Workplace Hearing Loss
Work-related hearing loss continues to be a critical workplace safety and health issue. It is estimated that over 22 million workers are exposed to hazardous noise on the job and an additional nine million are at risk for hearing loss from other agents such as solvents and metals. The National Institute for Occupational Safety and Health (NIOSH) has a long history of working to prevent workplace hearing loss. While noise-induced hearing loss is 100 percent preventable, once acquired, hearing loss is permanent and irreversible.
Surveillance
Surveillance of occupational hearing loss and noise exposure is vital to prevention. It can identify the most problematic industries, occupations, and work activities, and can be used to evaluate the effectiveness of intervention activities. The National Academies Institute of Medicine evaluated the NIOSH Hearing Loss Research Program in 2005. While the program received high marks, the National Academies concluded that it was difficult for NIOSH to establish and prioritize research goals due to the lack of surveillance data on occupational hearing loss and noise exposure for U.S. workers. Currently the U.S. does not have a national surveillance or injury reporting system for hearing loss. The Bureau of Labor Statistics annually reports hearing loss standard threshold shifts reported on OSHA Form 300. However, BLS data are not representative of the true magnitude of occupational hearing loss due to several barriers to the reporting system. The Michigan Sensor program is one possible model for collecting reliable and representative data on hearing loss, but funding is lacking. As such, comprehensive data on the prevalence and economic impact of hearing loss are not available. To address this issue, NIOSH published two articles to estimate the national burden of hearing difficulty among workers in the U.S.: "Exposure to Hazardous Workplace Noise and Use of Hearing Protection Devices Among U.S. Workers—NHANES, 1999–2004"1 and "Hearing Difficulty Attributable to Employment by Industry and Occupation: An Analysis of the National Health Interview Survey—United States, 1997 to 2003."2 The articles extrapolate data from the National Health and Nutrition Examination Survey (NHANES) of 9,275 employed workers to the entire working population. The analysis revealed:
- More than 22 million U.S. workers were exposed to hazardous workplace noise.
- Workers in the mining industry had the highest prevalence of workplace noise exposure with almost 3 out of 4 mining industry workers exposed. The mining industry has the second highest prevalence of hearing difficulty among all industrial sectors.
- Over one third of all manufacturing workers (5.7 million workers total) reported exposure to loud noise.
- One in four manufacturing workers exposed to loud noise reported non-use of hearing protection devices.
To get a better picture of the full extent of workplace hearing loss, NIOSH has developed an ongoing surveillance program of occupational hearing loss in collaboration with audiometric services providers. NIOSH will develop a database and protocols to manage and analyze individual level audiometric data. Data from this surveillance effort will be used in several important ways. It will help to identify emerging hearing loss problems, including those associated with new industries, new technologies, or new pieces of equipment. The analysis of the data will also produce national reference statistics for the incidence (or prevalence) rate of occupational hearing loss across industry and occupations. By 2012, a total of 15 providers will be recruited to participate in this surveillance program. For more information about this surveillance program or if you are interested in participating in the surveillance program, send an e-mail to dvo9@cdc.gov.
Prevention
Better surveillance can help NIOSH and others provide better prevention programs. As mentioned earlier, noise-induced hearing loss is entirely preventable but once acquired, hearing loss is permanent and irreversible. Therefore, prevention measures must be taken by employers and workers to ensure the protection of workers' hearing. There are many solutions for eliminating noise in the workplace. Engineering noise control is the best approach to eliminate the problem. If that is not possible, administrative control of exposure and hearing protection are essential elements of a hearing conservation program. The NIOSH Noise and Hearing Loss Prevention Topic Page contains a Hearing Conservation Program Evaluation Checklist, a Hearing Conservation Toolbox, and a Compendium of Hearing Protection Devices, among other useful tools.
In 2006 NIOSH partnered with the National Hearing Conservation Association (NHCA) to create the Safe-in-Sound Award—an award for excellence in hearing loss prevention. The objectives of this award are to recognize organizations that document measurable achievements in hearing loss prevention programs, obtain information on their real-world successes, and widely disseminate information on how others can use these successful strategies.
Input
NIOSH is interested in strengthening its efforts to prevent hearing loss in the workplace. Through this blog, NIOSH would like to learn more about:
- Practices that have proven useful to promote the use of noise control in the workplace
- Government policies that can be improved to promote effective hearing conservation practices
- Tools that have been effective in promoting the use of hearing protection with workers
- Successes in integrating hearing protectors into hearing conservation programs
- Mechanisms that have been effective in training and engaging workers' participation in the hearing conservation program
- Economic benefits from quieting the environment (noise control) over using hearing protection. For example, has the elimination of the hearing conservation program due to the control of noise in the workplace led to a reduction in accidents, increased cost savings from not having to buy hearing protection and scheduling annual audiograms, or increased worker morale?
Please provide your input in the comment section below. Thank you.
—Capt. William Murphy, Ph.D., and SangWoo Tak, Sc.D., MPH
Dr. Murphy is the co-leader of the Hearing Loss Prevention Team in the NIOSH Division of Applied Research and Technology and is a Captain in the Commissioned Corps of the U.S. Public Health Service.
Dr. Tak is an epidemiologist in the NIOSH Division of Surveillance, Hazard Evaluations, and Field Studies.
References
- Tak S, Davis R, Calvert G. Exposure to Hazardous Workplace Noise and Use of Hearing Protection Devices among US Workers --- NHANES, 19992004. American Journal of Industrial Medicine, 2009, Vol 52, No 5, pp 358-371.
- Tak S, Calvert GM. Hearing difficulty attributable to employment by industry and occupation: an analysis of the National Health Interview Survey United States, 1997-2003. Journal of Occupational and Environmental Medicine, 2008, Vol 50, No 1, pp 46-56.
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Comments
It would be helpful if all equipment (power tools, lawn equipment, lab equipment, firearms, etc) came with a decible level on them. This would help the employer know if a hearing protection program is needed and/or engineering controls or PPE is needed. If not on the equipment, could NIOSH post the decibles somewhere?
Posted 11/24/09 at 1:54 pm
We agree that labeling of this sort would be helpful, however at present there are no regulations in the U.S. that require such labeling. Many consumer appliances are now being sold on the basis of how quiet they are. Dishwashers, for instance, are tested for sound power (sound power is like the wattage rating of a light bulb). Many dishwashers have ratings of about 50 dB and some very quiet ones have ratings less than 50 dB. Similarly, IT equipment has been tested for its noise production. A noisy computer in a quiet office space is less likely to be accepted than a quiet computer. Some years ago, a major computer vendor was advertising that its computer was only 37 dB. Unfortunately, no descriptors of where that level was measured or whether all of the fans on the computer were running during the measurement was given.
Recently, there has been a movement to work out a consumer label for noise production that would inform the public and hopefully push the market to producing quieter equipment. At NIOSH, the Hearing Loss Prevention Team has conducted tests of more than 120 different electric powered hand tools and published the database of measurements on the NIOSH web site, http://wwwn.cdc.gov/niosh-sound-vibration/. These tools have been measured in both the loaded and unloaded condition. The loaded tests were conducted by actually operating the tool with real material for cutting, grinding, drilling etc. Unloaded tests were conducted with the tool running without it being in contact with a work-piece.
With respect to firearms, NIOSH has been involved in conducting measurements and Health Hazard Assessments of shooters at firing ranges. In 2009, NIOSH published an Alert on Preventing Occupational Exposures to Lead and Noise at Indoor Firing Ranges, http://www.cdc.gov/niosh/docs/2009-136/pdfs/2009-136.pdf. As a part of that document noise levels from ten weapons measured at an indoor firing range were presented. The peak sound pressure levels ranged from about 156 dB to 170 dB. A recent article in Sound and Vibration magazine describes a detailed series of measurements for a rifle, http://www.sandv.com/downloads/0908rasm.pdf. As can be seen in that paper, the noise levels around the rifle vary considerably. Additional papers may be found in the October 2009 issue of Noise and Health regarding the risk of hearing loss due to civilian firearms and fireworks http://www.noiseandhealth.org/currentissue.asp.
Measuring and rating firearms (or fireworks) is far more complicated than sound power measurements of tools. One must consider the transient nature of the weapon's discharge, the proximity to the source and the nonlinear effects of sound propagation. Suffice it to say, hearing protection is recommended for use with firearms every time the weapon is discharged. If one is planning to do a considerable amount of target practice, then double hearing protection is recommended. No single metric has been developed to rate the level of a weapon.
Posted 11/25/09 at 11:35 am
Re Elizabeth's comment: Some countries do have this information on tools. Although it is helpful it cannot be taken as gospel as the noise level will increase as the tool becomes older & worn. ALso it is the output of the tool itself, as soon as it is USED (eg an angle grinder) the noise level rises, in some cases dramatically.
Posted 11/25/09 at 8:17 am
NIOSH, the regulatory authorities and national and international standards-setting organization, along with trade associations representing high noise industries, must work together to encourage equipment manufacturers to lower the decibels. If only quiet machines and equipment are available for purchase, much of the hearing loss problem will disappear.
Posted 11/25/09 at 10:59 am
One policy that I think is a good idea is to require the use appropriate hearing protection whenever exposures may occur to sound levels exceeding the occupational exposure limit, regardless of the duration of the exposure. Many private companies do not follow that policy, only prescribing hearing protection whenever exposure times at a given sound level would result in an overexposure.
Posted 11/27/09 at 8:36 am
The Europeans have had quiet jackhammers for decades. As soon as there is a market manufacturers will adapt. One problem is OSHA doesnt enforce the noise standard in construction.
Posted 11/27/09 at 8:37 am
I wonder if OSHA could promulgate a standard whereby businesses are required to perform an annual noise survey of their premises or at least demonstrate that there is no noise hazard at their business. Since hearing loss is preventable, it seems that a proactive approach could be useful and might spur noisy industries to do more.
Posted 12/1/09 at 9:38 am
The small and handy instrument EAR SEAL can be used for ear protection to reduce noise by about 17 dB. It is very economical and is easily available in the market. During working hours people can use this small instrument as a safety measure.
Apart from this, Clinical examination of people who are more exposed to excessive noise can be accomplished by audiometric testing by which temporary or permanent hearing loss or the extent of reduction in hearing capacity can be found out.
Posted 12/4/09 at 8:33 am
interesting information here, US Government so care about this. Hope my country do the same. Thanks for sharing.
Posted 12/8/09 at 3:52 am
Re: Tim Sheehan's comment,
That is a good policy but often workers do not wear hearing protectors correctly so they only get minimal attenuation. Quieting the tool or quieting the process would be the best solution, if at all possible. Many tool manufacturers sell in the European Union where the noise regulations are more comprehensive. It would be great if they would adapt their EU tools to the American market.
Posted 12/10/09 at 12:04 pm
Policies and regulations are helpful for many workers. Our agriculutral workers though are often self-employed and working in isolation. Often they do not have access to occupational health, hearing services, or financial resources in the rural community. Rural physicians and providers of audiometric services need to work with the local agricultural community to assess the population, describe the need, work for affordable, local access of acceptable products for hearing conservation, and identify funding sources for those who need assistance.
Posted 12/11/09 at 10:30 am
Decibel Noise levels should be labelled on all power tools.
If you were to go the tool review of FineWoodworking.com you can find a small sander at 82 dBA and another sander at 87 dBA. Both remove the same material and cature dust equally and cost the same.
There is more than just noise exposure in the workplace, chronic exposure to carbon monoxide to welders or foundry workers could cause a synergiqtic effect to hearing loss.
There should be an insentive program to reduce noise. There will certainly be a long term competative to those that do.
Posted 12/11/09 at 3:34 pm