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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 does the HLR Program Do?

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Research Goal 1

Research Goal 2

Research Goal 3

Research Goal 4

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R&D Portfolio - Research Goal 3 : Develop Engineering Controls to Reduce Noise Exposures

Application of engineering noise controls is the most desirable approach to reducing exposure to noise in the workplace and the noise induced hearing loss that often results. Engineering noise controls reduce or eliminate the noise at its source and insure that workers are not overexposed. Other approaches to reducing exposure, such as administrative controls and personal protection, are less effective because they rely on human actions.

NIHL occurs across all industries but has the highest incidence in the construction and mining industries where over 3.3 million workers are exposed to damaging noise levels. NIHL is the most prevalent occupational disease in these industries. For example, approximately 50% of construction workers, 90% of coal miners, and 49% of metal/nonmetal miners exhibit a hearing loss by the age of 50.[1],[2],3 in contrast, only 10% of the non-occupational-noise exposed population have a hearing impairment at that age.[3]

In the mining industry, the use of heavy equipment, the drilling of rock and the confined work environment are some of the factors that contribute to high levels of noise exposure. Eighty percent of the nation’s miners work in an environment where the time weighted average (TWA) noise exposure exceeds 85 dB(A). Moreover, 25% of theminers are exposed to a TWA that exceeds 90 dB(A), the PEL.

In the construction industry, NIHL may be attributed to noise exposures from large earth moving machinery, powered hand tools, and other activities. Exposures are often in excess of the NIOSH- REL of 85 dB(A) and OSHA’s PEL of 90 dB(A). A 1995 HHE revealed that carpenters aged 25-35 years with 7 to 17 years experience in the industry have the hearing equivalent of a 55 year-old worker who has not been exposed to excessive noise.[4] Recent studies conducted at the University of Washington found that 40% of the noise exposure measurements collected for carpenters and laborers were over the PEL established in the state of Washington–85 dB(A) for 8 hours.[5] They also found that other so-called “quiet” trades are also exposed to noise. Twenty-four percent of the measurements made on those working in the trades, such as electricians, were also over this PEL. In this study, 50% of the construction workers at age 50 or older, and 57% of carpenters employed for over 20 years suffered hearing impairment.

MSHA supports the preference for engineering noise controls in mining. In September of 1999, it released a revised health standard for occupational noise exposure in coal, metal, and nonmetal mines (30 CFR Parts 56, 57, 62, 70, and 71).[6] Unlike its predecessor, the rule emphasizes the primacy of engineering controls as the strongest defense against excessive exposure to noise and the prevention of NIHL among miners and disallows reliance on HPDs as a means of compliance with the standard.

Regulation of noise exposure in the construction industry currently falls under OSHA 29 CFR 1926.52. It does not include an emphasis on the primacy of engineering controls, nor does it disallow the use of HPDs. In addition, it does not have noise exposure reduction requirements that are as strong as those in effect for other industries (OSHA 29 CFR 1910.95). OSHA citations for violations of the construction noise standard have been relatively infrequent with small associated fines.[7] To date, this regulation does not appear to be having a marked impact on reducing noise exposure in the construction industry as exposure levels have not been reduced. This further highlights the need for cost effective engineering noise controls to reduce worker exposures.

The HLR program began to focus some of its efforts on engineering controls of noise in the mining and construction industries in 2001. The program’s approach is to first gather and analyze information on noise emission levels to identify the highest noise producing equipment used in the mining and construction industries. Once the equipment is identified, existing engineering noise controls are investigated for their effectiveness and feasibility. Where controls do not exist, engineering controls must be designed, developed, implemented, and tested for the noise producing equipment. The final stages of this approach is then to motivate the use of engineering noise controls through collaboration with other government agencies, unions, equipment manufacturers, and standard’s setting bodies; and to develop necessary dissemination activities.[8],[9],[10]

In 2001, the HLR program had fewer than three employees partially focused on engineering noise control research, primarily in mining. Currently, about 15 engineers and scientists are working on noise controls, assessing their effectiveness and feasibility of application, identifying areas for which no engineering noise controls exist, and providing recommendations to reduce noise emissions.[11],[12] For instance, noise reduction coatings for a continuous mining machine conveyor have proven to be effective in lab and field trials. Also, NIOSH testing facilities identified that drilling systems originally developed to control dust also have a significant noise reduction benefit. These and other interventions are being promoted and disseminated to all applicable sectors of the industry and workforce through technical communication and social marketing. The potential impact of these and other interventions will be followed through long-term evaluations to determine if workers are being exposed to less noise and if fewer of them develop a hearing loss.

In addition to our in-house engineering controls research effort, we also have a small extramural effort that has funded two university grants in recent years.[13],[14] Both of these grants are aimed at the application of active noise control technology to reduce noise levels in a variety of occupational settings. At this time no reportable outcomes are available. While expanding our research portfolio in the area of engineering controls for reducing worker noise exposure, these extramural grants also provide a mechanism for fostering capacity building of a base of future engineering control researchers.


[1] Sweeney MH, Fosbroke D, Goldenhar L, Jackson L, Linch K, Lushniak B, Merry C,Schneider S, Stephenson M [2000]. Health consequences of working in construction. In: 24 Coble R, ed. Construction safety and health management, Upper Saddle River, New Jersey: Prentice Hall, pp. 211-234.

[2] Franks J. [1997]. Prevalence of hearing loss for noise –exposed metal/nonmetal miners, Internal Report. National Institute for Occupational Safety and Health, Cincinnati, OH, pp. 1-5, and cover letter to Andrea Hricko from Gregory Wagner, October 7, 1997.

[3] Franks J. [1996]. Analysis of Audiograms for a Large Cohort of Noise-Exposed Miners, Internal Report. National Institute for Occupational Safety and Health, Cincinnati, OH, pp. 1-7, and cover letter to Davitt McAteer from Linda Rosenstock, August 6, 1996.

[4] NIOSH [2002]. Hazard Evaluation and Technical Assistance files 95-0249 and 96-0007, National Institute for Occupational Safety and Health, Cincinnati, OH.

[5] Neitzel R, Seixas N, Camp J, Yost M [1999]. An assessment of occupational noise exposures in four construction trades. Am Ind Hyg Assoc J, 60(6):807-817.

[6] Federal Register, 1999:  Health Standards for Occupational Noise Exposure; Final Rule. Department of Labor, Mine Safety and Health Administration, 30 CFR Part 62, Vol. 64, No. 176, September 13, pp. 49630 - 49634.

[7] Schneider S, Spencer ER, Babich DR, Healy T, Bailey C, Moir S, Kardous CA, Ogle T, Ringen K [2002]. Construction noise control in the 21st century. In:  Proceedings of the 12th Annual Construction Safety and Health Conference “Power Through Partnerships.”  Rosemont, IL:  Construction Safety Council, pp. 39-44.

[8] Hayden CS II [2001]. Engineering Noise Controls in the Construction Industry – Current and Past Efforts. Presented at the 2001 International Conference on Roadway Work Zone Safety, St. Louis, MO, May 10-12, 2001.

[9] Hayden CS II [2002]. Application of Noise Controls To Power Tools Used In the Construction Industry – NIOSH/Academia Partnership Case Studies. Presented at the 12th Annual Construction Safety Conference and Exposition, Chicago, IL, May 2002.

[10] NIOSH DART HLPS [2001]. Noise workshop in Cincinnati, OH. Hosted by NIOSH DART. Engineering Control of Noise Workshop, August 2001.

[11] Hayden CS II, Reeves E [2001]. Identification and Assessment of Engineering Noise Controls in the Mining and Construction Industries. Presented at the 2001 US-India Symposium On Emerging Trends in Vibration and Noise, Columbus, OH, December 10-11, 2001.

[12] Hayden CS II, Yantek DS, Kovalchik PG, Davis RR [2003]. NIOSH Engineering Noise Controls in the Construction and Mining Industries. State of the Art Concepts in Noise and Hearing Loss Seminar, Seattle, WA, October 2003.

[13] Hodgson M, Li D, “Active Control of Workplace Noise Exposure,” University of British Columbia, prepared for National Institute for Occupational Safety and Health under Grant No. 1 R01 OH003963, October 2004.

[14] Luo Y, “Engineering Control of Longwall Machine Noises,” West Virginia University, prepared for National Institute for Occupational Safety and Health under Grant No. 5R01 OH007732, August 2005.


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