Comments on Occupational Noise
to the OSHA Standards Planning Committee*
Docket No. C-04
November 28, 1994

by Alice H. Suter, Ph.D.
*published with permission of the author

       Noise has long been recognized as one of the most prevalent workplace hazards. It was identified by NIOSH as one of the 10 leading occupational problems in its consensus conference, "Proposed National Strategies for the Prevention of Leading Work-Related Diseases and Injuries" (NIOSH, 1988). According to the preamble of OSHA'S hearing conservation amendment (OSHA, 1981), more than 5 million workers are exposed to potentially hazardous levels of noise in manufacturing and utilities. Hazardous levels of noise are defined here as time-weighted average levels of 85 dB(A) and above, although it is well known that some more susceptible workers will incur hearing losses at levels below 85 dB (A) . An additional 300,000 agricultural workers, 500,000 construction workers, and approximately 150,000 workers in oil and gas drilling and servicing are exposed to these noise levels (see EPA, 1981; Suter, 1990). These additional workers do not have the benefit of hearing conservation regulations.

        According to OSHA'S 1981 estimates, at least one million workers in manufacturing and utilities had sustained occupational hearing impairments greater than 25 dB at the averaged audiometric frequencies of 1000, 2000, and 3000 Hz, which is OSHA'S definition of hearing handicap.

        Noise exposure does not kill people, at least directly. There is, however, recent evidence of what common sense has told us all along, that high levels of noise and the resulting hearing losses contribute to industrial accidents (Moll van Charante and Mulder, 1990; Wilkins and Acton, 1982). There is also reason for concern that hearing protection devices, which are worn to prevent noise-induced hearing loss, may actually impair work safety under certain conditions (See Suter, 1992a). In addition, there is growing evidence that noise adversely affects general health, and the cardiovascular system in particular, (Ising and Kruppa, 1993; Peterson et al ., 1978, 1981, and 1983; Rehm, 1983; Zhao, et al , 1993), which directly affects mortality. Although dose-response relationships for these factors are many years away, research evidence from outside the U.S. is steadily mounting.

Page 1

Return to NPC Library
Return to NPC Home Page

        But noise-induced hearing loss is a critical health problem in its own right. Anyone who has suffered a handicapping hearing loss or who has had a close friend or relative who has, will understand its implications. Like other neurological deficits, hearing impairment degrades, even destroys the quality of life. Helen Keller used to maintain that the handicap from deafness was worse than that from blindness because deafness separates you from people, whereas blindness separates you from things. Hearing impairment interferes not only with the ability to hear music and the sounds of nature, but, more importantly, with the ability to communicate with family and friends. This is especially true of the attempt to communicate in groups or in noisy backgrounds. The handicap of hearing impairment eventually leads to withdrawal from social situations and dependency upon one's spouse or another family member for virtually all communication needs. The result is often loneliness, isolation, depression, and lowered self-esteem.

        Because of the prevalence of hazardous noise exposure and the seriousness of the effects, the Standards Planning Committee should consider the following recommendations:

1. OSHA should immediately withdraw the compliance memo imposed by the Reagan Administration CPL 2-2.35 "Guidelines for Noise Enforcement." dated November 9, 1983. This memo instructs Federal OSHA compliance officers not to issue citations for the absence of feasible engineering controls to companies where workers' time-weighted average exposure levels are 100 dB(A) or less, so long as these companies have "effective hearing conservation programs." This is a pernicious policy, and it is most likely illegal because it changes both the intent and the letter of the noise standard without benefit of rule making.

        The result of this policy has been to discourage the development and use of engineering noise control in U.S, workplaces and to expose workers unnecessarily to hazardous levels of noise. One of the problems is that OSHA has never defined an "effective hearing conservation program," and if the Agency were to accept the definition of the consensus community (ANSI, 1991), OSHA would most likely find the vast majority of hearing conservation programs ineffective. The main reason why these programs are ineffective is that hearing protectors, as they are worn in the field, provide only a fraction of the attenuation that their "noise reduction ratings" (NRRS) imply. The result is that many thousands of workers are being exposed to hazardous levels of noise with little help from hearing protection devices.

        A copy of CPL 2-2.35 is included with these comments for the Committee's information.

2. OSHA should re-emphasize engineering noise control. This is the original intent of the standard and is consistent with OSHA

Page 2

Return to NPC Library
Return to NPC Home Page

policy throughout the years. Between 1983 and the present time, numerous studies, reports, and articles on engineering noise control have been published. OSHA or NIOSH could obtain these data with the help of several professional associations, such as the Institute of Noise Control Engineering or the Acoustical Society of America, some of which have established noise control data bases.

        In fact, a popular OSHA publication, "Noise Control: A Guide for Workers and Employers" (OSHA, 1980), is currently being revised and updated by its author, Stig Ingemansson of Sweden, and is being published serially in the journal, Noise News International (Ingemansson, 1994a and b). Copies of the two Noise News International articles and the cover and two informational pages from the OSHA noise control booklet are attached.

3. OSHA should renew its efforts to enforce the noise standard. In addition to the serious decline in enforcement of the noise control requirements, OSHA has decreased its enforcement activities of the hearing conservation amendment's provisions. This was true between 1981 and 1987, and, in all probability is true today as well.

        In recent years, two consensus conferences sponsored by Federal agencies have recommended more diligent enforcement of noise regulations in the workplace. NIOSH, in its "Proposed National Strategy for the Prevention of Noise-Induced Hearing Loss" (Chapter 8 in NIOSH, 1988) listed noise enforcement as a top priority in its short-term objectives for regulations. Section (a) calls for the full enforcement of current federal noise regulations for the workplace. Section (b) calls for OSHA to rescind its instruction CPL 2.45 [sic], "Guidelines for Noise Enforcement," stating that "It is extremely foolhardy to regard hearing protection as a preferred way to limit noise exposures..."(p. 55). See the attached copy of Chapter 8 from the NIOSH strategy document.

        The National Institutes of Health also conducted a consensus conference on noise (NIH, 1990). The panel of experts included in its recommendations the "vigorous enforcement of existing regulations, particularly for the workplace and consumer product labeling..." and the "application of existing technologies for source noise control, especially in the manufacture of new equipment and construction of new facilities...." See the attached "Consensus Statement" from the conference.

4. OSHA should extend coverage of the noise standard as amended for hearing conservation programs to workers who are not presently being covered. As mentioned above, certain groups of workers who come under OSHA'S purview are not receiving comparable protection to those in manufacturing and utilities. Some 500,000 construction workers and 150,000 workers in oil and gas well

Page 3

Return to NPC Library
Return to NPC Home Page

drilling and servicing and not covered by the hearing conservation amendment's provisions. Annual audiometric tests, periodic noise exposure assessment, hearing protector evaluation, training and education, and record keeping requirements are not mandatory, and, therefore, few of these workers receive these benefits. In addition, some 300,000 agricultural workers are not covered by any noise regulations at all. Failing to provide equal protection for these groups of workers constitutes a serious oversight.

        While most of the amendment's provisions could be adopted outright, some of the provisions would need to be modified to suit the particular work environment and schedules for these occupations. By proposing to extend the amendment as it is, OSHA would most likely acquire the necessary information for these modifications from the affected workers, their representatives, and their employers.

5. OSHA should make some long overdue changes to the noise standard. Some of the most critical elements of OSHA'S noise standard have remained unchanged for more than 25 years. It used to be that the U.S. led the way with respect to noise regulation, but in recent decades, European, Canadian, and other foreign governments have improved and modernized their noise standards, whereas OSHA has maintained the status quo. Other nations have incorporated procedures that we have not yet attempted, such as regulating specific industries and processes for noise, labeling noisy machinery, issuing separate standards for newly constructed workplaces, and devising instructions for the purchase of quiet equipment. See the attached paper entitled, "Current Standards for Occupational Exposure to Noise" (Suter, 1994).

        OSHA could accomplish certain changes, such as improvements to the hearing conservation provisions, relatively easily. Others will most likely require more extensive rule making, but the time to initiate these changes is now. See the attached article entitled, "Now is the Time to Improve OSHA'S Noise Standard" (Suter, 1993a) for details on suggested changes.

a. Certain changes are necessary to the hearing conservation program requirements, partly because they were adopted without technical merit in 1983 and partly because a decade's experience with some provisions have proven them to be either ineffective or counterproductive. Explanations and justifications for these revisions may be found in the attached article "Now is the Time to Improve OSHA'S Noise Standard." Here is a summary of these beneficial changes:

(1) Delete the statement: "A technician who operates microprocessor audiometers does not need to be certified."

(2) Baseline audiograms should either be conducted pre- employment or they should be preceded by at least 14 hours away

Page 4

Return to NPC Library
Return to NPC Home Page

from workplace noise. There should be no exemption involving the use of hearing protectors.

(3) The annual audiogram should be required to be conducted well into the workshift so as to identify temporary changes in hearing threshold level before they become permanent.

(4) The term "standard threshold shift" (STS) should be returned to the original "significant threshold shift" wording and the numerical definition should be revised to be more conservative and more efficient.

(5) A persistent work-related STS should be recorded on the OSHA 200 log. The present policy to record shifts only after they have reached an average level of 25 dB or more at 2000, 3000, and 4000 Hz is misleading and totally inadequate, and it should be withdrawn immediately.

(6) The requirements for medical referral or other follow-up should be revised and clarified so that they are not contingent upon STS.

(7) The current requirements for background sound levels in audiometer rooms date from a 1960 ANSI standard and are woefully inadequate. Since that time the ANSI standard (S3.1) has been revised twice!

(8) The wearing of hearing protection should be contingent upon noise levels rather than average noise exposures in most cases.

(9) The noise reduction rating (NRA) used to assess the adequacy of hearing protector attenuation should be divided in half (derated by 50 %).

(10) OSHA should issue a requirement for hearing conservation program evaluation.

b. OSHA should initiate the process of revising the permissible exposure level (PEL). The Agency has been struggling with this issue for years, acknowledging the fact in 1970 that 90 dB(A) could produce a "disabling loss of hearing in more than 20 percent of the exposed population" (DOL, 1970). In the preamble of the 1981 hearing conservation amendment, OSHA stated that the risk of hearing handicap from a lifetime's exposure to 90 dB(A) was in the range of 20 to 29 percent, from exposure to 85 dB(A) the risk was estimated at 10 to 15 percent, and only when exposure levels were reduced below 80 dB(A) would the risk be negligible. These predictions of percentage risk of hearing loss are greatly influenced by the audiometric frequencies and "fences" and by the populations used in the predictions. But it is quite clear that nearly all exposed workers will incur some amount of hearing loss from a 90-dB(A) PEL.

Page 5

Return to NPC Library
Return to NPC Home Page

        Although there is no doubt that the economic impact of reducing noise levels in all workplaces to 80 dB(A) or even 85 dB(A) would be considerable, it is time for OSHA to recognize the fact that its current PEL is inadequate for thousands, if not millions of workers and the Agency needs to move in a more Protective direction. Lower levels for new plants and processes, extended periods of time for compliance, and more assistance to employers in noise control methods are just a few of the ways in which a lower PEL could be implemented gradually.

        There is ample precedent for an 85-dB(A) PEL. An 85-dB(A) PEL was recommended in the NIOSH Criteria Document (NIOSH, 1972), it was recommended to OSHA by the U.S. EPA in 1974 (EPA, 1974a), and it was adopted by the ACGIH in 1977 (ACGIH, 1976). It is also the PEL used by a majority of nations recently surveyed (Suter, 1994), although some of these nations still permit employers not to use engineering controls at average levels below 90 dB(A). A PEL of 85 dB(A) has been recommended by the Working Party on Upper Noise Limits in the Workplace by the International Institute of Noise Control Engineering (Embleton, 1994).

c. OSHA should initiate the process of revising the exchange rate. The exchange rate, sometimes called the doubling rate or the time-intensity tradeoff, reflects the relationship between the allowable duration and level of noise in a standard or regulation. OSHA has used a 5-dB exchange rate since 1969, even though the vast majority of other nations use the more conservative 3-dB exchange rate, most of them for many years. The 3-dB rule is incorporated in the ISO standard 1999 (1971 and 1990), it is used by the U.S. EPA and other Federal agencies to assess the effects of community noise (EPA, 1973, 1974b), it has been recommended by the EPA for occupational noise exposure regulations (EPA, 1974a), it is used by the U.S. Air Force and the U.S. Army, and it has recently been adopted by the ACGIH (ACGIH, 1994).

        A recent NIOSH contractor report points out that OSHA'S adoption of the 5-dB exchange rate in 1969 was not scientifically supportable for a number of reasons (Suter, 1992b, 1993b). First, it allows uninterrupted periods of noise at dangerously high noise levels, which violates the stated principles of those who sought to justify it solely on the grounds of intermittency. It also assumes unrealistically spaced intervals of quiet between noise bursts, and it assumes unrealistically low levels of noise between bursts to allow for recovery from temporary hearing loss. The 5-dB rule is not appropriate for indoor noise environments with the resulting reverberant build-up of sound. If OSHA wishes to make an adjustment for the ameliorative effects of truly intermittent noise (in an outdoor setting), the Agency could make a small upward adjustment to the PEL. To compromise the 3-dB exchange rate, however, is not in keeping with the research evidence, and would be incorrect and underprotective.

Page 6

Return to NPC Library
Return to NPC Home Page

In conclusion, if OSHA wishes to rectify a situation that has languished for years, now is the time for the Agency to take action on the above recommendations. It is not acceptable for an Agency charged with the health of American workers to allow them to become hearing handicapped with such indifference.


ACGIH (1976). Threshold Limit Values for Chemical Substances and Physical Agents in the Workroom Environment with Intended Changes for 1977. American Conference of Government Industrial Hygienists, Cincinnati, OH.

* ACGIH (1994). Noise [7/29/94] TLV. [This document is labeled "draft" because minor editorial changes may be made before printing, but there are to be no further substantive changes.] American Conference of Government Industrial Hygienists, Cincinnati, OH.

ANSI (1991). Draft American National standard: Evaluating the effectiveness of hearing conservation programs. ANSI S12.13-1991. Acoustical Society of America, New York, NY.

DOL (1970). Guidelines to the Department of Labor's occupational noise standards for federal supply contracts. Bulletin 334. U.S. Dept. Labor, Workplace Standards Administration, Bureau of Labor Standards, Washington, DC.

Embleton, T.F.W. (1994). Report by I-INCE Working Party on "Upper Noise Limits in the Workplace." Proceedings of INTER-NOISE 94, Yokohama, Japan.

EPA (1973). U.S. Environmental Protection Agency. Public health and welfare criteria for noise. Report 550/9-73-002, Washington, DC.

EPA (1974a). U.S. Environmental Protection Agency. Proposed OSHA occupational noise exposure regulation: request for review and report. 39 Fed. Reg. 43802-43809.

EPA (1974b). U.S. Environmental Protection Agency. Information on levels of environmental noise requisite to protect public health and welfare with an adequate margin of safety. Report 550/9-74-004, Washington, DC.

* Ingemansson, S. (1994a). Noise control: Principles and practice

Page 7

Return to NPC Library
Return to NPC Home Page

Noise News International, 2 (2), 107-115. Institute of Noise Control Engineering, Poughkeepsie, N.Y.

* Inqemansson, S. (1994b). Noise control: Principles and practice Noise News International, 2 (3), 185-193. Institute of Noise Control Engineering, Poughkeepsie, NY.

Isinq, H. and Kruppa, B. (Eds.) (1993). Larm und Krankheit: Noise and Disease. Stuttqart/New York, Gustav Fischer Verlag.

ISO (1971). International Organization for Standardization, Acoustics, R 1999, Assessment of occupational noise exposure for hearing conservation purposes. Geneva, Switzerland.

ISO (1990). International Organization for Standardization, ISO 1999.2, Acoustics: Determination of occupational noise exposure and estimate of noise-induced hearing impairment. Geneva, Switzerland.

Moll van Charante, A.W. and Mulder, P.G.H. (1990). Perceptual acuity and the risk of industrial accidents. Am. J. Epidemiol., 131, 652-663.

* NIH (1990). Noise and hearing loss: Consensus statement. NIH Consensus Development Conference, Jan. 22-24, 1990. National Institutes of Health, Bethesda, MD.

NIOSH (1971) . Criteria for a recommended standard for occupational exposure to noise. HSM 73-l1001. National Institute for Occupational Safety and Health, Cincinnati, OH.

* NIOSH (1988). A proposed national strategy for the prevention of noise-induced hearing loss. Chapter 8 in Proposed National strategies for the Prevention of Leading Work-Related Diseases and Injuries, Part 2. National Institute for Occupational Safety and Health, Cincinnati, OH.

OSHA (1980). Noise control: A guide for workers and employers. U.S. Dept. Labor, OSHA, Office of Information, Washington, DC.

OSHA (1981). Occupational Safety and Health Administration, Occupational noise exposure: Hearing conservation amendment. 46 Fed. Reg. 4078-4179.

* OSHA (1983) . OSHA Instruction CPL 2-2.35, Nov. 9, 1983. Guidelines for Noise Enforcement. Occupational Safety and Health Administration, U.S. Department of Labor, Washington, DC.

Peterson, E.A., Auqenstein, J.S., and Tanis, D.C. (1978) . Continuing studies of noise and cardiovascular function. J. Sound Vib., 59, 123.

Page 8

Return to NPC Library
Return to NPC Home Page

Peterson, E.A., Augenstein, J.S., Tanis, D., and Augenstein, D.G., (1981). Noise raises blood pressure without impairing auditory sensitivity. Science, 211, 1450-1452.

Peterson, E.A., Augenstein, J.S., Tanis, D.C., Warner, R., and Heal, A. (1983). In: Rossi, G., (Ed.) Proceedings of the Fourth International Congress on Noise as a Public Health Problem, Vol. 2, Milan, Centro Ricerche e Studi Amplifon.

Rehm, S. (1983). Research on extraaural effects of noise since 1978. In: Rossi, G., (Ed.) Proceedings of the Fourth International Congress on Noise as a Public Health Problem, Vol. 1, Milan, Centro Ricerche e Studi Amplifon.

Suter, A.H. (1983). The relationship of the exchange rate to noise-induced hearing loss. Report prepared under contract to JRB Associates and submitted to the Occupational Safety and Health Admin., U.S. Dept Labor, Washington, DC (Docket OSH 011 no. 511).

Suter, A.H. (1990). Popular misconceptions about occupational noise exposure. Proceedings of Noise Con-90, Austin, TX. Institute of Noise Control Engineering, Poughkeepsie, NY.

Suter, A.H. (1992a). Communication and Job Performance in Noise: A Review, ASHA Monographs No. 28. American Speech-Language-Hearing Assoc., Rockville, MD.

Suter, A.H. (1992b). The relationship of the exchange rate to noise-induced hearing loss. Prepared under contract to the National Institute for Occupational Safety and Health, Cincinnati, OH (NTIS No. PB-93-l18610).

* Suter, A.H. (1993a). Now is the time to improve OSHA'S noise standard. Spectrum, 10 (4), 1, 16-21. Newsletter of the National Hearing Conservation Association, Des Moines, IA.

* Suter, A.H. (1993b). The relationship of the exchange rate to noise-induced hearing loss. Noise News International, 1(3), 131-l5l. Institute of Noise Control Engineering, Poughkeepsie, NY.

* Suter, A.H. (1994). Current standards for occupational exposure to noise. Paper presented at the conference, "Effects of Noise on Hearing: Fifth International Symposium", Gothenburg, Sweden. To be published in the conference proceedings, 1995.

Wilkins, P.A. and Acton, W.I. (1982). Noise and accidents: A review. Ann. Occup. Hyg., 2, 249-260.

Page 9

Return to NPC Library
Return to NPC Home Page

Zhao, Y., Zhanq, S., Selvin, S., and Spear, R.C. (1993). A dose-response relationship between cumulative noise exposure and hypertension among female textile workers without hearing protection. In Vallet, M. (Ed.) Noise & Man 93: Noise as a Public Health Problem, 3. 94114 Arcueil Cedex, France, Institut National de Recherche sur les Transports et leur Securite.

* denotes materials submitted as attachments to these comments.

Page 10


NPC Menu Bar NPC Home Page Support NPC Ask NPC Search the NPC Home Page NPC QuietNet NPC Resources NPC Hearing Loss and Occupational Noise Library NPC Noise News NPC Law Library NPC Library