The Quest for Hearing Health

Despite decades of effort to tackle occupational noise and hearing issues, workers are still suffering hearing loss. Our hearing experts explain the missing steps for hearing conservation success.

Why does industry continue to suffer hearing loss instead of hearing health? Audiologist Michael J. Metz, Ph.D., says the answer is that hearing conservation programs fail to include hearing as a "life asset" to which everyone has a right. Metz calls it the "failed hearing conservation paradigm."

"The value placed upon hearing -- either in the workplace, in the public's mind or in the federal government's eyes -- is so slim and meaningless that an injury of this type is not considered important enough to pay a lot of attention to," says Metz, director of audiology for Ear Professional International Corp., a national coalition of hearing health care physicians and audiologists.

If employees were exposed to chemicals and radiation to the same degree as they are to noise hazards, he claims, industry would be more responsive against such hazards. But because hearing loss usually occurs slowly, even imperceptibly, few consider it a serious workplace health issue.

As a result, even though noise-induced hearing loss is preventable, many companies fail to have adequate hearing conservation programs. They may be missing an evaluation mechanism, lack noise assessment and monitoring, ignore engineering controls or fail to properly fit test and train workers who often are disinterested and uneducated about hearing protection. This is the case even though OSHA requires many of these program elements in its occupational noise standard, 29 CFR 1910.95.

Hearing conservation experts point out that if employers take steps to ensure that their programs are complete, employees will more likely value their hearing. The result will be hearing health instead of hearing loss.

Program Evaluation

The problem. Audiologist consultant Alice Suter contends that many employers do not know if their hearing conservation programs (HCPs) are effective, let alone complete, because they have not evaluated them. Part of the problem is that nothing in 1910.95 gives guidance to employers on how to evaluate their HCPs, says Suter, who should know because she helped draft the OSHA standard in the early 1980s.

Simply doing audiometric testing is not enough, says Suter, who was not able to get the agency to include an evaluation element in the standard. Too often, employers file away audiograms after testing and never assess them.

Further, she says, it is too simplistic to base program effectiveness on whether workers suffer hearing loss. Many questions are left unanswered: Is the hearing loss due to age or nonoccupational factors? How much hearing loss is being recorded? The professional consensus, Suter says, is that, if adjusted for aging, a person should have little, if any, standard threshold shift (STS), which is a change in hearing threshold relative to a baseline level of a person's hearing.

"I've heard people say that 'effective' means workers are not losing their hearing. Does this mean STS rates have to be zero?" she asks of the vagueness of determining whether an HCP is effective. "It's a problem OSHA really needs to grapple with."

The solution. Guidance, albeit limited, is available to help employers evaluate their health conservation programs, Suter says. Preventing Occupational Hearing Loss -- A Practical Guide by the National Institute for Occupational Safety and Health (NIOSH) provides, in Appendix B, a program evaluation checklist. Areas covered are training and education, supervisor involvement, noise measurement, engineering and administrative controls, monitoring audiometry and recordkeeping, referrals, hearing protection devices and administrative issues.

An American National Standards Institute draft standard on hearing conservation program evaluation (S12.13) is good for large companies and those with lots of hearing data, but would be difficult to use for smaller companies, Suter says. As one way to measure program effectiveness, the draft standard uses test-retest comparisons, which measure the proportions of thresholds improving compared to those decreasing.

Noise Assessment

The problem. Vern Larson, an audiology manager who directs the acoustical testing lab for Howard Leight, a maker of hearing protectors, is surprised at the number of companies that have not implemented a noise monitoring program.

Many companies have never determined their noise levels, a starting point in any effective hearing conservation program, Larson says. He knows because he gets at least one call a week from someone who wants advice on what type of hearing protector to buy, but has no idea how much noise intensity or frequency is in the plant.

The solution. Use noise monitors, such as a sound-level meter or a dosimeter, to measure sound levels over a specified interval to determine the intensity, frequency, dose, time-weighted average and other relevant parameters. According to 1910.95, employers must monitor all employees whose noise exposures are equivalent to or greater than an exposure averaged over eight hours where the noise level is constantly 85 decibels, or dB(A). Employers are also required to provide hearing protection for employees exposed to an eight-hour, time-weighted average (TWA) of 85 dB(A) or greater, though the standard does not require workers to wear protection until 90 dB(A) TWA.

Employers should notify noise-exposed employees of their exposures and auditory risks, and transmit results to supervisors and other key individuals.

Monitoring is not a one-time task. If there have been changes in work areas, equipment or processes that have altered noise exposures, take follow-up measurements.

If employers do not know the level of noise in their workplaces, they could be inadvertently providing too little or too much hearing protection for their workers. While it is clear that too little protection can lead to hearing loss, too much hearing protection has its own issues.

Brian Myers, marketing director for Aearo's E-A-R and Peltor line of hearing protectors, says users who simply buy a product because it has a high noise reduction rating (NRR) may have too much protection that blocks out necessary sounds such as warning signals and speech.

"You can certainly appreciate that they are trying to provide the best protection for their employees," Myers says, "but the biggest number doesn't always equate with what's best for a particular situation." Workers who cannot hear these necessary sounds, Myers adds, may not properly wear their hearing protection devices or use them at all.

A rule of thumb, based on data used in OSHA's 1983 hearing conservation amendment, is that about 95 percent of workers in hearing-hazard environments are exposed to noise levels of 95 dB(A) or less. "That tells me that most people really only need about 10 dB(A) of protection," Myers says.

Engineering Controls

The problem. Suter contends that not enough companies are doing engineering noise control by using retrofits or buying quieter equipment.

Some U.S. equipment manufacturers make quieter products to fulfill European noise standards, Suter says, but do not include noise-reducing features on the same products sold in the United States because domestic employers do not demand quieter equipment. One reason, she claims, is because OSHA does not adequately enforce the engineering control portion of 1910.95.

The solution. Mark Stephenson, Ph.D., bioacoustics researcher and audiologist for NIOSH, touts European engineering controls that could be used in the United States. For example, reduce noise significantly by changing the pitch angle or the number of teeth on a saw blade.

EHS managers should search databases for noise control solutions (even in other countries). Do not assume that all controls are expensive; some are inexpensive and easy to implement, Suter says.

Steve Hacker, CIH, an industrial hygiene manager for Solutia, a specialty chemical company, understands how engineering control costs can be a real opportunity for the practicing hearing conservation program manager. Many are not aware of engineering controls that are not very costly but would significantly reduce noise levels. During economic downturns, such as what the country is going through in 2001, it is even more difficult to persuade management to spend money to abate and control noise, says Hacker, chairman of the American Industrial Hygiene Association's (AIHA) noise committee. Less-costly solutions include mufflers and silencers on machines.

Worker Attitudes

The problem. Too many employees have one of two attitudes about their hearing, according to Stephenson. The first is that hearing loss will occur no matter what precautions they take. "Because [noise] is so common," he says, "people have this expectation that they expect to lose their hearing."

The second common attitude workers have is that hearing loss will not happen to them. Stephenson calls this the "illusion of invulnerability." This false perception is fed when workers do not notice hearing loss immediately.

"You can't trust your body to tell you when you are losing your hearing," he says. "Unfortunately, when you're talking about noise-induced hearing loss, by the time you notice it, it's usually permanent."

Aearo's Myers concurs with Stephenson that the majority of hearing loss is not from noises that cause pain or are clearly hazardous. In general, he says, most noise-induced hearing loss occurs where the sound simply seems to be an annoyance.

The solution. Stephenson says education is the best way to combat unhealthy worker attitudes toward hearing loss. To reach workers who feel invulnerable, for example, incorporate a negative message or fear approach to get their attention.

When Myers holds focus groups, he asks participants why they wear hearing protection. Nearly everyone answers that it's because their employer requires it. Only about a third, however, say they believe it will protect their hearing or that their hearing is in danger. The rest do not realize that "hearing protection starts between the ears."

"I absolutely believe that if you can get somebody motivated to be concerned and think about their hearing and think that their hearing is too valuable to lose, you're at least 90 percent of the way there," he says. "Then they will pay attention during training, try to wear the plug right and ask questions if they don't think they're getting a proper fit."

One of the best ways to motivate employees, Myers says, is a testimonial from a worker who has suffered hearing loss. Another idea is to use a recorded demonstration of sound levels with and without hearing loss to simulate for workers what it would be like to lose a portion of their hearing.

If workers appreciate the potential for suffering hearing loss, they may be less likely to offer the excuses for not properly wearing hearing protection that Hacker has encountered in his visits to Solutia plants. Employees complain that hearing protectors are uncomfortable and they take time to insert properly, and they ask why they need protection if they will only be in a noisy area for a short time or do not recognize the noise level as a hazard. Hacker has seen increased participation by employees in wearing hearing protection because of awareness and peer pressure.

Fit Testing

The problem. Hearing conservation experts know of more HCPs than they care to count that consist of nothing more than employers providing or passing out hearing protection devices, essentially earplugs, and leaving it up to employees to use them correctly.

"That's not considered adequate by OSHA, nor is it adequate in terms of protecting the health and safety of the workers," says Jeffrey Birkner, vice president of technical services for Moldex-Metric, a hearing protector manufacturer.

The solution. Fit test workers to determine what device will best protect their hearing because no one size or type of hearing protector fits all ears. With earplugs, Birkner explains, check to ensure that a plug fits properly into a worker's ear canal and blocks out the correct amount of noise.

As part of being fit tested, train workers on how to properly use the protector. Myers says he has heard that 99 percent of workers who wear hearing protectors have never been asked to fit the protector in front of someone who knows a good fit.

With foam earplugs, for example, users often do not properly prepare the plug to fit into the canal and expand. The result is that the plug may not be inserted fully and could let in too much sound.

"A lot of people just try to shove it in," Aearo's Myers says. Instead, the user should roll down the plug until it's about the diameter of a pencil and lay it in the ear canal.

One way to determine whether an earplug is fitted properly, he says, is to tightly cup a hand over the ear in the presence of noise. The user should hear roughly the same noise level as before. If there is a difference, the plug is not fitted properly.

Conclusion

An effective hearing conservation program has ramifications far beyond preventing hearing loss. Suter, in the fourth edition of AIHA's Noise & Hearing Conservation Manual, wrote that an HCP "can improve employee morale and general feeling of well-being, it can improve the quality of production, and it may reduce the incidence of stress-related disease. Over and above the benefits of hearing saved, the hearing conservation program seems like a chance worth taking."

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