Appendix G
Regulations and Voluntary Use of Hearing Protection Devices

Both industrial workers and military personnel, the largest users of hearing protection devices (HPDs), are governed by regulations. In fact, regulation is a major reason the use of HPDs has proliferated. This appendix reviews the history of these regulations, focusing on the laws that affect the majority group (i.e., U.S. workers).

OSHA GENERAL INDUSTRY AND CONSTRUCTION REGULATIONS CIRCA 1971

OSHA—General Industry

The Occupational Safety and Health Administration (OSHA) Noise Standard for General Industry (29 CFR 1910.95(a)) specifies: “Protection against the effects of noise exposure shall be required when the sound levels exceed those shown in Table G-16 when measured on the A-scale of a standard sound level meter at slow response.” Table G-16 specifies a 90-dB(A) time weighted average (TWA) “criterion level” for an 8-hour exposure, including a 5-dB exchange rate between increased noise exposures and allowable exposure durations per day. So, for example, 95-dB(A) TWA is allowed for 4 hours, 100-dB(A) TWA is allowed for 2 hours, and so on, with a not-to-exceed 140-dB peak sound pressure level for impulsive or impact noise.

29 CFR 1910.95(b)(1) further states: “When employees are subjected to sound exceeding those listed in Table G-16, feasible administrative or engineering controls shall be utilized. If such controls fail to reduce sound levels within the levels of Table G-16, personal protective equipment shall be provided and used to reduce sound levels within the levels of the table.” Thus, this first OSHA regulation, via the words “shall be utilized,” required that feasible administrative or engineering controls take priority over hearing protection. However, a significant weakness was that the word “feasible” was not defined specifically in terms of technical, economical, or other criteria. This left room for industries to claim infeasibility.

Nevertheless, only if engineering or administrative controls fail to reduce noise to within the limits of Table G-16 are hearing protectors to be relied on under OSHA (1971b). Thus, in the earliest OSHA general industry regulations, HPDs were regulated as an augmentation to, and not a replacement for, administrative or engineering noise controls. In practice, however, HPDs are relied on in many industrial plants as the first line of defense against noise hazards to workers’ hearing, which violates the letter of the OSHA law.

OSHA—Construction

The law for construction work, 29 CFR 1926.52, cites Table D-2 (a duplicate of Table G-16) for exposure limits; it also includes the same statement about administrative and engineering controls having priority over HPDs (OSHA, 1971a). However, the construction regulation in 29 CFR 1926.101 has additional stipulations: (a) “Whenever it is not feasible to reduce the noise levels or duration of exposures to those specified in Table D-2, Permissible Noise Exposures, in 1926.52, ear protective devices shall be provided and used.” (b) “Ear protective devices inserted in the ear shall be fitted or determined individually by competent persons. (c) Plain cotton is not an acceptable protective device” (OSHA, 1971b). Subparts (b) and (c) may be a slight improvement over the general industry standard. However, overall, the construction standard became much weaker because it was never updated, as the general industry standard was.

OSHA GENERAL INDUSTRY—HEARING CONSERVATION AMENDMENT CIRCA 1983

The Hearing Conservation Amendment significantly improved the original OSHA noise standard by specifying that a multifaceted hearing conservation program is required when daily TWA noise exposures exceed 85 dB(A) (equivalent to a 50 percent noise dose; OSHA, 1983). The priority



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Appendix g Regulations and Voluntary use of Hearing Protection Devices Both industrial workers and military personnel, the largest Nevertheless, only if engineering or administrative con- users of hearing protection devices (HPDs), are governed by trols fail to reduce noise to within the limits of Table G-16 regulations. In fact, regulation is a major reason the use of are hearing protectors to be relied on under OSHA (1971b). HPDs has proliferated. This appendix reviews the history of Thus, in the earliest OSHA general industry regulations, these regulations, focusing on the laws that affect the major- HPDs were regulated as an augmentation to, and not a re- ity group (i.e., U.S. workers). placement for, administrative or engineering noise controls. In practice, however, HPDs are relied on in many industrial plants as the first line of defense against noise hazards to OSHA gENERAL INDuSTRy AND CONSTRuCTION workers’ hearing, which violates the letter of the OSHA REguLATIONS CIRCA 1971 law. OSHA—general Industry OSHA—Construction The Occupational Safety and Health Administration (OSHA) Noise Standard for General Industry (29 CFR The law for construction work, 29 CFR 1926.52, cites 1910.95(a)) specifies: “Protection against the effects of noise Table D-2 (a duplicate of Table G-16) for exposure limits; exposure shall be required when the sound levels exceed it also includes the same statement about administrative and those shown in Table G-16 when measured on the A-scale engineering controls having priority over HPDs (OSHA, of a standard sound level meter at slow response.” Table 1971a). However, the construction regulation in 29 CFR G-16 specifies a 90-dB(A) time weighted average (TWA) 1926.101 has additional stipulations: (a) “Whenever it is not “criterion level” for an 8-hour exposure, including a 5-dB feasible to reduce the noise levels or duration of exposures to exchange rate between increased noise exposures and allow- those specified in Table D-2, Permissible Noise Exposures, able exposure durations per day. So, for example, 95-dB(A) in 1926.52, ear protective devices shall be provided and TWA is allowed for 4 hours, 100-dB(A) TWA is allowed for used.” (b) “Ear protective devices inserted in the ear shall be 2 hours, and so on, with a not-to-exceed 140-dB peak sound fitted or determined individually by competent persons. (c) pressure level for impulsive or impact noise. Plain cotton is not an acceptable protective device” (OSHA, 29 CFR 1910.95(b)(1) further states: “When employees 1971b). Subparts (b) and (c) may be a slight improvement are subjected to sound exceeding those listed in Table G-16, over the general industry standard. However, overall, the feasible administrative or engineering controls shall be uti- construction standard became much weaker because it was lized. If such controls fail to reduce sound levels within the never updated, as the general industry standard was. levels of Table G-16, personal protective equipment shall be provided and used to reduce sound levels within the levels OSHA gENERAL INDuSTRy—HEARINg of the table.” Thus, this first OSHA regulation, via the words CONSERVATION AMENDMENT CIRCA 1983 “shall be utilized,” required that feasible administrative or engineering controls take priority over hearing protection. The Hearing Conservation Amendment significantly However, a significant weakness was that the word “feasible” improved the original OSHA noise standard by specifying was not defined specifically in terms of technical, economi- that a multifaceted hearing conservation program is required cal, or other criteria. This left room for industries to claim when daily TWA noise exposures exceed 85 dB(A) (equiva- infeasibility. lent to a 50 percent noise dose; OSHA, 1983). The priority 67

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68 TECHNOLOGY FOR A QUIETER AMERICA of engineering and administrative noise controls remained; which do not require human intervention to protect workers’ in addition to other facets of a hearing conservation pro- hearing and prevent noise-induced hearing loss. gram (including noise monitoring, employee notification, audiometric testing, worker training, access to information DATA AND LABELINg REguLATIONS and training materials, and exposure and audiometric re- cordkeeping), the amendment specified the use of HPDs in Labeled Versus In-Field Attenuation Performance more detail. Perhaps the most significant addition, at 29 CFR The labeling of HPDs has been the subject of debate for 1910.95(i), was (1) that “employers shall make hearing more than two decades, much of it about the differences protectors available to all employees exposed to an 8-hour between on-package EPA-required attenuation data and the time-weighted average of 85 decibels or greater at no cost actual protection provided for users in the field (Berger and to the employees. Hearing protectors shall be replaced as Casali, 1997; Casali and Robinson, 2003). To comply with necessary” and (2) that “employers shall ensure that hearing OSHA (1983) and other applications, the adequacy of an protectors are worn: (i) by an employee who is required by HPD for a given noise exposure is determined by subtract- paragraph 1910.95(b)(1) of this section to wear personal ing, in a prescribed way, the attenuation data required by protective equipment [i.e., mandatory HPD use at exposures the U.S. Environmental Protection Agency (EPA) from the equal to or greater than 90 dB(A) TWA] and (ii) by any TWA noise exposure for the affected worker (see OSHA, employee who is exposed to an 8-hour TWA of 85 decibels 1983, Appendix B: Methods for Estimating the Adequacy or greater, and who” has not had a baseline audiogram, or of Hearing Protector Attenuation). who has experienced a standard threshold shift (as defined Attenuation data are obtained from psychophysical real- by OSHA). In addition, employers were required, under ear-attenuation-at-threshold tests at nine 1/3-octave bands paragraph 3, to provide “a variety of suitable hearing pro- with centers of 125 to 8,000 Hz performed on human listen- tectors” for the employee to select from; under paragraph 4 ers; the signed, arithmetic difference between thresholds to provide training in the use and care of all hearing protec- with the HPD and without it constitutes the attenuation at tors; and under paragraph 5 to ensure proper initial fitting a given frequency. Both the spectral attenuation statistics and supervision in the correct use of all hearing protectors. (means and standard deviations) and the broadband single- Finally, in part (j) the amendment specified computational number noise reduction rating (NRR), which is computed procedures for evaluating HPDs for adequacy of protection therefrom, are provided, and either of them can be used to in specific noise exposures, with the requirement that the estimate HPD adequacy for a given exposure, per OSHA protected exposure levels be brought to less than or equal to (1983) Appendix B. 90-dB(A) TWA, or to less than or equal to 85-dB(A) TWA if Labeled ratings are the primary means by which end users the worker has experienced a standard threshold shift.1 compare different HPDs and determine if they will provide The OSHA Hearing Conservation Amendment greatly adequate protection and OSHA compliance in a given noise impacted the requirements for hearing protection, and the environment. Therefore, the accuracy and validity of label numbers of HPDs supplied in occupational settings dramati- ratings are very important. cally increased as a result. Although engineering or adminis- trative controls were still required for TWA exposures above Current EPA-Required Labeling and Cited Test Standards 90 dB(A), the amendment provided, at no cost to workers, a selection of HPDs to everyone exposed to 85-dB(A) TWA The labeling of hearing protectors is controlled by EPA or above. The 5-dB(A) difference between the 90-dB(A) via federal law per 40 CFR Part 211, Subpart B, which was OSHA “criterion” level imposed as a result of OSHA (1971) promulgated in September 1979 and remains in effect as of and the 85-dB(A) OSHA “action” level imposed as a result of this writing. This section of the law applies to “any device the 1983 OSHA Hearing Conservation Amendment defined or material, capable of being worn on the head or in the ear an exposure window wherein thousands of workers who had canal, that is sold wholly or in part on the basis of its ability not been protected by law were now to be supplied with a to reduce unwanted sound that enters the user’s ears” (40 selection of suitable HPDs. CFR Part 211, Subpart B). Unfortunately, the law references In this sense the new 85-dB(A) TWA action level was a an outdated, superseded ANSI standard (1974) for obtaining major step forward in protecting workers against the hazards the real-ear attenuation of threshold data on which the EPA of noise exposures; however, the OSHA Hearing Conserva- label, which includes an NRR, is based. tion Amendment should not be understood as an indication The data on HPD packaging are obtained under optimal that HPDs are preferable to engineering noise controls, laboratory conditions with properly fitted protectors worn by trained, well-practiced human subjects. However, numer- ous research studies (e.g., Berger et al., 1998; Berger and Casali, 1997; Park and Casali, 1991) have shown that the 1The reader is referred to OSHA (1983) and Casali (2006) for more details “experimenter-fit” protocol and other aspects of the EPA- on computing HPD adequacy.

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6 APPENDIX G required test procedure do not represent the conditions under standard to obtain passive attenuation data along with a which HPDs are selected, fitted, and used in the workplace. new means of broadband rating. This rating is likely to be Therefore, the attenuation data used in the octave band or called the single-number rating, even though it will probably NRR formulas are highly inflated and cannot be assumed to provide a range of values. This differs from NRR, which represent the protection achieved in the field. provided a single number. Figure G-1 shows the results of a review of research stud- The proposed regulation is also likely to include elements ies in which manufacturers’ on-package NRRs (in the back- of another testing standard, ANSI S12.42 (ANSI, 2004), ground) were compared against NRRs computed from actual to enable physical, microphone-based testing in real ears subjects using HPDs in field settings (in the foreground). and acoustical test fixtures; this will enable comprehensive Clearly, there are large differences between laboratory and testing of active noise cancellation, as well as certain other field estimates, especially for earplugs (Berger, 2003). HPD HPD types that are currently not amenable to the 1979 EPA consumers must take this difference into account when se- regulation for labeling and thus cannot currently be marketed lecting protectors. as hearing protectors. Elements of ANSI S12.68 (ANSI, 2007) are also likely to be added to prescribed methods of estimating protected exposure levels under HPDs. At the “Proposed” Revisions for Labeling and Cited Test time of this writing, none of the details of the proposed EPA Standards revised labeling regulation had been finalized. For updates ANSI Working Group S12/WG11 developed a new test- the reader should go to www.regulations.go (docket number: ing standard, ANSI S12.6-1997(R2002), which includes both EPA-HQ-OAR-2003-0024). a “Method A” provision for experimenter-supervised fitting of an HPD and a “Method B” provision for self-fitting of the REFERENCES HPD and with test subjects who have not been trained. The ANSI (American National Standards Institute). 1974. Method for the Mea - new standard has much improved experimental controls and surement of Real-Ear Protection of Hearing Protectors and Physical human factors protocol over the current standard. Neverthe- Attenuation of Earmuffs. ANSI S3.19-1974. New York: ANSI. less, even though the Method B (subject-fit) testing protocol ANSI. 2004. Microphone-in-Real-Ear and Acoustic Test Fixture Methods has been experimentally demonstrated to yield attenuation for the Measurement of Insertion Loss of Circumaural Hearing Protec - data that are more representative of those achievable under tion Devices. ANSI S12.42-1995(R2004). New York: ANSI. ANSI. 2007. Methods of Estimating Effective A-Weighted Sound Pressure workplace conditions (Berger et al., 1998), as of this writ- Levels When Hearing Protectors Are Worn. ANSI S12.68-2007. New ing it appears that Method A (experimenter-supervised fit) is York: ANSI. likely to be adopted by EPA for a revised regulation. Berger, E.H. 2003. Hearing protection devices. Pp. 379–454 in The Noise EPA has given notice (see EPA Docket OAR-2003-0024) Manual, Revised 5th Ed., edited by E.H. Berger, L.H. Royster, J.D. in public workshops and presentations of a plan to revise the Royster, D.P. Driscoll, and M. Layne. Fairfax, VA: American Industrial Hygiene Association. 1979 labeling regulation, in conjunction with the require- Berger, E.H., and J.G. Casali. 1997. Hearing protection devices. Pp. ment to replace ANSI S3.19-1974 with the current ANSI 967–981 in Encyclopedia of Acoustics, edited by M. Crocker. New York: John Wiley. Berger, E.H., J.R. Franks, A. Behar, J.G. Casali, C. Dixon-Ernst, R.W. Kieper, C.J. Merry, B.T. Mozo, C.W. Nixon, D. Ohlin, J.D. Royster, and L.H. Royster. 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. Journal of the Acoustical Society of America 103(2):665–672. Casali, J.G., and G.S. Robinson. 2003. Augmented Hearing Protection De - vices: Active Noise Reduction, Level-Dependent, Sound Transmission, Uniform Attenuation, and Adjustable Devices—Technology Overview and Performance Testing Issues. EPA Docket OAR-2003-0024. Wash- ington, DC: U.S. Environmental Protection Agency. Casali, J.G. 2006. Sound and noise. Pp. 612–642 in Handbook of Human Factors, 3rd Ed., edited by G. Salvendy. New York: John Wiley. OSHA (Occupational Safety and Health Administration). 1971a. Occu- pational Noise Exposure (Construction Industry). 29 CFR 1926.52. Federal Register. OSHA. 1971b. Hearing Protection (Construction Industry). 29 CFR 1926.101. Federal Register. OSHA. 1983. Occupational Noise Exposure; Hearing Conservation Amend- ment; Final Rule. 29 CFR 1910.95. Federal Register. FIGURE G-1 Comparison of hearing protection device NRRs Park, M.Y., and J.G. Casali. 1991. A controlled investigation of in-field at- Figure_4-3-G-1.eps by device type: manufacturers’ laboratory data versus real-world tenuation performance of selected insert, earmuff, and canal cap hearing “field” data. Adapted with permission from Berger (2003), Fig. bitmaps (4 wedges) protectors. Human Factors 33(6):693–714. 10.18, p. 421.

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