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What is the Hearing Loss Program

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Program Overview


Occupational hearing loss is one of the most common work-related illnesses. Depending on the definition of exposure and impairment, NIOSH estimates that there are between 5 and 30 million workers in the U.S. who are exposed to noise levels at work that put them at risk of hearing loss.[1], [2], [3], [4]  An additional 9 million may be at risk due to exposure to ototoxic chemicals.[5]  Estimates for other nations indicate a similar public health burden.[6], [7],[8] Occupational hearing loss is a permanent condition, with no recovery currently possible. Hearing loss may impair job performance and can prevent workers from communicating effectively. Workers with severe hearing loss are estimated to earn 50-70 percent of their non-hearing impaired peers.[9] Occupational hearing loss may also severely affect workers’ quality of life away from work.[10], [11] Occupational hearing loss is a problem that persists in spite of decades of study, regulation, and workplace interventions.10, [12], [13]

NIOSH is executing a planned program of research in occupational hearing loss. The mission of the HLR program is to provide national and world leadership to reduce the prevalence of occupational hearing loss through a focused program of research and prevention. It is divided into four areas of research:

·    Hearing loss prevention programs

·    Hearing protection devices

·    Engineering control of noise sources

·    Surveillance and risk factors

In each area we have set a general research goal. The goals are based on the advice of internal and external researchers, occupational safety and health practitioners, manufacturers of protective devices, employers and worker groups. We are managing the program to be accountable to those goals and so that both the goals and the program can be adjusted for progress and emerging issues. We also manage the program to ensure scientific relevance, quality, and performance, using peer-review and regular management review of research activities and outputs.

Research program activities to address the goals are varied by geographic location, type and number of staff, physical facilities, extramural-intramural ratio, and budget allocation. HLR program activities are coordinated across four different operating divisions of NIOSH. Research is conducted in the field as well as our laboratories, and sometimes we take our laboratories to the field. Partnerships are a feature of most of our research, with employers and workers playing a role in all of our field projects.

Our research has resulted in a number of outputs including papers, journal articles, conferences, advice to standards organizations, NIOSH communication products, and patents. These outputs have advanced the field of research. Some of them have been very influential, as evidenced by the way they have been cited in the regulatory and consensus standards activities of other agencies and professional organizations, and the repackaging and use of our recommendations by other entities. Another indicator of their influence is their repackaging and use by professional organizations. In addition, our outputs are in demand from the public. Thus, we claim to have an influence on health and safety outcomes in the workplace and we are confident that our current research will lead to more contributions in the future.

We describe and document the extent of our influence in the sections of this evidence package that follow. Examples of this influence include recommendations for exposure limits and other standards, the recognition that certain chemicals may interact with noise to produce a greater hearing loss, development of industry-accepted noise control mechanisms, and improved worker training programs which result in increased use of personal protective equipment. There are management review and oversight procedures in place to assure that the HLR program will continue to be a positive influence on public health outcomes. However, there are also areas where we can improve our performance.

This overview will cover our planning and research activities in more detail. It will also provide a report of major outputs and intermediate outcomes, a summary of external factors that either have or are expected to affect the program and an assessment of emerging issues. We begin this overview with a short historical perspective on the HLR program.

HLR Program History

Hearing loss research has been a part of occupational safety and health research for over three decades. Before the inception of NIOSH, a small research team devoted to hearing loss existed in the Bureau of Occupational Safety and Health, a federal public health agency. Since it began in 1970, NIOSH has had an active research program in occupational hearing loss, as evidenced by the publication of a noise criteria document in 1973.[14]

In 1996, both Pittsburgh and Spokane Research Laboratories, part of the former U.S. Bureau of Mines, joined NIOSH. At the time, the PRL included a small research effort on hearing loss prevention in the mining sector. Also in 1996, using input received from the occupational health community at large, NIOSH developed NORA, in which 21 topics were identified as priority areas for OSH research. “Hearing Loss” and “Mixed Exposures” are two of the priority topics in NORA that are addressed by the HLR program. The program also does work related to the NORA priority topics, “Control Technology and Personal Protective Equipment,” “Exposure Assessment Methods,” and “Intervention Effectiveness Research.” Currently the program supports strong streams of new research in ototoxic (harmful to hearing) chemical exposures and their synergistic and additive effects to noise exposure, engineering control of noise, research on the efficacy of new technologies in hearing protection devices, and efforts to understand the components of an effective hearing loss prevention program in the workplace.


[1] NIH [1990]. Consensus conference: Noise and Hearing Loss. J. Am. Med. Assoc. 263(23), 3185-3190.

[2] NIOSH [1998]. Criteria for a Recommended Standard Occupational Noise Exposure: Revised Criteria 1998. U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, DHHS (NIOSH) Publication No. 98-126.

[3] NIOSH [1996]. Preventing Occupational Hearing Loss—A Practical Guide. Cincinnati, OH: U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, DHHS (NIOSH) Publication No. 96-110.

[4] Franks JR [1992]. Unpublished analysis of noise-exposed workers from SIC codes and Bureau of Labor Statistics data.

[5] NIOSH [1996].  National Occupational Rsearch Agenda.  Cincinnati, OH: U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, DHHS (NIOSH) Publication No. 96-115.

[5] Franks JR [1992]. Unpublished analysis of noise-exposed workers from SIC codes and Bureau of Labor Statistics data.

[6] Burns W, Robinson DW. [1970]. Hearing and Noise in Industry (Her Majesty’s Stationary Office, London).

[7] Passchier-Vermeer, W. [1968]. Hearing loss due to exposure to steady-state broadband noise, Report No. 35 and Supplement to Report No. 35, Institute for Public Health Engineering, The Netherlands.

[8] Dobie RA [1993]. Medical-Legal Evaluation of Hearing Loss. New York: Van Nostrand Reinhold, Inc.

[9] Mohr PE, Feldman JJ, Dunbar J et al. The societal costs of severe to profound hearing loss in the United States. Int J Technol Assess Health Care 2000; 16: 1120-35.2

[10] Berger EH. [2000]. “Hearing Conservation, Why Do It?” in “The Noise Manual 5th Ed.” Eds. Berger EH, Royster LH, Royster JD, Driscoll DP, Layne M. (AIHA Press Fairfax VA). pp 1-18.

[11] Humes LE, Jollenbeck LM and Durch JS [2005]. “Noise and Military Service, Implications for Hearing Loss and Tinnitus,” Inst. Of Medicine of the National Academies, The Natl. Academies Press, Washington DC.

[12] Hoffman H and  Themann CL. [2005].  “Hearing Examination of Adults (20 to 69 years old) in the National Health and Nutrition Examination Survey (NHANES), 1999-2004” presented at the meeting of the National Hearing Conservation Association Tucson AZ, Feb. 24 2005.

[13] Murphy, WJ, Themann, CL and Franks JR. [2005].  “Hearing Levels in US Adults Aged 20 69 Years - NHANES 1999 to 2002”  J. Acoust. Soc. Am. 117 No. 4 Pt.2, 2395.

[14] NIOSH[1972]. NIOSH criteria for a recommended standard: occupational exposure to noise. Cincinnati, OH: U.S. Department of Health, Education, and Welfare, Health Services and Mental Health Administration, National Institute for Occupational Safety and Health, DHEW (NIOSH) Publication No. HSM 73-11001.


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