quebec National Institute of Public Health and the Quebec Workers’ Compensation Board. The group has completed a number of retrospective studies by reviewing records for over 50,000 occupational workers.  They concluded that injuries were associated with both high noise exposure and worker hearing loss. Exposure to extremely noisy environments (equivalent 8-hour noise exposures of 90 dBA and above) and hearing loss were associated with higher risk of accidents. Overall, they attributed 12% of workplace accidents to a combination of noise exposure and hearing loss.  Furthermore, the risk of multiple accidents/injuries was three times higher for severely hearing-impaired workers. Seriousness of injury was associated with noise exposure as well. The researchers found an association between injuries severe enough to require hospitalization and noise exposures of 100 dBA and above. And for each dB of hearing loss, a statistically significant increase in hospitalization was observed.  

The Canadian researchers have also studied traffic accidents by reviewing data available from the Quebec state agency responsible for motor vehicle insurance and the compensation of victims of traffic accidents. These results revealed that occupational noise exposure and hearing loss were linked to traffic accidents, similar to associations they found for industrial accidents.  

This type of research is also ongoing in the United States. In 1996, NIOSH established the National Occupational Research Agenda (NORA) as a framework to guide research and focus efforts to prevent work-related illness and injury.  Occupational hearing loss has been included among the top research priority areas. NORA recognizes that a diminished ability to communicate with co-workers or monitor sounds in the work environment can reduce productivity and place workers at increased risk for accidents. NIOSH has continued to place emphasis on answering unresolved questions regarding the effects of noise and determining best practice prevention programs. For more information on NIOSH’s noise and hearing loss research, see the topic webpage: http://www.cdc.gov/niosh/topics/noise/.

Options for Reducing Risk 

There are two basic tasks an employer can undertake to reduce the potential risk of accidents associated with noisy environments: 1. address jobs and work areas where background noise may interfere with warning signals, vehicle detection/alarms, or speech communication and 2. identify and assist workers who have significant hearing loss. If communication is required, and miscommunication could cause an accident, the situation should be evaluated and addressed. 

If companies are concerned that noise may be interfering with communication and warning sounds, then a detailed noise evaluation should be conducted. Engineering controls may be needed to reduce noise at its source. When noise control is not possible, consider visual cues, pre-coded messages, redesign of warning systems, and employing specialty communication devices that block out background noise without compromising communications. Usually these systems consist of a standard hearing protection device (earplug or earmuff) that attenuates or blocks the noise, in combination with a small speaker embedded in the earplug or earmuff to deliver the communication signal directly to the ear. Keep in mind that binaural (both ear) listening systems typically provide a significant advantage over monaural (one ear listening). Options for limiting output of electronic systems are also important for safe listening. 

Next, workers with significant hearing loss can be identified through audiometric evaluation and consultation with your hearing conservation program audiologist. As needed, develop job-specific protocols for hearing-critical jobs, and create individualized plans for hearing-impaired workers. Emergency preparedness, alerting device options, training accommodations, and specialty hearing protection are all important considerations. 

Contact CavCom to discuss options for improving your company's productivity, safety, and communication capabilities.

References

Girard, S A, Leroux, T, et al. 2014. Occupational noise exposure and noise-induced hearing loss are associated with work-related injuries leading to admission to hospital.  Injury Prevention, injuryprev-2013-040828; 17 March 2014 [epub ahead of print].

Girard, S A, Picard, M et al. 2009. Multiple work-related accidents: tracing the role of hearing status and noise exposure. Occup Environ Med, 66: 319-324. 

Morata, T C, et al. 2005. Working in Noise with a Hearing Loss: Perceptions from Workers, Supervisors, and Hearing Conservation Program Managers. Ear & Hearing, 26(6): 529-545. http://www.cdc.gov/niosh/mining/UserFiles/works/pdfs/winwa.pdf.

Picard, M, Girard, S A, Simard, M. 2008. Association of Work-Related Accidents with Noise Exposure in the Workplace and Noise-Induced Hearing Loss Based on the Experience of some 240,000 Person-Years of Observation. Accid. Anal. Preven, 40: 1644–1652. 

Picard, M, Girard, et al. 2008. Could Driving Safety be Compromised by Noise Exposure at Work and Noise-Induced Hearing Loss? Traffic Injury Prevention, 9: 489-499. 

A new scientific report provides evidence for something companies have known for years. Hearing protection ratings, and de-ratings, are not helpful with the day-to-day success of a hearing conservation program. It's long been understood that the laboratory-based Noise Reduction Rating (NRR) does not accurately predict real-world performance of a hearing protector. But unfortunately, it's now clear that the numerous de-rating schemes developed over the years to compensate for NRR shortcomings aren't accurate either.

A new comprehensive analysis was recently published in the Journal of the Acoustical Society of America (JASA). Researchers from the National Institute for Occupational Safety and Health, the Department of Defense and others examined four real-world hearing protection attenuation studies. Results of Individual Fit Testing for workers were compared to product NRRs and various NRR de-rating schemes. The good news: individualized earplug fitting and training was shown to dramatically improve "real-world" protection for many workers. The not-so-good news was that NRR de-rating schemes failed to accurately predict real-world protection for the majority of workers tested. In many cases, real-world results far exceeded hearing protector performance predicted by NRR de-rating schemes. Because hearing protector fit testing systems are now readily available for use in the workplace, the authors concluded it is a better approach than relying on de-rating formulas.

NRR Ratings and De-Rating Schemes

Hearing protection devices provide a wide range of protection against noise depending on the design of the protector and the fit in the individual user's ear. When OSHA promulgated the Hearing Conservation Amendment for general industry in the early 1980s, it incorporated the Environmental Protection Agency's Noise Reduction Rating (NRR) as a way to help employers evaluate and compare expected performance of available hearing protectors. The NRR is a laboratory-derived estimate of the attenuation (sound reduction) expected from a hearing protector when it is fitted and worn as designed. Shortly after the Hearing Conservation Amendment went into effect, however, it became evident that the actual amount of attenuation achieved in the workplace often fell short of the laboratory-predicted NRR.

Since that time, regulatory and scientific groups have proposed a variety of schemes for adjusting hearing protector ratings in an attempt to better adapt NRR ratings to real-world performance. Some recommendations included cutting the NRR in half; others suggested a percent reduction according to the class of hearing protector. It's a commonly held misconception that OSHA, MSHA and other compliance authorities require that employers de-rate NRRs. Instead, companies should use the NRR calculation to help determine which types of hearing protectors will likely offer adequate reduction for workplace noise exposures. However, to find out what is happening in the real world for each worker, it is far more useful to conduct an Individual Fit Test to ensure that the chosen hearing protector is actually performing as intended. Read more about the NRR and other ratings here.

Real-World Measures

Individual Fit Test systems are designed to measure the noise reduction provided for an individual worker using their own hearing protector as it is routinely fit and worn. Although assessment equipment and procedures are not completely standardized, most fit test systems generate a Personal Attenuation Rating (PAR). Given the inability of laboratory ratings and de-rating schemes to accurately predict real world attenuation, PARs provide employers with beneficial information about fit and protection for each employee.

CavCom‘s experience mirrors the recent analysis published in JASA. Through Individual Fit Testing, we find our hearing protectors and earsets yield significantly higher actual protection via PARs than would be predicted by an NRR-based calculation, de-rated or not. In particular, custom-fitted hearing protectors are less susceptible to poor insertion, and generally provide more consistent and higher attenuation in the real world. Read more about Individual Fit Testing here.

The Bottom Line about NRR De-Rating Schemes

Stated simply, NRRs and de-rated NRRs do not accurately predict real-world performance of hearing protectors. For this reason, decisions regarding worker noise exposures and hearing protection are more accurate when based on real-world PAR values. Better information also helps companies tailor hearing protection to the work environment and avoid such pitfalls as overprotection. Overprotection is a situation where the worker receives more attenuation than necessary, leading to potential communication complications and safety concerns. Read more about overprotection here.

Lastly, it's important to remember that subjective considerations such as comfort and convenience are also key factors in hearing protector acceptance and wear time. It's often said, and is worth repeating, that the "best" hearing protector is the one that is worn correctly and consistently whenever the worker is exposed to hazardous noise. Read more about comfort here.

Contact Us

Not sure which hearing protectors are optimal for your workforce? Contact CavCom to discuss options and to learn more about how our innovative hearing protectors and communication earsets can improve safety and communication in your workplace.

Resources:

• Murphy, Gong, Karch, Federman and Schulz (2022). Personal attenuation ratings versus derated noise reduction ratings for hearing protection devices, The Journal of the Acoustical Society of America, 152 (2), 1074-1089. https://doi.org/10.1121/10.0013418.
• The Noise Reduction Rating (NRR), CavCom SoundBytes.
• Individual Fit Testing and Personal Attenuation Rating (PAR), CavCom SoundBytes.
• The Risk of Overprotection, CavCom SoundBytes.
• Improving In-Ear Comfort, CavCom SoundBytes.

You provide hearing protection and training for your noise-exposed workers. But how do you know your efforts are truly effective? How can you be confident your workers are consistently and correctly wearing their hearing protectors, and getting the protection they really need?

To be truly successful, a hearing loss prevention program must emphasize employee education, buy-in, and self-motivation. That's why pro-active companies now include Individual Fit Testing as an integral part of any hearing conservation program. Individual Fit Testing is recognized by OSHA, NIOSH and prominent professional organizations as a best practice.

NRR vs. PAR

When OSHA promulgated its Hearing Conservation Amendment for general industry in the early 1980s, the new regulation incorporated the Environmental Protection Agency's noise reduction rating (NRR) for estimating hearing protector performance. The NRR is a laboratory-derived estimate of the attenuation (sound reduction) that can be expected from a hearing protector. Shortly after the Hearing Conservation Amendment went into effect, however, it became evident that the actual amount of attenuation achieved in the workplace often fell short of the laboratory predicted NRR.

In 2008, an alliance between OSHA, NIOSH and the National Hearing Conservation Association recognized a new technology designed to obtain individualized hearing protection attenuation ratings for each worker. This group of experts acknowledged the limitations of relying on laboratory conditions and group statistics to predict an individual user's hearing protector performance in the field: "The consequence of this approach is that an individual user may actually receive more but usually less attenuation than is stated on the hearing protector label."  Based on their review of research and emerging trends and technologies, the Alliance identified Individual Fit Testing as a recommended best practice for hearing conservation programs.

Individual fit testing of hearing protectors is similar in concept to fit testing for respirators. Preferred methods produce a single-number overall estimate of real-world attenuation for each worker; this measure is generally represented as a Personal Attenuation Rating or PAR. In our experience, hearing protection products that are custom fitted to individual workers are less susceptible to poor insertion, and generally perform better in the real world.

Example real-world data:

Data Sources

CavCom Customs: CavCom internal individual fit testing for over 700 industrial workers. Average PAR under everyday field conditions (tested with earplug fit as normally worn).
Flanged and Foam: Field testing of 390 steelworkers. Michael and Byrne (2002) "Current State of Insert-Type Hearing Protector Fit Testing." NHCA Spectrum, Vol. 19(1).

Basics of Popular Individual Fit Test Equipment and Protocols

At CavCom, we often receive inquiries from customers about Individual Fit Test technology and available products. Unfortunately, at the current time, there is little standardization in equipment and protocols. We have reviewed numerous commercially available systems, and have determined that "real ear at threshold" (REAT) methodology typically provides the best opportunity for personal interaction and effective fitting and education of individual employees. You may choose to purchase your own equipment for in-house programs or ask CavCom‘s CAOHC-certified and experienced technical staff to do the testing, fitting and training for you.

REAT (real ear at threshold)

 This type of Fit Test is a familiar protocol, very similar to a routine hearing test. The individual employee listens for tones presented via earcups or speakers. The amount of protection, PAR, is calculated by comparing threshold results for open/unoccluded ears (no earplugs) to results when the individual's own earplugs are in place. Therefore, if the employee's hearing protector is the wrong size, worn out/damaged, or fitted incorrectly, REAT can reveal the problem. The test procedure is generally quick and easy to understand, although listeners with significant hearing loss may have difficulty or be unable to complete the test. Any manufacturer's insert hearing protector can be tested with this method.

MIRE (microphone in real ear)

 In this type of test, a probe microphone is inserted into an earpiece or earplug placed in the user's earcanal, while test signals are presented via earcups or speaker. A calculated "pass/fail" or PAR is based on probe microphone measurements. This procedure requires use of a manufacturer-specific surrogate earplug with built-in microphone, or removal of core components of the worker's earplug to be replaced by the manufacturer's probe microphone apparatus. MIRE technology can only be used with the manufacturer's own earplugs and cannot provide a true "audit" of the worker's hearing protector as worn. The acoustic measure portion of the test does not require employee participation, but substantial attention to set-up/calibration of the microphone and speakers is imperative.

Why CavCom conducts Individual Fit Testing using REAT technology

• Universal: allows you to test any manufacturer's insert hearing protector
• Ability to audit real-world performance and fit: tests each employee's own earplug without modification, the actual earplug the way it is typically fit and worn each day
• Easy set-up: REAT is a "relative measure" that compares occluded vs. unoccluded results for each worker; does not rely on precise placement/calibration of speakers and microphone
• Gold standard: REAT is as familiar as an annual hearing test and follows the same basic ANSI test protocol used for NRR (laboratory) testing

Lastly, no matter what type of Individual Fit Test protocol you choose, remember that test results alone do nothing to bolster compliance. A trained and qualified health and safety professional must take time to review PAR results for accuracy, retest if needed, and refit, retrain, coach, or fit alternate hearing protectors. The goal is to achieve adequate noise reduction and instill a sense of self-reliance for each individual user. That's what hearing conservation is all about.

Assistance is a click away

To help you with hearing protector attenuation estimates for your workforce, we have created a quick and easy calculator for comparing NRR and PAR values for both single and dual hearing protector configurations. Contact CavCom to request our free hearing protection attenuation calculator  and to learn more about our   Individual Fit Testing services.

The U.S. Equal Employment Opportunity Commission (EEOC) recently issued an updated technical assistance document regarding workers with hearing loss: Hearing Disabilities in the Workplace and the Americans with Disabilities Act, EEOC-NVTA-2014-1, 1-24-23. The document explains considerations for both job applicants and current employees under the Americans with Disabilities Act of 1990. It also addresses common employer concerns about safety, assistive technologies, and reasonable accommodations. For more information about hearing-impaired workers and hearing conservation programs, see CavCom‘s article: Special Considerations for Workers with Hearing Loss.

A new National Occupational Research Agenda (NORA) for Hearing Loss Prevention was published July 2019 and is now available from the CDC. NORA is a partnership program intended to stimulate innovative research and workplace interventions to reduce injuries and illnesses. NORA serves as a research framework for the National Institute for Occupational Safety and Health (NIOSH). The 2019 Hearing Loss Prevention Agenda was developed collaboratively among working groups and with a public comment period. 

There are five main research objectives:

1. Provide scientific basis for hearing loss prevention efforts such as promoting individual fit testing, assessing mixed exposures to noise and ototoxic chemicals, updating age correction data for hearing test evaluations, and developing better technologies

2. Develop effective, evidence-based education designed to improve hearing conservation program outcomes for exposed workers

3. Develop, commercialize, and widely implement noise control solutions on jobsites in key industries

4. Develop improved audiological tests such as early detection indicators and speech intelligibility

5. Improve occupational hearing loss surveillance by better tracking of hearing loss, tinnitus and related health outcomes

NORA documents are intended to identify research, information, and actions most urgently needed to prevent occupational injuries and illnesses. Each NORA agenda serves as a guide for promoting high priority research at the government level and in the private sector. To learn more and to download the 2019 NORA for Hearing Loss Prevention, visit the CDC webpage.  

The ability to detect, identify, and localize sounds during military operations is essential. Unfortunately, hazardous noise is a constant threat to military personnel during training exercises, active duty, and even off-the-job activities. Noise-related hearing loss and tinnitus (ringing in the ears) are the two most frequently reported disabilities of military service, affecting millions of veterans - including over 750,000 Gulf War era veterans alone.

To help address this threat to hearing and quality of life, the US military is focusing on early identification, immediate intervention, and an ongoing support system for veterans. Military researchers and clinicians recently collaborated to create a Clinical Practice Guideline (CPG) published last month by the Association of Military Surgeons. This CPG provides guidance for audiologists, otologists and emergency response personnel for the evaluation and treatment of service members exposed to blast injury and acoustic trauma. After life-threatening injuries have been addressed, damage to outer ear/eardrum and inner ear hearing and balance must be assessed, treated and monitored. The CPG is intended to increase awareness among hearing healthcare providers and to improve early identification and treatment of acoustic trauma.

To assist veterans and their families and researchers/providers on an ongoing basis, the Department of Defense has also created the Hearing Center of Excellence (HCE). The HCE is a multi-branch effort with the Veteran's Administration (VA) to promote prevention, diagnosis, treatment, rehabilitation and research of hearing loss and auditory injury. The HCE's primary responsibilities include:

• Develop a data registry to track hearing loss and auditory injuries across the Armed Forces, and share the registry data with the VA
• Encourage and facilitate hearing health research
• Develop best practices and clinical education, and
• Ensure the coordination and delivery of VA rehabilitation benefits and services to former Service members

The HCE educational website provides help and support for active military personnel, veterans, and their families. Visitors to the HCE website can find a provider and learn about VA healthcare and disability benefits. The Resources section provides training resources, real patient video stories, frequently asked questions, and links to helpful websites. Sign up for a newsletter and check out news articles, podcasts, and apps about hearing-related topics.

Hearing Center for Excellence website  

Additional resources:

• Esquivel, et al. (2018) Clinical Practice Guide: Aural Blast Injury/Acoustic Trauma and Hearing Loss. Military Medicine, Vol. 183, 9/10: 78-82.
• Wells, et al. (2015). Hearing loss associated with US military combat deployment, Noise Health. 2015 Jan-Feb; 17(74): 34–42. 
• Institute of Medicine (2006). Noise and Military Service: Implications for Hearing Loss and Tinnitus. Washington, DC: The National Academies Press. 

Need a quick sound check on the go? Turn your iOS device into a sound level meter by downloading a free app developed by researchers at the National Institute for Occupational Safety and Health (NIOSH). While the app is not meant to replace a professional sound level meter or noise dosimeter for compliance purposes, it does allows you to estimate A-weighted and C-weighted sound levels, maximum and peak levels and Time-Weighted Average (TWA) and Dose.

To download the app, go to the iTunes store and search "NIOSH SLM" 

For more information:

• NIOSH Sound Level Meter app webpage
• CavCom SoundBytes. Smartphone Apps for Noise Measurement. 

photo source: NIOSH, cdc.gov

In previous issues of our SoundBytes newsletter, we have reported on tests of accuracy of smart phone "apps" designed to measure noise. Preliminary research by the National Institute of Occupational Safety & Health (NIOSH) indicated a select few commercially available apps could measure noise with reasonable accuracy. New studies have determined under what circumstances these smart phones and apps may be most useful.

Previous studies compared sound level readings recorded using smart phones to sound level values taken simultaneously with a standard precision sound level meter. Although some combinations of phones and apps appeared promising, problems related to calibration of the cell phone's internal microphone presented practical challenges to accuracy. More recently, researchers from the University of Michigan and NIOSH compared measurements taken via iOS phones using the internal microphone and two external microphone options. Their results indicated that certain combinations of phones and apps can provide noise measurements as accurately as a Type 2 sound level meter. However, use of a quality external microphone and a method of calibration are also required. For practical purposes, the researchers concluded that it is unlikely smartphones would be useful for regulatory compliance measurements in the near future. They do have value in documenting "crowd sourced" information about environmental noise and have potential for future development.

For more information:

Kardous, C. & Shaw, P. B. (2013). So How Good are These Smartphone Sound Apps? CAOHC Update, Vol. 25, Issue 3.

Benjamin Roberts, Chucri Kardous & Richard Neitzel (2016). Improving the Accuracy of Smart Devices to Measure Noise Exposure, Journal of Occupational and Environmental Hygiene.

Kardous, C. & Shaw, P. B. (2014). Evaluation of smartphone sound measurement applications. Journal of the Acoustical Society of America. 135, EL186–EL192 and NIOSH Science Blog, April 2014.

Nast, D., Speer, W. & LePrell, C. (2014.) Sound level measurements using smartphone "apps‟: Useful or inaccurate? Noise & Health, 16, 251–256.

(photo: cdc.gov)

Traditionally hearing conservationists have been concerned about the effects of noise on sensory cells within the inner ear. These sensory cells are called hair cells in reference to tiny cilia structures that resemble hairs when seen under a microscope. New research, however, indicates that excessive noise may damage neural structures of the inner ear as well.

Recent scientific studies with animals reveal that noise and the aging process progressively interrupt connections between the sensory hair cells and neurons within the inner ear, eventually leading to death of the neurons themselves. With age, the connections tend to be lost gradually over a lifetime. With loud noise, the nerve damage can be immediate, observed even in cases of temporary hearing loss when there is no obvious damage to the sensory hair cells. Researchers speculate that loss of neurons in the inner ear may contribute to common auditory perception problems, such as difficulty understanding speech in noisy background situations. Studies continue, with the ultimate goal of developing better measures for early detection and prevention of hearing loss.

References and further reading:

Kujawa S (2014). Putting the 'Neural' Back in Sensorineural Hearing Loss, Hearing Journal: 67(11) 8.

National Institute on Deafness and Other Communication Disorders Topic Pages:

Age-related hearing loss 
Noise-induced hearing loss 

Noise-induced hearing loss is one of the most prevalent conditions today, associated with excessive noise exposures both on and off the job. To tackle noise problems at the source, government agencies and professional associations have developed initiatives and resources to promote quieter and safer environments at workplaces and local communities.

"Buy Quiet" initiatives encourage companies and individuals to purchase or rent quieter equipment to reduce noise exposure. These initiatives also call upon manufacturers to design quieter equipment by publishing noise data and creating a demand for quieter products. "Quiet by Design" programs are focused on engineering or re-engineering processes and systems to produce less noise. Potential benefits of these programs include reducing the risk of hearing loss, lowering long term costs associated with workplace injuries and hearing loss, and reducing the impact of noise and hearing loss in the community. To learn more:

• NIOSH - Buy Quiet: NIOSH recently announced the official launch of its new Buy Quiet website. The new materials highlight the benefits of a Buy Quiet program, explain how to establish a program in your workplace, and provide resources for locating quieter tools and machinery.
• NASA - BuyQuietRoadmap: NASA's initiative supports the procurement of low-noise products in the context of an ongoing hearing conservation program. Resources were developed by a NASA team and are available for use by hearing conservationists, acoustical engineers, and educators. 
• National Academy of Engineering - Technology for a Quieter America: This 2010 report was compiled by an expert panel gathered by NAE. The report reviews the most commonly identified sources of noise, standards and regulations that govern noise, cost-benefit trade-offs between efforts to mitigate noise and the improvements they achieve, and information sources available to the public. 

Intrinsic safety certification is a highly involved process that measures the energy risk in a specific device according to each component. CavCom‘s intrinsically safe products are built from the ground up and IS certified. We offer the protection workers need in inherently hazardous work locations. 

Manufacturers of products that are certified intrinsically safe must follow strict requirements for recordkeeping and documentation. Companies are inspected by the certifying body on a quarterly basis to ensure continued quality control and compliance. Manufacturers must also provide customers instructions for use of the product in hazardous locations. Lastly, products must be clearly marked with applicable intrinsic safety (IS) ratings. Following is an example of a permanent product label affixed to CavCom‘s intrinsically safe RadioGear® earsets. See key below to better understand IS classifications for North America. Please contact us if you have questions regarding IS certifications or if we can be of assistance.

*Product Intrinsic Safety Ratings

 Area Classifications

• Class I: Explosive Gas Atmospheres (flammable gases, flammable and combustible liquid-produced vapors)
• Class II: Explosive Dust Atmospheres (combustible dust)
• Class III: Ignitable Fibers/Flyings (easily ignitable fibers or materials producing combustible flyings)

Exposure Division

• Division 1: Where ignitable concentrations of flammable gases, vapors/liquids, combustible dust, or combustible fibers/flyings can exist all of the time or some of the time under normal operating conditions
• Division 2: Where ignitable concentrations of flammable gases, vapors/liquids or combustible dust are not likely to exist under normal operating conditions; where easily ignitable fibers are stored or handled but not manufactured/used

Hazard Group

• Group A: Acetylene
• Group B: Hydrogen
• Group C: Ethylene
• Group D: Propane
• Group E: Metal dust (Div 1 only)
• Group F: coal (carbonaceous) dust
• Group G: non-conductive dust such as flour, grain, wood, plastic, etc.

Temperature Class/Range

• Over a dozen temperature classifications; see "Temperature Range" for details on individual product specifications 

Through its Total Worker Health® (TWH) Program, the National Institute for Occupational Safety and Health (NIOSH) recommends an integrated approach to addressing the safety and health of workers. While protecting hearing on the job is essential, NIOSH recommends addressing noise risks outside of work as well.

Because exposure to hazardous noise is common in daily life, not just in the workplace, it is important to raise awareness and encourage healthy hearing habits outside of work. The TWH Program advocates for a comprehensive approach to improve overall health and well-being both on and off the job. NIOSH's new Hearing Health Solutions document focuses on promoting better hearing health and reducing the risks associated with noise exposure at work and at play. Recommendations are included for workers, employers, and hearing healthcare providers.

To learn more:

• Themann CL, Morata T, and Afanuh S (2019). Using Total Worker Health® Concepts to Address Hearing Health, NIOSH Publication 2019-155 
• Non-Occupational Noise: Quantifying Noise Exposures, SoundBytes 
• Guidance for Recreational Firearm Noise, SoundBytes 
• Helping Musicians Protect Their Hearing, SoundBytes 

Despite long-standing regulations requiring hearing conservation programs for noisy workplaces, there are no universally-accepted methods for evaluating program effectiveness. The National Institute for Occupational Safety and Health (NIOSH) recently funded a study of hearing loss prevention programs and announced tools for companies to evaluate their own programs.

In 2017, researchers from NIOSH, the University of Michigan, the University of Washington and Yale University studied hearing conservation programs at 14 facilities across the U.S. operated by a single manufacturing company. The research team conducted focus groups, interviews, anonymous surveys, noise dosimetry, walk-throughs, and an analysis of hearing test and noise data for each workplace.

The research group found that most facilities had a strong management commitment to hearing loss prevention as well as personal commitment among individual workers. However, few sites showed the same commitment to protecting hearing off the job. Based on the results of their research, the team created two self-evaluation tools, a checklist and a calculator that allows companies to estimate the cost of their hearing loss prevention efforts. In this study, the average annual cost was $295 per employee.

Both tools are available at the NIOSH hearing loss prevention website and a special webpage at the University of Washington. 

Do you suffer from ringing in the ears? You're not alone! The National Institute on Deafness and Other Communication Disorders (NIDCD) estimates that over 20 million Americans experience chronic ringing in the ears, known as tinnitus (pronounced "TIN-a-tus" or "Tin-EYE-tus"). Tinnitus is an annoying and sometimes debilitating condition, commonly defined as the perception of noise in one or both ears when no sound is actually present. Tinnitus is usually described as a high-pitched ringing, but it might also be perceived as roaring, clicking, hissing or buzzing. The condition can be mild, intermittent, or so severe that it interferes with your sleep, concentration, and enjoyment of daily life.

A recent analysis of data collected as part of the National Health Interview Survey indicated that noise-exposed workers in the United States are 3 times more likely to report suffering from tinnitus than their non-noise-exposed counterparts. According to the U.S. Department of Veteran Affairs, tinnitus and hearing loss are the top two service-connected disabilities for U.S. service members. Veterans of Iraq and Afghanistan have been exposed to a number of hazards known to cause hearing loss and tinnitus, including loud noise, blasts/explosions, and ototoxic chemicals. Service members who have suffered a traumatic brain injury are 3 times more likely to experience tinnitus than other veterans. Those exposed to solvents, a class of ototoxic chemicals, are twice as likely to report ringing in the ears.

Tinnitus itself is not a disease. Instead, it can be a sign that something is wrong with the outer, middle or inner ear, the auditory nerve, or parts of the brain that process sound. Noise exposure, acoustic trauma, exposure to chemicals, and ear diseases/infections are some of the most common causes of tinnitus. Complicating its diagnosis and treatment, tinnitus has many other causes as well, including disorders of the heart/circulatory system, stress, hormone changes, and as a side effect of medications, smoking, or too much salt or caffeine. Sometimes the cause of tinnitus is unknown.

So what can a person experiencing tinnitus do about this annoying and on occasion even incapacitating condition? Follow our Top Tips and check out Resources listed below. And of course, when it comes to hearing protection, we've got you covered. Contact CavCom to learn more about our many solutions for controlling noise on and off the job.

The World Trade Center Health Program (WTCHP) was established in 2010 as a federal program to provide medical monitoring and no-cost treatment to eligible 9/11 responders and survivors. To date, over 110,000 individuals have enrolled in the program including 80,000 first responders and 30,000 survivors of the attacks. The WTCHP reports that 58% of individuals monitored have at least one certified WTC-related health condition. Top reported issues include: chronic rhinosinusitis, gastroesophageal reflux disease (GERD), cancers, asthma, sleep apnea, and post-traumatic stress disorder (PTSD).

Researchers have also tracked hearing loss and ear-related conditions among those exposed to WTC health hazards as part of rescue and recovery efforts. Among WTC-exposed firefighters and emergency medical service workers, the risk of hearing loss is higher than in the general public. Those first responders who spent more than 6 months at the WTC site have the highest risk of hearing loss among those studied. Similar comparisons of WTC registry residents and passersby show increased risk of hearing loss, particularly for those with persistent sinus problems, headaches, PTSD, and other chronic disease histories.

• 9.11 World Trade Center Health Program website
• Azofeifa A, Martin GR, Santiago-Colón A, et al. (2021). World Trade Center Health Program — United States, 2012−2020. MMWR Surveill Summ 70 (No. SS-4):1–21. DOI: http://dx.doi.org/10.15585/mmwr.ss7004a1.
• Cone J, Stein C, Lee D, Flamme G and Brite J (2019). Persistent Hearing Loss Among World Trade Center Health Registry Residents, Passersby and Area Workers, 2006-2007. Intl J Environ Res Public Health 16, 3864. DOI: 10.3390/ijerph16203864.
• Flamme G, Goldfarb D, Zeig-Owens R, et al. (2019). Hearing Loss Among World Trade Center Firefighters and Emergency Medical Service Workers. J Occup Environ Med 61(12)996-1003. DOI: 10.1097/JOM.0000000000001717

Reports of hearing loss and tinnitus (ringing in the ears) have been associated with COVID-19 for some patients. A scientific review published recently in the International Journal of Audiology summarizes these trends.

Researchers from the University of Manchester conducted a systematic review of available scientific literature regarding COVID-19 and associated hearing loss and tinnitus published through December 2020. Based on stringent criteria for meta-analysis and bias risk, the authors rejected 850 records while 28 case reports and 28 cross-sectional studies met their inclusion criteria. Their analysis of the data revealed that 7-15% of adults diagnosed with COVID-19 reported auditory (ear/hearing) and/or vestibular (balance) symptoms. The most common symptoms

• Tinnitus (ringing in the ears) – studies show ringing in the ears lasting weeks or months after the infection had cleared.
• Hearing difficulties
• Vestibular issues such as dizziness or vertigo.

To access the full report:

• Almufarrij, I and Munro, KJ (2021). One year on: an updated systematic review of SARS-CoV-2, COVID-19 and audio-vestibular symptoms, International Journal of Audiology, DOI: 10.1080/14992027.2021.1.

To review an example case study:

• Koumpa FS, Forde CT, Manjaly JG (2020). Case Report: Sudden irreversible hearing loss post COVID-19; British Medical Journal 13:e238419. doi:10.1136

For more information on managing hearing loss and tinnitus:

• American Speech-Language Hearing Association: Tips for Communicating Effectively while Wearing Masks and Physical Distancing
• American Tinnitus Association: Tinnitus and the Corona Virus
• National Institute on Deafness and Other Communication Disorders: Health Information

Let's start by saying that earwax is a good thing. That's right... earwax, or cerumen, is normal and even healthy for your ears. In average amounts, cerumen acts as a protective barrier to keep out infection, dust/dirt, and even foreign objects. A lack of earwax can lead to dry and itchy ears that are more vulnerable to infections such as "swimmer's ear." But as is often the case, too much of a good thing can be, well, not good.

For most of us, our outer ears are self-cleaning. Both old skin and earwax typically migrate slowly out the ear canal opening and are discarded. Sometimes, however, earwax can get trapped, and even impacted. Although not well understood, certain people tend to produce more earwax than others. It's also a normal part of the aging process for earwax to become drier and harder, increasing the likelihood of impaction.

An overabundance of earwax can lead to discomfort, tinnitus (ringing in the ears), a feeling of fullness in the ears, and even hearing loss. Although there is no evidence that wearing hearing protection increases the occurrence of wax impactions, excessive earwax or other outer ear problems can certainly interfere with the comfortable use of earplugs. When necessary, a worker in high noise may need to wear earmuffs instead of earplugs until medical clearance is received.

Tips for maintaining healthy ear canals:

• Remember your ear canals are generally self-cleaning. As needed, use a damp washcloth only in the outer part of the ear.
• Do not attempt to clean your ears with cotton swabs or other objects such as pencils and keys; this will only push earwax further down into the ear and may result in impacted wax and scratches to the ear canal, leaving you vulnerable to infections.
• See your doctor if you routinely have earwax build-up or experience pain, tinnitus, hearing loss, or a feeling of fullness in your ears.
• With your physician's guidance, if needed, consider routine home treatments such as mineral oil, glycerin, or commercially available earwax softening kits. Do not attempt "ear candling," which is generally considered ineffective and could result in injury.
• Routinely wipe down hearing protectors or electronic earsets after use and clear sound tubes of any excess earwax.

To learn more about cerumen and ear care, check out these helpful resources:

Medline Plus, National Institutes of Health. Earwax.

American Academy of Otolaryngology. Earwax blockage and care.

CavCom SoundBytes. Aging and the Ear Canal.

CavCom SoundBytes. Swimmer's Ear.

U.S. Food and Drug Administration. Don't Get Burned: Stay Away from Ear Candling.

CONTACT CAVCOM to request an Earset Care Kit and educational materials about caring for your hearing protectors and electronics.

How many times have you seen employees break the seal of an earplug or earmuff because they can't communicate in the workplace? Individuals who are hard of hearing are often the worst offenders. Not only are these workers at risk of exposing themselves to hazardous noise, but communication typically isn't even improved. So what can we do to help?

According to the National Institutes of Health, approximately 17 percent of American adults report some degree of hearing loss. That's roughly 36 million people. Over 20 million Americans experience tinnitus, or annoying ringing in the ears. In noisy workplaces, individuals with hearing impairment face special challenges such as communicating with co-workers, detecting warning signals during emergencies, and working safely around motorized vehicles and heavy machinery. For people with severe hearing loss or hearing that is significantly worse in one ear, a common difficulty is localization. That is, the person may hear a sound, but not know which direction it's coming from...a real problem in situations where auditory alerts such as forklift back-up alarms are crucial to safety.

Another concern in noisy environments is that conventional hearing protectors may degrade speech audibility for hearing-impaired workers. Namely, conventional earplugs and earmuffs provide more sound reduction for high pitch sounds than lower pitches. In speech, vowel sounds (a, e, i, o, u) are fairly low in pitch, while consonants (such as k, s, t, f, sh, etc.) are higher pitched. For a worker with high frequency hearing loss (very common), wearing hearing protectors can exacerbate the high frequency deficit, and in turn, speech intelligibility is reduced. A common complaint for people with hearing loss is "I can hear you talking, I just can't understand what you're saying." Experiencing a hearing loss can be like reading a newspaper with holes in it. For those with high frequency hearing loss, missing out on the consonants of speech can leave the listener struggling to interpret vowel sounds that come across as mere mumbling or gibberish. Often listeners misinterpret consonant sounds; usually the brain tries to "fill in the blanks," sometimes arriving at inaccurate interpretations. Resulting miscommunications day to day can range from harmless to heartbreaking. In an industrial or first responder situation, miscommunications can affect job performance and efficiency, and can be dangerous, even deadly. The following is an example of how hearing loss (or loud background noise) can seriously affect speech communications on the job.

For these reasons, it is important for companies to consider ways to address the special needs of their hearing-impaired workers. Options to consider:

Develop visual cues: Where obstructed vision is not a problem, consider developing a system of hand signals or written text to clearly convey messages without relying on auditory communication. For emergency alerts, investigate alarm systems with flashing lights or vibrating pagers.

Create pre-coded messages: In advance, develop a predetermined set of short, predictable code words and key phrases for your most typical operations. Expected messages are typically easier to recognize than novel communications.

Improve the listening environment: There are two basic ways to improve an individual's ability to hear in noise: 1. increase the level of the speech or warning signal and 2. decrease the level of the background noise. Engineering controls in the workplace may help decrease noise at its source. The other part of the equation can be more difficult. For face-to-face communication, there is a physiologic limit to how loud and how long a speaker can shout to be heard. Cranking the volume of a PA system above loud background noise may help detection, but potentially adds to noise exposures for all workers in the area.

Utilize specialized hearing protectors: Another solution is to provide employees with specialized hearing protectors that block out background noise without compromising the speech or warning signal. Although these protectors are not hearing aids, by their design they often improve communication capabilities for all, including those with hearing loss. Options include:

Communication headsets/earsets: These systems consist of a standard hearing protector (earplug or earmuff) that attenuates or blocks the noise, in combination with a small speaker imbedded in the earplug or muff to deliver the communication signal directly to the ear. Systems may be designed for one-way or two-way communication. There are a variety of products in the marketplace with pros and cons to consider, including comfort and compatibility with other personal protective equipment. When it comes to communication effectiveness, there are two important features to look for:

1. Binaural (both ear) listening provides a significant advantage over monaural (one ear listening). Our auditory system is clearly designed to work with input from both ears. The brain processes and compares signals from each ear for localization, understanding speech, and separating speech from background noise. Most research studies agree that the more complex the signal, the more complex and loud the competing background noise, and when fewer visual cues are available, the binaural advantage is most robust. As a result, signals such as radio transmissions don't have to be as loud if a listener is using both ears. The practical result of this phenomenon is that volume settings typically don't need to be as high if using a binaural headset compared to one with a monaural listening configuration.

2. Output limiting promotes safer listening levels. Whether a worker has normal hearing or hearing loss, it is important that signals delivered to the ear do not add to a noise hazard on the job. When purchasing a communication headset for any employee, make sure the device has an electronic feature to limit outputs to safe levels. Again, a binaural listening feature allows most users to choose a lower, safer, listening level than would be possible with a monaural system.

Flat or uniform-attenuating hearing protectors: Special filters imbedded in these earplugs or earmuffs are designed to block out high and low frequency sounds nearly equally. Workers with high frequency hearing loss may find these filters helpful.

Level-dependent or non-linear devices: These hearing protectors block louder sounds such as gunfire, but still let in lower level sounds either through special filters or electronic circuitry. Electronics may even amplify quiet sounds, so it is important to choose only devices that limit amplification to safe levels. This type of device is especially helpful in intermittent noise environments where extended periods of quiet are common.

Hearing Aids: Some hearing-impaired workers own hearing aids and ask if they can wear them in noisy workplaces. It is important to remember that hearing aids amplify all sounds, speech as well as unwanted background noise. As a result, hearing aids typically should not be worn in loud noise environments. Even if turned off, hearing aids are not designed to be hearing protectors. OSHA has issued a letter of interpretation stating employees with hearing loss "cannot satisfy the requirement to wear hearing protection simply by turning off their hearing aids when working in a high noise area." (OSHA, 8/3/04). There is one more option to consider. In rare cases, it may be possible for a worker to wear hearing aids (volume set at a safe level) underneath earmuffs. One study showed improvements in speech intelligibility for this configuration, but warned that an audiologist would need to make the determination on a case-by-case basis and that employees should be monitored closely (Verbsky, 2004 - CAOHC Update).  A potential drawback with this option is the possibility of acoustic feedback (squealing) when a hearing aid is covered, making this option impractical in some cases.

Hearing conservation: Some companies mistakenly believe that it's too late to intervene if a worker's hearing abilities are "too far gone." But even individuals considered severely hearing impaired or "deaf" typically have some residual hearing. It's important to protect any remaining hearing the worker may have. For best practice suggestions, see OSHA's Safety and Health Information Bulletin 12-27-2005: Hearing Conservation for the Hearing-Impaired Worker

Individual review & accommodations: Because job requirements vary and workers' hearing abilities differ, consider developing job-specific protocols for hearing-critical jobs and individualized plans for your hearing-impaired workers. Emergency preparedness, alerting device options, and training accommodations are all important considerations. For best practice suggestions, see OSHA's Safety and Health Information Bulletin 07-22-2005: Innovative Workplace Safety Accommodations for Hearing-Impaired Workers. The U.S. Equal Employment Opportunity Commission (EEOC) provides technical guidance regarding workers with hearing loss under the ADA: Hearing Disabilities in the Workplace and the Americans with Disabilities Act, EEOC-NVTA-2014-1, 1-24-23.

If you would like to learn more about improving listening in noise, more resources are just a click away:

Communication demonstrations: Check out CavCom‘s video demonstrations of filtered hearing protectors and radio communications in high noise areas.

Contact CavCom for more information about improving your company's productivity, safety, and communication capabilities.

Recently CavCom has received questions from customers who are concerned about a significant hearing loss or standard threshold shift (STS) observed in only one ear. Is this common with occupational noise exposures? The answer is, well, not really. Single-ear hearing issues could be a warning sign.

First, let's be clear - no hearing loss is a good one. That said, a significant change in hearing in one ear (much more so in one ear than the other) is unusual. A high number of single-ear shifts in hearing among your workers is suspicious, especially if concentrated in one department or work group.

In most work environments, the ears are exposed to similar sound levels at the same time. Even if the noise appears to be coming from one side more often, most workers are moving their head/body throughout a day, and there isn't that much distance between our two ears after all. Most sound waves easily bend around the head to reach the other ear, especially in a reverberant environment. Although there is some discrepancy in the scientific literature, most well-controlled studies have shown hearing loss among noise-exposed workers to be fairly similar (symmetrical) between ears.

For these reasons, a significant difference between the ears indicates the need for special review and follow-up. Medical issues or injury to the head can cause one-sided hearing loss, ranging from mild to serious in nature. Some of the more common noise-related causes include:

• Impulse noise sources such as gunfire, explosions. Because of the high concentration of sound energy associated with gunfire or other impulse sounds (peaks may exceed 135 dB SPL), the sound pathway is often directional, and damage is concentrated on the nearer ear. Asymmetrical hearing loss in the nearer ear is well-documented for shooters (if rifle resting on shoulder for example) and for those exposed to other loud impulses.
• Poor fitting hearing protector or failure to use hearing protector in one ear. Ears come in different sizes and shapes, so each ear should be fit individually. Some users have more difficulty inserting an earplug correctly in one ear than the other. Worse yet, some workers mistakenly remove an earplug or one cup of an earmuff when experiencing trouble hearing in their surroundings. They may feel hearing protection makes it more difficult to hear their machine or people talking. This is often a misconception, but at the very least is a communication challenge in need of solving.
• Single-ear earphones or headsets. Because some headsets or earbuds exhibit uncontrolled outputs at high volume settings, it is possible that workers are receiving significant noise exposures from their communication devices. Another complication, listening with only one ear typically requires a higher volume level to achieve intelligibility. If the employee is wearing an unlimited headset or earbud in only one ear, or places a lapel speaker mic on one shoulder without adequate hearing protection, a single-ear shift in hearing may result.

Whenever a shift in hearing is noted, timely individual follow-up with that worker is essential. When patterns in hearing shifts are observed, an evaluation of the entire hearing conservation program is warranted. Best practices include:

• Professional review/referral. Medical/audiological evaluation should include a case-by-case evaluation to determine if an event/exposure in the workplace caused or contributed to the change in hearing and if medical follow-up is advised.
• Individual counseling/re-training. Take time to evaluate employee concerns or objections about using hearing protection. Address misconceptions and alleviate apprehensions about communicating safely in the workplace; provide solid communication solutions that meet needs of the job and complement other PPE. Employees should also be counseled about the potential effects of off-the-job noise exposure, such as hunting or recreational activities, and the need for protecting hearing at home as well as at work.
• Fit Testing. Individual fit testing of hearing protectors is a vital component of an effective hearing conservation program, not a luxury. Especially for those who have shown a shift in hearing, individual fit testing will provide insight into the amount of real-world protection received for that worker. Subtle differences in fit or insertion between the ears may be illuminated. Another major advantage is the opportunity to refit and retrain individual workers in real time, so they clearly see the result of proper fit and insertion of their own personal hearing protector.
• Specifications for communication headsets. In order to facilitate effective communication while at the same time protecting workers' hearing, communication headsets or earsets must be carefully vetted. Insist on the following key specifications to achieve your goals:
  • Effective hearing protection. Require devices that sufficiently attenuate or block workplace noise; a good seal of the ear canal is essential. For best results, look for a microphone and/or receiver integrated into the hearing protector so that signals are delivered directly to the ear while simultaneously blocking outside noise.
  • Binaural (both ear) listening. Binaural listening provides a significant advantage over monaural (one ear) listening. The human auditory system is designed to work most effectively with input from both ears. The brain processes and compares signals from each ear for localization, understanding speech, and separating speech from background noise. As a result, signals such as radio transmissions do not need to be as loud if a listener is using both ears. The practical result of this phenomenon is that comfortable, and most importantly, SAFER volume settings are possible if using a binaural earset compared to one with a single-ear listening configuration. Preferred listening levels are typically 3-6 dB lower when using both ears, a significant and important advantage of binaural devices.
  • Volume-limited outputs. Whether a worker is in low or high noise areas, it is important that signals delivered to the ear do not add to noise exposure on the job. When purchasing a communication headset for any employee, make sure the device has an electronic feature to limit outputs to safer levels. And again, a binaural listening configuration allows most users to choose a lower, safer, listening level than would be possible with a monaural system.

At CavCom, we are committed to customizing solutions for your most difficult listening challenges. Don't hesitate to contact us if we can be of assistance with your communication systems and your hearing conservation program. 

To learn more:

• Cavcom SoundBytes. Effective 2-way communication. 
• Cavcom SoundBytes. Non-occupational noise. 
• Cavcom SoundBytes. The NRR – What's in a number? 
• Dobie, Robert (2014). Does occupational noise cause asymmetric hearing loss? Ear & Hearing, Vol 35(5).
• Masterson et al. (2016). Asymmetrical hearing loss in cases of industrial noise exposure: a systematic review of the literature, Otology & Neurotology, Vol 37.

According to the U.S. Bureau of Labor Statistics, occupational hearing loss represents one-third of work-related illnesses reported annually in the manufacturing sector. In 2015, a total of nearly 17,000 cases of hearing loss were reported by private industries nationwide. OSHA recently issued a new interpretation regarding how to consider an employee's use of hearing protection when determining if a hearing loss is work-related.

As part of a hearing conservation program, companies conduct baseline and annual audiometric testing for their noise-exposed workers. Based on results, employers must record on the OSHA 300 Log any cases of work-related hearing loss that meet the following criterion:

1. Standard Threshold Shift (STS): an average change of 10 dB or more at 2000, 3000, and 4000 Hz in either ear compared to the baseline hearing test (age-adjustments allowed),

AND

2. Hearing Loss/Impairment: the employee's average hearing level at the same frequencies in the same ear is 25 dB HL or greater (regardless of employee's age).

It is important to remember that not all shifts in hearing are due to noise on the job. Medical concerns or non-occupational noise can also cause changes in hearing. For this reason, a professional case-by-case review is recommended. OSHA states that hearing loss work-relatedness must be determined according to specifications of section 1904.5. If an event/exposure in the workplace caused or contributed to the shift in hearing or "significantly aggravated" a previously existing hearing loss, then the case is considered recordable. OSHA's latest interpretation clarifies how to consider a worker's use of hearing protection as part of the review process.

"First, OSHA does allow the worker's use of hearing protection to be considered by an employer when making determinations of work relatedness. However, this should not be the sole criterion in such determinations, nor should the determination be reduced to an equation. Under OSHA's recordkeeping regulation, an employer must consider many factors when determining whether hearing loss is work-related, and such determinations must be made on a case-by-case basis." (OSHA, 2016)

For more information:

Overview:  Recording Occupational Hearing Loss on the OSHA 300 Log, by Susan Cooper, PhD, CAOHC Update, 2013. 

Regulations and Interpretations:

  Federal OSHA:

Regulation: 29 CFR, 1904.10. Recording criteria for cases involving occupational hearing loss. OSHA, 66 FR 6129, Jan. 19, 2001; 66 FR 52034, Oct. 12, 2001; 67 FR 44048, July, 1, 2002; 67 FR 77170, Dec. 17, 2002 

Interpretation Letters: 

OSHA (2003). Interpretation letter dated 5/8/03 from Richard E. Fairfax, Director, Directorate of Enforcement Programs to Linda Ballas, regarding audiogram baseline revision.

OSHA (2003). Interpretation letter dated 8/14/03 from Richard E. Fairfax, Director, Directorate of Enforcement Programs to Joan E. Piosa, regarding STS retests.

OSHA (2004). Interpretation letter dated 3/4/04 from Frank Frodyma, Acting Director, Directorate of Evaluation and Analysis, to Carl Sall, regarding timeframe for retests, line-outs, and application of 1904.10 to the construction industry.

OSHA (2005). Interpretation letter dated 9/9/05 from Richard E. Fairfax, Director, Directorate of Enforcement Programs to Laurie Wells, President of NHCA, regarding audiometric baseline revision.

OSHA (2007). Interpretation letter dated 8/29/07 from Keith Goddard, Director, Directorate of Evaluation and Analysis to Theresa Schulz, CAOHC Chair, regarding audiometric reviewer qualifications.

OSHA (2016). Interpretation letter dated 4/29/16 from Thomas Galassi, Director, Directorate of Enforcement Programs to Richard Stepkin, regarding consideration of hearing protection use in determining work-relatedness for purposes of recording occupational hearing loss on Form 300.

OrOSHA: Oregon Administrative Rules, Chapter 437, Division 1, Recordkeeping and Reporting, 437-001-0700 (11)(b): Occupational Hearing Loss Recording Criteria. 

WISHA: Washington Chapter WAC 296-27-01113 Recording criteria for cases involving occupational hearing loss. h

Professional Guidelines:

NHCA (2011). Guidelines for Recording Hearing Loss on the OSHA 300 Log, National Hearing Conservation Association, approved by the Executive Council on April 26, 2011. 

NHCA (2013). Guidelines for Audiometric Baseline Revision, National Hearing Conservation Association, approved by the Executive Council on February 20, 2013. 

In 2009, the National Institute for Occupational Safety and Health (NIOSH) began an ambitious program to develop and maintain a national surveillance system for tracking hearing loss among occupational workers. The Occupational Hearing Loss (OHL) Surveillance Project uses a novel approach for data collection by partnering with audiometric service providers and other outside parties to collect worker audiograms. To date, NIOSH has partnered with 18 data providers and collected 9 million hearing tests for noise-exposed workers.

Project director Elizabeth Masterson, PhD, CPH, COHC explains the program: "To prevent more workers from losing their hearing, we need to know the size of the problem, identify the workers most at risk, and monitor trends in worker hearing loss for improvement." The OHL Project is longitudinal by design, continuing to collect hearing tests and recruit new data providers on an ongoing basis. An initial analysis of the OHL database revealed that 18% of noise-exposed workers had some form of hearing loss (results outside the normal range of hearing). Not unexpected, the prevalence of hearing loss was higher, 24% or more, within the Mining, Construction and Manufacturing industries. An analysis of significant changes (shifts) in hearing showed that 6% of workers sampled from the database had experienced a significant change in hearing, an OSHA Standard Threshold Shift (STS, age-adjusted). The number climbed to 14% for the group if STS age-adjustments were not considered. Higher still was the rate of shifts in hearing according to a more conservative NIOSH-recommended criterion: 20% of workers.

For more information on procedures, statistics, publications, and data provider partnerships, visit the OHL Surveillance Project website. Additional references:

Masterson, et al. (2014). Prevalence of workers with shifts in hearing by industry: a comparison of OSHA and NIOSH hearing shift criteria. Journal of Occupational & Environmental Medicine, 56(4), 446-455. 

Masterson, et al. (2013). Prevalence of hearing loss in the United States by industry. American Journal of Industrial Medicine, 56(6), 670-681. 

The U.S. Equal Employment Opportunity Commission (EEOC) recently issued an updated technical assistance document regarding workers with hearing loss: Hearing Disabilities in the Workplace and the Americans with Disabilities Act, EEOC-NVTA-2014-1, 1-24-23. The document explains considerations for both job applicants and current employees under the Americans with Disabilities Act of 1990. It also addresses common employer concerns about safety, assistive technologies, and reasonable accommodations. For more information about hearing-impaired workers and hearing conservation programs, see CavCom‘s article: Special Considerations for Workers with Hearing Loss.

Traditionally hearing conservationists have been concerned about the effects of noise on sensory cells within the inner ear. These sensory cells are called hair cells in reference to tiny cilia structures that resemble hairs when seen under a microscope. New research, however, indicates that excessive noise may damage neural structures of the inner ear as well.

Recent scientific studies with animals reveal that noise and the aging process progressively interrupt connections between the sensory hair cells and neurons within the inner ear, eventually leading to death of the neurons themselves. With age, the connections tend to be lost gradually over a lifetime. With loud noise, the nerve damage can be immediate, observed even in cases of temporary hearing loss when there is no obvious damage to the sensory hair cells. Researchers speculate that loss of neurons in the inner ear may contribute to common auditory perception problems, such as difficulty understanding speech in noisy background situations. Studies continue, with the ultimate goal of developing better measures for early detection and prevention of hearing loss.

References and further reading:

Kujawa S (2014). Putting the 'Neural' Back in Sensorineural Hearing Loss, Hearing Journal: 67(11) 8.

National Institute on Deafness and Other Communication Disorders Topic Pages:

Age-related hearing loss 
Noise-induced hearing loss 

With the unfortunate rise in wildfires throughout the west, it's timely to pause and consider one of the often overlooked hazards of this high-risk occupation – noise. Wildland fire fighters may work 12 to 16 hour shifts for up to 14 consecutive days. And although noise exposures and hearing loss have been well-documented for structural fire fighters, wildland exposures have only recently come to light.

Wildland fire-fighters encounter numerous well-known noise sources such as chainsaws, leaf blowers, wood chippers, pumps, bulldozers and airplanes. The United States Forest Service, in partnership with the National Institute for Occupational Safety and Health (NIOSH), recently concluded a 3-year study to assess wildland fire fighters' exposures. Noise dosimetry was conducted for over 150 fire fighters across 10 different wildfires. Measured noise doses frequently exceeded OSHA occupational and NIOSH recommended exposure limits, particularly for those operating chainsaws, chippers, and masticators. Researchers recommended a comprehensive approach to protecting wildland fire fighters, including noise and administrative controls and enrolling fire fighters in an ongoing hearing conservation program.

To learn more:

• Wildland Firefighter Health: Some Burning Questions, NIOSH Science Blog, posted on September 28, 2020 by LCDR Corey Butler et al.
• Noise Exposure Among Federal Wildland Fire Fighters, NIOSH Science Blog, posted on April 17, 2017 by George Broyles , LCDR Corey Butler, CAPT Chuck Kardous 
• Broyles, et al. (2017). Noise exposure among federal wildland fire fighters, Journal of the Acoustical Society of America, 141(2), published online 
• National Interagency Fire Center Wildfire Situation Report (updated regularly)
• NIOSH Fire Fighters Resource page 
• NIOSH Emergency Responder Health Monitoring and Surveillance Program
• U.S. Fish & Wildlife Service, Fire Management page 
  (photo source: fws.gov)

Noise pollution is a serious concern for quality of life. Assessing possible effects of noise on general health is notoriously difficult to study. People who are exposed to noise throughout a day are also exposed to many other environmental and societal factors that likewise can affect health. It's difficult to tease out strong relationships and particularly cause and effect.

Researchers from the Canadian Department of Health have recently published results from the Canadian Health Measures Survey, a comprehensive ongoing epidemiological study of a broad cross-section of the Canadian population. This report did not support an association between loud noise exposure and changes in biomarkers for cardiovascular disease outcomes, such as hypertension, myocardial infarction, or stroke. Researchers reported expected results for hearing loss, but concluded their data did not support the theory that noise is a serious contributor to cardiovascular disease. Other researchers continue to study the matter, and we'll be sure to watch and report any emerging trends.

• Canadian Health Measures Survey website
• Michaud, DS, Marro, L and McNamee, JP (2021). Self-reported exposure to occupational noise and cardiovascular disease in Canada: Results from the Canadian Health Measures Survey. The Journal of the Acoustical Society of America, 150, 990 (DOI: 10.1121/10.0005588).

It is estimated that 40 million Americans show some form of hearing loss. The odds of hearing loss go up with age, with over two-thirds of individuals over the age of 60 having difficulty hearing high pitch sounds and 1 in 4 having difficulty hearing speech. Worse yet, many people who think they have good hearing don't even realize they already have some hearing loss.

Invest just 2 minutes of your time– take this quick 10 question quiz to determine if it's time for you (or someone you love) to get a hearing test.

For more information:

 Who Can I Turn to for Help with My Hearing Loss? National Institute on Deafness and Other Communication Disorders 

Hearing Loss and Older Adults. National Institute on Deafness and Other Communication Disorders 

Hearing Loss in Children. National Center on Birth Defects and Developmental Disabilities  

photo source: NIDCD, nih.gov

Do you suffer from ringing in the ears? You're not alone! The National Institute on Deafness and Other Communication Disorders (NIDCD) estimates that over 20 million Americans experience chronic ringing in the ears, known as tinnitus (pronounced "TIN-a-tus" or "Tin-EYE-tus"). The condition can be mild, intermittent, or so severe as to interfere with sleep, concentration, and enjoyment of daily life.

A recent analysis of data collected as part of the National Health Interview Survey indicated that noise-exposed workers in the United States are 3 times more likely to report suffering from tinnitus than their non-noise-exposed counterparts. According to the U.S. Department of Veteran Affairs, tinnitus and hearing loss are the top two service-connected disabilities for U.S. service members. Veterans of Iraq and Afghanistan have been exposed to a number of hazards known to cause hearing loss and tinnitus, including loud noise, blasts/explosions, and ototoxic chemicals. Service members who have suffered a traumatic brain injury are 3 times more likely to experience tinnitus than other veterans. Those exposed to solvents, a class of ototoxic chemicals, are twice as likely to report ringing in the ears.

Tinnitus is an annoying and sometimes debilitating condition, commonly defined as the perception of noise in one or both ears when no sound is actually present. Usually described as high-pitched, it might also be perceived as roaring, clicking, hissing or buzzing. Tinnitus can be a sign that something is wrong with the outer, middle or inner ear, the auditory nerve, or parts of the brain that process sound. Noise exposure, acoustic trauma, exposure to chemicals, and ear diseases/infections are common causes of tinnitus. Complicating its diagnosis and treatment, tinnitus has many other causes as well, including disorders of the heart/circulatory system, stress, hormone changes, and as a side effect of medications, smoking, or too much salt or caffeine. Sometimes the cause of tinnitus is unknown.

So what can a person experiencing tinnitus do about this annoying and on occasion even incapacitating condition? The first step in managing tinnitus is to get an evaluation. See your primary care doctor to determine if a medical condition or medication may be causing or aggravating the ringing. If needed, you will be referred for a complete audiological and otological examination to establish if there is an underlying ear or hearing problem. Although there often is no cure for long-term tinnitus, there are treatments and therapies that can help people cope with the annoyance and frustration of this condition. And because noise is a leading cause, remember that you can reduce the likelihood of developing or worsening tinnitus by limiting time spent around loud noise and wearing well-fitted and effective hearing protectors when needed.

For more information/resources:

• National Institute on Deafness and Other Communication Disorders – Tinnitus Topic Page 
• American Tinnitus Association  (ATA)
• ATA "Managing your tinnitus" 
• Department of Defense Hearing Center of Excellence – Tinnitus Topic Page
• Griest, et al. (2018). Risk factors associated with tinnitus and hearing loss in current and recently separated service members across military branches. Annual conference of the National Hearing Conservation Association. Orlando, February 2018.
• NIOSH Press Release (2016). Putting an Ear to the Ground: NIOSH Study looks at Prevalence of Hearing Difficulty and Tinnitus among Workers 

Although the first goal of an effective hearing conservation program is to reduce noise at the source, the reality is that many workers rely on daily use of personal hearing protection devices (HPDs) to reduce the risk of noise induced hearing loss. Even a well-designed and expertly-fitted HPD may take some getting used to. For older workers, the challenge can be even greater.

According to the U.S. Bureau of Labor Statistics, approximately 20% of American workers are 65 years or older. With an aging population and workforce, many companies are now taking notice of what is required to keep their employees safe and healthy for a long working lifetime. Keys to HPD success include optimal fit, care and consistent and continued use during the entire workshift. We're often asked if the ear canal changes due to age and if this could affect older workers' ability to be protected from noise on the job.

Although there is a great deal of individual variability, we know that one aspect of the ear that does not seem to change with age is the basic size of the earcanal. Anatomical studies show that the outer ear and ear canal are fully developed by puberty, and that the overall size/volume of the canal does not change significantly over time.

All the same, it's important to recognize that other anatomical changes that accompany aging could affect comfort and successful use of HPDs. Some common transformations in the earcanal associated with getting older include:

• Thinning of the skin that lines the earcanal and loss of elasticity
• Atrophy/loss of fatty tissue that pads the earcanal
• Reduced secretions from glands in the canal, leading to dry skin
• Earwax can be drier, harder and more likely to become impacted
• Sagging, or "collapsing" of the cartilage in the outer portion of the earcanal
• For men, growth of wiry hair at the opening of the canal

Next, it's important to consider the implications of these changes that could impact older workers and hearing protection use:

• Older workers may require more frequent medical care for outer ear infections or earwax build-up. It may be necessary to wear earmuffs instead of earplugs until medical clearance is received.
• Individuals who have thinning skin and decreased fat pads in the ear canal may find earplugs less comfortable than they used to be. Forcing any object into the earcanal could even cause bruising or breaking the skin. It may be necessary to try different styles and materials of HPDs to determine the most comfortable fit (subjective but essential to acceptance and compliance).
• If a worker experiences collapsed canals, it may be more difficult for him or her to insert a hearing protector. It's especially helpful to follow the preferred protocols: using the opposite hand, pull up and out on the outer ear to straighten the earcanal prior to inserting an earplug.
• Jaw motion may cause earplugs to dislodge easier for certain workers, including older individuals with softer ear canals. Again, try different styles and materials of HPDs. Remind employees that they may need to reseat earplugs regularly if they become loose throughout the day.

And most importantly, carefully check the fit and seal of the hearing protector for all of your employees on a regular basis, including older workers. Many companies are now routinely conducting individual fit testing for HPDs, similar in concept to fit testing for respirators. NIOSH, OSHA and professional organizations have identified individual fit testing as a best practice for hearing conservation programs.

To learn more about aging, the earcanal and ear care, see:

American Academy of Otolaryngology. Earwax and care. 

NIOSH. Productive Aging and Work. 

Oliveira, RJ (1997). The active earcanal. Journal of the American Academy of Audiology, 8: 401-410.

Staab, W (2014). The human earcanal, series: I-VIII. Hearing Health Matters.

Prior to 2001, there were no standards for the use of respiratory protection devices against chemical, biological, radiological, and nuclear (CBRN) hazards encountered by U.S. emergency response teams. Several federal agencies partnered to conduct research and develop programs and resources. The National Institute for Occupational Safety and Health (NIOSH) has recently released a new comprehensive guideline for Respiratory Protection in CBRN applications.

The new NIOSH publication, Chemical, Biological, Radiological, and Nuclear (CBRN) Respiratory Protection Handbook, summarizes detailed technical information on CBRN respiratory protective devices. The handbook also provides practical guidance for the selection, use, and maintenance of CBRN respirators. Chapters feature useful tips on developing effective training programs and administering a comprehensive respiratory protection effort.

To learn more:

• NIOSH [2018]. CBRN Respiratory Protection Handbook. By Janssen L, Johnson AT, Johnson JS, Mansdorf SZ, Medici OR, Metzler RW, Rehak TR, Szalajda JV. Pittsburgh, PA: U.S. Department of Health and Human Services, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, DHHS (NIOSH) Publication No. 2018-166.
• NIOSH National Personal Protective Technology Laboratory (NPPTL)
• NIOSH Searchable list of approved respirators (respirators used in CBRN applications must be tested/approved by the NIOSH NPPTL).
• US Department of Health & Human Services Chemical Hazards Emergency Medical Management webpage

The U.S. Court of Appeals recently dismissed legal challenges to OSHA's new standard for silica dust exposure, clearing the way for rules to go into effect. OSHA began enforcing most provisions of the silica standard for construction in September 2017; enforcement for most provisions for general and maritime industries will begin June 23, 2018. Because the new rule lowers the permissible exposure limit, more industries will need to implement controls to reduce silica dust exposures and more workers will wear respirators.        

Crystalline silica is a mineral commonly found in sand, stone, concrete, and mortar. It is also used to make products such as glass, pottery, ceramics, bricks, and artificial stone. Respirable crystalline silica consists of extremely small particles (at least 100 times smaller than ordinary sand) and is often created when cutting, grinding, drilling or crushing rock, concrete, brick, and mortar. These activities can result in worker exposures to respirable crystalline silica dust. Industrial sand used in operations such as foundry work and hydraulic fracturing (fracking) is also a source of respirable crystalline silica exposure.

OSHA estimates that over 2 million people in the U.S. are exposed to silica on the job. Workers who inhale these tiny crystalline silica particles are at increased risk of developing serious silica-related diseases, including:

• Silicosis, an incurable lung disease
• Lung cancer
• Chronic obstructive pulmonary disease
• Kidney disease

To learn more about the new standards and how to control silica in your workplace:

• U.S. Court of Appeals D.C. Circuit, Decision No. 16-1105, 12-27-2017 
• OSHA Silica webpage 
• NIOSH Silica webpage 
• NIOSH Pocket Guide to Hazards: Silica, crystalline (as respirable dust) 

(photo source: NIOSH)

How a Shortage of PPE Impacts More than Health

In times of unbelievable scenarios and adversity driven by a global pandemic, the medical industry continues to innovate and respond to one crisis after another. Shortages of PPE (personal protective equipment), overflowing facilities, limited respirators, ICU capacity, and even staffing shortages are just some of the situations that are wreaking havoc across the nation. Amidst all that, the way thousands of medical professionals are adjusting to communicating is something that could drive change permanently.

No Shortage of PPE Problems in Healthcare

Within hospitals, physicians and nurses are facing shortages in PPE, driving organizations to alter protocol and adapt to what’s available in terms of safety. The N95 respirator shortage continues. In response, and under certain FDA guidance, for less critical situations, half mask ventilation is being used, a common style is called P100. This design, while designed to purify the air and protect against infectious, airborne materials, also constricts the mouth and the ability to hear the voice out of those respirators. This particular type of filtered mask respirator is likely the style that’s going to be used more for the day to day work of nurses and medical support staff. Communication is hampered when people wear half mask ventilation.

In more serious cases, PAPR (powered air-purifying respirators) respirators are being worn by critical care teams in healthcare settings. These respiratory protective devices are intensive by design, engineered to protect industrial and medical professionals from the most detrimental fumes and hazards. When you imagine a setting where the absolute most comprehensive protective device is necessary, this is the go-to style.

The product includes a helmet or hood with a motorized fan that blows air over the head and produces some noise inside the hood. That design minimizes difficulties caused by constricting the mouth or the voice, but because of the noise from the fan and because they have a hood over their face, it makes it difficult to hear and understand each other. These respirators are typically going to be used in regard to the higher-level cases of COVID-19 patient care. So when they have a patient who is coding and requires an intubation team, those medical professionals will be wearing PAPR respirators.

In more serious cases, PAPR (powered air-purifying respirators) respirators are being worn by critical care teams in healthcare settings. These respiratory protective devices are intensive by design, engineered to protect industrial and medical professionals from the most detrimental fumes and hazards. When you imagine a setting where the absolute most comprehensive protective device is necessary, this is the go-to style.

The product includes a helmet or hood with a motorized fan that blows air over the head and produces some noise inside the hood. That design minimizes difficulties caused by constricting the mouth or the voice, but because of the noise from the fan and because they have a hood over their face, it makes it difficult to hear and understand each other. These respirators are typically going to be used in regard to the higher-level cases of COVID-19 patient care. So when they have a patient who is coding and requires an intubation team, those medical professionals will be wearing PAPR respirators.

The Dangers of Miscommunication Between a Care Team

Communication in a hospital can literally translate to the difference between life and death. Clarity and continuity between medical professionals as they navigate new safety standards and adapt to different equipment are compromised each and every day.

For example, for a confirmed COVID-19 patient, the care team offers supportive care including supplemental oxygen, medication, and fluids akin to treating pneumonia or other severe lung conditions. The WHO tracking data show that one in six COVID-19 patients become seriously ill, requiring intensive treatment. The team might be comprised of roles including:

• Respiratory therapist
• Trauma specialist
• Circulating nurse
• Intubation specialist
• Anesthesiologist
• Laboratory personnel

Those who are bedside administering care are likely wearing PAPR respirators. Those who aren’t in direct contact with the patient might be wearing a P100 mask, perhaps it’s a documenting nurse, who's going to be outside of the room and that individual essentially needs to communicate with the nurses inside the room. In this critical scenario, one set of PPE is hindering hearing while the other is limiting speech and the entire team needs to communicate together with 100 percent certainty. You can imagine the outcome if communication is rendered ineffective or even impossible.

What's Working Right Now? 

We know the world will never be the same after this pandemic subsides. Every industry has now realized, in real-time, the gaps that exist between proper communication and required equipment. How to be innovative in the face of shortages and crises. How to simply maintain as the world shifts on its axis. Knowing how medical teams are adjusting to self-protection while facing equipment shortages means those same teams are altering communication practices for both hearing and speaking alike. CavCom product technology is helping bridge the gap in instances where communication is more crucial than ever — like hospitals.

And in these instances in healthcare settings, communication may be conducted between either a cell phone or a two-way radio. Cell phone users may be talking with their teams via some kind of a group chat, like Zoom, or some kind of an app where they can all communicate on their cell phones together. Two-way radios are also ideal communication tools that can vastly enhance comms between individuals and work teams. A variety of accessories are available for cell phones and two-way radios that further enhance the user’s ability to communicate clearly.

CavCom Phantom™ Lightweight Headsets have proved successful to facilitate that group chat-style communication with 2-way radios and cell phones with many styles of PPE, including PAPRs.  As the name implies, the lightweight design doesn’t add to or interfere with hooded PPE. The binaural design supports both ear listening which is optimal.

Another option is CavCom CellEarz™. This style offers a corded earset with the familiarity of a standard smartphone-style with the advanced technology to enhance clarity, the ability to listen, speak and be heard in high-noise environments like a chaotic emergency room.

If you could talk normally in high noise environments, what kind of a difference would that make? Take, for example, a steel mill with noise levels averaging 100 dBA or more. What if your daily PPE involves a respirator, face shield, helmet or protective suit?  Imagine the difference in radio communication if noise and respirators were no longer barriers to your ability to communicate. It is possible with Talk Through Your Ears®.

How Does It Work? 

In the simplest terms, Talk Through Your Ears® (TTYE) uses in-ear communications to bypass many of the problems associated with communicating in high noise environments. 

Unlike external communication technologies, like a throat mic or boom mic, TTYE uses an in-ear microphone. The microphone picks up whatever you say and transmits it via your radio. Sealing the ear is a hearing protector, so your communications don’t have to compete with environmental noise like you might be used to.  Mouth covered by a respirator? No problem – again, the microphone is in the ear canal, so no interference from a face mask or even SCBAs.

I know this might sound a bit too good to be true, but I assure you it isn’t. If background noise poses a challenge for radio communications for your team, TTYE might be just what your facility needs. 

Who Uses TTYE Technology? 

TTYE is well-suited to high noise manufacturing environments. 

Some examples include steel mills, paper mills, textile factories, chemical plants, and nuclear power plants. In each of these settings, there are employees struggling because they’re not outfitted with technology that both protects their hearing and enables them to hear and be heard. 

In addition to high noise, TTYE also excels in HazMat and other in-suit environments. With these PPE, the issue isn’t so much about noise, it’s about communicating while using a respirator. Instead of yelling, TTYE makes in-suit communications as clear as if you were speaking in person without a face-piece or mask on.

See it in action: 

Whether it’s an industrial workplace or an emergency response team, TTYE allows for in-suit communications via two-way radio. With it, you can communicate clearly in:

• Any suit
• Any radio
• Any respirator
• Any environment

Do You Need TTYE?

Knowing if you would benefit from TTYE is the same as asking, do you need to communicate in high noise environments?  Or does your HazMat team need to communicate? This technology makes it possible to communicate in any harsh environment. Ditch the yelling, hand signals, and the danger to personal safety with TTYE.

The hazardous effects of noise are well known, and most companies now have active hearing conservation programs to protect their workers. Less understood are the effects of "ototoxicants" (ear poisons). These chemicals or compounds can cause hearing loss, tinnitus and balance problems, sometimes accelerated when combined with noise exposures. OSHA and the National Institute for Occupational Health (NIOSH) have recently published a new safety and health bulletin on this important topic.

Chemical ototoxicity (meaning poisonous to the ear) first came to the attention of researchers in the 1970s and 80s; however, comprehensive studies and clear conclusions about the hazards are still in the making. Certain chemical substances are ototoxic when airborne, ingested, or absorbed through the skin. Some ototoxicants affect the inner ear in the same manner as noise; others target the balance center in the inner ear or "higher" parts of the auditory system such as the auditory nerve, cortex, and brainstem centers.

Not only can ototoxic agents cause temporary or permanent damage to the auditory system independently, they can also interact with noise to accelerate the risk of hearing loss. In occupational settings, because noise is often present where chemical exposures occur, it can be difficult to separate the degree of hazard from each agent.

Some of the occupational compounds implicated as being ototoxic:

• Solvents such as carbon disulfide, n-hexane, toluene, styrene, xylene, ethylbenzene
• Asphyxiants such as carbon monoxide, hydrogen cyanide, and tobacco smoke
• Metals such as mercury, lead and organic tin compounds
• Nitriles
• Certain pharmaceuticals

Jobs where ototoxicants may be present (and can often combine with noise exposures):

• Painting
• Printing
• Manufacturing of metal, leather, chemical, petroleum, paper and many other products
• Construction
• Firefighting
• Mining
• Utilities
• Fueling vehicles and aircraft
• Pesticide spraying
• Shipbuilding

Currently there are no regulations requiring monitoring of a worker's hearing due to occupational exposure to ototoxic chemicals. However, appropriate use of a respirator and/or skin protection can protect against chemical exposures, while effective hearing protection can protect against noise. Proactive companies are beginning to take into account special cases of chemical exposures in the workplace, including audiometric testing to monitor hearing levels.

To learn more, check out these helpful resources:

• OSHA, NIOSH (2018). Preventing Hearing Loss Caused by Chemical (Ototoxicity) and Noise Exposure. Safety and Health Information Bulletin 03-08-2018; NIOSH Publication No. 2018-124. 
• Estill, Rice, Morata and Bhattacharya (2017). Noise and neurotoxic chemical exposure relationship to workplace traumatic injuries: a review. Journal of Safety Research, 60, 35-42. 
• The National Research Council (2014). Review of Styrene Assessment In the National Toxicology Program, National Academies Press. 
• OSHA (2013). OSHA Technical Manual, Section III: Chapter 5, II. G. Noise and Solvent Interactions (Updated 08/15/2013). 
• Themann C, Suter A, Stephenson M (2013). National Research Agenda for the Prevention of Occupational Hearing Loss—Part 1. Semin Hear; 34(03): 145-207 
• European Agency for Safety and Health at Work (2009). Combined exposure to noise and ototoxic substances (literature review). 

Millions of workplace injuries occur every year in the U.S. resulting in 5,000 fatalities annually. Noise in the workplace can damage hearing, and neurotoxic chemical exposures can affect central nervous system functions including hearing and balance. In collaboration with the University of Cincinnati, the National Institute for Occupational Safety and Health (NIOSH) recently conducted a thorough review of available scientific evidence to determine if there is an association between exposure to noise or neurotoxins and injury.

The report summarizes results of 41 published research studies of noise exposure, hearing loss, and neurotoxic chemical (solvent) exposure. Some researchers studied workplace accidents while others reported on accidents outside of work and health outcomes such as sick days, decreased cognitive ability, and disability retirement. In general, higher exposures to noise were associated with injury and negative health outcomes, although the relationship was not well understood. Solvent exposures were also linked to accidents and other health outcomes such as balance disorders. Some of the strongest relationships were found among workers with hearing loss and the rate of accidents, injuries, and disability retirement.

To learn more:

• Estill, Rice, Morata and Bhattacharya (2017). Noise and neurotoxic chemical exposure relationship to workplace traumatic injuries: a review. Journal of Safety Research, 60, 35-42.
• CavCom, SoundBytes. Accident Risk and Noise
• CavCom, SoundBytes. Special Considerations for Workers with Hearing Loss
  (photo source: cdc.gov)

In 2013, OSHA launched the Temporary Worker Initiative (TWI), a project to help prevent work-related injuries and illnesses among temporary workers. The TWI's most recent safety bulletins focus on Respiratory Protection and Noise Exposure.

Temporary and contract workers are believed to have increased risk of work-related injury and illness. OSHA created the Temporary Worker Initiative (TWI) due to multiple reports of temporary workers suffering serious or fatal injuries, some in their first days on the job. For the purposes of TWI's recommended practices, "temporary workers" includes those supplied to a host employer and paid by a staffing agency, whether or not the job is actually temporary. It is OSHA's position that the staffing agency and its customer (host employer) are joint employers of temporary workers and, therefore, both are responsible for providing and maintaining a safe and healthy work environment.

In 2018, OSHA published two new TWI bulletins addressing temporary worker health and safety:

• Bulletin 8. Respiratory Protection: provides guidance for the protection of temporary workers exposed to airborne contaminants under OSHA's general industry and maritime standards. Both staffing agency and host are jointly responsible that workers wear respirators, but the two entities may agree in advance to a division of responsibilities. The host employer will usually have the primary responsibility for evaluating exposure levels, implementing and maintaining engineering, administrative, and work practice controls, providing an appropriate respirator, and maintaining a respiratory protection program in accordance with OSHA requirements. The staffing agency should also ensure its employees are protected, including being aware of respiratory hazards to which employees may be exposed and the customer's protective measures including any requirements for respiratory protection at the host employer's worksite.
• Bulletin 9. Noise Exposure and Hearing Conservation: this bulletin provides guidance for protecting temporary workers exposed to hazardous noise levels. Again, both staffing agency and host are jointly responsible for protecting workers against noise but may agree in advance to a division of responsibilities. The host employer will typically have primary responsibility for determining noise exposure levels, implementing and maintaining engineering/administrative controls, providing appropriate hearing protection, and maintaining a hearing conservation program. The staffing agency should also make sure individuals are protected by informing temporary employees of the noise hazards they may encounter, and ensuring as far as possible, that workers are adequately protected, including wearing hearing protection.

For more information:

• OSHA Temporary Worker Initiative main page
• OSHA TWI Bulletin No. 8: Respiratory Protection, OSHA 3952-06, 2018 
• OSHA TWI Bulletin No. 9: Noise Exposure and Hearing Conservation, OSHA 3953-06, 2018 
• NIOSH/OSHA Joint Statement on Recommended Practices – Protecting Temporary Workers, HHS (NIOSH) Publication Number 2014-139; OSHA – 3735, 2014 
• OSHA Interpretation Letter – Minimum exposure for inclusion in the hearing conservation program (HCP); removal criteria, Richard Fairfax, Directorate of Enforcement Programs, February 13, 2004.  

For many students, summer break is spent earning money for college, a car, and other personal items. But teens and parents beware, job-related injury rates are high for young workers. Limited job experience and training can put young people at increased risk.

Teen workers have higher rates of work-related injuries than their older, more experienced counterparts. Young people often work on a part-time or temporary basis, and may not receive adequate safety training and oversight. Some experts point out that middle and high school workers also may not have the physical strength and cognitive maturity needed to perform certain job duties. To help address this problem, the U.S. Public Health Service developed a Healthy People objective to reduce rates of work-related injuries among young people aged 15-19.

To learn more and to access helpful training resources, see:

• NIOSH Topic Page: Young Worker Safety. 
• OSHA Topic Page: Safe Work for Young Workers. 

In 2016, the National Institute for Occupational Safety and Health (NIOSH) launched a new online resource database. This searchable archive serves as a compendium of federal regulations and consensus standards related to all types of Personal Protective Equipment (PPE).

NIOSH's National Personal Protective Technology Laboratory developed the PPE-INFO database in collaboration with key partners including the International Safety Equipment Association, OSHA, MSHA, and members of the PPE Conformity Assessment Working Group. The database is comprised of standards and regulations published by U.S. Government Agencies and consensus standards organizations such as ANSI and ISO.

The goal of the project is to provide employers and workers with reliable information about occupational PPE in the United States. Future plans call for expanding the database to include international standards, conformity assessments standards, and a list of products that conform to these standards.

For more information:

NIOSH Announcement, Science Blog, May 2016 

PPE-INFO database 

Recently, we had the opportunity to talk with a current customer who's had a CavCom communication system in place for 15 years. Here's a little bit about their work environment and their CavCom solution.

The Work Environment

We spoke with Mark, Shift Supervisor at International Paper. Mark and the employees he oversees manufacture corrugated boxes at a facility that operates 24 hours a day, five days a week. The work environment is fast-paced and the noise level qualifies as extremely high noise. If you've never seen this type of work, it might be hard to imagine.

The machine they use is very loud, very long, and powered by steam. More often than not, employees working on either side of the machine are not able to see each other clearly. Plus, the temperature around the machine keeps their work environment at about 90-95 degrees.

In order to complete their work, employees need to be able to communicate with each other from one end to the other. But due to the nature of the work environment, making clear communication between workers can be an obstacle.

Prior to partnering with CavCom, the employees protected their hearing by wearing headsets. Big and bulky, these headsets held onto heat and got pretty heavy over the course of an eight-hour shift. The headsets also had a built-in microphone that employees used to communicate. It wasn't exactly ideal, but until they engaged with CavCom, it was the best they had.

Enter CavCom

International Paper knew that in order to maintain the standard of safety for employees and the quality of the product, their employees needed to be able to communicate properly. So when they learned about CavCom and found out they had a communication system that protected hearing, allowed for clear communication in high noise environments and kept employees comfortable, they wanted to learn more. 

Here at CavCom, we love to talk about our solutions and how they help our customers. And from time to time, we’re able to share some of those stories here on our blog. Today, we’re sharing the story of how CavCom solutions support communication and hearing conservation at Menasha Corporation. 

Meet Menasha 

Menasha Corporation is a privately held company specializing in the design and production of corrugated packaging solutions. A corrugator is a steam-powered machine. It’s loud, and it puts off a lot of heat. For instance, if it’s 80 degrees outside, the corrugator crew is working in temperatures around 120 degrees. 

We spoke with Brian, a Shift Coordinator who’s been with Menasha for 20 years, “When I started here we had no CavCom, no communication besides PA speakers and a mic that we had to speak into. We wore these big, heavy headsets along with foam earplugs. The problem was, you had to be able to hear the PA, so if you were on the other side of the machines, you were not going to hear what was being called out.” 

Being unable to communicate effectively made this more difficult than it needed to be for the employees working in the high noise environment. On their production floor, and throughout their entire company, Menasha prioritizes safety, quality and production. But with their PA system communications, they weren’t equipping employees to support those priorities. 

Enter CavCom

Menasha employees needed to communicate in a high noise environment. This meant they needed something to provide hearing protection and something to enable communication. Here at CavCom, both of those needs are met by Talk Through Your Ears® (TTYE). TTYE are uniquely engineered earpieces that combine an in-ear microphone and speakers within a hearing protector. They work with any suit, any respirator, and any radio. And they were exactly what Menasha’s corrugator crew needed. 

Each member of the crew was molded for custom earsets and provided a pair of TTYE. These sets, each engraved with their employees’ name, provided each worker with hearing protection, comfort and most importantly, the ability to communicate in high noise. Menasha’s CavCom solution did what it was supposed to do. Here’s a look at how TTYE supported Menasha’s top three priorities: safety, quality and production. 

Safety

“We just had our hearing tests back in October, and mine came out awesome. It just helps to have a good seal in your ear and wear your hearing protection. Your hearing is the one thing you’ll never get back.”

In addition to supporting Menasha’s hearing conservation program, TTYE provided cleanliness, too. “With the foamies, you end up with wrappers all over the place. Since we have the custom fits, we don’t have garbage lying around. And since we’re an BRC company that deals with food and medical-grade boxes, I bet not having litter all over the place helps us keep our AA rating.” 

Quality

“You know, being able to communicate on the floor also helps to empower your own employees. They might run into a problem while I’m 400 feet away. With these earsets, they’re able to describe what’s going on and get help from me no matter where I’m at. Since I can hear what’s going on and be heard at all times, we can solve issues without having to shut down the machine and troubleshoot. And that machine does not like to stop and start. It works best if you can just keep it running the whole time.” 

Production

“We make some items that cost a high dollar. It’s fast-paced, important work. And if you don’t have the communication to make sure you’re on the right course or doing what you need to do for quality checks, there’s a lot of chances for mistakes. With the custom earsets, if somebody needs to step away from the machine, they can just buzz into my radio and it doesn’t cause any issues or confusion.”

Menasha Corporation has had its CavCom solution for the past 15 years. Over that time, the devices have continued to support the company’s hearing conservation program and given employees the resources they need to communicate during production hours. Since first outfitting the corrugation team, Menasha has gone on to outfit their entire facility,  including those who do not work in high noise,  with custom fitted earset and earplugs (including RadioGear®, CellEarz™ and EarzON® products).

Thank you, Brian, for sharing your experience with CavCom TTYE technology!

The National Institute for Occupational Safety & Health (NIOSH) has long designated the Oil & Gas industry as a priority for research and action. NIOSH's medical surveillance group recently published prevalence rates for hearing loss among US workers in Mining and those in Oil and Gas extraction sectors. Prevalence of hearing loss was particularly high in Construction Sand & Gravel Mining and Natural Gas Liquid Extraction.

For more information:

Oil & Gas a Top NIOSH Priority, CavCom SoundBytes.

Hearing Conservation in Mining, CavCom SoundBytes.

Lawson, S. M., Masterson, E. A, & Azman, A. S. (2019). Prevalence of hearing loss among noise-exposed workers within the Mining, and Oil and Gas Extraction Sectors, 2006-2015. American Journal of Industrial Medicine.

NIOSH Oil & Gas Extraction Program information page 

NIOSH Mining Program information page

Ammonia is widely used as a refrigerant in industrial workplaces such as food and beverage processing, cold storage warehouses, petrochemical sites, and food processing/storage facilities aboard ships. Ammonia is considered a significant health hazard because it is corrosive to the skin, eyes, and lungs and is also flammable. Because of the need for extensive personal protective equipment such as respirators or Level A HazMat gear, workers often have significant difficulty communicating, especially when working in high noise environments such as compressor rooms and production areas.

OSHA has recently released a new fact sheet regarding refrigeration system hazards aboard shipping vessels. Employers are reminded that when workers are alone or in confined spaces, they must be accounted for by sight or verbal communication at regular intervals to ensure safety. See helpful resources below, and contact CavCom to learn more about effective communication systems designed for refrigeration and other challenging work environments.

Resources:

• OSHA Fact Sheet (November 2015). Hazards during the Repair and Maintenance of Refrigeration Systems on Vessels 
• NIOSH Ammonia Topic Page 
• OSHA Ammonia Refrigeration Topic Page 
• OSHA Ammonia Refrigeration E-Tool 

NIOSH director John Howard, MD routinely announces top priorities for NIOSH research and action in the upcoming year. In 2017, due to increased energy production and development of new techniques such as hydraulic fracturing, health and safety for the Oil and Gas industry topped the list.

Size of the Oil & Gas workforce has increased, including those involved in drilling and servicing wells, and workers in refineries and preparing oil and gas for shipment. NIOSH scientists are conducting research to characterize and eliminate the risks faced by workers to respirable crystalline silica, and volatile organic compounds including naphthalene, benzene, toluene, ethylbenzene, xylene, and other hazards. Because some of these chemical compounds can be ototoxic (poisonous to the ear), use of respirators and hearing protection is critical to hearing loss prevention as well as general worker safety.

To learn more:

Ototoxic Chemicals, CavCom SoundBytes 

Oil & Gas: Health Concerns in Flowback Operations, CavCom SoundBytes

Occupational Health Issues in the USA, NIOSH Science Blog, January 10, 2017 

NIOSH Oil and Gas Program 

Although physical safety hazards for oil and gas extraction operations are well known, there is very little published research regarding the types and magnitude of health risks linked to hazardous chemicals. Of recent concern are chemical exposures associated with flowback operations (storing and processing fluids involved in hydraulic fracturing). Results from initial field studies by the National Institute for Occupational Safety and Health (NIOSH) suggest that certain flowback activities can result in elevated concentrations of volatile hydrocarbons which could be acutely toxic at high concentrations (affecting eyes, breathing, nervous system, and possibly heart rhythms). NIOSH plans to conduct further studies and has recently requested assistance from oil and gas stakeholders. Based on limited information, their preliminary recommendations include reviewing tank gauging procedures, hazard awareness training, ensuring workers do not work alone, monitoring worker exposures, and using appropriate respiratory protection. For more information, see: Reports of Worker Fatalities during Flowback Operations and Oil and Gas Extraction Program.

According to the National Institute for Occupational Safety and Health (NIOSH), one out of every four mine workers has a severe hearing problem. Hearing loss can interfere with a miner’s ability to communicate with family, friends, and co-workers. Hearing loss, particularly in a noisy environment, can also present a safety hazard when workers are unable to hear moving machinery and warnings.

Metal and non-metal mining and mineral processing operations such as sand and gravel follow noise and hearing conservation regulations set out by the Mine Safety and Health Administration (MSHA) under Part 62. NIOSH also serves as a valuable resource for the mining industry through its Hearing Loss Prevention Branch which recently received the 2014 Research and Educational Excellence Award from the Society for Mining, Metallurgy & Exploration. This group was recognized for its research into better understanding noise exposures experienced by underground workers and helping develop commercially available noise controls to reduce those exposures. To learn more about hearing loss prevention for mining and mineral operations, visit: http://www.cdc.gov/niosh/mining/topics/HearingLossPreventionOverview.html.

With the unfortunate rise in wildfires throughout the west, it's timely to pause and consider one of the often overlooked hazards of this high-risk occupation – noise. Wildland fire fighters may work 12 to 16 hour shifts for up to 14 consecutive days. And although noise exposures and hearing loss have been well-documented for structural fire fighters, wildland exposures have only recently come to light.

Wildland fire-fighters encounter numerous well-known noise sources such as chainsaws, leaf blowers, wood chippers, pumps, bulldozers and airplanes. The United States Forest Service, in partnership with the National Institute for Occupational Safety and Health (NIOSH), recently concluded a 3-year study to assess wildland fire fighters' exposures. Noise dosimetry was conducted for over 150 fire fighters across 10 different wildfires. Measured noise doses frequently exceeded OSHA occupational and NIOSH recommended exposure limits, particularly for those operating chainsaws, chippers, and masticators. Researchers recommended a comprehensive approach to protecting wildland fire fighters, including noise and administrative controls and enrolling fire fighters in an ongoing hearing conservation program.

To learn more:

• Wildland Firefighter Health: Some Burning Questions, NIOSH Science Blog, posted on September 28, 2020 by LCDR Corey Butler et al.
• Noise Exposure Among Federal Wildland Fire Fighters, NIOSH Science Blog, posted on April 17, 2017 by George Broyles , LCDR Corey Butler, CAPT Chuck Kardous 
• Broyles, et al. (2017). Noise exposure among federal wildland fire fighters, Journal of the Acoustical Society of America, 141(2), published online 
• National Interagency Fire Center Wildfire Situation Report (updated regularly)
• NIOSH Fire Fighters Resource page 
• NIOSH Emergency Responder Health Monitoring and Surveillance Program
• U.S. Fish & Wildlife Service, Fire Management page 
  (photo source: fws.gov)

There are three types of radio communication types: Simplex, Half-Duplex, and Full-Duplex. Each has its place in workplace communication. In Simplex Communication, data is sent in only one direction. In Half-Duplex Communication, data can only be sent from one device at a time. Once that device has finished sending its data, the other device may send data. In a Full-Duplex Communication, all devices on the network may transmit data at any time. Knowing the advantages and ideal applications of each can help make communication more efficient and also help choose the most cost-effective solution.

A new scientific report provides evidence for something companies have known for years. Hearing protection ratings, and de-ratings, are not helpful with the day-to-day success of a hearing conservation program. It's long been understood that the laboratory-based Noise Reduction Rating (NRR) does not accurately predict real-world performance of a hearing protector. But unfortunately, it's now clear that the numerous de-rating schemes developed over the years to compensate for NRR shortcomings aren't accurate either.

A new comprehensive analysis was recently published in the Journal of the Acoustical Society of America (JASA). Researchers from the National Institute for Occupational Safety and Health, the Department of Defense and others examined four real-world hearing protection attenuation studies. Results of Individual Fit Testing for workers were compared to product NRRs and various NRR de-rating schemes. The good news: individualized earplug fitting and training was shown to dramatically improve "real-world" protection for many workers. The not-so-good news was that NRR de-rating schemes failed to accurately predict real-world protection for the majority of workers tested. In many cases, real-world results far exceeded hearing protector performance predicted by NRR de-rating schemes. Because hearing protector fit testing systems are now readily available for use in the workplace, the authors concluded it is a better approach than relying on de-rating formulas.

NRR Ratings and De-Rating Schemes

Hearing protection devices provide a wide range of protection against noise depending on the design of the protector and the fit in the individual user's ear. When OSHA promulgated the Hearing Conservation Amendment for general industry in the early 1980s, it incorporated the Environmental Protection Agency's Noise Reduction Rating (NRR) as a way to help employers evaluate and compare expected performance of available hearing protectors. The NRR is a laboratory-derived estimate of the attenuation (sound reduction) expected from a hearing protector when it is fitted and worn as designed. Shortly after the Hearing Conservation Amendment went into effect, however, it became evident that the actual amount of attenuation achieved in the workplace often fell short of the laboratory-predicted NRR.

Since that time, regulatory and scientific groups have proposed a variety of schemes for adjusting hearing protector ratings in an attempt to better adapt NRR ratings to real-world performance. Some recommendations included cutting the NRR in half; others suggested a percent reduction according to the class of hearing protector. It's a commonly held misconception that OSHA, MSHA and other compliance authorities require that employers de-rate NRRs. Instead, companies should use the NRR calculation to help determine which types of hearing protectors will likely offer adequate reduction for workplace noise exposures. However, to find out what is happening in the real world for each worker, it is far more useful to conduct an Individual Fit Test to ensure that the chosen hearing protector is actually performing as intended. Read more about the NRR and other ratings here.

Real-World Measures

Individual Fit Test systems are designed to measure the noise reduction provided for an individual worker using their own hearing protector as it is routinely fit and worn. Although assessment equipment and procedures are not completely standardized, most fit test systems generate a Personal Attenuation Rating (PAR). Given the inability of laboratory ratings and de-rating schemes to accurately predict real world attenuation, PARs provide employers with beneficial information about fit and protection for each employee.

CavCom‘s experience mirrors the recent analysis published in JASA. Through Individual Fit Testing, we find our hearing protectors and earsets yield significantly higher actual protection via PARs than would be predicted by an NRR-based calculation, de-rated or not. In particular, custom-fitted hearing protectors are less susceptible to poor insertion, and generally provide more consistent and higher attenuation in the real world. Read more about Individual Fit Testing here.

The Bottom Line about NRR De-Rating Schemes

Stated simply, NRRs and de-rated NRRs do not accurately predict real-world performance of hearing protectors. For this reason, decisions regarding worker noise exposures and hearing protection are more accurate when based on real-world PAR values. Better information also helps companies tailor hearing protection to the work environment and avoid such pitfalls as overprotection. Overprotection is a situation where the worker receives more attenuation than necessary, leading to potential communication complications and safety concerns. Read more about overprotection here.

Lastly, it's important to remember that subjective considerations such as comfort and convenience are also key factors in hearing protector acceptance and wear time. It's often said, and is worth repeating, that the "best" hearing protector is the one that is worn correctly and consistently whenever the worker is exposed to hazardous noise. Read more about comfort here.

Contact Us

Not sure which hearing protectors are optimal for your workforce? Contact CavCom to discuss options and to learn more about how our innovative hearing protectors and communication earsets can improve safety and communication in your workplace.

Resources:

• Murphy, Gong, Karch, Federman and Schulz (2022). Personal attenuation ratings versus derated noise reduction ratings for hearing protection devices, The Journal of the Acoustical Society of America, 152 (2), 1074-1089. https://doi.org/10.1121/10.0013418.
• The Noise Reduction Rating (NRR), CavCom SoundBytes.
• Individual Fit Testing and Personal Attenuation Rating (PAR), CavCom SoundBytes.
• The Risk of Overprotection, CavCom SoundBytes.
• Improving In-Ear Comfort, CavCom SoundBytes.

The ability to detect, identify, and localize sounds during military operations is essential. Unfortunately, hazardous noise is a constant threat to military personnel during training exercises, active duty, and even off-the-job activities. Noise-related hearing loss and tinnitus (ringing in the ears) are the two most frequently reported disabilities of military service, affecting millions of veterans - including over 750,000 Gulf War era veterans alone.

To help address this threat to hearing and quality of life, the US military is focusing on early identification, immediate intervention, and an ongoing support system for veterans. Military researchers and clinicians recently collaborated to create a Clinical Practice Guideline (CPG) published last month by the Association of Military Surgeons. This CPG provides guidance for audiologists, otologists and emergency response personnel for the evaluation and treatment of service members exposed to blast injury and acoustic trauma. After life-threatening injuries have been addressed, damage to outer ear/eardrum and inner ear hearing and balance must be assessed, treated and monitored. The CPG is intended to increase awareness among hearing healthcare providers and to improve early identification and treatment of acoustic trauma.

To assist veterans and their families and researchers/providers on an ongoing basis, the Department of Defense has also created the Hearing Center of Excellence (HCE). The HCE is a multi-branch effort with the Veteran's Administration (VA) to promote prevention, diagnosis, treatment, rehabilitation and research of hearing loss and auditory injury. The HCE's primary responsibilities include:

• Develop a data registry to track hearing loss and auditory injuries across the Armed Forces, and share the registry data with the VA
• Encourage and facilitate hearing health research
• Develop best practices and clinical education, and
• Ensure the coordination and delivery of VA rehabilitation benefits and services to former Service members

The HCE educational website provides help and support for active military personnel, veterans, and their families. Visitors to the HCE website can find a provider and learn about VA healthcare and disability benefits. The Resources section provides training resources, real patient video stories, frequently asked questions, and links to helpful websites. Sign up for a newsletter and check out news articles, podcasts, and apps about hearing-related topics.

Hearing Center for Excellence website  

Additional resources:

• Esquivel, et al. (2018) Clinical Practice Guide: Aural Blast Injury/Acoustic Trauma and Hearing Loss. Military Medicine, Vol. 183, 9/10: 78-82.
• Wells, et al. (2015). Hearing loss associated with US military combat deployment, Noise Health. 2015 Jan-Feb; 17(74): 34–42. 
• Institute of Medicine (2006). Noise and Military Service: Implications for Hearing Loss and Tinnitus. Washington, DC: The National Academies Press. 

Risk of Hearing Loss

With acoustic impulses in the range of 145 to 175 dB peak Sound Pressure Level, even a single gun shot can result in damage to the delicate nerve structures of the inner ear. Shooting ranges in both indoor and outdoor settings provide additional risks where bench-rest shooting, platforms, covers, or other solid surfaces can reflect and amplify the sound energy. Unfortunately, many shooting enthusiasts report they seldom wear hearing protection when exposed to gunfire, especially when hunting. Even when shooters themselves understand the potential danger to their own ears, many don't realize that bystanders are also at risk. Recent efforts have been focused on protecting children who often begin hunting and target shooting at a very young age.

Strategies to Reduce Risk

Over the years, legislation has been introduced to loosen restrictions on the use of gun suppressors. Supporters say reducing noise from guns would protect hearing of the general public; opponents fear misuse of the technology. To provide more guidance on the matter of hearing loss prevention related to gunfire, the National Hearing Conservation Association (NHCA) has published a guideline on firearm noise. Strategies that can reduce the risk include wearing appropriate and properly fitted hearing protection, choosing smaller caliber firearms, using specialized ammunition, shooting in a non-reverberant environment, and avoiding shooting in groups. Although using firearms equipped with noise suppressors can help reduce the level of the sounds, NHCA warns that suppressors do not eliminate risk.

Specialty Hearing Protection

Let's be clear, traditional hearing protectors can effectively block out loud noise – whether in an occupational setting or during recreational activities. Gun sports, however, present a unique challenge because the offending impulse sounds may be extreme, but they are only milliseconds in duration and often only occasional. Most hunters want to have the best possible hearing when listening for game in the brush, but then be protected when taking a shot. Thankfully, in recent years, new technologies have emerged that are effective in protecting against impulse noise such as gunfire and at the same time are user-friendly for typical hunting/shooting activities.

Impulse Filters

Traditional hearing protection can be very effective against loud noise. However, most hearing protectors are not selective in the amount of protection they provide (that is, they block both loud and quiet sounds by the same amount). This means that although the user is protected, he or she may miss out on important cues such as speech and environmental sounds. For these situations, specialty "impulse filters" are available that let most low level sounds pass through the filter with minimal muffling. However, when a loud impulse such as a gunshot is present, the filter effectively reduces the "bang" to a safe level.

Electronic Hearing Protectors

Electronic hearing protectors can be even more sophisticated in their ability to sample and manage incoming sounds at the ear. Electronic protectors use battery-powered electronic circuitry to sample ambient sounds in real time. Quiet sounds are allowed to pass through the earpiece, and very quiet sounds can even be amplified to provide a "hearing boost" for the user. But when an incoming sound is too loud, then the electronic circuitry automatically shuts down effectively reducing that sound to a safe level. This way, users can hear game sounds and conversations normally, or even with an enhanced volume boost. But when sounds become dangerously loud, the technology will keep hearing protected.

A Word of Caution

We are aware that many products on the open market claim to offer selective protection against impulse noise. However, in our experience, fewer actually deliver on that promise. As always, be an informed consumer and do your research before purchasing. Only purchase products from a reliable manufacturer with appropriate warranties and fit guarantees (for custom products).  

• Hit the Mark: Firearms training without damaging your hearing. NIOSH Science Blog, March 3, 2017
• NHCA Position Statement: Recreational Firearm Noise, 2017
• Meinke, D. K., Finan, D. S., Flamme, G. A., Murphy, W. J., Stewart, M., Lankford, J. E., & Tasko, S. (2017). Prevention of Noise-Induced Hearing Loss from Recreational Firearms. Seminars in hearing, 38(4), 267–281. https://doi.org/10.1055/s-0037-1606323

To learn more about CavCom‘s complete line of electronic and passive hearing protectors for shooters, check out WildEar.com.

Noise pollution is a serious concern for quality of life. Assessing possible effects of noise on general health is notoriously difficult to study. People who are exposed to noise throughout a day are also exposed to many other environmental and societal factors that likewise can affect health. It's difficult to tease out strong relationships and particularly cause and effect.

Researchers from the Canadian Department of Health have recently published results from the Canadian Health Measures Survey, a comprehensive ongoing epidemiological study of a broad cross-section of the Canadian population. This report did not support an association between loud noise exposure and changes in biomarkers for cardiovascular disease outcomes, such as hypertension, myocardial infarction, or stroke. Researchers reported expected results for hearing loss, but concluded their data did not support the theory that noise is a serious contributor to cardiovascular disease. Other researchers continue to study the matter, and we'll be sure to watch and report any emerging trends.

• Canadian Health Measures Survey website
• Michaud, DS, Marro, L and McNamee, JP (2021). Self-reported exposure to occupational noise and cardiovascular disease in Canada: Results from the Canadian Health Measures Survey. The Journal of the Acoustical Society of America, 150, 990 (DOI: 10.1121/10.0005588).

We at CavCom hope you and your family enjoy the great outdoors this summer... and when fun gets loud, remember to use hearing protection!
Many outdoor activities such as lawn work with mowers and blowers, attending loud concerts or sporting events, motorcycles/speedboats, and even enjoying fireworks have the potential of damaging hearing if you are exposed long enough and often enough. To learn more about protecting your family's hearing, check out the Loud Noise website from the Centers for Disease Control and Prevention.

  Quick Tips - How to Protect Your Hearing

1. Turn down the volume on music players or other entertainment
2. Buy quieter equipment (power tools, mowers, etc.)
3. Avoid loud, noisy activities and places
4. Take breaks from loud noise
5. Wear effective hearing protection when you can't avoid loud noise

And for more information on recreational noise exposures, please see this SoundBytes article about Non-Occupational Noise Exposures.

It is estimated that 40 million Americans show some form of hearing loss. The odds of hearing loss go up with age, with over two-thirds of individuals over the age of 60 having difficulty hearing high pitch sounds and 1 in 4 having difficulty hearing speech. Worse yet, many people who think they have good hearing don't even realize they already have some hearing loss.

Invest just 2 minutes of your time– take this quick 10 question quiz to determine if it's time for you (or someone you love) to get a hearing test.

For more information:

 Who Can I Turn to for Help with My Hearing Loss? National Institute on Deafness and Other Communication Disorders 

Hearing Loss and Older Adults. National Institute on Deafness and Other Communication Disorders 

Hearing Loss in Children. National Center on Birth Defects and Developmental Disabilities  

photo source: NIDCD, nih.gov

Do you suffer from ringing in the ears? You're not alone! The National Institute on Deafness and Other Communication Disorders (NIDCD) estimates that over 20 million Americans experience chronic ringing in the ears, known as tinnitus (pronounced "TIN-a-tus" or "Tin-EYE-tus"). The condition can be mild, intermittent, or so severe as to interfere with sleep, concentration, and enjoyment of daily life.

A recent analysis of data collected as part of the National Health Interview Survey indicated that noise-exposed workers in the United States are 3 times more likely to report suffering from tinnitus than their non-noise-exposed counterparts. According to the U.S. Department of Veteran Affairs, tinnitus and hearing loss are the top two service-connected disabilities for U.S. service members. Veterans of Iraq and Afghanistan have been exposed to a number of hazards known to cause hearing loss and tinnitus, including loud noise, blasts/explosions, and ototoxic chemicals. Service members who have suffered a traumatic brain injury are 3 times more likely to experience tinnitus than other veterans. Those exposed to solvents, a class of ototoxic chemicals, are twice as likely to report ringing in the ears.

Tinnitus is an annoying and sometimes debilitating condition, commonly defined as the perception of noise in one or both ears when no sound is actually present. Usually described as high-pitched, it might also be perceived as roaring, clicking, hissing or buzzing. Tinnitus can be a sign that something is wrong with the outer, middle or inner ear, the auditory nerve, or parts of the brain that process sound. Noise exposure, acoustic trauma, exposure to chemicals, and ear diseases/infections are common causes of tinnitus. Complicating its diagnosis and treatment, tinnitus has many other causes as well, including disorders of the heart/circulatory system, stress, hormone changes, and as a side effect of medications, smoking, or too much salt or caffeine. Sometimes the cause of tinnitus is unknown.

So what can a person experiencing tinnitus do about this annoying and on occasion even incapacitating condition? The first step in managing tinnitus is to get an evaluation. See your primary care doctor to determine if a medical condition or medication may be causing or aggravating the ringing. If needed, you will be referred for a complete audiological and otological examination to establish if there is an underlying ear or hearing problem. Although there often is no cure for long-term tinnitus, there are treatments and therapies that can help people cope with the annoyance and frustration of this condition. And because noise is a leading cause, remember that you can reduce the likelihood of developing or worsening tinnitus by limiting time spent around loud noise and wearing well-fitted and effective hearing protectors when needed.

For more information/resources:

• National Institute on Deafness and Other Communication Disorders – Tinnitus Topic Page 
• American Tinnitus Association  (ATA)
• ATA "Managing your tinnitus" 
• Department of Defense Hearing Center of Excellence – Tinnitus Topic Page
• Griest, et al. (2018). Risk factors associated with tinnitus and hearing loss in current and recently separated service members across military branches. Annual conference of the National Hearing Conservation Association. Orlando, February 2018.
• NIOSH Press Release (2016). Putting an Ear to the Ground: NIOSH Study looks at Prevalence of Hearing Difficulty and Tinnitus among Workers 

Along with researchers at the University of Kansas, CavCom‘s Dr. Susan Cooper has published a new method for quantifying noise exposures both on and off the job. Published in the Journal of the American Academy of Audiology, this detailed, task-based analysis tool results in an annual noise exposure value based on time and duration of exposures throughout the previous year.

The evaluation tool is a self-administered Noise Exposure Questionnaire (NEQ), which takes approximately 10 minutes to complete. Individuals are asked to recall noisy activities during the past year, including routine activities and any that are seasonal or infrequent (e.g., hunting, snowmobiling, attending music concerts or sporting events). Answers to the NEQ are then used to compute an annual noise exposure (ANE) value.

Current case history tools typically focus on whether a person participates in noisy activities but do not quantify the time spent in these activities. In the new ANE approach, both occasional and routine/daily exposures are combined to produce an overall noise exposure estimate. It is the combination of sound level and duration that increases risk: how loud, how long, and how often. These tools can be used by hearing conservation professionals to focus hearing loss prevention efforts toward those individuals at greatest risk on or off the job.

For a copy of the questionnaire, contact Dr. Susan Cooper 

To learn more:

Johnson, Cooper, Stamper & Chertoff (2017). Noise Exposure Questionnaire: A Tool for Quantifying Annual Noise Exposure, Journal of the American Academy of Audiology 

Noise Pollution Update, CavCom SoundBytes

Understanding Noise Exposure Limits: Occupational vs. General Environmental Noise. NIOSH Science Blog, February 8, 2016. 

Throughout day to day life, there are standards and benchmarks that exist to give people an idea of thresholds and recommendations for safety. There are posted speed limit signs on every drivable surface. The proper number of life jackets must accompany boaters and watercraft. Capacity limits in elevators, airlines, and even restaurants for fire code. Many people are well-versed in knowing these regulations and rules (even if they don't always adhere to them) but what about the guidelines for everyday noise exposures and safety precautions to protect our hearing?

Noise Without Knowing It

I had this conversation with my wife the other day when it came to our kids. She was blown away by the fact that if our kids are listening to music, it could be too loud. The bad equation here, so to speak, is the noise level plus time exposed. It's not uncommon for people to spend a few hours listening to their devices. Sound is being piped directly into the ear. And it can be intense.

Hearing loss is insidious and more likely to occur over time without people even knowing it. I use the example of people experiencing changes in vision or sight loss. You'll know something is amiss when your vision starts to falter. You can literally see it happening. We're not as lucky when it comes to our hearing. Of course, in high-noise industries and careers where hearing protection comes standard every day, there's more awareness of noise damage and how to combat it to protect hearing. Yet, there are plenty of places where noise is more unsuspecting, instances where people simply might not be aware of the threat.

Unsuspecting Culprits of Noise

• Military —I'm a military veteran and the military is full of heavy equipment and artillery. Whether training, occasional duty weekends, or full deployment — it's all loud and ongoing.
• Landscaping and power tools — I just told my dad last year when he was operating a chainsaw that he should really use hearing protection. He told me it wasn't that loud; I told him it could easily be over over 100 dBA. That's extremely loud! This goes for homeowners and weekend warriors alike, not just professional services.
• Vehicle noise — diesel rigs are extremely loud, but motorcycles and snowmobiles can be too
• Musicians, music fans and concert-goers
• Entertainment venues — think of loud restaurants or bars where you have to continually raise your voice to order a drink or engage with a server. There's sporting events, too.

Simple Lack of Awareness = Significant Cost

I mentioned the scenario with my dad on that list because, in my opinion, people damage their hearing due to a fundamental lack of awareness. It's not generational; it's not younger people who don't think about hearing protection or think they'll be immune to hearing loss. It's simply being unaware of how much noise we're exposed to in unlikely places. Think about the ways vision, for example, is portrayed in advertisements and media. There's a lot. Protect your eyes. Wear protective sunglasses and safety goggles. Maintain preventative eye exams. Etcetera. There just isn't the same push from hearing. Have you ever even seen an ad focused specifically on hearing loss and ways to counteract its effects across our population?

When people do think about hearing loss, a lot of times, it's just, well, I'll just get a hearing aid when I need it. That's not going to work for everyone, and even though hearing aids can help many people, it's not the same as your natural hearing. People have no idea what truly is at risk. It's not something we talk about every day.

Hearing loss may occur slowly, and all of a sudden, you have damage you weren't even tracking as happening in real-time. They don't realize it until they're in their 50's, and all of a sudden, they can't hear grandkids or their kids talk to them. In some situations, you'll see people who are not necessarily reading lips but trying to understand what the person is saying by looking at their mouths as they speak. They're not necessarily reading exactly what they're saying, but they're catching the vowels and the consonants when people move their lips a certain way.

Consonants become especially tricky in hearing loss: it can be the difference between comprehending the words fist and fish and differentiating between the two. That will make for some confusion.

They likely have just associated this hearing loss as an everyday thing, or age-related and normal, to an extent. With this realization comes clarity: situations that people wouldn't normally think are loud, like radios, televisions, operating household items, etc. truly are. Everyone around that person is responding with it's extremely loud and hearing has been damaged, and usually irreversibly.

Protecting Hearing at All Costs

My general rule of thumb for people is, if you have to raise your voice above any noise or din, you need hearing protection. And you need to be consistent.

When I walk into a facility, and I see someone without hearing protection in or it's improperly inserted, I immediately go up to that person and mention for educational purposes that they might be wearing hearing protection wrong. A lot of times, those individuals are surprised and mention how they haven't been told right from incorrect. Hearing conservation programs are one way to ensure an entire workforce is safely operating in order to protect their hearing. But protecting yourself in a workplace, especially high-noise where safety mandates are status quo, is different than recognizing the ways you're exposing yourself to hearing damage in everyday life.

How Loud is Too Loud

• Remember the One-Yard Rule: If you have to shout to be heard by others one yard away, then the background noise is likely in a hazardous range.
• You notice after being exposed to noise:
  • Tinnitus (ringing) or pain in ears
  • Speech seems muffled
  • Turning up the volume on radio or TV

What You Can Do to Protect Yourself

• Turn down the volume
• Walk away from loud noise
• Buy quieter equipment and tools
• Wear effective hearing protection whenever you are exposed to loud noise
• Get your hearing tested on a routine basis

Make sure your hearing lasts a lifetime!

Resources for Learning More about Recreational Noise

• How’s My Hearing? 
• Noise-Induced Hearing Loss
• Smartphone Apps for Measuring Sound
• Hunters/Gunsports
• Musicians
• Young People
• Research on Non-Occupational Noise Exposures

Although the first goal of an effective hearing conservation program is to reduce noise at the source, the reality is that many workers rely on daily use of personal hearing protection devices (HPDs) to reduce the risk of noise induced hearing loss. Even a well-designed and expertly-fitted HPD may take some getting used to. For older workers, the challenge can be even greater.

According to the U.S. Bureau of Labor Statistics, approximately 20% of American workers are 65 years or older. With an aging population and workforce, many companies are now taking notice of what is required to keep their employees safe and healthy for a long working lifetime. Keys to HPD success include optimal fit, care and consistent and continued use during the entire workshift. We're often asked if the ear canal changes due to age and if this could affect older workers' ability to be protected from noise on the job.

Although there is a great deal of individual variability, we know that one aspect of the ear that does not seem to change with age is the basic size of the earcanal. Anatomical studies show that the outer ear and ear canal are fully developed by puberty, and that the overall size/volume of the canal does not change significantly over time.

All the same, it's important to recognize that other anatomical changes that accompany aging could affect comfort and successful use of HPDs. Some common transformations in the earcanal associated with getting older include:

• Thinning of the skin that lines the earcanal and loss of elasticity
• Atrophy/loss of fatty tissue that pads the earcanal
• Reduced secretions from glands in the canal, leading to dry skin
• Earwax can be drier, harder and more likely to become impacted
• Sagging, or "collapsing" of the cartilage in the outer portion of the earcanal
• For men, growth of wiry hair at the opening of the canal

Next, it's important to consider the implications of these changes that could impact older workers and hearing protection use:

• Older workers may require more frequent medical care for outer ear infections or earwax build-up. It may be necessary to wear earmuffs instead of earplugs until medical clearance is received.
• Individuals who have thinning skin and decreased fat pads in the ear canal may find earplugs less comfortable than they used to be. Forcing any object into the earcanal could even cause bruising or breaking the skin. It may be necessary to try different styles and materials of HPDs to determine the most comfortable fit (subjective but essential to acceptance and compliance).
• If a worker experiences collapsed canals, it may be more difficult for him or her to insert a hearing protector. It's especially helpful to follow the preferred protocols: using the opposite hand, pull up and out on the outer ear to straighten the earcanal prior to inserting an earplug.
• Jaw motion may cause earplugs to dislodge easier for certain workers, including older individuals with softer ear canals. Again, try different styles and materials of HPDs. Remind employees that they may need to reseat earplugs regularly if they become loose throughout the day.

And most importantly, carefully check the fit and seal of the hearing protector for all of your employees on a regular basis, including older workers. Many companies are now routinely conducting individual fit testing for HPDs, similar in concept to fit testing for respirators. NIOSH, OSHA and professional organizations have identified individual fit testing as a best practice for hearing conservation programs.

To learn more about aging, the earcanal and ear care, see:

American Academy of Otolaryngology. Earwax and care. 

NIOSH. Productive Aging and Work. 

Oliveira, RJ (1997). The active earcanal. Journal of the American Academy of Audiology, 8: 401-410.

Staab, W (2014). The human earcanal, series: I-VIII. Hearing Health Matters.

Summer is the time of year for enjoying the wonderful outdoors, including frequent visits to the pool or nearest beach. Most of us have experienced "swimmer's ear" at some point, but what exactly is this painful condition and how can we prevent it from spoiling our summer fun?
Acute otitis externa (AOE) is the technical name for an infection or inflammation of the lining of the ear canal. The condition gets the name "swimmer's ear" because it is more likely to occur among swimmers or surfers, especially in warm, humid climates. The condition usually develops after water gets trapped in the ear canal, then a bacterial or fungal infection sets in. Factors that may increase the risk of developing swimmer's ear include: contact with excessive bacteria in hot tubs or polluted water, excessive cleaning of the ear canal with cotton swabs or other foreign objects, a cut in the skin of the ear canal, and other skin conditions affecting the ear canal such as eczema or seborrhea.

Although swimmer's ear is usually considered a mild illness, its impact is not. The U.S. Centers for Disease Control and Prevention (CDC) estimate that the condition results in an estimated 2.4 million health care visits costing over half a billion dollars in direct health care costs each year. The most common symptoms of swimmer's ear include pain (often severe) and itching inside the ear canal. Sufferers may also experience redness/swelling, drainage from the ear, fever, a feeling that the ear is blocked, or even hearing loss. If left untreated, it may lead to recurring ear infections, hearing loss, and even more serious complications. Immediate treatment by a medical professional is recommended to reduce pain and prevent the spread of infection.

Tips for prevention include:

• Use well-fitted earplugs when swimming
• Do not swim in polluted water
• Towel off or use a hair dryer to dry your ears
• Tilt your head to each side to allow water to escape the ear canal
• Do not use cotton swabs or other objects to remove earwax; this usually just packs earwax and dirt deeper in the ear canal (a thin layer of earwax actually helps protect your ear canal from infection)
• Check with your doctor on a regular basis if you have frequent cases of swimmer's ear or any other ear problems such as itchy, flaky or scaly ears, or excessive earwax that blocks your ear canal

To learn more:

• Centers for Disease Control and Prevention: Swimming & Ear Infections
• Centers for Disease Control and Prevention: Facts about "Swimmer's ear"
• Centers for Disease Control and Prevention (2011). Estimated burden of acute otitis externa – United States, 2003-2007. MMWR, Vol. 60 (19), 2011.

(photo source: cdc.gov)

Help the young people in your life develop healthy hearing habits now. Check out these campaigns designed specifically for educating school-age children on the hazards of noise and protecting hearing. Many guidelines, handouts, posters, and games are available for download at no charge (some in Spanish); great tools for teachers!

It's a Noisy Planet  is administered by the U.S. Department of Health and Human Services. This public education campaign is designed to increase awareness among children ages 8 to 12 about the causes and prevention of noise-induced hearing loss. It's a Noisy Planet website features fun and friendly informational sections for kids and preteens, parents, educators and health professionals. Noisy Planet's three key prevention messages are:

• Lower the volume.
• Move away from the noise.
• Wear hearing protectors, such as earplugs or earmuffs.

Another teacher favorite is Dangerous Decibels. The Dangerous Decibels project is based on a collaboration between basic science researchers, clinicians, museum educators, health communication experts, teachers, and public health professionals. Teachers can request a free Educator Resource Guide that includes curricula and a collection of hands-on activities, background information, and experiments that can be used in the classroom. Be sure to check out the online Virtual Exhibit for interactive games, demonstrations and activities that will entertain and educate young people on the importance of protecting hearing.

The U.S. Bureau of Labor Statistics estimates that over 200,000 Americans work as professional musicians, singers, and music directors. Many more are employed as music teachers, audio engineers, band crew members, and nightclub DJs. Because their livelihood depends on excellent hearing, many music professionals are taking note of the potential risks of prolonged sound exposure. The National Institute for Occupational Safety and Health (NIOSH) has published a new guideline to help musicians and those who work in the music industry protect their hearing.

NIOSH's new guideline was initiated in response to a series of sound exposure studies of teachers and students involved in music classes and marching bands. NIOSH researchers found that performances and rehearsals often exceeded 90 dBA, sound levels capable of causing permanent hearing damage for students and teachers with sufficient exposure. Countless studies have also shown that sound levels at concerts and night clubs can exceed safe levels, a special concern for professionals who practice and perform many hours a week.

To help reduce the risk of developing hearing loss and tinnitus (ringing in the ears), NIOSH recommends that musicians, employers, schools and music venue operators:

•  Implement a hearing conservation program that includes training and routine hearing tests.
•  Increase distances between individuals and instruments when feasible.
•  Play music and sound amplification systems at lower levels.
•  Encourage participation in educational and awareness campaigns on music-induced hearing loss.
•  Identify hearing protection solutions that work best for individual musicians and related workers.

A special challenge for musicians can be their reluctance to wear hearing protectors. As a general rule, traditional earplugs and earmuffs block out more high frequency (pitch) sounds than low frequencies. Musicians often complain that their ability to monitor music is compromised because the treble is cut more than the bass. Newer high-tech hearing protectors can provide a solution. Specialty hearing protectors offering "uniform-attenuation" are designed to preserve the frequency balance of sound. The result is that attenuated sounds have roughly the same quality as the original sounds, only quieter. Uniform-attenuating hearing protectors are an excellent solution for workers needing to understand speech communications in noise, as well as musicians who insist on the highest sound fidelity possible.

For more information and helpful resources for music exposures, see:

NIOSH (2015). Workplace Solutions: Reducing the Risk of Hearing Disorders among Musicians.

NIOSH (2012). Health Hazard Evaluation: Noise exposures in school music classes and marching band rehearsals.

Chasin (2008). Musicians and the Prevention of Hearing Loss: An Introduction. Audiology Online. 

CavCom SoundBytes. Benefits of Uniform Attenuation. 

Researchers at the University of Michigan and the Network for Public Health Law would like to change public policy when it comes to noise pollution. In an article published recently in Environmental Health Perspectives, the authors argue that noise in everyday life not only poses a threat to hearing, but is also associated with general health problems such as sleep disturbance, stress, hypertension, heart disease, and even injuries. They call for noise to be included in federal and state public health agendas and offer recommendations for managing noise that currently impacts millions of Americans. "I can't think of any other environmental hazard that affects so many people and yet is so ignored," says Rick Neitzel, assistant professor of environmental health science at MU.

Read the Full Article

Wind power is rapidly becoming a popular alternative to fossil fuel. Towering wind turbines are now a routine sight across our landscapes. In spite of their potential environmental benefits, however, wind turbines are not without controversy. Of particular concern is the noise they produce and fear of health effects for those living near large operations.

Wind turbines emit noise that is very low in frequency, often so low that the sound cannot be heard or is barely audible (infrasonic). For many years, scientists assumed infrasound posed little or no threat to humans, the old adage "what we can't hear can't hurt us." Some are now challenging that notion. Although researchers have been studying the effects of environmental noise on human health for many decades, there is still much unknown. Noise annoyance, or sensitivity, is a perception of how bothered a person is by noise. Perception is often individual in nature and difficult to predict. Even less understood is whether environmental noise might be linked to health effects such as sleep disturbance, hypertension, or heart disease.

Early studies of wind turbine noise often regarded perceptions and "indirect" effects such as annoyance, sleep disruption, and associated stress as unimportant. Now researchers are considering the possibility that indirect effects may hold potential for long-term physical harm. Still, studies are difficult to design and carry out. Controlled longitudinal studies over many years would be needed. People come and go, other environmental concerns such as air pollution are difficult to factor out, and even potential health effects such as elevated blood pressure could take years or decades to show up.

Toward this goal, Health Canada is currently studying a group of over 1000 people living near wind-turbine developments. Initial results indicated no conclusive overall link between illness and wind turbine exposure. But when researchers looked closer, they found a statistically significant relationship between such health issues as blood pressure, migraines, tinnitus, dizziness, and stress for residents who reported being highly annoyed by wind turbine noise, vibration, blinking lights, etc. Researchers were careful to point out they had no way of knowing whether these health conditions may have pre-dated residents' exposure to wind turbines. Still, the findings support a potential link between high annoyance and health. Further study is warranted. Due to the large volume of acoustical data, Health Canada will continue its data analysis and publish additional findings in future.

References and further reading:

Seltenrich N (2014). Wind turbines: a different breed of noise? Environ Health Perspect 122:A20–A25; 

Health Canada (2013). Wind Turbine Noise and Health Study: Summary of Results. 

NIDCD News (2010). Scientist Challenges the Conventional Wisdom That What You Can't Hear Won't Hurt You.

We all remember the news last year – U.S. diplomats fell ill after hearing strange sounds on assignment in Havana, Cuba. Now, nearly a year later, physicians and scientists have arrived at a frustrating conclusion: many embassy employees show symptoms of traumatic brain injury, but the source is still unknown.

Theories of poisonings, biologic attack, and ultra-sonic weapons immediately proliferated. Diplomats were removed from the embassy in Havana, the U.S. State Department issued travel warnings, and Congress held hearings to investigate. By late 2017, 24 of 80 embassy employees had been diagnosed with mild traumatic brain injury. After extensive medical evaluation, researchers from the University of Pennsylvania School of Medicine published results of a preliminary review of medical findings in the February issue of the Journal of the American Medical Association.

Injured diplomats consistently reported exposure to auditory and sensory phenomena coming from a distinct direction in their homes or hotel rooms. Patients experienced headaches, sleep abnormalities, and cognitive, balance, visual and auditory problems. Because of neurological symptoms, these individuals were referred to an academic brain injury center for multidisciplinary evaluation and treatment. Upon review of the medical data, researchers determined that the diplomats had sustained injury to widespread brain networks without associated head trauma. Although the origin of the injuries is still unclear, many experts are skeptical of sonic attacks. And so, studies and debate will continue.

To learn more:

Swanson, Hampton, et al. (2018). Neurological Manifestations Among US Government Personnel Reporting Directional Audible and Sensory Phenomena in Havana, Cuba. Journal of the American Medical Association, 319(11):1125-1133. doi:10.1001/jama.2018.1742

Need a quick sound check on the go? Turn your iOS device into a sound level meter by downloading a free app developed by researchers at the National Institute for Occupational Safety and Health (NIOSH). While the app is not meant to replace a professional sound level meter or noise dosimeter for compliance purposes, it does allows you to estimate A-weighted and C-weighted sound levels, maximum and peak levels and Time-Weighted Average (TWA) and Dose.

To download the app, go to the iTunes store and search "NIOSH SLM" 

For more information:

• NIOSH Sound Level Meter app webpage
• CavCom SoundBytes. Smartphone Apps for Noise Measurement. 

photo source: NIOSH, cdc.gov

In previous issues of our SoundBytes newsletter, we have reported on tests of accuracy of smart phone "apps" designed to measure noise. Preliminary research by the National Institute of Occupational Safety & Health (NIOSH) indicated a select few commercially available apps could measure noise with reasonable accuracy. New studies have determined under what circumstances these smart phones and apps may be most useful.

Previous studies compared sound level readings recorded using smart phones to sound level values taken simultaneously with a standard precision sound level meter. Although some combinations of phones and apps appeared promising, problems related to calibration of the cell phone's internal microphone presented practical challenges to accuracy. More recently, researchers from the University of Michigan and NIOSH compared measurements taken via iOS phones using the internal microphone and two external microphone options. Their results indicated that certain combinations of phones and apps can provide noise measurements as accurately as a Type 2 sound level meter. However, use of a quality external microphone and a method of calibration are also required. For practical purposes, the researchers concluded that it is unlikely smartphones would be useful for regulatory compliance measurements in the near future. They do have value in documenting "crowd sourced" information about environmental noise and have potential for future development.

For more information:

Kardous, C. & Shaw, P. B. (2013). So How Good are These Smartphone Sound Apps? CAOHC Update, Vol. 25, Issue 3.

Benjamin Roberts, Chucri Kardous & Richard Neitzel (2016). Improving the Accuracy of Smart Devices to Measure Noise Exposure, Journal of Occupational and Environmental Hygiene.

Kardous, C. & Shaw, P. B. (2014). Evaluation of smartphone sound measurement applications. Journal of the Acoustical Society of America. 135, EL186–EL192 and NIOSH Science Blog, April 2014.

Nast, D., Speer, W. & LePrell, C. (2014.) Sound level measurements using smartphone "apps‟: Useful or inaccurate? Noise & Health, 16, 251–256.

(photo: cdc.gov)

Do you suffer from ringing in the ears? You're not alone! The National Institute on Deafness and Other Communication Disorders (NIDCD) estimates that over 20 million Americans experience chronic ringing in the ears, known as tinnitus (pronounced "TIN-a-tus" or "Tin-EYE-tus"). Tinnitus is an annoying and sometimes debilitating condition, commonly defined as the perception of noise in one or both ears when no sound is actually present. Tinnitus is usually described as a high-pitched ringing, but it might also be perceived as roaring, clicking, hissing or buzzing. The condition can be mild, intermittent, or so severe that it interferes with your sleep, concentration, and enjoyment of daily life.

A recent analysis of data collected as part of the National Health Interview Survey indicated that noise-exposed workers in the United States are 3 times more likely to report suffering from tinnitus than their non-noise-exposed counterparts. According to the U.S. Department of Veteran Affairs, tinnitus and hearing loss are the top two service-connected disabilities for U.S. service members. Veterans of Iraq and Afghanistan have been exposed to a number of hazards known to cause hearing loss and tinnitus, including loud noise, blasts/explosions, and ototoxic chemicals. Service members who have suffered a traumatic brain injury are 3 times more likely to experience tinnitus than other veterans. Those exposed to solvents, a class of ototoxic chemicals, are twice as likely to report ringing in the ears.

Tinnitus itself is not a disease. Instead, it can be a sign that something is wrong with the outer, middle or inner ear, the auditory nerve, or parts of the brain that process sound. Noise exposure, acoustic trauma, exposure to chemicals, and ear diseases/infections are some of the most common causes of tinnitus. Complicating its diagnosis and treatment, tinnitus has many other causes as well, including disorders of the heart/circulatory system, stress, hormone changes, and as a side effect of medications, smoking, or too much salt or caffeine. Sometimes the cause of tinnitus is unknown.

So what can a person experiencing tinnitus do about this annoying and on occasion even incapacitating condition? Follow our Top Tips and check out Resources listed below. And of course, when it comes to hearing protection, we've got you covered. Contact CavCom to learn more about our many solutions for controlling noise on and off the job.

Reports of hearing loss and tinnitus (ringing in the ears) have been associated with COVID-19 for some patients. A scientific review published recently in the International Journal of Audiology summarizes these trends.

Researchers from the University of Manchester conducted a systematic review of available scientific literature regarding COVID-19 and associated hearing loss and tinnitus published through December 2020. Based on stringent criteria for meta-analysis and bias risk, the authors rejected 850 records while 28 case reports and 28 cross-sectional studies met their inclusion criteria. Their analysis of the data revealed that 7-15% of adults diagnosed with COVID-19 reported auditory (ear/hearing) and/or vestibular (balance) symptoms. The most common symptoms

• Tinnitus (ringing in the ears) – studies show ringing in the ears lasting weeks or months after the infection had cleared.
• Hearing difficulties
• Vestibular issues such as dizziness or vertigo.

To access the full report:

• Almufarrij, I and Munro, KJ (2021). One year on: an updated systematic review of SARS-CoV-2, COVID-19 and audio-vestibular symptoms, International Journal of Audiology, DOI: 10.1080/14992027.2021.1.

To review an example case study:

• Koumpa FS, Forde CT, Manjaly JG (2020). Case Report: Sudden irreversible hearing loss post COVID-19; British Medical Journal 13:e238419. doi:10.1136

For more information on managing hearing loss and tinnitus:

• American Speech-Language Hearing Association: Tips for Communicating Effectively while Wearing Masks and Physical Distancing
• American Tinnitus Association: Tinnitus and the Corona Virus
• National Institute on Deafness and Other Communication Disorders: Health Information

At CavCom you will find a culture of passionate people. Preservation of hearing is our passion. Building and fitting communications products for individuals to prevent hearing loss, maximizing production efforts, and improving safety in a facility by furthering the ability to communicate define our commitment. We're proud of the people we serve and the solutions we offer across the country.

Passion, pride and commitment. Together, they create three pillars of our business philosophy and influence our actions each day. That's the CavCom difference.

Passion to Protect

CavCom has a foundation of lifelong contributions to the principle of hearing health in industry work. Individual career contributions to the many organizations they have participated in and/or chaired, there is a wealth of knowledge and experience in our people. Our products reflect the commitment and expertise these dedicated people have put forth in their careers. Our products evolved from the combined experience of our founder, Jeff Morrill, and the many people dedicated to Hearing Conservation that have or are currently working with him.

See the complete history of CavCom here

The protection of hearing is the basis of the communication products CavCom designs and manufactures for Industry, Emergency Response, Public Safety, and anyone who needs to communicate in High Noise or unusual PPE applications that prevent speech from being shared via two-way radios, i.e. respirators.

We started at the ear to protect hearing and ended at the radio, a major difference when you compare other accessory devices, that were designed so that you could hear your radio first and then some level of hearing protection, or not, applied.

Committed to Solve

We're fortunate to have a culture of people who are committed — but the definition of commitment extends beyond their individual roles. They are completely dedicated to their careers in ways that benefit our customers and the industries we serve. Our team sees beyond "the sale" to the solution. This is a key differentiator. When you have a team focused on what success looks like tailored to the individual customer, the outcome suddenly becomes crystal clear. CavCom is in the business of solving the most complex, challenging problems that hinder communication and compromise hearing.

Our company was founded on the principle of creating practical, effective solutions for companies facing high noise and communication challenges. Jeff's vision was different. His background afforded him an up-close experience of the perils of noise and lack of effective safety equipment to combat it. He took that as an opportunity to create a solution — it's been our driving commitment since our inception.

Pride, More Than Ever

Success doesn't exist in a vacuum.

As an organization, we all celebrate our accomplishments and how we impact the lives and wellbeing of customers. Everything we achieve requires the help of one another. From our researchers and audiologists to our field technicians and support staff, we're all interconnected. We're incredibly proud of each other, our products, and the relationships we have. By definition, pride is about possessing positive feelings for something that has deep, personal meaning. At CavCom, we're rooted in pride and it shows in how we stay engaged, even in times of chaos and crisis.

We're still in the midst of the pandemic that has changed everything in the world around us. As humanity, we're making adjustments. As a business serving humanity, we're making strides to improve upon our products and services in order to ensure the needs of our customers always come first. We're proud to say we've positioned ourselves in alignment with some of the most essential businesses and services and are more committed than ever to meeting those needs.

Critical Value

Company culture is truly representative of the values and standards the business possesses. That's true at CavCom. Yet there's a distinct difference in our culture that in turn sets our entire organization apart. It's the passion, the pride, and the commitment our people embody and bring to work with them daily. It's an honor to work alongside this team who is tirelessly in pursuit of making this company the best it can be in order to bring that level of great to our customers, community, and vendors.

CavCom was founded on the idea of creating practical, effective solutions for companies facing high noise and communication challenges. Founded 20+ years ago, our solution-centered approach integrates extensive experience, proprietary cutting-edge technology, and dedicated customer support to address virtually any challenging communication solution. I'm Jeff Morrill, CavCom‘s founder and President, and this is our story.

CavCom: Our History

The origins of CavCom stretch back to the early 1970s. Back then, I was the founder/owner of an audiologist-based company that developed hearing conservation services for noisy industries throughout North America. As an audiologist who conducted hearing tests and performed noise surveys, we worked with hearing protection programs for companies all across the United States.

The 1970 OSHAct did not specify what constituted hearing conservation and I was one of a few field pioneers who independently and in parallel with OSHA scientists contributed to the final OSHA 1910.95 Hearing Conservation Amendment enacted in 1983. I was fortunate to have a front-row seat in the development and implementation of innovative solutions for affected companies and their workers. Throughout the years following the OSHA rule, I participated in professional organizations (AIHA, NHCA, CAOHC) via committee and task force activities to further the advancement of hearing conservation.

The new OSHA requirement mandated annual audiometric testing for employees, review of tests to detect deterioration of hearing, reporting negative shifts in hearing as OSHA recordable events, training in the use of hearing protection devices, conducting noise exposure surveys and more. Many industries differed with the mandate challenging enforcement and employees fought the mandate to wear hearing protection.

The task to convince employers of benefits to their company was difficult with the threat of OSHA looming over their heads. The difficulty in convincing employees of the health and safety payback was equally challenging. Thus, the successors in industrial hearing conservation service companies were those who developed convincing data for employers and employees as well as practical, affordable programs whereby the contractor absorbed the workload. My company was in the forefront of the effort and emerged as the largest provider of on-site hearing conservation services in North America at the time. Within my audiology-based testing company, two things became abundantly clear:

1. Employers were handing out hearing protection like popcorn.
2. Employees were losing their hearing.

In addition to the lack of understanding about the risks of noise induced hearing loss, the availability of effective/dependable hearing protectors was limited at that time. The reality is that ears come in all shapes and sizes and the concept that one type/size of hearing protector could be used across all employees led to unnecessary hearing loss from noise exposure. You see, despite having access to more hearing protection than they knew what to do with, employee hearing was still in decline. As it turns out, a large part of the problem was due to the product. Back in the mid-70s, there wasn't a large variety of hearing protection devices like there is today. Moreover, the types that were being worn were not adequate for the environments they were being worn in, and often fitting and training of hearing protector use was unavailable.

By immersing myself in these high noise industries, I also witnessed the difficulty workers had in communicating via radio headsets in high noise. The earmuffs did not offer adequate hearing protection and the radio signal could be significantly louder than the factory noise. These aviation style headsets were also hot and heavy and left workers fatigued at the end of the day. Having used these devices in my work, it was evident that a better technology could be developed to improve hearing protection, offer safer listening levels and enhance employee comfort. I saw the conditions employees were working in on a day-to-day basis. I also witnessed the struggle to communicate using radio headsets on the shop floor, maintaining a front-row seat to the evolution of hearing protection technology and industrial hearing conservation programs. I thought, there has got to be a better technology. There has to be something out there that's able to protect each employee's hearing.

Enter Talk Through Your Ears®

It was from that space where the concept of CavCom, and its one-of-a-kind Talk Through Your Ears® (TTYE) technology originated. Now, TTYE is a revolutionary product within the realm of hearing conservation. It protects hearing, provides limited volume listening, and it's comfortable to wear. Using an in-ear microphone inside the hearing protector, TTYE bypasses the issue of combating high noise environments by picking up communication within the ear canal, instead of from the mouth.

Years later, we adapted the technology to also function for in-suit communications, making it compatible with respirators. While TTYE is CavCom‘s flagship product, we've gone on to develop a wide array of hearing protection and communication technologies to fit nearly every identifiable need.

The CavCom Team

If you ever listen to a founder and President, who says they did it all alone, know that I'm not in that camp. From the onset, CavCom has been a company where each individual shares the vision and passion that CavCom is built upon. Here's a brief look at the individuals who join me as members of CavCom‘s Executive Team.

Barb Morrill

As co-owner of CavCom, Barb has been with us since the early 2000s. During those early years, it was Barb running the business end of the company while I was managing the technical and selling components. Barb helped take what was a traditional, entrepreneurial startup and shape it into the company we are today.

Beth Orton

As CavCom‘s Vice President of Operations, Beth brings experience in finance, administration, and programming that remains essential to CavCom‘s success and growth. She's truly learning the business from the bottom to the top and owns expert-level knowledge in every aspect of what we do.

Susan Cooper, PhD

Susan is a nationally-recognized expert in the area of hearing conservation. As a certified audiologist by the American Speech-Language-Hearing Association (ASHA), she's managed hearing conservation programs for nearly two decades. As CavCom‘s Vice President of Technology, Susan is responsible for product technology, quality, and R&D efforts. Susan also serves as hearing conservation advisor and editor of our company newsletter. She is a former CAOHC chair, former President of NHCA, and currently serves on professional committees including the AIHA Noise Committee.

Looking Toward The Future

As the countless industries we serve continue to grow and evolve, so will our technologies. Whether it's due to requirements changing or technology evolving into greater capabilities than once were, we'll continue to invest in what it takes to get CavCom products to the employees who need protection.

As our organization continues to grow, we've kept our products and their distribution in-house. We continue to believe that our customers deserve a level of service that only a manufacturer and inventor can provide. We manufacture it. We sell it. We service it. We fix it. We build on it. Here at CavCom we are – and we will continue to be - the true experts on everything we put out into the world.

Providing hearing conservation solutions isn't just our business. It's our passion. There are folks out there who are losing their hearing. And once it's lost, it's not coming back. Hearing loss is a devastating problem that takes its toll on and off the clock. Just as much as we're helping people hear on the job, we're also trying to ensure grandparents can retire still being able to hear their grandkids say I love you. Put simply, preservation of hearing is our passion.

A Demo With CavCom

CavCom offers on-site two-way communication demonstrations for prospective customers. That's where a member of our team will travel to your site, demonstrate our equipment, work with your people and have them try our equipment in the actual environment where they need to communicate. Sound good? Request a demo now. 

Preparing for the Demo

Before anything can start, the ball is in your court. Requesting a demo via our website is easy. It's going to let us know you're interested in seeing CavCom products and experiencing them within your work environment.

Since we have a wide variety of products and potential solutions, we're going to have some about your environment, what communication technology you're currently using, and what obstacles you're experiencing. Depending on your specific circumstances, we will help to determine if CavCom products are a good fit for your needs. Then, we'll go over what a demo includes and determine whether an on-site demo would work best for you (as opposed to a product trial). This qualification process will also help our team determine which products to demonstrate while we are on site (or which products to line up for a mail-out trial).

Next, you're going to work with CavCom field services scheduling staff to set a date. The demos tend to schedule a few weeks out, so if your facility or organization requires a tighter timeline, a mail-out trial might work better for you. Either way, we're going to get CavCom products in your hands so that you and your team can get a feel for them.

The On-Site Demo

The day of the demo is your opportunity to experience CavCom products in action, put their features to use in your environment, and hear the quality of your radio transmissions. And depending on the environment, your demo is going to look different. For instance, emergency response teams will likely be able to set aside an hour or two to have the entire team attend a demo. Production facilities, on the other hand, aren't going to shut down a machine for two hours for a product demo. Sometimes, the workday doesn't stop no matter who comes on-site, and we respect that.

If we are conducting a demo for a production line at a manufacturing facility, we're going to start with the production supervisor and usually one crew member at a time getting educated and fitted. We're going to lead the first couple of crew members through the system, get them set up and have them take it right out on the floor and into their high noise environment.

As we're briefing the shift supervisor, the purchaser, and (ideally) the plant manager on the system, employees can come in and get a quick brief on how the system works. We include information on why sealing the ear is important, then hook them up with either their radio or our demo radio, make sure they can communicate and send them right back out to test the equipment in their high noise situation. All the while, we're available for questions as they come up.

Typical Demo Feedback

When most people get their first experience with CavCom hearing protection, they're going to notice how comfortable it is. Employees accustomed to bulky headsets will feel lighter and cooler. Even more than that, they're going to be able to hear clearly. I know it sounds simple, but the difference is pretty stunning.

There are plenty of benefits, but know that some employees may be less open to change and more reluctant when it comes to trying something different. While it may take a bit longer for some, we find the vast majority of users welcome the upgrade and come to fully embrace our technology and solutions.

How About a Communication Evaluation?

While we're on-site for a demo, we're more than willing to provide a communication evaluation of your environment. This can include evaluating each shift — yes, even third shift — and assessing your facility for all your communication needs. We can help evaluate:

• High noise areas
• Dead zones
• Radio equipment
• Radio infrastructure

Basically, we'll assess any and all communication needs your facility. For instance, if your compressor room is a dead zone for radio comms, we can try different solutions to bridge that gap. Oftentimes, having the right equipment will allow you to communicate where you previously couldn't.

Feel It, Hear It, Try It

When it comes to CavCom products and solutions, we can talk about their features and capabilities all day — and we do! But the true test is when you get the equipment in front of you. When you can feel how the products are lightweight yet durable, when you can experience the quality built into each radio, that's when it really makes sense.

For employees who've struggled to communicate day in and day out, year over year, having the ability to communicate clearly and effectively is a real game changer. Our on-site demos make it possible to feel, hear, and try CavCom products in your workplace environment. Request your on-site demo today.