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October 2020 - New President Announcement

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December 2019 - New options for EarzON custom hearing protection

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Communication in Noise

Effective 2-way Communication

Worker_pulls_eda77404269 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 sounds 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 becomes 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 varies, boom-style, bone-conduction, or even CavCom‘s Talk Through Your Ears® technology. Of course, 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 lower if using binaural earsets compared to one 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 feature allows most users to 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 ear(s) 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.

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.

Video/Audio Demonstration – Communicating in High Noise: Join CavCom‘s Jeff Morrill and Matt Morrill for a 2 ½ minute video demonstration of 2-way radio communications in a 100 dBA industrial noise environment.

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

Special Considerations for Workers with Hearing Loss

How many times have you seen an employee break the seal of an earplug or earmuff because he 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.

img_miscommunication

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

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

Communication demonstration: Join CavCom‘s Jeff Morrill and Matt Morrill for a 2 1/2 minute video demonstration of 2-way binaural radio communications in a 100 dBA industrial noise environment.

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

The Noise Reduction Rating (NRR)

The NRR and other important indicators of hearing protector performance

new_CavCom_guy_2019 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. Sidebar_-_Best_HPD_2020

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.

EarzON_Filtered_NRR_Primary_Label_March_2020 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

Dual_HPD 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.

individual_fit_testi-b58a5 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.

Sidebar_Dont_rely_on-6d0ca 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

It's true that your first step in accomplishing successful hearing protection is to identify a number of quality earplugs and earmuffs with noise Sidebar_Variety_and_-319a1

reduction capabilities sufficient for the work environment. But there's more to hearing protection than attenuation, whether measured via NRR or PAR. Employees must have the opportunity to select from a suitable variety of devices. Comfort, convenience, compatibility with other PPE, and the ability to communicate are usually the deciding factors in individual choices. Lastly, workers must be individually fitted and thoroughly trained in the proper fit, care and use of the protector. Annual audiometric testing ultimately helps you verify that your efforts have been successful.

Not sure which hearing protectors would be best for your workers? Contact CavCom to discuss the options and to learn more about how our innovative products and systems can improve safety and communication in your workplace.

SC_editor_bio_stamp-f0b0c

Update: Accident Risk and Noise

Does Noise Increase the Risk of Accidents?

img_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.

Hearing Protection

Individual Fit Testing for Hearing Protectors

individual_fit_testing_with_earphones_FCS 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:

SoundBytes_fit_test_-9b943

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.

Fit_Testing_Graphic_-_refit__retrain

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.

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Improving In-Ear Comfort

Custom_Silicone_2tone 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, looser, 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. Our newest offering is a soft silicone custom earset. With the addition of silicone construction, workers can now choose between acrylic or silicone custom earsets to suit personal preferences and operational demands.

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.

Custom Hearing Protection Solutions Promote Success

EarzON_in_eara474600a6b 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.

The Noise Reduction Rating (NRR)

The NRR and other important indicators of hearing protector performance

Regulatory matters

What is the NRR?

Other Rating Systems

How is the NRR used?

NRR METHOD

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

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

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)

PAR METHOD

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

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

Noise Reduction Isn't Everything

It's true that your first step in accomplishing successful hearing protection is to identify a number of quality earplugs and earmuffs with noise Sidebar_Variety_and_-319a1

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Effective 2-way Communication

Key factors affecting speech communication

Options for improving communication

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

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

CavCom QUIZ - Custom Hearing Protection

Guidance for Recreational Firearm Noise

Hearing Protection for Recreational Firearms Users

hunters_cdc.gov With hunting season well underway, it's a good time for a reminder about protecting your hearing during this popular, but loud, recreational activity. Research shows gunfire to be one of the leading causes of noise-induced hearing loss and tinnitus (ringing in the ears).

At impulses in the range of 155 to 175 dB peak Sound Pressure Level, even a single 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 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.

The bottom line: it's just good practice for everyone involved in gun sports to consistently wear well-fitted hearing protection when shooting. The National Institute for Occupational Safety and Health (NIOSH) recommends wearing both earplugs and earmuffs for best protection. A variety of hearing protectors is readily available through shooting ranges, sporting goods stores, and web-based vendors. And of course, annual hearing tests are a good way to confirm hearing protector effectiveness.

For more information about gunfire noise, check out these helpful resources:

Take Aim at Protecting Yourself, NIOSH Science Blog, May 18, 2009
Don't Let Gun Sports Backfire on You: Use Ear Protection and Hang on to Your Hearing, National Institute on Deafness and Other Communication Disorders/National Institutes of Health, 2006
Flamme, et al. (2009). Estimates of auditory risk from outdoor impulse noise II: civilian firearms, Noise & Health, 11: 231-242
Murphy et al. (2013). Bystander Impulse Noise Exposure from Small-Caliber Weapons: How Close is Too Close? Update, Council for Accreditation in Occupational Hearing Conservation, Vol. 25, Issue 1
Stewart et al. (2014). Shooting habits of youth recreational firearm users, International Journal of Audiology, 53:S26-S34

Hearing Conservation Programs

New NIOSH Resource for Total Hearing Health

Single-ear Hearing Loss: a Red Flag

Worker_cant_hear_cropped_Fotosearch_k10452212 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.

Hearing Loss and OSHA 300 Log

osha_recordkeepin 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.

Is Your Hearing Conservation Program Working?

Tracking Occupational Hearing Loss

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.

New Guideline - Ototoxic Chemicals

Chemical_stora2f64e44fb9 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).

Noise, Neurotoxins and Injuries

OSHA Guidance for Temporary/Contract Worker - Noise & Respiratory Protection

OSHAtemp-workers 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.

Young Workers at Higher Risk

PPE Technical Database from NIOSH

Update: Accident Risk and Noise

Does Noise Increase the Risk of Accidents?

Identifying Listening Challenges

Is There a Link to Accidents?

Options for Reducing Risk

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

References

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.

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.

Individual Fit Testing for Hearing Protectors

NRR vs. PAR

Example real-world data:

SoundBytes_fit_test_-9b943

Basics of Popular Individual Fit Test Equipment and Protocols

REAT (real ear at threshold)

MIRE (microphone in real ear)

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

Fit_Testing_Graphic_-_refit__retrain

Assistance is a click away

SC_editor_bio_stamp

Improving In-Ear Comfort

The Importance of Comfort

Personal perceptions

Work Environment

PPE Compatibility

Implications of Uncomfortable Hearing Protection

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.

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.

Occupational Noise

National Research Agenda for Hearing Loss Prevention

Hearing Loss in the Military

noise-blast2_usdva_va.gov 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.

HCE_Web_Cardbda1782e28

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.

Free App for Measuring Sound

Smartphone Apps for Noise Measurement - Accuracy Research

NIOSH_cell_pho96f913e08b 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 "appsâ€Ÿ: Useful or inaccurate? Noise & Health, 16, 251–256.

(photo: cdc.gov)

Noise Control: Buy Quiet

New Insights on Noise Damage

New NIOSH Resource for Total Hearing Health

Is Your Hearing Conservation Program Working?

Hearing Loss in Mining, Oil and Gas

Hearing & Hearing Loss

Managing Earwax

Ear_RIGHT_Fotosearch-58b6a 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: custom_earset_cleaning_with_wax_pick

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.

Special Considerations for Workers with Hearing Loss

img_miscommunication

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

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

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

Single-ear Hearing Loss: a Red Flag

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.

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.

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.

Hearing Loss and OSHA 300 Log

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).

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:

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 (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.

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.

Tracking Occupational Hearing Loss

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

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

New Insights on Noise Damage

Fighting Wildfires - and Noise

How’s Your Hearing?

Ringing in the Ears

Tinnitus_2018 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

Aging and the Earcanal

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. Outer_Ear_in_blue_2015Fotosearch_k20806234

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.

Swimmer’s Ear

swimmers_ear_cdc.gov 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", but what exactly is this painful condition and how do 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 (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 (remember that 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:

American Academy of Otolaryngology/Head & Neck Surgery: Swimmer's ear
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)

CavCom QUIZ - hearing loss in teens

teens_talking_shutterstock_527458141 How does today's prevalence of hearing impairment among US teens compare to 50 years ago?

a. Fewer youth with hearing impairment today
b. Percent of hearing impairment is about the same
c. More teens with hearing impairment today
d. Unknown; there are no controlled studies for comparison

Answer:

The best answer is a. fewer teens (i.e. lower percent) with hearing loss. It may defy conventional wisdom, but researchers tracking hearing impairment via controlled national epidemiology studies find that prevalence of hearing loss among teens has decreased in recent years. National studies of young people (aged 12 years to 17-19 years) show that rates of hearing loss in both the speech range of hearing and high frequency hearing declined significantly between the 1960s and exams conducted 1988-1994. Better disease prevention and health care, as well as reductions in smoking, job-related noise, and use of firearms may be contributing factors. This is good news, indicating that better awareness and interventions have likely helped improve hearing outcomes.

The continuing challenge is that later studies conducted 2005-2010 showed no additional decreases in the prevalence of hearing impairment. So there is still work to be done! Developing healthy hearing habits at a young age is a worthy goal, since hearing impairment can be permanent and the effects may last a lifetime.

To help the young people in your life, check out these resources designed specifically for educating children and teens on the hazards of noise and the value of protecting hearing. Many guidelines, handouts, posters, and games are available for download at no charge (some in Spanish).

Back to School – Educator Resources. CavCom SoundBytes.

For more information:

Hoffman, Dobie, Losonczy, Themann & Flamme (2018). Kids nowadays hear better than we did: declining prevalence of hearing loss in US youth, 1966-2010. Laryngoscope, 129(8): 1922-1939.

Su and Chan (2017). Prevalence of hearing loss in US children and adolescents. JAMA Otolaryngology-Head & Neck Surgery; 143(9): 920-927.

Respiratory Protection Programs

New CBRN Respirator Handbook

OSHA Silica Rule Moves Forward

New Guideline - Ototoxic Chemicals

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

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).

Noise, Neurotoxins and Injuries

OSHA Guidance for Temporary/Contract Worker - Noise & Respiratory Protection

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.

Young Workers at Higher Risk

PPE Technical Database from NIOSH

Oil and Gas: Health Concerns in Flowback Operations

Industry News

Hearing Loss in Mining, Oil and Gas

Refrigeration Hazards on Land and Sea

Oil & Gas a Top NIOSH Priority

Oil and Gas: Health Concerns in Flowback Operations

Fighting Wildfires - and Noise

Hearing Conservation for Mining Operations

Hearing Loss in the Military

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

HCE_Web_Cardbda1782e28

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.

Non-Occupational/General Interest

Hearing Protection for Military Dogs

CavCom QUIZ - Custom Hearing Protection

Enjoy Summer Activities but Protect Your Hearing

How’s Your Hearing?

Ringing in the Ears

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

Non-Occupational Noise - Quantifying Noise Exposures

Guidance for Recreational Firearm Noise

Hearing Protection for Recreational Firearms Users

For more information about gunfire noise, check out these helpful resources:

Take Aim at Protecting Yourself, NIOSH Science Blog, May 18, 2009
Don't Let Gun Sports Backfire on You: Use Ear Protection and Hang on to Your Hearing, National Institute on Deafness and Other Communication Disorders/National Institutes of Health, 2006
Flamme, et al. (2009). Estimates of auditory risk from outdoor impulse noise II: civilian firearms, Noise & Health, 11: 231-242
Murphy et al. (2013). Bystander Impulse Noise Exposure from Small-Caliber Weapons: How Close is Too Close? Update, Council for Accreditation in Occupational Hearing Conservation, Vol. 25, Issue 1
Stewart et al. (2014). Shooting habits of youth recreational firearm users, International Journal of Audiology, 53:S26-S34

Aging and the Earcanal

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.

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.

Swimmer’s Ear

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 (remember that 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:

American Academy of Otolaryngology/Head & Neck Surgery: Swimmer's ear
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)

Back to School - Educator Resources

Helping Musicians Protect Their Hearing

Musicians_Foto636a830009

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.

Making Noise About Noise Pollution

Wind Turbine Noise: Annoyance or Hazard?

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.

Sonic Attacks in Cuba?

CavCom QUIZ - hearing loss in teens

teens_talking_shutterstock_527458141 How does today's prevalence of hearing impairment among US teens compare to 50 years ago?

a. Fewer youth with hearing impairment today
b. Percent of hearing impairment is about the same
c. More teens with hearing impairment today
d. Unknown; there are no controlled studies for comparison

Answer:

Back to School – Educator Resources. CavCom SoundBytes.

For more information:

Hoffman, Dobie, Losonczy, Themann & Flamme (2018). Kids nowadays hear better than we did: declining prevalence of hearing loss in US youth, 1966-2010. Laryngoscope, 129(8): 1922-1939.

Su and Chan (2017). Prevalence of hearing loss in US children and adolescents. JAMA Otolaryngology-Head & Neck Surgery; 143(9): 920-927.

Free App for Measuring Sound

Smartphone Apps for Noise Measurement - Accuracy Research

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 "appsâ€Ÿ: Useful or inaccurate? Noise & Health, 16, 251–256.

(photo: cdc.gov)

Managing Earwax

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: custom_earset_cleaning_with_wax_pick

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.

News & Articles

Looking for the latest news and information on noise exposure, healthy hearing habits, hearing protection and more? From OSHA requirements to NIOSH guidelines and other best practices, CavCom keeps you in-the-know and up-to-date. Click any category below to expand.

CavCom News

New colors now available for EarzON® custom hearing protectors!

NEW Heavy Duty Headset with Bluetooth

BIG NEWS FOR LIGHTWEIGHT COMMS

Communication in Noise

Key factors affecting speech communication

Options for improving communication

Hearing Protection

NRR vs. PAR

Basics of Popular Individual Fit Test Equipment and Protocols

REAT (real ear at threshold)

MIRE (microphone in real ear)

Why CavCom conducts Individual Fit Testing using REAT technology

Assistance is a click away

Key factors affecting speech communication

Options for improving communication

Hearing Conservation Programs

NRR vs. PAR

Basics of Popular Individual Fit Test Equipment and Protocols

REAT (real ear at threshold)

MIRE (microphone in real ear)

Why CavCom conducts Individual Fit Testing using REAT technology

Assistance is a click away

Occupational Noise

Hearing & Hearing Loss

Respiratory Protection Programs

Industry News

Non-Occupational/General Interest