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NIOSH - National Institute for Occupational Safety and Health
NIOSH Hearing Loss Research Program Review NIOSH Publications on Noise and Hearing The National Academies - Advisors to the Nation on Science, Engineering, and Medicine

What has the program achieved?

In this section ....



Power Tools Database


Hearing loss among workers in the construction industry exceeds the normal rate of hearing loss observed in other industries. The cause has been attributed to a combination of lack of hearing loss prevention programs and a lack of information about the noise exposures received by workers. A widely-accessible database of sound power measurements from commonly used, electric powered hand tools was needed.


The HLR program developed a database that contains sound power levels, sound pressure levels in the operator's hearing zone and downloadable exposure files for commonly used power tools. Tools selected for study were based on market share research reports and Securities and Exchange Commission (SEC) filings to provide a broad picture of the available products. Inquiries to power tool distributors and dealers were also made to learn which models had the highest stock turnover or were bestsellers.

Sound power level testing (LW) measurement of power tools were conducted in the hemi-anechoic chamber (having a measurement radius of 2 meters). Tools that were too large for the chamber were excluded. The LW measurement of electric power tools was performed in accordance with the ANSI standard, 12.15-1992.[1] This standard prescribes the environment, instrumentation, operation, loading, device under test, setup, microphone locations, and data analysis for determining LW's. The standard also specifies calibration, operation, and maintenance for all data acquisition hardware. Most of the tests were conducted for an unloaded condition.


NIOSH Power Tools Database

What's Ahead?

HLR researchers are commencing the loaded condition tests. In addition to collecting sound power measurements, tool vibration measurements are now also performed. These data may be used to investigate hand-arm vibration problems, correlate with spectral peaks in the acoustic signature and help identify areas where noise control could be incorporated into the tool design.


Hearing Protector Compendium


Both employers and workers need a database on hearing protectors that are available in the U.S.


The HLR program collected current data to augment or replace the data last collected for the "1994 Hearing Protector Compendium."[2] All companies listed in various industry, technical, and professional directories were invited to submit data. All manufacturers are welcome to submit data for this effort.

Data collected and organized included the mean attenuations and standard deviations for each HPD as they were stated by the manufacturer. The database also has information about the construction, materials, and other features of each HPD that may aid in selection for specific situations.

Many companies that were listed in the 1994 compendium have merged with other companies or have ceased to manufacturer or sell hearing protectors. As of June 2003, the compendium contains data from 23 manufacturers nationwide (down from 53 in the 1994 compendium) on 292 hearing protectors (up from 241 in the 1994 compendium). Although only 23 of the 67 companies contacted responded to the request for data, these 23 represent a majority of the market share. All data in the compendium were provided by the manufacturers.


2003 Hearing Protector Compendium

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Hearing Protector Attenuation Measurements


In the course of developing recommendations for standards on hearing protector measurements and rating methods, the HLR program collected data from several hearing protector studies conducted as a part of NIOSH research. If made available, these data could benefit other research efforts.


In 1990, HLR program researchers conducted an interlaboratory study which provided a basis for conducting the 1992 interlaboratory study. Four hearing protector testing laboratories collaborated to complete the study. Included in the database are the laboratory and subject trials for attenuation at several frequencies. The data formed the basis of the revision to the ANSI S12.6-1984 standard.[3] The data are available to interested parties for further analysis of the spectral effects on attenuation and protected noise exposure. Data from the current interlaboratory study between six labs will be added.


ANSI S12.6-1997 [2002]. American national standard: Methods for measuring the real-ear attenuation of hearing protectors. New York: American National Standards Institute, Inc., ANSI S12.6-1997.

Berger E H, Franks JR, Behar A, Casali JG, Dixon-Ernst C, Kieper RW, Merry CJ, Mozo BT, Nixon CW, Ohlin D, Royster JD, Royster LH [1998]. Development of a new standard laboratory protocol for estimating the field attenuation of hearing protection devices. Part III. The validity of using subject-fit data. J Acoust Soc Am 103 (2): 665-672.

Gauger D, Berger E [2004]. A new hearing protector rating: The noise reduction statistic for use with A-weighting (NRSA).

Murphy WJ, Franks JR, Krieg EF [2002]. Hearing protector attenuation: Models of attenuation distributions. J Acoust Soc Am 111 (5) Part 1: 2109-2116.

Murphy WJ, Franks JR, Berger EH, Behar A, Casali JG, Dixon Ernst C, Krieg EF, Mozo BT, Ohlin DH, Royster JD, Royster LH, Simon SD, Stephenson C [2004]. Development of a new standard laboratory protocol for estimation of the field attenuation of hearing protection devices: Sample size necessary to provide acceptable reproducibility. J Acoust Soc Am 115 (1): 311-323.

Royster LH [1995]. In Search of a Meaningful measure of Hearing protector Effectiveness, Spectrum 12(20 1,6-13.

Royster JD, Berger EH, Merry CJ, Nixon CW, Franks JR, Behar A, Casali JG, Dixon-Ernst C, Kieper RW, Mozo BT, Ohlin D, Royster LH [1996]. Development of a new standard laboratory protocol for estimating the field attenuation of hearing protection devices. Part I. Research of Working Group 11, Accredited Standards Committee S12, Noise. J Acoust Soc Am 99, 1506-1526.

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The Worker Health Chartbook 2004


There is a need for a variety of occupational health surveillance data and information in a single volume. Such a volume would facilitate ongoing systematic collection, analysis, and interpretation of health data essential to the planning, implementation, and evaluation of public health practices.


NIOSH compiled the first "Worker Health Chartbook" in 2000 ( The 2004 update of the chartbook is a descriptive epidemiologic reference on occupational morbidity and mortality in the U.S. This edition describes the magnitude of the Nation's occupational health problem by providing a view of the distribution and trends for occupational injuries, illnesses, fatalities, and other measures of health status. The document presents national and state data to the extent that they are available. Data are presented from BLS on labor force demographics and employment projections.[4][5] Health status measures are described by age, race/ethnicity, severity of injury or illness, occupation, and industry of the affected workers.[6][7]


The Worker Health Chartbook 2004 (

Cross-Sectional Survey Database


For exposure assessment, engineering control research selection, and research program planning, NIOSH needed industry-wide exposure data for mine workers.


From 1999 to the present, NIOSH conducted the Cross-Sectional Survey project to obtain information on worker noise exposure in the mining industry. The survey has been conducted across the mining industry including surface and underground coal, coal preparation plants, surface and underground stone, and sand and gravel. It involved on-site visits to 42 mines or plants employing approximately 6,500 employees in 575 occupational categories. Nearly 550 worker exposures were recorded and over 200 equipment noise profiles were completed.

Individual, commodity-specific results of the studies (the database) have been published, but a comprehensive analysis of the data remains unpublished. The entirety of the database will be made public at project end. The studies found that nearly 100% of the miners surveyed were exposed to hazardous noise levels (as indicated by a dose measurement above  the MSHA PEL). Although exposures above 85 dB(A) were of short duration for most of the miners, some significant exposures were found. These included approximately 40% of the underground coal miners with exposures above the MSHA PEL of 100%, or an eight-hour time-weighted average (TWA8) of 90 dB(A). In other mining commodities, 10 to 30% of the workers experienced exposures above the MSHA PEL. These results suggest that from 22,000 to 88,000 mine workers are potentially exposed to hazardous noise levels.


Bauer, ER and JL Kohler [2000]. Cross-Sectional Survey of Noise Exposure in the Mining Industry. Proceedings of the Thirty-First Annual Institute of Mining Health, Safety and Research, Aug. 27-30, Roanoke, VA, pp. 17-30.

Bauer, ER, DJ Podobinski, and ER Reeves [2001]. Noise Exposure in Longwall Mining and Engineering Noise Control Research. Proceedings Longwall USA 2001 International Exhibition and Conference, June 13-15, Pittsburgh, PA, pp. 51-69.

Bauer, ER and DR Babich [2003]. Worker exposure and equipment noise in large surface coal mines. SME Preprint 03-051, 6 pp.

Bauer, ER and DR Babich [2004]. Administrative controls for reducing worker noise exposures. SME Preprint 04-09, Feb., 9 pp.

Bauer, ER and DR Babich [2004]. Worker exposure and equipment noise in large surface coal mines. Mining Engineering, v. 56, No. 4, April, pp. 49-54.

Bauer, ER, ER Reeves, TM Durr, DR Zuchelli, and D Armour [2005]. Testing and Evaluation of an Engineering Noise Control on a Longwall Stageloader. SME Preprint 05-58, Society for Mining, Metallurgy, and Exploration, Inc., Littleton, CO, 12 pp.

Yantek, DS, P Jurovcik, and ER Bauer [2005]. Noise and Vibration Reduction of a Vibrating Screen. SME Preprint 05-71, Society for Mining, Metallurgy, and Exploration, Inc., Littleton, CO, 13 pp.

What's Ahead?

Mine site surveys will continue in order to collect additional noise exposure data. Emphasis will be placed on surveying the commodities not yet examined, as well as adding to the current database from previously surveyed commodities. Eventually, the database will provide an industry-wide summary of occupational noise exposure of mine workers. The database will be available to the public.

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National Occupational Hazard Survey (NOHS) and the National Occupational Exposure Survey (NOES).


For hazard assessment, research program planning, and to carry out other responsibilities under the Occupational Safety and Health Act, NIOSH needed broad-based workplace exposure data.


From 1972 to 1974, NIOSH conducted the National Occupational Hazard Survey (NOHS) to obtain information regarding safety conditions in US workplaces. It was conducted across a representative sample of manufacturing and non-manufacturing workplaces. From 1981-1983, NIOSH conducted a second survey of workplace hazards, known as the National Occupational Exposure Survey (NOES). This database contains measurements similar to the NOHS on potential occupational exposures to chemical, physical, and biological agents.

The survey involved on-site visits to 4,490 establishments in 522 industry types employing approximately 1,800,000 workers in 377 occupational categories. Nearly 13,000 different potential exposure agents and over 100,000 unique tradename products were observed during these on-site visits.

Field guidelines, sampling methodology, and an analysis of management interview responses have been published [NIOSH 1988, 1989a, 1989b]. However, the bulk of the data remains unpublished. The NOES database has not been updated since July 1, 1990.

The NOES found that 17% of manufacturing workers were exposed to hazardous noise levels (unpublished data from NOES database). This database includes noise measurements at the employee's ear which were 85 dB(A) or greater, regardless of duration. The survey estimated that over 7,500,000 workers were potentially exposed to hazardous noise, including 23% of all employees in manufacturing (NIOSH, 1974).


NIOSH [1988]. National occupational exposure survey field guidelines. Vol. I. Seta JA, Sundin DS, Pedersen DH, eds. Cincinnati, OH: U.S. Department of Health and Human Services, Centers for Disease Control, National Institute for Occupational Safety and Health, DHHS (NIOSH) Publication No. 88-106.

NIOSH [1989a]. National occupational exposure survey analysis of management interview responses. Vol. III. Pedersen DH, Sieber WK, eds. Cincinnati, OH: U.S. Department of Health and Human Services, Centers for Disease Control, National Institute for Occupational Safety and Health, DHHS (NIOSH) Publication No. 89-103.

NIOSH [1989b]. National occupational exposure survey sampling methodology. Vol. II. Sieber WK, ed. Cincinnati, OH: U.S. Department of Health and Human Services, Centers for Disease Control, National Institute for Occupational Safety and Health, DHHS (NIOSH) Publication No. 89-102.

Burkhart G, Schulte PA, Robinson C, Sieber WK, Vossenas P, Ringen K.Job tasks, potential exposures, and health risks of laborers employed in the construction industry. Am J Ind Med. 1993 Oct;24(4):413-25.

Davis RR, Sieber WK. Hearing protector use in noise-exposed workers: a retrospective look at 1983. AIHA J (Fairfax, Va). 2002 Mar-Apr;63(2):199-204.

Davis RR, Sieber WK [1998]. Trends in hearing protector usage in American manufacturing from 1972 to 1989. American Industrial Hygiene Association Journal 59:715-722.

Franks,JR. Number of Workers Exposed to Occupational Noise. Seminars in Hearing 1988 Nov; 9(4):287-298.

Morata TC, Dunn DE, Sieber WK. Occupational exposure to noise and ototoxic organic solvents. Arch Environ Health. 1994 Sep-Oct; 49(5):359-65.

What's ahead?

The HLR program is in the early stages of two programs to collect updated noise exposure data. The National Occupational Exposure Database (NOEDB) will provide a repository for exposure information collected through NIOSH activities. It will provide U.S.-wide occupational exposure data. The HLR program has been an active contributor to the NOEDB development team, defining noise-related data elements and evaluating potential software systems. The NOEDB has the potential to alleviate the current situation of large amounts of inconsistent and/or irretrievable exposure data. This will be a step forward for the HLR program.

The HLR program has also actively contributed to the survey plans, defining minimum data elements, establishing protocols for noise measurement, and developing relevant questionnaire items for a new survey, the National Exposure at Work Survey (NEWS). NEWS will collect data on a sector-basis. The healthcare sector will be surveyed first, with field implementation scheduled for late 2005. Because noise was not indicated by stakeholders to be a problem in healthcare, noise-related data collection in this sector will be limited to a questionnaire item (no measurements will be taken). HLR program participation in NEWS will continue when subsequent sectors are sampled.

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Occupational Noise and Hearing Survey


Data from a range of noisy occupational settings was needed to perform risk assessments and examine the association between noise exposure and hearing loss.


The data used for risk assessment were collected by the HLR program in 13 noise and hearing surveys, collected from 1968 to 1972. The industries in the surveys included steelmaking, paper bag processing, aluminum processing, quarrying, printing, tunnel traffic controlling, woodworking, and trucking. Questionnaires and audiometric examinations were given to noise-exposed and non-noise exposed workers who had consented to participate in the surveys. More than 4,000 audiograms were collected. The population that met inclusion criteria consisted of 1172 (792 noise-exposed and 380 " controls" ) predominately white male workers from a cross section of industries within the United States. The analysis focused on how risk estimates vary according to various model assumptions, including shape of the dose-response curve and the amount of noise exposure among low-noise exposed workers (or controls).


National Institute for Occupational Safety and Health (NIOSH), Criteria for a Recommended Standard. Occupational Noise Exposure. DHHS (NIOSH) Publication No. 98-126. June, 1998.

National Institute for Occupational Safety and Health (NIOSH). Criteria for a Recommended Standard. Occupational Exposure to Noise,'' HSM 73-11001, U.S. Department of Health, Education, and Welfare, U.S. Government Printing Office, Washington, DC, pp. 1-142, 1972.

Prince MM, Gilbert SJ, Smith RJ, Stayner LT. Evaluation of the risk of noise-induced hearing loss among unscreened male industrial workers. J Acoust Soc Am. 2003 Feb; 113(2):871-80.

Prince MM.Distribution of risk factors for hearing loss: implications for evaluating risk of occupational noise-induced hearing loss. J Acoust Soc Am. 2002 Aug; 112(2):557-67.

Dobie RA. Comments on " A re-examination of risk estimates from the NIOSH Occupational Noise and Hearing Survey." J. Acoust. Soc. Am. 101, 950-963 (1997)
J Acoust Soc Am. 1998 May;103(5 Pt 1): 2734-9.

Prince MM, Stayner LT, Smith RJ, Gilbert SJ. A re-examination of risk estimates from the NIOSH Occupational Noise and Hearing Survey (ONHS). J Acoust Soc Am. 1997 Feb;101(2):950-63.

Lempert, BL and Henderson, T.L.. Occupational Noise and Hearing 1968-1972,'' HEW Publication No. (NIOSH) 74-116, U.S. Department of Health, Education, and Welfare, U.S. Government Printing Office., Washington, DC, pp. 1-51, 1973.

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Databases Created by Extramural Researchers

Audiometric Database


A database of industrial audiometric data was needed to provide researchers with validated measures of HLPP effectiveness. Specifically, hearing threshold trends of noise-exposed employees was needed.


The database (a computer tape) includes data from twenty-two companies representing different types of industries from different areas of the U.S. and Canada. Eleven data sets were verified for data accuracy by comparison to original hard copy records, and eleven data sets acquired as machine-readable tapes were screened for data accuracy by error-trapping programs. The tape contains the same data sets used by the ANSI S12-13 Working Group in its process of creating hearing conservation program evaluation criteria. The data are anonymous with respect to company and individual. There are 15,297 employees with at least four audiograms within the 22 data sets, and 3,958 employees with at least 8 audiograms.

The tape includes several control groups of low-noise or non-noise-exposed individuals. Six data sets each include at least 100 employees with noise exposures below a TWA of 85 dBA on their first four audiograms. One other data set consists entirely of low-noise or non-noise-exposed employees. Another data set includes employees with a TWA of 87 dBA who consistently wear hearing protection devices.

Additional data for each employee include age and sex (all 22 data sets), race (12 data sets), and non-occupational or medical hearing factors (5 data sets).


American National Standard Institute. Draft American National Standard ANSI S12.13-1991 (DANS). Evaluating the effectiveness of hearing conservation programs. Acoustical Society of America, New York: 21pp.

Adera T, Donahue AM, Malit BD, Gaydos JC. Assessment of the proposed Draft American National Standard method for evaluating the effectiveness of hearing conservation programs. J Occup Med. 1993 Jun; 35(6):568-73.

Driscoll DP, Royster LH. Comparisons between the median hearing threshold levels for an unscreened black nonindustrial noise exposed population (NINEP) and four presbycusis data bases. Am Ind Hyg Assoc J. 1984 Sep; 45(9):577-93.

Royster JD, Royster LH. Using audiometric data base analysis. J Occup Med. 1986 Oct; 28(10):1055-68.

Royster JD, Royster LH, Pearson, RG. Hearing conservation programs (HCPs): the effectiveness of one company's HCP in a 12-hr work shift environment. Am Ind Hyg Assoc J. 1990 Aug; 51(8):437-46.

Royster JD, Royster LH. New draft ANSI standard enhances efforts in hearing conservation. Occup Health Saf. 1991 Oct; 60(10):86, 89-90.

Simpson TH, Stewart M, Kaltenbach JA. Effects of audiometric threshold step size on proposed ANSI S12.13 outcomes for characterizing hearing conservation program effectiveness. J Am Acad Audiol. 1993 Jul; 4(4):258-63.

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Farm Family Health and Hazard Surveillance


The U.S. Congress expressed a concern that agricultural workers and their families experience a disproportionate share of disease and injury associated with the chemical, biological, physical, ergonomic, and psychological hazards of agriculture.

A database was needed to help identify health status and health risks for agricultural workers and their families.


The NIOSH Farm Family Health and Hazard Surveillance (FFHHS) Cooperative Agreement Program was developed to respond to the Congress's concerns. NIOSH developed these agreements with education and health agencies in New York, Kentucky, Ohio, Iowa, Colorado, and California, to collect questionnaire data, hazard observation data, and medical screening data. The survey sample size varies from 200 farms to 600 farms per state for on-farm hazard observations and medical screening, and up to 4,500 farms for questionnaire data.

In previous cooperative agreement awards, NIOSH provided general guidelines to these states about the use of standard modules for questionnaires, medical screening protocols, and hazard observation protocols. Each survey incorporated some or all of the standardized modules, while also including survey components unique to the needs of the farming population and surveillance needs in each state. The surveys also differed with respect to coverage of selected sub-populations (for example, farm children) and selected farm commodities. Geographic coverage varied from a sample of counties to an entire state.

The FFHHS included a noise and hearing loss component. Questionnaires gathered data on prevalence and degree of hearing loss; cumulative lifetime noise exposure due to farming, other occupational, and recreational activities; and use of hearing protection devices. Audiometric thresholds were obtained from farm operators and in some cases from his or her spouse and children. A variety of noise measurements were made during the hazard observation walk-throughs on many of these same farms. The FFHHS data set comprises the largest database of noise and hearing data on the agricultural population to date.


Farm Family Health and Hazard Surveillance web site, with reports by state

Beckett WS, Hallman E, May J, Hwang SA, Gomez M, Eberly S, Cox C. Follow-up to Farm Family Health and Hazard Survey. J Occup Environ Med. 2004 Apr; 46(4):314-5.

Gomez MI, Hwang SA, Sobotova L, Stark AD, May JJ.A comparison of self-reported hearing loss and audiometry in a cohort of New York farmers. J Speech Lang Hear Res. 2001 Dec; 44(6):1201-8.

Hwang SA, Gomez MI, Sobotova L, Stark AD, May JJ, Hallman EM. Predictors of hearing loss in New York farmers. Am J Ind Med. 2001 Jul;40(1):23-31.

Beckett WS, Chamberlain D, Hallman E, May J, Hwang SA, Gomez M, Eberly S, Cox C, Stark A.Hearing conservation for farmers: source apportionment of occupational and environmental factors contributing to hearing loss. J Occup Environ Med. 2000 Aug; 42(8):806-13.

Reynolds-SJ; Merchant-JA; Stromquist-AM; Burmester-LF; Taylor-C; Lewis-MQ; Kelly-KM. Self-reported noise exposures among Ohio cash grain farmers. J Agric Saf Health 1998 May; 4(Special Issue 1): 79-88

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National Agricultural Safety Database (NASD)


An information resource was needed to distribute prevention information to agricultural safety specialists, managers, and workers.


NASD is a national central repository of agricultural health, safety, and injury prevention materials for the agricultural community and especially for agricultural safety specialists. The expansion and maintenance of NASD is being partially funded by NIOSH. NASD is made available through the NIOSH Web site to enhance public access. NASD contains over 3,000 agricultural health and safety publications from 32 states (agricultural extension agents and universities), four federal agencies and five national organizations covering many topics. The collection includes OSHA and EPA standards, extension publications in English and Spanish, a database of abstracts and ordering information for over 2,000 agricultural safety-related videos, a NIOSH bibliography database with over 500 scientific publications, a resource directory with contact information for over 1,500 people and organizations involved in agricultural safety and health, slide presentations, posters, conference proceedings, a library of graphics, clip art and photos, sample news releases, training materials and public service announcement scripts. Noise and hearing loss prevention topics are among these materials.


National Agricultural Safety Database (NASD) web site

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The Fels Longitudinal Study


The Fels Longitudinal Study (Fels) began in 1929 and is the world's longest running study on human growth, body composition, maturation, and aging. Its objective is to research the changes that occur in " normal" individuals throughout their life span. Data on occupationally-related hearing loss would add dramatically to the value of the study to the HLR program.


The first participants in Fels were enrolled prenatally and are now in their mid-sixties. Children, grandchildren, and even great-grandchildren of the original participants are now enrolled in Fels. Nearly 5000 persons have participated overall. Participants are examined on a schedule that emphasizes key developmental stages or other times in life when major changes are occurring. The study is currently managed by the Lifespan Health Research Center (LHRC) at the Wright State University School of Medicine.

From 1977-1983, data on auditory and human developmental characteristics as well as noise exposures were serially collected on groups of children and young adults in the Fels program in order to study how hearing ability develops in humans relative to various individual and environmental factors. In 2003, the HLR program helped establish an auditory performance laboratory at the LHRC. The laboratory will provide a longitudinal reference population, and the possibility of evaluating the effect of genetics versus noise exposure on hearing threshold shift progression. The HLR program provides training to the Fels staff, assists with equipment maintenance and calibration, and will cooperate in the analysis of audiometric data. Initial results should be available in 2007. These data will be used to develop methods for assessing work-relatedness of hearing loss. By adding auditory function tests to this unique longitudinal and multi-generational study (N­=2500), HLR program scientists will be able to examine such important questions as: is the hearing of U.S. workers staying the same, getting better, or getting worse? How is their noise exposure affecting their hearing and overall health? Current plans call for the HLR program to maintain the equipment and provide assistance in analyzing auditory function data. LHRC staff will coordinate and administer subject participation and collect the data.


Not available yet.

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Sentinel Event Notification System for Occupational Risk (SENSOR)


There is a need for hearing loss surveillance data.


Michigan and the HLR program aimed to establish a case ascertainment system using reports from employers, audiologists, and otolaryngologists. We developed a follow-up system to characterize reported cases, and instituted referral procedures at companies that do not have hearing conservation programs. From 1992-2000, and beginning again in 2002, the HLR program provided technical and financial support to the State of Michigan through the Sentinel Event Notification System for Occupational Risk (SENSOR) program for a noise-induced hearing loss surveillance and prevention system.

Although Michigan researchers believe that there are still a substantial number of cases which were not reported, the data in this database provide a point from which progress can be measured. Additionally, as company-reported cases are more likely to represent new instances of occupational hearing loss than those reported by health providers (non-company), there may be some evidence that the ascertainment system and subsequent follow-up and referral activities are reducing the incidence of occupational hearing loss.

Although the need for national data is still great, the HLR program has not yet been able to implement surveillance in any other state. Consequently, we are working with OSHA to track occupational hearing loss by means of the OSHA form for recording occupational illnesses and injuries. We resolved many of the problems raised about this approach. Effective January 1, 2004, OSHA implemented a revised Form 300 which addressed these problems, redefining recordable threshold shift in order to count hearing loss cases more accurately, requiring state OSHA programs to use the same definition of threshold shift, and implementing a separate column for recording occupational hearing loss.[8]


The Michigan SENSOR program publishes reports annually and maintains a program web site:

Reilly MJ, Rosenman KD, Kalinowski DJ (1998). Occupational noise-induced hearing loss surveillance in Michigan. J Occup Environ Med, 40(8):667-74.

NIOSH [2000]. NIOSH Worker Health Chartbook. U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, NIOSH Publication No. 2000-127.

NIOSH [2004]. NIOSH Worker Health Chartbook. U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, NIOSH Publication No. 2004-146.

Intermediate Outcomes

The Bureau of Labor Statistics has published preliminary statistics from the OSHA 300 log for calendar year 2004. ( These data represent the first national statistics on the incidence of occupational hearing loss and will provide a valuable baseline from which progress in hearing loss prevention can be tracked.

Data from the OSHA 300 log will be used by Michigan to evaluate the efficacy of current regulations and prevention practices, target and prioritize hearing conservation efforts, and permit individual employers to compare the performance of their hearing conservation program not merely against their own prior record, but also against the record of other employers within the same industry. Data from the OSHA 300 log will also be used to evaluate the success of the Healthy People 2010 goal 20-11: Reduce by 50% the incidence of noise-induced hearing loss.[9]

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National Health and Nutrition Examination Survey (NHANES)


When determining excess risk of hearing loss due to occupational exposures, it is necessary to have accurate comparison data for a reference population. Currently, reference data are based on audiometric data collected in the 1960s and 1970s,[10],[11] data collected from one regional area,[12] or self-assessment of hearing ability which can result in underestimation of hearing trouble.[13] In 1988 and again in 1996, the HLR recognized the need to establish contemporary reference databases of hearing ability in the general population.


The National Health and Nutrition Examination Survey (NHANES) is a program conducted by the National Center for Health Statistics. It collects nationally-representative data on the health and nutritional status of the civilian, non-institutionalized population of the U.S. through questionnaires, physical examinations, and laboratory analyses. The surveys were conducted periodically from 1959 to 1999, at which time the program was authorized to collect data on a continuous basis.

Audiometric testing has been conducted in every cycle of the NHANES survey. However, the general adult population was only tested twice: in 1960-62 and in 1971-75. The HLR program proposed audiometric testing of adults during the 1988-1994 cycle, and testing was included in the pilot stage. But it was dropped from the final survey protocol. The HLR program re-applied for the survey cycle which began in 1999. Hearing testing in adults aged 20-29 was included for the six-year cycle of the survey that was completed in 2004. In addition to hearing data, the survey collected information on occupational and non-occupational noise exposures. The HLR program provided technical assistance for the current NHANES audiometry component, including protocol and questionnaire development, technician training, and oversight of data collection.

NHANES data collected from 1999-2002 are available, are currently being analyzed and publications are being prepared. Data from the 2003-2004 NHANES will complete the database and should be available by 2006.

While NHANES is filling a longstanding research need in occupational hearing loss research, it initially only collected data through age 69 and those data are cross-sectional. The HLR program has been involved in other studies that address these limitations. The Age, Gene/Environment Susceptibility Study (AGES) is the current phase of a prospective research program established in 1967 known as the Reykjavik Study. The project has collected longitudinal data from a cohort of more than 20,000 individuals resident in the Reykjavik area and born between 1907 and 1934. The primary purpose of AGES is to sequence the human genome and identify candidate genes that will allow substantial innovation in the epidemiologic study of aging. AGES is also conducting audiometric testing on approximately 10,000 individuals aged 67 and older participating in this phase of the project. The HLR program is providing technical assistance with the audiometric portion of this study, which is designed to be essentially identical to the NHANES protocol. Data collection for the AGES project will continue through 2006 and be available for analysis shortly thereafter.


Preliminary findings from the NHANES data were presented at professional conferences and are being used as a reference population for the HLR program study of hearing in carpenters.

What's Ahead?

The 1999-2004 NHANES data will provide a national reference database of hearing thresholds in the general population, as well as from a completely non-noise-exposed sub-population. It will also be possible to stratify the data by demographics and other health and exposure variables, providing the opportunity to look for interactions between hearing ability and many other factors. NHANES is now a continuous survey and the HLR program is continuing to provide support for audiometric testing. During 2005-2006, participants aged 12-19 and those aged 70 and older are receiving hearing testing. The hope is to keep audiometry as a permanent part of the NHANES program, periodically shifting the age range tested, so that an updated reference population will be available for a given age group every ten years or so.

The AGES study will have utility as additional reference populations, as data sets that can be correlated with longitudinal history and medical information, and as a means of studying the influence of genetics on hearing ability. Because previous threshold data exists for the Fels participants, that data will also be useful in evaluating the effect of genetics versus the effect of exposure on threshold progression.

[1] American National Standard for Acoustics - portable electric power tools, stationary and fixed electric power tools, and gardening appliances - measurement of sound emitted, American National Standards Institute ANSI S12.15-1992 (Acoustical Society of America, New York, 1992).

[2] NIOSH [1994]. The NIOSH compendium of hearing protection devices. 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. 95-105.

[3] ANSI S12.6-1984 [1984]. American National Standards Institute: Methods for measuring the real-ear attenuation of hearing protectors. New York: American National Standards Institute, Inc., ANSI S12.6-1984.

[4] BLS [2001]. Non-fatal cases involving days away from work: selected characteristics. Washington, D.C.: U. S. Department of Labor, Bureau of Labor Statistics.

[5] BLS [2002a]. Case and demographic data for SIC 17 during 1998-2000 was provided to NIOSH as an Excel spreadsheet. Washington, D.C.: Department of Labor, Bureau of Labor Statistics.

[6] BLS [2003b]. Survey of occupational injuries and illnesses. Nonfatal (OSHA recordable) injuries and illnesses. Case and demographic characteristics. Washington, DC: U.S. Department of Labor, Bureau of Labor Statistics, Safety and Health Statistics Program.

[7] BLS [2003c]. Occupational injuries and illnesses in the United States: profiles data 1992-2001, version 9.0, CD-ROM. Washington, DC: U.S. Department of Labor, Bureau of Labor Statistics, Safety and Health Statistics Program.

[8] OSHA (2002). Occupational Injury and Illness Recording and Reporting Requirements. Federal Register, 67:77165-77170.

[9] US Department of Health and Human Services. Healthy People 2010, 2nd ed. Volume II: Objectives for Improving Health Part B: Focus Areas 15-28. Washington DC: US Government Printing Office, November 2000.

[10] Glorig A & Roberts J (1965). Hearing levels of adults by age and sex: United States, 1960-1962. Vital and Health Statistics, Series 11, No. 11. (PHS) 1000.

[11] Rowland M (1980). Basic data on hearing levels of adults 25-74 years: United States, 1971-75. Vital and Health Statistics, Series 11, No. 215.

[12] ANSI S3.44 (1996). American National Standard: Determination of Occupational Noise Exposure and Estimation of Noise-Induced Hearing Impairment.

[13] NCHS (2005). Summary health statistics for U.S. adults: National Health Interview Survey, 2003. Vital and Health Statistics, Series 10, No. 225 (PHS) 2005-1553.

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