[Federal Register Volume 61, Number 243 (Tuesday, December 17, 1996)]
[Proposed Rules]
[Pages 66348-66469]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 96-30733]



[[Page 66347]]

_______________________________________________________________________

Part II





Department of Labor





_______________________________________________________________________



Mine Safety and Health Administration



_______________________________________________________________________



30 CFR Parts 56, 57, 62, 70 and 71



Health Standards for Occupational Noise Exposure in Coal, Metal, and 
Nonmetal Mines; Proposed Rule

  Federal Register / Vol. 61, No. 243 / Tuesday, December 17, 1996 / 
Proposed Rules  

[[Page 66348]]



DEPARTMENT OF LABOR

Mine Safety and Health Administration

30 CFR Parts 56, 57, 62, 70 and 71

RIN 1219-AA53


Health Standards for Occupational Noise Exposure

AGENCY: Mine Safety and Health Administration (MSHA), Labor.

ACTION: Proposed rule.

-----------------------------------------------------------------------

SUMMARY: This proposed rule would replace MSHA's existing standards for 
occupational noise exposure in coal mines and in metal and nonmetal 
mines with a single new standard applicable to all mines.
    This action is part of the Agency's ongoing review of its safety 
and health standards. The review found that the Agency's existing noise 
standards, which had been promulgated more than 20 years ago, are 
inadequate to prevent the occurrence of occupational noise-induced 
hearing loss (NIHL) among miners. There remains a significant risk to 
miners of material impairment of health from workplace exposure to 
noise over a working lifetime. The risk becomes significant when 
exposure exceeds an 8-hour time-weighted average of 85 dBA.

DATES: Comments must be received on or before February 18, 1997. Submit 
written comments on the information collection requirements by February 
18, 1997.

ADDRESSES: Comments on the proposed rule may be transmitted by 
electronic mail, fax, or mail. Comments by electronic mail must be 
clearly identified as such and sent to this e-mail address: 
[email protected]. Comments by fax must be clearly identified as such and 
sent to: Mine Safety and Health Administration, Office of Standards, 
Regulations, and Variances, 703-235-5551. Send mail comments to: Mine 
Safety and Health Administration, Office of Standards, Regulations, and 
Variances, Room 631, 4015 Wilson Boulevard, Arlington, VA 22203-1984. 
Interested persons are encouraged to supplement written comments with 
computer files or disks; please contact the Agency with any questions 
about format. Written comments on the information collection 
requirements may be submitted directly to the Office of Information and 
Regulatory Affairs, OMB New Executive Office Building, 725 17th Street, 
NW., Rm. 10235, Washington, D.C. 20503, Attn: Desk Officer for MSHA.

FOR FURTHER INFORMATION CONTACT: Patricia W. Silvey, Director; MSHA; 
Office of Standards, Regulations, and Variances; 703-235-1910.

SUPPLEMENTARY INFORMATION:

Comprehensive Summary

    The proposal would retain the existing permissible exposure level 
(PEL) but establish a new ``action level''. The action level would be 
an 8-hour time-weighted average of 85 dBA; the PEL would remain an 8-
hour time-weighted average of 90 dBA.
    Whenever a miner's noise exposure exceeds the action level, the 
miner would receive special training in noise protection.
    When the miner's noise exposure exceeds the action level, but is 
below the PEL, the operator would be required to make annual 
audiometric (hearing) examinations available to the miner through 
enrollment in a hearing conservation program, and to provide properly 
fitted hearing protection in three circumstances--before the initial 
hearing examination, if a significant threshold shift in hearing acuity 
is detected, and at any other time upon miner request. If it will take 
more than 6 months for the initial examination because of the need to 
wait for a mobile test van, or a significant threshold shift in hearing 
acuity is detected, the operator would also be required to ensure the 
miner uses the provided hearing protection.
    If a miner's exposure exceeds the PEL, the proposal would require 
that the mine operator use all engineering and administrative controls 
which it is feasible for that mine operator to utilize to reduce noise 
to the PEL. The proper combination of engineering and administrative 
controls would be left to the discretion of the mine operator.
    Should the use of all feasible engineering and administrative 
controls not reduce a miner's noise exposure to the PEL, the operator 
would have to use those controls to lower exposure to as close to the 
PEL as is feasible. In addition, the operator would have to provide any 
such miner properly fitted hearing protection, ensure the miner uses 
such protection, and ensure the miner takes the annual audiometric 
examinations. Should a miner's exposure exceed an 8-hour time-weighted 
average of 105 dBA, the operator must ensure the miner is provided and 
uses both a plug and a muff type protector.
    MSHA recognizes that successful implementation of these new uniform 
health rules will require training of MSHA personnel and guidance to 
miners and mine operators, particularly small mine operators. 
Accordingly, the Agency proposes that the final rule take effect one 
year after the date of publication of the final rule, and solicits 
comments on whether a phased-in approach would permit some elements of 
the new rule to be implemented more quickly.
    The Supplementary Information accompanying this notice is detailed. 
Accordingly, to facilitate review and comment by the mining community, 
this material begins with questions and answers summarizing key points 
about the proposal. Included are two charts comparing the main features 
of the proposal to existing standards in the mining industry and those 
applicable to other industries under the Occupational Safety and Health 
Act. Also included are MSHA's estimates of the impacts of the proposal 
from the Agency's preliminary Regulatory Impact Analysis (RIA), copies 
of which are available from the Agency.

I. Questions and Answers, Required Notices, and History

(A) Questions and Answers About Key Features of this Proposal

(1) What Are the Key Features of This Proposal?
    MSHA has developed a proposal that it estimates can reduce by two-
thirds the number of miners currently projected to suffer a material 
impairment of their hearing--but which it estimates can be implemented 
at a cost of less than $9 million to the mining industry as a whole.
    The focus of the proposal is on the use of the most effective means 
to control noise--engineering controls to eliminate the noise, or 
administrative controls (e.g. rotating miner duties) to minimize noise 
exposure--whenever feasible.
    Specifically, the proposal requires that an operator use all 
feasible engineering or administrative controls to reduce noise to the 
PEL--a TWA8 of 90 dBA. While MSHA has determined there is a 
significant risk of harm at a TWA8 of 85 dBA, the Agency believes 
that it may not be feasible at this time for the mining industry to 
control noise to this level using engineering and administrative 
controls.
    The proposal would require that steps be taken when noise exceeds a 
TWA8 of 85 dBA, the ``action level'', to prevent hearing loss. 
Operators would have to provide special instruction in noise, make 
annual hearing examinations available, and provide properly fitted 
hearing protection--before the initial examination, if a significant 
threshold shift in hearing acuity is detected, and at any other time 
upon a miner's

[[Page 66349]]

request. If it will take more than 6 months to take the initial 
examination because of the need to wait for a mobile test van, or if a 
significant threshold shift is detected, an operator would also be 
required to ensure that the miner uses the hearing protection.
    The proposal also provides for supplemental protection in those 
cases in which individual operators are unable to reduce noise to the 
PEL through the use of all feasible engineering or administrative 
controls. The operator must ensure any miner so exposed takes the 
annual hearing examinations, must provide properly fitted hearing 
protection to all miners so exposed, and must ensure the hearing 
protection is used by all miners so exposed.
    The focus on engineering and administrative controls would 
significantly change the way noise is addressed in the coal mining 
industry. Currently, hearing protectors generally are allowed when a 
coal miner's noise exposure exceeds the PEL. The proposal would require 
a coal mine operator to use all feasible engineering and administrative 
controls to reduce exposure to the PEL--the practice currently required 
in the rest of the mining industry. MSHA estimates that this change 
alone can prevent 3 out of every 5 impairments projected to occur due 
to occupational noise exposure in the coal mining industry.
    While this change would cost the coal mining industry more money 
for implementation of engineering controls, MSHA estimates these costs 
would be significantly offset by the paperwork savings the coal mining 
industry will accrue under the proposal. In particular, MSHA is 
proposing to replace the costly, paperwork-intensive requirements for 
biannual coal miner noise exposure surveys, supplemental noise surveys, 
calibration reports, survey reports, and survey certifications with a 
performance-oriented requirement that mine operators establish a 
monitoring program that effectively evaluates miner exposures. MSHA 
believes the existing requirements have not been effective.
    Other parts of the proposal would change current practices 
throughout the mining industry. No actions are currently required if 
noise exposures are below the PEL. Moreover, the proposal requires, for 
the first time, certain explicit protections if an operator cannot 
feasibly reduce noise exposures to the PEL through the use of all 
feasible engineering and administrative controls.
    MSHA's proposal also incorporates revisions warranted by our 
increased understanding of the effects of noise, to the extent that the 
Agency determined such changes would be feasible for the mining 
industry to implement. For example, to reflect that exposure to sound 
levels above 80 dBA is now generally recognized as harmful, the 
proposal would include exposure to such sound levels in determining a 
miner's noise dose. Such adjustment will result in more miners than at 
present being determined to have noise exposures over the PEL, but the 
Agency has determined that the industry can feasibly accommodate this 
change.
(2) Do I Need To Read This Entire Notice To Understand the Proposal?
    The Agency hopes these questions and answers will provide the 
information most of the mining community will want. Nevertheless, MSHA 
is accompanying publication of this proposed rule with a detailed 
discussion of the information it has considered in developing the 
proposal. That way, those interested in a particular topic can have the 
benefit of the Agency's thinking in developing their comments.
    The information is divided into five parts. Part I includes a 
review of the projected impacts of the proposal, including benefits, 
costs and paperwork, taken from the Agency's preliminary RIA. Part II 
is the Agency's analysis of the current risks to miners from 
occupational noise exposure. Part III is a section-by-section 
discussion of the elements of the proposal. Part IV is an analysis of 
the technological and economic feasibility of the proposal and of key 
alternatives considered by the Agency. Part V is a complete list of 
publications referenced by the Agency.
(3) What Are the Projected Impacts of the Proposed Rule?
    The estimated benefits and costs and paperwork requirements of the 
proposed rule are summarized in the following table, ``Summary of Key 
Impacts of MSHA's Noise Proposal,'' followed by a brief explanation. 
The Agency's estimates, and a complete description of the methodology 
used to obtain them, are contained in the Agency's preliminary RIA, a 
copy of which can be obtained from the Agency.

                                Summary of Key Impacts of MSHA's Noise Proposal *                               
----------------------------------------------------------------------------------------------------------------
                                                                Coal          Metal/nonmetal       All mining   
----------------------------------------------------------------------------------------------------------------
Benefits:                                                                                                       
    % hearing impairments avoided......................                 81                 57                 67
    # miners saved from hearing impairment.............             15,300             15,300             30,600
Annual costs (in millions of dollars)..................               $0.3                 $8               $8.3
Paperwork burden hours added/saved.....................           (88,740)             73,755          (14,985) 
----------------------------------------------------------------------------------------------------------------
* Rounded.                                                                                                      

    The analysis of benefits compares the number of miners who are 
projected to incur a material impairment of their hearing under the 
current rule with the number of miners who are projected to incur such 
an impairment under the proposed rule. Overall for the mining 
community, the proposal would reduce the risk of material impairment by 
67%. More than 30,000 miners otherwise expected to develop a material 
impairment would be spared.
    As displayed in the chart entitled ``Benefits of MSHA Noise 
Proposal in Saving Miners From Hearing Impairment,'' the most 
significant benefits are expected in the coal sector. Engineering and 
administrative controls are expected to significantly reduce noise 
exposures above the PEL. A significant benefit also accrues from the 
establishment of an action level: based on the assumption that most 
employees exposed to noise between the action level and the PEL will 
elect to use hearing protection for the first time at such levels. 
While the metal and nonmetal mining industry already uses engineering 
controls above the PEL, additional benefits are anticipated in this 
regard; primarily because the change in the way noise dose would be 
measured under the proposal would require the use of engineering and 
administrative controls in more cases than at present. Like coal, a 
benefit in

[[Page 66350]]

this sector is anticipated from the establishment of an action level.
    As indicated by this chart, MSHA projects that even after 
implementation of the proposal some miners will continue to develop a 
material impairment of hearing. This is of serious concern to the 
Agency. The Agency believes, however, that the mining industry may not 
be able at this time to feasibly take actions which would eliminate the 
remaining risk (see response to Questions 9 and 13 on this point). MSHA 
is seeking comments on this issue.

Benefits of MSHA Noise Proposal in Saving Miners From Hearing Impairment
------------------------------------------------------------------------
                                                                Miners  
------------------------------------------------------------------------
Coal:                                                                   
    Current expected impairment..  15% of miners...........       18,947
    Saved by eng/admin controls..  58% of projected               11,072
                                    impairment.                         
    Saved by hearing protectors..  22% of projected                4,232
                                    impairment.                         
    Saved by proposal............  81% of projected               15,304
                                    impairment.                         
    Remaining expected impairment  3% of miners............        3,643
Metal and Nonmetal:                                                     
    Current expected impairment..  13% of miners...........       26,977
    Saved by eng/admin controls..  11% of projected                2,693
                                    impairment.                         
    Saved by hearing protectors..  46% of projected               12,320
                                    impairment.                         
    Saved by proposal............  57% of projected               15,283
                                    impairment.                         
    Remaining expected impairment  6% of miners............       11,694
Mining Industry as a Whole:                                             
    Current expected impairment..  14% of miners...........       45,924
    Saved by eng/admin controls..  31% of projected               14,035
                                    impairment.                         
    Saved by hearing protectors..  36% of projected               16,552
                                    impairment.                         
    Saved by proposal............  67% of projected               30,587
                                    impairment.                         
    Remaining expected impairment  5% of miners............       15,377
------------------------------------------------------------------------

    MSHA's estimates of cost follow a standard approach in which 
initial costs of compliance (like equipment purchase costs) are 
amortized over ten years at seven percent and added to costs that recur 
each year. The assumptions on what controls would be needed, how many 
hours have to be spent on particular tasks, and the costs of the 
personnel performing various tasks are set forth in detail in the 
Agency's preliminary RIA.
    MSHA estimates that the proposed rule would increase the mining 
industry's costs by approximately $8.3 million annually for the first 
10 years. MSHA estimates the proposed rule will cost the coal mining 
industry about $300,000 a year; because while there will be additional 
costs under the proposal, they will be significantly offset by the 
elimination of the requirements for biannual noise surveys of coal 
miners. Costs to the metal and nonmetal industry would rise by about $8 
million annually.
    The most costly aspect of the proposed rule would be the provision 
of audiometric examinations--about $3.6 million, with about $2 million 
of that borne by the metal and nonmetal mining industry. The provision 
of engineering controls is estimated to cost about $3.5 million, with 
about $2.2 million of this borne by the coal mining industry--which 
would no longer be permitted, as at present, to substitute hearing 
protectors for engineering or administrative controls. MSHA's costing 
assumptions are described in its preliminary RIA; comments on this 
methodology are being solicited.
    The table entitled ``Cost Impacts of MSHA Noise Proposal'' 
summarizes the net annual costs of the proposal's requirements. An 
explanation of the requirements is included in the questions and 
answers that follow.

                                       Cost Impacts of MSHA Noise Proposal                                      
----------------------------------------------------------------------------------------------------------------
                              Task                                  Total cost       M/NM cost       Coal cost  
----------------------------------------------------------------------------------------------------------------
Engineering Controls............................................      $3,475,700      $1,289,000      $2,186,700
Dose Determination..............................................     (1,928,550)       1,734,895     (3,663,445)
Notification....................................................          45,910          28,085          17,825
Record of Noise Surveys, et al..................................     (1,653,565)  ..............     (1,653,565)
Administrative Controls.........................................          16,595           6,580          10,015
HPDs (provide, selection, fit)..................................         926,710         792,560         134,150
Training........................................................       1,834,560       1,071,140         763,420
Audiograms (base, annual); notice to miners.....................       3,574,030       1,964,970       1,609,060
Audiometric Test Procedures.....................................         195,835         113,835          82,000
Evaluation of Audiogram.........................................         892,215         492,215         400,000
Follow-up Evaluation............................................         145,780          78,865          66,915
Follow-up Corrective Measures...................................          99,440          52,455          46,985
Notification of Results.........................................         138,710          74,340          54,370
Access to Records...............................................          23,710          18,865           4,845
Transfer of Records.............................................           5,040           2,950           2,090
Contractors.....................................................         541,640         316,320         225,320
                                                                 -----------------------------------------------
      Total.....................................................       8,323,760       8,037,075         286,685
----------------------------------------------------------------------------------------------------------------

    MSHA's estimates of paperwork burden hours reflect the requirements 
and definitions in the Paperwork Reduction Act. Overall, the proposal 
would decrease paperwork requirements in the mining industry by about 
14,985 burden hours. This reflects a savings to the coal mining 
industry of 88,740 burden hours, as a result of a proposal to eliminate

[[Page 66351]]

existing requirements for biannual surveys of coal miners and other 
various reports. The metal and nonmetal mining sector would have a net 
increase of about 73,755 burden hours. The chart entitled ``Paperwork 
Impacts of MSHA Noise Proposal'' summarizes the projected paperwork 
burdens.

                                    Paperwork Impacts of MSHA Noise Proposal                                    
----------------------------------------------------------------------------------------------------------------
                                     Paperwork requirement and associated                                       
              Section                               tasks                      Coal         M/NM        Total   
----------------------------------------------------------------------------------------------------------------
62.120............................  Evaluate miners' noise exposure;         (140,545)        5,295    (135,250)
                                     notify miner of overexposure,                                              
                                     prepare and post administrative                                            
                                     controls; give miners copy of                                              
                                     administrative controls.                                                   
62.130............................  Prepare and file a training                  4,000        6,270       10,270
                                     certification.                                                             
62.140............................  Perform audiograms, notify miners to        30,655       39,275       69,930
                                     appear for testing and need to avoid                                       
                                     high noise.                                                                
62.150............................  Compile an audiometric test record,          3,930        5,245        9,175
                                     obtain a certification.                                                    
62.160............................  Provide information and audiometric          9,340       12,015       21,455
                                     test record, perform audiometric                                           
                                     retests.                                                                   
62.170............................  Perform audiometric evaluations and            475          570        1,045
                                     follow-up evaluations.                                                     
62.180............................  Prepare a training certification for           335          365          700
                                     retrained miners, review                                                   
                                     effectiveness of engineering and                                           
                                     administrative controls.                                                   
62.190............................  Inform miner of test results, inform         2,715        3,585        6,300
                                     miner of STS.                                                              
62.200............................  Provide access to records............          255        1,000        1,255
62.210............................  Transfer records.....................          100          135          235
All...............................  (any discrepancies due to rounding)..     (88,740)       73,755     (14,985)
----------------------------------------------------------------------------------------------------------------

(4) What Special Consideration Did MSHA Give to Alternatives for the 
Smallest Mines?
    MSHA estimates that as a result of this proposal, metal and 
nonmetal mines with less than 20 miners would incur an average cost 
increase of about $500 per year in annual costs and annualized first 
year costs. Coal mines with less than 20 miners would have an average 
savings per mine of about $30, reflecting the elimination of the 
numerous survey and paperwork requirements in the current noise rules 
for the coal sector.
    MSHA compared the proposed costs for small mines in each sector to 
the estimated revenues and profits for small mines in each sector. MSHA 
did this at various size levels. In each case, the costs as a 
percentage of revenue are less than 1%, and the costs do not appear to 
have any appreciable impact on profits. Accordingly, for the purposes 
of the Regulatory Flexibility Act, MSHA has certified that the proposed 
rule does not have a significant economic impact on a substantial 
number of small entities.
    The limited impacts on small mines reflect decisions by MSHA not to 
propose more costly regulatory alternatives. In considering regulatory 
alternatives for small mines, MSHA must observe the requirements of its 
authorizing statute. Section 101(a)(6)(A) of the Mine Act requires the 
Secretary to set standards which most adequately assure, on the basis 
of the best available evidence, that no miner will suffer material 
impairment of health over his/her working lifetime. In addition, the 
Mine Act requires that the Secretary, when promulgating mandatory 
standards pertaining to toxic materials or harmful physical agents, 
consider other factors, such as the latest scientific data in the 
field, the feasibility of the standard and experience gained under the 
Act and other health and safety laws. Thus, the Mine Act requires that 
the Secretary, in promulgating a standard, attain the highest degree of 
health and safety protection for the miner, based on the ``best 
available evidence,'' with feasibility a consideration.
    As a result of this requirement, MSHA seriously considered two 
alternatives that would have significantly increased costs for small 
mine operators--lowering the PEL to a TWA8 of 85 dBA, and lowering 
the exchange rate to 3 dB. In both cases, the evidence in favor of 
these approaches was strong. But in both cases, MSHA has tentatively 
concluded that it may not be feasible for the mining industry to 
accomplish these more protective approaches. The impact of these 
approaches on small mine operators was an important consideration in 
this regard.
    Part IV of this preamble contains a full discussion of MSHA's 
preliminary conclusions about these alternatives. The graph labeled 
``Effect of Alternative Exchange Rates and PELs on Allowable Exposure 
Times at Various Decibel Levels'' provides an indication of what the 
Agency's decisions in this regard mean in practice.

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BILLING CODE 4510-43-C

    In accordance with the Small Business Regulatory Enforcement and 
Fairness Act (SBREFA), MSHA is taking actions to minimize the 
compliance burden on small mines. The proposed effective date of the 
rule would be a year after final promulgation, to provide adequate time 
for small mines to achieve compliance. MSHA will also mail a copy of 
the proposed rule to every mine operator which primarily benefits small 
mine operators. MSHA is committed to writing the final rule in plain 
English so it can be readily understood by miners and mine operators. 
The Agency has committed itself to issuance of a compliance guide, and 
is inviting comment on whether compliance workshops or other such 
approaches would be valuable. (These proposed actions are discussed in 
more detail in other Questions and Answers.)
    The approximately 350 small sand and gravel or crushed stone 
operations run by State, local and tribal governments may also be 
interested in MSHA's analysis on the impacts of the proposed rule on 
such entities. Such an analysis is required by the Unfunded Mandates 
Reform Act of 1995. Like other small metal and nonmetal mines, their 
costs for prevention of hearing loss are expected to average about $500 
per year. Benefits to these governmental entities include fewer hearing 
impairments and reduced workers' compensation costs.
(5) Why Is the Proposed Rule Needed?
    MSHA has concluded that the existing rules to protect miners from 
workplace noise exposure must be revised because current noise 
exposures continue to create a significant risk of material impairment 
of health to miners. MSHA estimates that 14% of U.S. miners--about 
46,000 of them--can be expected under current exposure conditions to 
develop a material impairment of hearing during a working lifetime. The 
figures are 15% (19,000) of U.S. coal miners and 13% (27,000) of U.S. 
metal and nonmetal miners.
    Generally, prolonged exposure to noise over a period of several 
years causes permanent damage to the auditory nerve and/or its sensory 
components: the higher the noise exposure the more rapid the loss. The 
loss may be so gradual, however, that a person may not realize that he 
or she is becoming impaired until a substantial amount of hearing is 
lost. This damage, known as noise-induced hearing loss or NIHL, is 
irreversible, and makes it difficult to hear as well as understand 
speech. In addition to the personal and social costs of hearing loss, 
the loss of the ability to understand speech can have a significant 
impact on miner safety which is highly dependent upon good 
communication.
    The Agency has carefully analyzed the risk miners currently face of 
incurring such harm. What follows is a short summary of MSHA's risk 
analysis (the complete analysis is presented as part II of the 
Supplemental Information accompanying this notice).
    First, the Agency considered the various definitions of impairment 
used in the risk analyses in the literature. Three definitions of 
impairment have been widely recognized within the scientific community 
as useful for the purposes of assessing risk. All three focus on the 
risks of acquiring a 25 dB hearing ``level''--the deviation from 
audiometric zero. The three accepted approaches differ in that they 
examine hearing acuity at a different set of frequencies. For the 
purpose of its analysis, MSHA chose the approach that measures hearing 
acuity at those frequencies most relevant to the ability to understand 
human speech. This is the approach developed in 1972 by the National 
Institute for Occupational Safety and Health (NIOSH) and subsequently 
used by the Occupational Safety and Health Administration

[[Page 66353]]

(OSHA): a 25 dB hearing level at 1000, 2000 and 3000 Hz. The Agency is 
aware that NIOSH is now considering a revised approach that would 
include hearing acuity at 4000 Hz, but believes it is inappropriate to 
utilize that approach until peer review has validated its utility.
    Next, the Agency reviewed the major studies on the level of risk at 
different noise exposures. The data consistently indicate that the risk 
of developing a material impairment of hearing, as a result of a 
working lifetime of occupational exposure, becomes significant when 
workplace noise exposures exceed an eight-hour time-weighted average 
(TWA8) of 85 dBA. The table entitled ``Excess Risk Estimates'' 
presents estimates by NIOSH of how the excess risk of developing a 
material impairment (using its 1972 definition) varies with exposure 
over a working lifetime.

                                              Excess Risk Estimates                                             
----------------------------------------------------------------------------------------------------------------
                                                                                                                
----------------------------------------------------------------------------------------------------------------
Exposure (TWA8).............          <80       80-84.9       85-89.9       90-94.9       95-99.9   1
                                                                                                             00 
Excess Risk.................            0            3%           15%           29%           43%           54% 
----------------------------------------------------------------------------------------------------------------

    MSHA also reviewed a large body of data on the effects of varying 
industrial noise exposures on worker hearing. These studies are 
supportive of the same conclusion. MSHA refined its picture of what 
occurs at lower sound levels by reviewing a number of other studies, 
particularly those of workers in other countries.
    To confirm the magnitude of the risks of NIHL among miners, MSHA 
asked NIOSH to examine a body of audiometric data collected over the 
years tracking hearing acuity among coal miners. The analysis (Franks, 
1996) supports the data from the risk studies. It indicates that 90% of 
these miners have a hearing impairment by age 50 as compared with only 
10% of the general population. Further, Franks stated that miners, 
after working 20 to 30 years, could find themselves in life-threatening 
situations because safety signals and ``roof talk'' could go unheard. 
(For the purposes of the analysis, NIOSH used a definition of hearing 
impairment including losses at 4000 Hz; MSHA conducted its own analysis 
of the data without the 4000 Hz, and the results are generally 
consistent with those of NIOSH).
    MSHA also examined other sources of data that might provide direct 
confirmation of the risks of hearing loss to miners--comments received 
in response to the Agency's Advance Notice of Proposed Rulemaking 
(ANPRM), (December 4, 1989, 54 FR 50209), the reports of hearing loss 
provided to the Agency by mine operators pursuant to 30 CFR part 50, 
and workers' compensation data. In each case, the available data are 
too limited to draw any conclusions. The Agency is requesting the 
public to provide further information along these lines.
    To develop a profile of the mining population at risk, MSHA began 
by gathering information on noise exposures in the U.S. mining 
industry.
    Current exposures appear to be gradually declining in the metal and 
nonmetal industry, where engineering or administrative controls are the 
primary means of miner protection against NIHL. But the data indicate 
that all sectors of the mining industry continue to have a significant 
number of overexposures.
    Charts II-9 and II-10 display exposure trends based on inspector 
samples. Only those samples that exceed the PEL are displayed. For 
1995, 14.4% of samples from the metal and nonmetal mining industry, and 
22.5% of samples from the coal industry, exceeded the PEL. (Because 
they are 3-D graphs, the data points sometimes look lower than they 
are; the actual data points can be found in part II, Tables II-9 and 
II-10.)

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BILLING CODE 4510-43-C

    These figures actually understate truly harmful exposures because 
the samples were taken in a way that did not count any exposures to 
sound levels below 90 dBA. As discussed herein (see Question 9), MSHA 
has concluded that exposures to sound levels above 80 dBA are harmful. 
Accordingly, to get a better picture of present harmful miner 
exposures, MSHA examined the results of a special survey taking 
thousands of

[[Page 66354]]

samples that included sound levels as low as 80 dBA. The results 
indicate that 36.8% of coal samples, and 26.9% of the metal and 
nonmetal samples would exceed the PEL if the lower, but still harmful, 
sound levels are counted in the dose measurement.
    To derive a risk profile of miners, the Agency utilized the 
exposure data from the survey and the excess risk estimates. (The 
methodology for developing the miner risk profile is explained in 
detail in the Agency's preliminary RIA. Among other adjustments to the 
sample data, MSHA assumed coal miners were currently receiving some 
protection from hearing protectors; as a result, the estimates of 
miners at excess risk are lower than might be suggested by the 
foregoing figures.) Based on its analysis, MSHA estimates that 14% of 
U.S. miners--about 46,000 miners--can be expected under current 
exposure conditions to develop a material impairment of hearing of 
handicapping or disabling proportions during a working lifetime. The 
figures are 15% (19,000) of U.S. coal miners as a group and 13% 
(27,000) of U.S. metal and nonmetal miners.
    The Agency is interested in receiving additional data with respect 
to the risks of noise exposure to workers and to the mining population 
in particular, as well as comments on its risk methodology and 
analysis.
(6) Why Proceed Without Waiting for NIOSH To Issue a New Criteria 
Document on Noise Exposure?
    As MSHA was preparing this notice for publication, the National 
Institute for Occupational Safety and Health (NIOSH) released for peer 
review a draft criteria document for occupational noise exposure to 
update the one issued in 1972.
    A summary of that draft, prepared and released by NIOSH, is 
included in the discussion of the rulemaking history in the 
Supplementary Information accompanying this notice. NIOSH is 
considering whether the evidence on noise since 1972 warrants a change 
in its recommendations. In some cases NIOSH is considering reiterating 
its prior recommendations, and in other cases it is considering 
changing its recommendations.
    MSHA has determined that it would not be appropriate to delay 
publication of this proposed rule to await the possible issuance of a 
new NIOSH criteria document. The NIOSH draft is still being peer 
reviewed, and MSHA does not believe it would be appropriate to delay 
acting based upon the uncertain timing of the document's redrafting and 
release. Moreover, many of the issues covered in the NIOSH draft have 
been considered by MSHA, as part of the Agency's review of all the 
latest scientific information on noise.
    Should a new criteria document be issued before MSHA promulgates a 
final rule, it will of course consider the NIOSH recommendations. The 
summary of the NIOSH draft included in this notice should provide ample 
notice to the mining community of the position NIOSH may take in a new 
criteria document.
(7) What Mines Are Covered by the Proposal?
    The proposal would apply one set of rules uniformly to all mines. 
Those who responded to MSHA's ANPRM generally agreed that consolidation 
and simplification of multiple standards into one rule may help to 
facilitate understanding of, and thus compliance with, the regulatory 
requirements for controlling noise exposures.
(8) Are There Special Definitions Applicable?
    To help mine operators and miners, the proposed rule would include 
definitions of some technical terms universally used in noise 
measurement. But the proposed rule also includes some terms used in a 
way that differs from usage in certain other contexts--e.g., under the 
OSHA standard.
    In particular, MSHA is proposing a non-standard use of the term 
``hearing conservation program'' or ``HCP.'' Most hearing conservation 
programs include provision for hearing examinations, training and the 
use of hearing protectors. Since audiograms would be new for the mining 
industry, unlike the other components, the Agency thought it might be 
less confusing to treat the components separately. Accordingly, under 
the MSHA proposal, hearing protector and training requirements are 
established independently, and a ``hearing conservation program'' is 
defined as a generic reference to those sections of the proposal that 
set forth the requirements for an audiometric testing program.
(9) How Is a Miner's Noise Dose To Be Determined Under the Proposal?
    The proposal sets forth a formula for dose computation, which is to 
be measured over a full shift, which corresponds to the readouts of 
most currently used personal noise dosimeters.
    The proposal would continue the use of a 5-dB exchange rate. The 
exchange rate is a measure of how quickly the dose of noise doubles. 
Accordingly, the measure is the rate determining how much a miner's 
exposure must be limited to compensate for increasing dose. Using the 
5-dB exchange rate, the exposure time permitted at a sound level of 90 
dBA is half that permitted at a sound level of 85 dBA--a miner gets the 
same noise dose in 4 hours at 90 dBA as at 8 hours at 85 dBA.
    The Agency gave serious consideration to changing the exchange rate 
from 5 dB to 3 dB, and is specifically seeking comment on this 
important matter. There is a consensus in the recent literature that 
noise dose actually doubles more quickly than measured by the 5-dB 
rate; the consensus is for an exchange rate of 3 dB. Moreover, the 
current 5-dB exchange rate incorporates an assumption that there is 
significant time for hearing to recover from high sound levels. MSHA 
has concluded that noise exposure under mining conditions does not 
warrant such an assumption. A 3-dB exchange rate does not incorporate 
this assumption.
    Nevertheless, the Agency is proposing to retain the existing 5-dB 
exchange rate because of feasibility considerations. Changing to a 3-dB 
rate from a 5-dB rate would significantly reduce the amount of time 
that miners could be exposed to higher sound levels without exceeding 
the PEL. For example, MSHA estimates that the percentage of miners 
whose exposure would be in violation of the PEL would just about double 
if a 3-dB exchange rate is used. This means mine operators would have 
to utilize controls to reduce exposures to the PEL much more 
frequently. Moreover, more expensive controls would often be required; 
if doses are doubling more quickly, the controls needed to reduce 
overexposures to the PEL would have to be more effective. Furthermore, 
if a 3-dB exchange rate is used, it is extremely difficult to reduce 
the noise exposures to the PEL with currently available engineering or 
administrative noise controls or a combination thereof. Accordingly, 
moving the industry to a 3-dB exchange rate may not be feasible at this 
time.
    The sound levels to be included in a miner's dose are being 
expanded. At present, only exposures to sounds of 90 dBA and above are 
included in determining a miner's dose under MSHA's standards. (Thus, 
90 dBA is considered the ``threshold.'') The proposed rule would 
include exposure to sound levels as low as 80 dBA. The Agency has 
concluded that capturing such sound levels is necessary if it 
establishes an action level based on an eight-hour time-weighted 
average of 85 dBA. Among other reasons, exposure of a miner to an 
extended shift (e.g.,16

[[Page 66355]]

hours) at just over 80 dBA can result in an exposure that exceeds the 
action level. OSHA uses this threshold for its action level, but a 
higher threshold for the PEL; based on the comments received in 
response to its Advance Notice of Proposed Rulemaking, MSHA concluded 
it would be easier for the mining industry to use a single threshold 
for both purposes.
    While necessary, this change will generally result in higher dose 
readings in both the coal and metal and nonmetal sectors than at 
present. (See the discussion of exposure data in response to Question 
5). In this case, however, MSHA has concluded that this change would 
clearly be feasible for the industry.
    The proposed regulation would not allow dose measurements to be 
adjusted to reflect the effect of hearing protectors. This provision 
would reinforce MSHA's intent to preclude the current practice in the 
coal mining industry of not issuing a citation based upon a noise 
exposure that exceeds the PEL when the miners are wearing hearing 
protection. (See Question 11 for additional information on this topic.)
(10) What Controls Are Required Whenever a Miner's Exposure Exceeds the 
Action Level?
    The proposal would require that all miners exposed above the action 
level be provided special instruction in the hazards of noise and 
protective methods. The training is to be provided annually for as long 
as exposure exceeds the action level. (The nature of this instruction, 
how it is to be provided, and how it can be coordinated with other 
required miner training are discussed in response to other questions.)
(11) What Additional Controls Are Required If a Miner's Exposure 
Exceeds the Action Level but Is Below the PEL?
    An operator will be required to enroll a miner whose exposure 
exceeds the action level in a hearing conservation program (HCP). While 
enrollment in the HCP would require the operator to make annual 
audiometric testing available to the miner, miners exposed to noise 
below the PEL would have the right to decline taking any annual 
audiometric testing. The requirements for such testing are discussed in 
more detail in response to other questions.
    MSHA is seeking comments on how to minimize the burden on mine 
operators of providing audiometric examinations for those miners with 
only a temporary attachment to the mining work force (e.g., summer 
employees), while recognizing the importance of detecting and tracking 
hearing loss among those who switch jobs.
    In addition, the operator must provide properly fitted hearing 
protection in 3 cases: before the initial hearing examination, if a 
significant threshold shift in hearing acuity is detected, and at any 
other time upon miner request.
    Both MSHA and OSHA normally require an employer or operator to 
ensure that personal protective equipment is in fact used; an operator 
can be cited for failure to enforce rules to this effect. In the case 
of this proposal, however, MSHA is making two exceptions in that 
regard. First, should the initial hearing examination take less than 6 
months to provide, the operator will not be required to ensure the 
provided hearing protection be worn. The operator is obligated to 
ensure protector use if more time is needed for the baseline 
examination (e.g., to wait for a mobile test van). Second, hearing 
protection provided because of miner request does not generate an 
operator obligation to enforce the use of the requested protection. At 
exposure levels above the action level but below the PEL, the 
proposal's goal is to encourage the use of hearing protection by 
training, providing choice, and encouraging proper fit--but the 
proposal would not require hearing protector use unless the miner has a 
significant threshold shift or unless the miner has to wait more than 6 
months for a baseline examination.
(12) What Controls Are Required If a Miner's Exposure Exceeds the PEL?
    If a miner's noise dose exceeds the PEL, the proposal would require 
the mine operator to use all feasible engineering and administrative 
controls to reduce the miner's noise exposure to that level. The mine 
operator has a choice of whether to use engineering controls, 
administrative controls, or both; but if administrative controls are 
utilized, a copy of the procedures involved must be posted, and copies 
given to the affected miners.
    Under the proposal, a consistent hierarchy of controls is 
established for all mines. Mine operators must first utilize all 
feasible engineering and administrative controls to reduce sound levels 
to the PEL before (as explained in response to question 15) relying on 
other controls to protect against hearing loss. This approach is 
consistent with that currently in place for metal and nonmetal mines, 
but would be a change for coal mines. In the coal mining industry, MSHA 
inspectors do not cite for noise overexposures without first deducting 
from the measured dose the attenuating value of hearing protectors 
being worn by the miners exposed to excessive levels of noise. In 
practice, this means that personal protective equipment is in most 
cases accepted as a substitute for engineering and administrative 
controls.
    MSHA has conducted research on the attenuating value of hearing 
protectors under actual mining conditions and has reviewed the 
literature on this issue. MSHA is aware that NIOSH is considering new 
approaches on how to establish a system that will accurately derate 
hearing protector attenuation values for actual workplace conditions; 
but the Agency's own research suggests that the attenuation of a 
hearing protector is highly variable in practice, and that the amount 
of attenuation cannot be predicted accurately. This is discussed in 
part III of the Supplementary Information accompanying this notice.
    MSHA has also considered the data showing declining noise exposures 
in the metal and nonmetal industry, and contrasted this with the data 
on the coal mining industry.
    The Agency has concluded that, in practice, reliance upon hearing 
protectors to reduce noise exposures simply does not provide effective 
protection against hearing loss to miners. The Agency does not contend 
that properly fitted and maintained hearing protectors are worthless; 
on the contrary, the Agency is proposing to rely upon them as a 
supplemental control, and has taken their value into account in 
conducting its risk and benefit analyses. MSHA has concluded, however, 
that hearing protectors should no longer be relied upon as a primary 
means of control, and that this change can bring about dramatic 
reductions in the rate at which coal miners would otherwise be expected 
to incur hearing impairments.
(13) For an Individual Mine Operator, What Are ``Feasible'' Engineering 
and Administrative Controls?
    The proposal would require a mine operator to use only such 
engineering controls as are technologically feasible, and to use only 
such engineering and administrative controls as are economically 
feasible for that mine operator. Those in the metal and nonmetal mining 
industry are already familiar with the Agency's policies and practices 
in this regard, but those in the coal mining industry may wish to take 
note of the following few paragraphs.
    The Federal Mine Safety and Health Review Commission (Commission) 
has addressed the issue of what MSHA must consider, with regard to 
MSHA's existing noise standard for metal and

[[Page 66356]]

nonmetal mines, when determining what is a feasible noise control for 
enforcement purposes at a particular mine. According to the Commission, 
a control is considered feasible when: (1) The control reduces 
exposure, (2) the control is economically achievable, and (3) the 
control is technologically achievable. See Secretary of Labor v. 
Callanan Industries, Inc., 5 FMSHRC 1900 (1983), and Secretary of Labor 
v. A. H. Smith, 6 FMSHRC 199 (1984).
    In determining technological feasibility of a proposed control, the 
Commission has ruled that a control is deemed achievable if through 
reasonable application of existing products, devices, or work methods 
with human skills and abilities, a workable engineering control can be 
applied to the noise source. The control does not have to be ``off-the-
shelf;'' but, it must have a realistic basis in present technical 
capabilities.
    In determining economic feasibility, the Commission has ruled that 
MSHA must assess whether the costs of the control are disproportionate 
to the ``expected benefits'', and whether the costs are so great that 
it is irrational to require its use to achieve those results. The 
Commission has expressly stated that cost-benefit analysis is 
unnecessary in order to determine whether a noise control is required. 
According to the Commission, an engineering control may be feasible 
even though it fails to reduce exposure to permissible levels contained 
in the standard, as long as there is a significant reduction in 
exposure. Todilto Exploration and Development Corporation v. Secretary 
of Labor, 5 FMSHRC 1894 (1983). No guidance has been provided by the 
Commission as to what level of reduction is considered significant. 
However, the Commission has accepted the Agency's determination that a 
3 dBA reduction is significant.
    In the metal and nonmetal mining industry, MSHA has interpreted the 
``expected benefits'' to be the amount of noise reduction achievable by 
the control. MSHA generally considers a reduction of 3 dBA or more to 
be a significant reduction of the sound level. Consequently, a control 
that achieves relatively little noise reduction at a high cost could be 
viewed as not meeting the Commission's test of economic feasibility.
    Accordingly, consistent with the case law, MSHA has considered 
three factors in determining whether engineering controls are feasible 
at a particular metal and nonmetal mine: first, the nature and extent 
of the overexposure; second, the demonstrated effectiveness of 
available technology; and third, whether the committed resources are 
wholly out of proportion to the expected results. Before a violation of 
these requirements of the standard could be found, MSHA would have to 
determine that a worker has been overexposed; that administrative or 
engineering controls are feasible; and that the mine operator failed to 
install or maintain such controls.
    Part III of the Supplemental Information accompanying this notice 
provides many examples of engineering controls that are feasible for 
mine operators to utilize, and the Agency and the former Bureau of 
Mines (USBOM) have available many other materials in this regard. 
Nevertheless, the Agency welcomes information about particular 
operations for which it may be particularly difficult to control noise.
(14) Is It feasible for the Coal Mining Industry, and for the Metal and 
Nonmetal Mining Industry, To Provide the Controls Proposed To Be 
Required When Noise Exposures Exceed the PEL?
    Part IV of the Supplementary Information in this notice provides a 
detailed discussion of the statute's requirements and the Agency's 
analysis in this regard. The Agency has concluded that the coal mining 
industry as a whole, and the metal and nonmetal mining industry as a 
whole, can meet these requirements at a PEL set at a TWA8 of 90 
dBA.
    In fact, the Agency seriously considered lowering the PEL. As noted 
in response to Question 5, MSHA has concluded that there is a 
significant risk of material impairment from noise exposures at or 
above a TWA8 of 85 dBA. MSHA believes, however, that such a change 
may not be feasible at this time for the mining industry. Based on an 
analysis of exposure survey data, MSHA has concluded that if the PEL 
were a TWA8 of 85 dBA, about two-thirds of the mine operators in 
the metal and nonmetal mining industry, and about three-quarters of the 
mine operators in the coal mining industry, would need to use 
engineering and administrative controls to reduce current exposures. 
Moreover, the engineering controls needed to reduce those exposures 
would be more expensive, because they would have to be capable of 
reducing the exposures further than with a PEL set at a TWA8 of 90 
dBA.
(15) What Supplemental Controls Are Required If a Miner's Exposure 
Cannot Be Feasibly Reduced to the PEL?
    If reducing the dose to this level with such controls is not 
feasible, the proposal requires the mine operator to use such controls 
to lower the noise exposure as much as is feasible.
    In addition, in such cases, the proposal requires that the operator 
take extra steps to protect miner hearing. The operator must ensure any 
miner so exposed takes the annual hearing examinations, must provide 
properly fitted hearing protection to all miners so exposed, and must 
ensure the hearing protection is used by all miners so exposed.
    MSHA believes that when a miner is exposed to such high levels of 
noise because engineering and administrative controls are not feasible 
for an operator, these supplemental obligations are necessary to 
protect miner hearing. Hearing protectors are not without their 
discomforts, but the risk of hearing loss at such exposure levels ought 
to be a controlling factor. While audiometric testing is not an 
invasive procedure, the Agency is concerned that there may be economic 
pressures and personal reasons that may lead miners to decline to take 
hearing examinations. The information generated by these tests is 
necessary, however, to trigger investigation of potentially serious 
flaws in the layers of noise controls required at these high exposure 
levels. In addition, the Agency believes that miners operating under 
such high noise conditions should be aware of the severity of any 
hearing loss; in a mining environment, this knowledge could have 
implications for the safety of the miner and the safety of others. 
Comments on this provision are specifically solicited.
(16) Is There an Absolute Maximum Noise Dose?
    Under the proposal, a miner, as at present, is never to be exposed 
to sound levels exceeding 115 dBA. This is because sound at that level 
provides the full dose permitted in a matter of minutes.
    There is, however, no dose which the Agency would require to be 
abated without regard to whether it is feasible for an individual mine 
operator. The proposal does provide that should a miner's noise 
exposure exceed a TWA8 of 105 dBA during any workshift, the mine 
operator shall, in addition to taking all actions required to protect 
miners exposed above the PEL, also require the miner to use dual 
hearing protection, i.e., both a plug type and a muff type hearing 
protector. A TWA8 of 105 dBA is a dose of 800% of the PEL, using a 
5-dB exchange rate. In the notice accompanying this proposal, the 
Agency presents information about the mining jobs at which the 
exposures of this level are occurring, and requests comment on

[[Page 66357]]

whether there should be an absolute dose ceiling regardless of the 
feasibility of control by an individual mine operator.
(17) What Are an Operator's Obligations Under the Proposal To Monitor 
Noise Exposures?
    The proposal would require mine operators to establish a system of 
monitoring which effectively evaluates each miner's noise exposure. 
This will ensure that mine operators have the means to determine 
whether a miner's exposure exceeds any of the limitations established 
by this section, as well as to assess the effectiveness of noise 
controls. The proposed rule is performance oriented in that the 
regularity and methodology used to make this evaluation are not 
specified; MSHA's own measurements will enable it to check on the 
effectiveness of an operator's monitoring program. Specific 
requirements for biannual noise surveys, monitoring records, 
supplemental noise surveys, calibration reports, survey reports, and 
survey certifications now applicable to the coal sector would be 
revoked, significantly reducing cost and paperwork burdens.
(18) When Must Miners Be Notified of Monitoring Results?
    The proposal would require that miners be notified in writing 
should their exposure exceed any of the levels specified by this 
section--whether based on operator or MSHA evaluations of noise. Notice 
would be required within 15 calendar days.
    The proposal has been designed to ensure that miners are made aware 
of the hazards they currently face. Miners exposed above the action 
level should be notified of that fact so, for example, they can 
consider the importance of using provided, properly fitted and 
maintained hearing protectors. On the other hand, the proposal does not 
require notification of a particular miner if an exposure measurement 
indicates that the miner's exposure has not changed and the miner has 
within the last year been apprised of the same information. No 
notification is required if a miner's measurement is below the action 
level--although operators might wish to provide such notification if 
this indicates a reduction in noise exposure.
(19) What Rules Are There To Ensure That Required Hearing Protectors 
Provide Effective Protection?
    Whenever hearing protectors are to be provided, they must be 
provided in accordance with specific requirements. The miner is to have 
a choice from at least one earplug type and muff type protector; and, 
in the event dual hearing protection is required, a choice of one of 
each. Whenever the mine operator is required to ensure that hearing 
protection is worn (the circumstances are noted in response to prior 
questions), it is worn by the miner when exposed to sound levels 
required to be integrated into a miner's dose measurement, i.e., any 
sound levels above 80 dBA. The hearing protector is to be fitted and 
maintained in accordance with the manufacturer's instructions. Hearing 
protectors and necessary replacements are to be provided at no cost to 
the miner. Finally, should the miner suffer a medical pathology of the 
ear, the miner is to be allowed to select a different hearing protector 
from among those offered by the mine operator.
    MSHA has concluded that existing rating systems for hearing 
protectors do not provide a reliable measure of effectiveness under 
normal mining working conditions. The Agency believes that the best way 
to ensure such devices can provide effective protection is to focus on 
the conditions affecting hearing protector use.
(20) How Frequently Must Required Training Be Provided?
    If a miner's noise exposure exceeds the action level, training is 
to be provided annually. The training is to be provided when the miner 
is first determined to have exceeded the action level and every 12 
months thereafter that the miner continues to exceed that level.
    Annual refresher training is necessary to reinforce the proper 
procedures for the use and care of hearing protectors, and the 
importance of administrative and engineering controls. Additionally, it 
serves to re-emphasize the hazards of noise and the purpose for 
audiometric testing for those miners exposed above the PEL. MSHA 
received comments in response to its Advance Notice of Proposed 
Rulemaking (ANPRM) that supported an annual training requirement. 
Studies have shown that the effectiveness of an HCP is highly dependent 
on the proper use of hearing protectors and the commitment of both 
management and the employees, both of which can be enhanced by 
training.
(21) What Specifications Are There With Respect to the Instruction To 
Be Provided During Required Training?
    Miners would receive instruction in hearing protection: (1) the 
need for such protection, (2) selection and fitting, and (3) proper use 
of such protectors. Miners would also receive instruction about hearing 
conservation programs: as to the operation of that program and the mine 
operator's noise control efforts. There are no special qualifications 
for instructors, nor any specifications on the hours of instruction. 
Training is required to be provided without cost to the miner. The mine 
operator would be required to certify the completion of any training 
required by this part, and maintain the most recent certification for a 
miner at the mine site for as long as the miner is required to use 
hearing protectors or be enrolled in an HCP, and at least 6 months 
thereafter.
(22) Can the Required Training Be Covered During Part 48 Training?
    Yes, but it may not always be feasible to do so.
    MSHA considered whether the requirements of part 48, ``Training and 
Retraining of Miners,'' were adequate to ensure the training required 
under this part. The requirements of part 48 specify the initial and 
annual retraining of all miners in a list of subjects, many specified 
in the law itself (section 115 of the Mine Safety and Health Act). The 
importance of this training is emphasized by statutory requirements for 
the submittal of training plans, on the specification of the hours to 
be devoted to the training, and on the qualifications of instructors. 
Training is required on noise, but it is in general terms, covering the 
purpose of taking exposure measurements and on any health control plan 
in effect at the mine. Mine operators may provide additional training, 
but the topics that need to be covered may make this impracticable 
within the prescribed time limits.
    After considering the available information about the importance of 
training requirements, and based upon its experience in implementing 
the requirements of part 48, MSHA has determined that the requirements 
of part 48 do not provide adequate noise training for those miners for 
whom exposure is clearly a problem. Most current part 48 training is 
neither comprehensive enough to provide such miners with the level of 
education needed for the proper use of hearing protection devices, nor, 
in the case of noisy mines, detailed enough on methods to reduce sound 
levels.
    Nevertheless, MSHA believes compliance with this proposal can in 
many cases be fulfilled at the same time as scheduled part 48 training. 
The Agency does not believe special language in proposed part 62 is 
required to permit this action under part 48, but welcomes comment in 
this regard. Mine operators who can do so are free to fulfill their 
noise training requirements by covering the topics in initial and

[[Page 66358]]

annual part 48 training, and may so certify on the separate form 
required by this part. If incorporated into part 48, mine operators 
would, however, be required to submit a revised training plan to the 
appropriate district office for approval. Some mine operators, however, 
may not be able to incorporate these topics in their part 48 plans. 
Moreover, it is important to note that there are some circumstances in 
which training required under the proposal will likely not fit within a 
regular schedule, e.g., the training required when a miner's exposure 
is determined to require selection of a hearing protector or a new 
protector.
    MSHA has endeavored to make the training requirements as simple as 
possible. If conducted separately from part 48 training, there are no 
specifications on trainer qualifications, no minimal training time, nor 
any training plans. If, however, the training is incorporated into part 
48, then all applicable part 48 requirements will have to be met.
(23) If a Mine Operator Is Required To Offer Audiometric Testing, When 
Must a Baseline Audiogram Be Taken?
    It is critical to obtain a baseline audiogram before exposure to 
hazardous noise. If this is not possible, then the baseline is to be 
obtained as soon as is reasonably possible.
    Due to remote locations and intermittent operations of many mines, 
MSHA determined that allowing six months (or 12 months if a mobile test 
van is used) for offering the baseline audiogram was reasonable. The 12 
month period would allow mine operators to schedule many baseline and 
annual audiograms simultaneously, and thus, substantially reduce the 
cost when mobile test vans are used. Miners enrolled in a hearing 
conservation program would be provided hearing protection until such 
time as the baseline audiogram is conducted. In the case of a miner who 
has to wait more than 6 months for a baseline examination because of 
the need for a mobile test van, and in the case of a miner whose 
exposures cannot be reduced to the PEL through the use of all feasible 
engineering and administrative controls, the operator would be required 
to ensure the hearing protection is worn.
    MSHA has also determined that a 14-hour quiet period should precede 
the baseline audiogram to ensure a valid result. Moreover, unlike the 
OSHA rule, MSHA's proposal would not permit the use of hearing 
protectors as a substitute for a quiet period. The Agency has 
determined this is necessary to ensure that a temporary threshold shift 
in hearing acuity does not occur during the quiet period, rendering the 
baseline audiogram inaccurate. Moreover, MSHA's research has not shown 
a reliable method for predicting hearing protector attenuation under 
actual working conditions. Under the proposal, miners are to be 
notified of the importance of compliance with the quiet period. MSHA is 
not proposing to require this quiet period for annual audiograms, 
although it may be in the mine operator's interest to do so.
(24) What Qualification Requirements Are Proposed for Those Who Will 
Take Audiograms?
    MSHA would require that an ``audiologist'' be certified by the 
American Speech-Language-Hearing Association or licensed by a state 
board of examiners. ``Qualified technicians'' would be required to have 
been certified by the Council for Accreditation in Occupational Hearing 
Conservation (CAOHC) or another recognized organization offering 
equivalent certification. CAOHC or equivalent certification would 
assure that the technicians are qualified. MSHA is not proposing to 
require qualifications for physicians.
(25) Does the Proposal Specify Audiometric Test Procedures?
     MSHA proposes not to include specific procedural requirements for 
conducting audiometric tests, calibrating audiometers, and qualifying 
audiometric test rooms. Instead, MSHA proposes a performance-oriented 
requirement that audiometric testing be conducted in accordance with 
scientifically validated procedures. MSHA would specify the test 
frequencies, but would allow the physician or the audiologist to use 
professional judgement in choosing the appropriate testing procedure(s) 
and require certification of the scientific validity of the procedures.
    While this approach may require somewhat more in the way of 
paperwork requirements, MSHA believes this is far preferable to the 
alternative of a detailed specification standard, which could stifle 
technology and impede improvements in methodology.
(26) What Test Records Must Be Maintained?
    The proposal would also specify what records must be maintained at 
the mine site and the retention duration. The proposed items included 
in the audiometric test record--name, job classification, audiograms 
and certifications as to the procedures used to take them, any exposure 
determinations, and the results of any follow-up examinations--would 
provide information essential for evaluating a miner's audiogram, among 
other purposes.
    The proposal would require that the audiometric records be retained 
for at least six months beyond the duration of the miner's employment. 
The six-month retention period at the mine site would assure that test 
records are not destroyed during what might be normal breaks in 
employment and remain available for use by the mine operator to conduct 
further evaluations upon the miner's return. In practice, MSHA believes 
that many mine operators will keep a miner's audiograms long after the 
miner's employment ceases, for use if the miner should file a 
subsequent workers' compensation claim for hearing loss.
(27) How Are Audiograms To Be Evaluated?
    MSHA's proposal would require that the mine operator inform the 
person evaluating the audiogram of the requirements of this part and 
provide such person with copies of the miner's audiometric test 
records. The mine operator would be responsible for having a physician, 
audiologist, or qualified technician determine if an audiogram is 
valid, and to determine if a standard threshold shift in hearing acuity 
(STS) or reportable hearing loss has occurred. Time frames within which 
these actions must occur are part of the proposal.
    The proposal would permit, but not require, mine operators to 
adjust audiometric test results by applying a correction for 
presbycusis, the progressive loss of hearing acuity associated with the 
aging process, before determining whether an STS or reportable hearing 
loss has occurred, and it includes tables for this purpose. The 
proposed adjustment for presbycusis is optional, however, if a mine 
operator uses this approach, it must be applied uniformly to both the 
baseline and annual audiograms in accordance with the procedures and 
values listed in the proposed standard. Although this is the position 
taken in the proposal, MSHA notes that NIOSH recently has advised 
against the use of presbycusis correction factors. Moreover, the Agency 
is concerned about locking-in particular presbycusis adjustment tables. 
MSHA, therefore, requests additional comments on whether to use 
presbycusis corrections for audiograms and, if so, how to

[[Page 66359]]

provide for such adjustment in a regulatory context.
(28) What Happens If an Audiogram Is Not Valid?
    A prompt retest is required.
    When a valid audiogram cannot be obtained due to a suspected 
medical pathology of the ear, and the physician or audiologist 
evaluating the audiogram believes that the problem was caused or 
aggravated by the miner's exposure to noise or the wearing of hearing 
protectors, a miner must be referred for a clinical audiological or 
otological evaluation as appropriate at mine operator expense.
    If the physician or audiologist concludes that the suspected 
medical pathology of the ear which prevents obtaining a valid audiogram 
is unrelated to the miner's exposure to noise or the wearing of hearing 
protectors, the miner is to be advised of the need for an otological 
evaluation; but in such cases, no financial obligation would be imposed 
on the mine operator.
    A mine operator would be required to instruct the physician or 
audiologist not to reveal to the mine operator any specific findings or 
diagnoses unrelated to the miner's exposure to noise or the wearing of 
hearing protectors without the written consent of the miner.
 (29) What Corrective Measures Are Required When a Standard Threshold 
Shift in Hearing Acuity (STS) Is Detected?
    STS is defined in this proposal, as in OSHA's standard, as a change 
in a worker's hearing acuity for the worse, relative to that worker's 
baseline audiogram, of an average of 10 dB or more at 2000, 3000, and 
4000 Hz in either ear.
    If the STS is determined to be permanent, a supplemental baseline 
is established and this becomes the baseline for determining any future 
STS. This definition is sufficiently restrictive to locate meaningful 
shifts in hearing, yet not so stringent as to create unnecessary 
follow-up procedures. The frequencies were chosen for this purpose to 
ensure hearing losses are detected as soon as feasible. While NIOSH is 
currently considering an approach that would not require averaging at 
several frequencies, this remains under peer review; moreover, the 
averaging of hearing levels at adjacent frequencies will reduce the 
effect of testing errors at single frequencies.
    MSHA's proposal would require that, unless a physician or 
audiologist determines that an STS is neither work-related nor 
aggravated by occupational noise exposure, mine operators would have 30 
days after the finding of an STS to--
    (1) Retrain the miner;
    (2) Provide the miner with the opportunity to select a hearing 
protector, or a different hearing protector if the miner has previously 
selected one; and
    (3) Review the effectiveness of any engineering and administrative 
controls to identify and correct any deficiencies. The proposal also 
requires that an operator ensure that a miner with an STS wear the 
provided hearing protector.
    A hearing loss of 10 dB from a miner's prior hearing level is of 
enough significance to warrant intervention by a mine operator, unless 
it is determined the loss is not work-related. If the controls in place 
are effective, including the training, this loss should not be 
occurring. It should be noted that the retraining required is to take 
place within 30 days after the finding of the STS, and thus it is 
unlikely mine operators can satisfy this requirement through their part 
48 training programs.
    MSHA's proposal does not include a provision for transferring a 
miner who incurs repeated STS's. A miner transfer program would be 
complex to administer, and would probably not be feasible in the metal 
and nonmetal sector. This sector consists largely of smaller mines 
which may be unable to feasibly rotate workers to other assignments on 
a long-term basis.
 (30) When Must MSHA Be Notified About Hearing Loss?
    Pursuant to 30 CFR part 50, MSHA must be notified of any 
``reportable'' hearing loss. There is currently no uniform definition 
of this term. The proposed rule would establish a uniform definition 
for reporting a miner's hearing loss--a change in hearing acuity for 
the worse relative to the miner's baseline audiogram of an average of 
25 dB or more at 2000, 3000, and 4000 Hz in either ear. MSHA intends 
that a loss for any miner need not be reported again until there is an 
additional 25 dB loss. Having a uniform definition will ease reporting 
burdens on mine operators while promoting the development of an 
improved data base on hearing loss in the mining community.
    MSHA has two specific questions in this regard on which it is 
seeking comment. First, MSHA would like comment on how to define 
``reportable'' hearing loss for those operators who do not have 
audiometric test data. Not all mine operators will be required to 
obtain audiometric test data under the proposed rule; thus, such 
operators may not be able to use a definition of reportable hearing 
loss defined in this manner.
    Second, MSHA is concerned that reporting only losses of 25 dB may 
not provide MSHA a full picture of hearing loss in the mining industry. 
A loss of 25 dB is used by many states as a basis for making disability 
awards. Some have recommended that any STS (10 dB loss) should be 
captured in a hearing loss data base. OSHA, which currently requires 
any 25 dB loss to be captured in an employer's log, has proposed to 
capture any 15 dB loss. MSHA accordingly solicits comment on this 
point.
 (31) When Must a Miner Be Notified of Audiometric Testing Results?
    The proposal would require the mine operator, within 10 working 
days of receiving the results of an audiogram, or receiving the results 
of a follow-up evaluation, to notify the miner in writing of the 
results and interpretations, including any finding that an STS or 
reportable hearing loss has occurred. The notification would include an 
explanation of the need and reasons for any further testing or 
evaluation that may be required.
    MSHA believes that informing miners of the results of their 
audiometric tests in a timely manner is critical to the success of an 
HCP. Immediate feedback upon completion of the testing provides the 
greatest benefit.
(32) Who Has Access to Exposure and Test Records Maintained by Mine 
Operators?
    Authorized representatives of the Secretaries of Labor and Health 
and Human Services would have access to all records required under this 
part.
    Moreover under the proposal, a miner or former miner, or his/her 
designated representative with written consent, would have access to 
all the records that the mine operator is required to maintain under 
this part for that individual miner or former miner. Also, the miners' 
representative is in all cases to have access, for miners they 
represent, to noise training records and to notices required to be made 
to miners exposed to noise above various levels.
    The mine operator would have 15 days from receipt of a written 
request to provide such access. The proposal would define ``access'' as 
the right to examine and copy records. The first copy of any record 
requested by a person is to be provided without cost to that person, 
and any additional copies requested by that person are to be provided 
at reasonable cost.

[[Page 66360]]

    Upon termination of employment, mine operators would be required to 
provide a miner, without cost, an actual copy of all his or her own 
records (those required under this part).
    The proposed standard would require mine operators to transfer all 
records (or a copy thereof) required by this part to any successor mine 
operator. The successor mine operator would be required to receive 
these records and maintain them for the period required. Additionally, 
the successor mine operator would be required to use the baseline 
audiogram obtained from the original mine operator (or supplemental 
baseline audiogram as appropriate) for determining an STS and 
reportable hearing loss.
    MSHA has no uniform records access provision. The provisions 
proposed here are similar to those in other health standards proposed 
in recent years by the Agency. The Agency welcomes comment on whether 
it needs to make changes to facilitate the use of electronic 
recordkeeping systems.
(33) How Does the Proposal Compare With the Existing Standards?
    MSHA has prepared two charts comparing some of the key features of 
the proposed standard to MSHA's existing standards. A comparison to 
OSHA's noise standard is also provided since many mine operators and 
others are familiar with that standard.
    It is important the reviewers exercise some caution in using these 
charts. The entries were ``shorthanded'' to fit into the chart. 
Accordingly, other parts of this preamble should be consulted for 
details. In comparing the proposed rule with OSHA's standard, for 
example, reviewers interested in differences on the definition of a 
hearing conservation program should consult the answer to Question 8; 
those interested in differences on the threshold should consult the 
answer to Question 9; those interested in differences on employer 
obligations to ensure the wearing of provided hearing protections 
should consult the answer to Question 11; and those interested in 
differences about the use of hearing protection in lieu of a quiet 
period before a baseline audiogram should consult the answer to 
Question 23.
    Care should also be taken in consulting the existing standards 
themselves. The entries in the charts and the discussions in the 
preamble reflect legal and/or policy interpretations of the various 
standards that now determine their meaning, something that would not be 
apparent from an examination of the text of the standards.
    To conserve space, the following abbreviations are used in the 
charts: HP (hearing protection), HCP (hearing conservation program), 
STS (standard threshold shift), TWA8 (time-weighted eight-hour 
average), dBA (decibel, A-weighted), PEL (permissible exposure limit); 
``admin'' (administrative), kHz (kilohertz), and N/A (none or not 
applicable).

                                   Comparison Chart 1: Exposure/Dose Triggers                                   
----------------------------------------------------------------------------------------------------------------
                                                  Existing metal/                                               
   TWA8 noise above            Proposal               nonmetal            Existing coal             OSHA        
----------------------------------------------------------------------------------------------------------------
85 dBA................  Provide training on    No action required...  No action required..  Enroll employee in  
                         noise; enroll miner                                                 HCP (must offer    
                         in HCP (must offer                                                  annual hearing     
                         annual hearing                                                      test); if more than
                         test); provide HP                                                   6 months before    
                         before baseline                                                     baseline audiogram 
                         audiogram taken, if                                                 taken (mobile van),
                         STS detected or upon                                                employee must be   
                         request of miner;                                                   provided and wear  
                         must ensure miner                                                   HP; employee must  
                         uses HP if more than                                                also be provided   
                         6 months for                                                        and use HP if STS  
                         baseline (mobile                                                    detected.          
                         van) or STS detected.                                                                  
90 dBA................  Use all feasible       Use all feasible       Use all feasible      Use all feasible    
                         engineering and        engineering or         engineering or        engineering or     
                         admin. controls to     admin. controls to     admin. controls to    admin. controls to 
                         reach; if can't        reach; if can't        reach * * * but can   reach * * * but if 
                         reach 90 using such    reach 90 using such    first reduce          exposure less than 
                         controls, use          controls, then must    exposure reading by   100 dBA, can first 
                         controls to get as     also provide HP.       rated value of HP     reduce reading by  
                         low as possible,                              minus 7 unless        value of HP        
                         provide HP to all                             cited for failure     attenuation =.50 x 
                         miners, ensure HP                             to require HP use;    (rated value of HP 
                         used and ensure                               must enroll miners    minus 7).          
                         hearing tests taken.                          in HCP if cited.                         
105 dBA...............  Dual HP must be        Limited requirement    n/a.................  n/a.                
                         provided and used.     for dual HP.                                                    
----------------------------------------------------------------------------------------------------------------


                                           Comparison Chart 2: Issues                                           
----------------------------------------------------------------------------------------------------------------
                                                        Existing metal/                                         
              Issue                    Proposal            nonmetal          Existing coal           OSHA       
----------------------------------------------------------------------------------------------------------------
Monitoring......................  Operator must       No requirement on   Mine operator       Employer must     
                                   establish system    mine operator.      required to         conduct          
                                   of monitoring                           conduct periodic    represent.       
                                   exposures.                              monitoring.         personal sampling
                                                                                               if info suggests 
                                                                                               noise exceeds    
                                                                                               action level.    
Notification of exposure level..  Notify miner of     Not required......  Not required......  Notify employee if
                                   measured exposure                                           exposure exceeds 
                                   level if: (a)                                               action level.    
                                   exposure changed,                                                            
                                   or (b) even if                                                               
                                   shows no change                                                              
                                   if miner not                                                                 
                                   notified within                                                              
                                   last year.                                                                   

[[Page 66361]]

                                                                                                                
Threshold: lowest sound levels    80 dBA............  90 dBA............  90 dBA............  80 dBA for        
 counted.                                                                                      monitoring & HCP 
                                                                                               enrollment but 90
                                                                                               dBA for PEL.     
Exchange rate...................  5 dB..............  5 dB..............  5 dB..............  5 dB.             
Ceiling.........................  115 dBA...........  115 dBA...........  115 dBA...........  115 dBA.          
Training on hearing protector     Annual if above     Part 48 general     Part 48 general     Annual if exposure
 selection & use.                  action level.       discussion.         discussion.         exceeds TWA8 of  
                                                                                               85 dBA.          
Training on audiology & employer  Annual if above     No................  No................  Audiology only;   
 program.                          action level.                                               annual if        
                                                                                               enrolled in HCP. 
Quiet period before aud. exam...  14 hours for        n/a...............  n/a...............  14 hours for      
                                   baseline                                                    baseline         
                                   audiogram; can                                              audiogram; can   
                                   not use hearing                                             use hearing      
                                   protectors.                                                 protectors.      
Standard threshold shift........  10 dB av. shift @   n/a...............  n/a...............  10 dB av. shift @ 
                                   2, 3, & 4 KHz.                                              2, 3, & 4 KHz.   
Reportable hearing loss.........  Must report 25 dB   Reporting required  Reporting required  No reporting; must
                                   av. shift @ 2, 3,   but level not       but level not       record 25 dB av. 
                                   & 4 kHz, either     defined.            defined.            shift @ 2, 3, & 4
                                   ear.                                                        kHz, either ear; 
                                                                                               1/96 proposal    
                                                                                               would drop to 15 
                                                                                               dB.              
Employee access to records......  Yes...............  No................  No................  Yes.              
----------------------------------------------------------------------------------------------------------------

(34) Is MSHA Going To Write the Final Rule in Plain English so Miners 
and Mine Operators Can Understand Their Obligations?
    The text of the proposed rule can be found at the very end of this 
notice. While the Agency endeavored to write clearly, it is interested 
in suggestions to make the final rule as comprehensible as possible to 
mine operators and miners.
    MSHA has developed two examples, based on the proposed rule, to 
illustrate some alternative approaches it could take.
    The first example illustrates one way in which a rule's 
organization can be reformulated so as to serve as a more useful 
reference tool. This proposal's table of contents begins as follows:

62.100  Purpose and scope; effective date.
62.110  Definitions
62.120  Limitations on noise exposure

    The alternative version presents the table of contents as a series 
of practical questions that are likely to be asked by the mining 
community. The sections have been subdivided so as to address questions 
one at a time. In the mining industry, the Department of the Interior 
has also experimented with this approach, e.g., proposed coalbed 
methane regulations (60 FR 47920).

62.100  What is the purpose of requiring mine operators to limit 
miner noise exposure?
62.101  What kinds of mining operations are covered by this 
regulation?
62.102  When does this regulation take effect?
62.110  What is meant by various technical terms used in this 
regulation?
62.120  How is a miner's noise dose calculated?
62.121  How is dose converted to 8-hour time-weighted averages?
62.122  Can a miner's dose measurement be adjusted to reflect the 
type of hearing protection being worn by the miner?
62.123  What are a mine operator's obligations to evaluate miner 
noise exposure?
62.124  When must miners and/or their representatives be notified of 
measured exposures?
62.130  What must a mine operator do whenever a miner's noise dose 
exceeds the action level?
62.131  What else must a mine operator do if a miner's noise dose 
exceeds the action level but remains below the PEL?
62.132  What else must a mine operator do if a miner's noise dose 
exceeds the PEL?
62.133  What is the highest sound level to which a miner may be 
lawfully exposed?

    The contents of several of these sections might be more clear if 
presented in a tabular format. This would be particularly useful where 
the mine operator may have choices or has to do more than one thing. An 
example involves the controls required at the action level. The current 
proposal, as it would appear in the Code of Federal Regulations, as 
paragraph (b) of proposed Sec. 62.120, is:

    (b) Action level. When a miner's noise exposure exceeds a 
TWA8 of 85 dBA during any workshift, or equivalently a dose of 
50%, the operator shall take the actions specified in paragraphs (b) 
(1) and (2) of this section and, at the request of the miner, also 
take the actions specified in paragraph (b)(3) of this section.
    (1) An operator shall provide the miner training that includes 
the instruction required by Sec. 62.130, at the time exposure 
exceeds the action level and every 12 months thereafter that 
exposure continues to exceed the action level.
    (2) An operator shall enroll the miner in a hearing conservation 
program which shall meet the requirements of Secs. 62.140 through 
62.190. Moreover, the operator shall, with respect to any miner 
enrolled in such program, provide hearing protection in accordance 
with the requirements of Sec. 62.125 until such time as a baseline 
audiogram has been obtained. If it takes more than 6 months to 
conduct the baseline audiogram, or if the miner is determined to 
have incurred an STS, the operator shall ensure that the hearing 
protection is provided to the miner and worn by the miner.
    (3) At the request of any miner, the operator shall provide 
hearing protection to the miner in accordance with the requirements 
of Sec. 62.125.

    The alternative format would appear, using the revised numbering 
and naming conventions from example 1, somewhat like the following:

62.131  What specifically must a mine operator do if a miner's noise 
dose exceeds the action level?

    If a miner's noise exposure exceeds a dose of 50% (a TWA8 of 
85 dBA):

------------------------------------------------------------------------
                You must                         Which means you        
------------------------------------------------------------------------
(a) Provide training...................  Provide a miner with the       
                                          training required by MSHA's   
                                          rules--                       
                                         (1) When his or her exposure   
                                          exceeds the action level; and 
                                         (2) Every 12 months thereafter 
                                          that his or her exposure      
                                          continues to exceed the action
                                          level.                        

[[Page 66362]]

                                                                        
(b) Enroll the miner in a hearing        (1) Offer the miner annual     
 conservation program.                    audiometric examinations that 
                                          comply with MSHA's rules for  
                                          hearing conservation programs;
                                          and                           
                                         (2) Provide a miner with       
                                          hearing protection until a    
                                          baseline audiogram has been   
                                          taken; and in the event that  
                                          will take more than 6 months  
                                          due to the needs to wait for a
                                          mobile test van, require the  
                                          miner to use the hearing      
                                          protector; and                
                                         (3) Provide a miner with       
                                          hearing protection, and       
                                          require its use, whenever an  
                                          STS is detected.              
(c) At the request of a miner, provide   Provide hearing protection in  
 the miner with hearing protection.       accordance with MSHA's rules. 
------------------------------------------------------------------------
MSHA's rules for training are discussed in Sec.  62.137. MSHA's rules   
  for hearing conservation programs are discussed in Secs.  62.140      
  through 62.190. MSHA's rules for hearing protection are discussed in  
  Sec.  62.135.                                                         

    MSHA has not yet consulted with the Office of the Federal Register 
on the specifics of such approaches; moreover, the examples noted above 
should not be considered as necessarily accurately representing the 
content of MSHA's proposed rule. These caveats notwithstanding, the 
Agency is interested in the potential of these approaches, and would 
welcome comment on these specific examples.
(35) Is MSHA Going To Provide Adequate Guidance Before Implementing the 
Rule?
    The Agency plans to take several steps toward this end.
    First, the Agency is proposing that the new standard not take 
effect until one year after the date of publication of the final rule. 
This should provide time to train MSHA personnel and provide mine 
operators with technical assistance and guidance. An alternative would 
be to phase in the new requirements. The Agency believes some could be 
phased in quickly, but wants to avoid confusion. The Agency requests 
comment on whether a phased-in approach is appropriate and how it might 
most effectively be designed.
    In addition, the Agency is committed to issuing a compliance guide 
for mine operators before a final rule takes effect. MSHA would welcome 
suggestions on matters that should be discussed in such a guide.
    MSHA would also welcome comments on other actions it could take to 
facilitate implementation, and in particular whether a series of 
workshops would be useful.
(36) Are There Special Enforcement Issues of Which the Mining Community 
Should Take Note?
    Question 13 addresses the question of what constitutes ``feasible'' 
engineering and administrative controls.
    Operators in the mining industry are aware that the Agency has 
traditionally not cited an operator for exceeding the PEL unless the 
Agency's measurement of noise shows that it exceeds a TWA8 of 92 
dBA. This provides adequate room to accommodate, in an enforcement 
context, any technical questions about MSHA's measurements. MSHA's 
citation policy does not, however, alter operator obligations of the 
rule, including those based on operator exposure readings.
    The Agency is interested in comment on whether the new final rule 
should include a provision requiring operators to develop a written 
plan in certain cases. At the present time, coal operators in violation 
of the PEL must submit for approval a plan for the administration of a 
continuing, effective program to assure compliance including provision 
for reducing environmental noise levels, hearing protectors, and 
audiograms. No such plans are provided in the metal and nonmetal 
sector. The proposed rule, which would establish a uniform approach to 
noise for both sectors, would eliminate the current coal requirement, 
because MSHA does not believe such plans need to be created every time 
an operator violates the PEL. The Agency recognizes, however, that 
achieving effective compliance in some cases would be furthered by the 
existence of a written plan. In particular, such plans may be 
appropriate when there is a history of multiple noise violations, or a 
failure to effectively abate. Such plans would include specific details 
on how operators will comply with the final rule; a failure to comply 
with the plan's specifications would be enforceable through MSHA's 
normal citation/order process. Making explicit provision in the 
standard for such plans would ensure clarity about the Agency's 
enforcement policy on noise.
    The Agency notes that in some cases the proposal would require 
operators to ensure certain miners wear hearing protection that is 
provided, and ensure certain miners take tests that are offered. 
Comment is welcome on how Agency personnel could distinguish these 
miners from others.

(B) Executive Order 12866

    In accordance with Executive Order 12866, MSHA has prepared a 
preliminary analysis of the estimated costs and benefits associated 
with the proposed revisions of the noise standards for coal and metal 
and nonmetal mines.
    The preliminary RIA containing this analysis is available from 
MSHA. MSHA welcomes comments on its analysis and methodology. The 
proposal would cost approximately $8.3 million and would save 765 
hearing impairment cases annually. The benefits are expressed in terms 
of cases of hearing impairment that can be avoided and have not been 
monetized. Although the Agency has attempted to quantify the benefits, 
it believes that monetization of these benefits would be difficult and 
inappropriate.
    Based upon the economic analysis, MSHA has determined that this 
rule is not an economically significant regulatory action pursuant to 
section 3(f)(1) of Executive Order 12866. The Agency does consider this 
rulemaking significant under section 3(f)(4) of the Executive Order for 
other reasons, and has so designated the rule in its annual agenda. 
This means that while the Office of Management and Budget was provided 
an opportunity to review this proposal and the preliminary RIA (as 
discussed in the History section of this preamble), specific 
determinations of the costs and benefits are not required pursuant to 
section 6(a)(3)(C) of the Executive Order.

(C) Paperwork Reduction Act

    This proposed rule contains information collections which are 
subject to review by the Office of Management and Budget (OMB) under 
the Paperwork Reduction Act of 1995 (PRA95). The title, description, 
and respondent description of the information collection are shown 
below with an estimate of the annual reporting burden. Included in the 
estimate is the time for reviewing instructions, gathering and 
maintaining the data needed, and completing and reviewing the 
collection of information. With respect to the following collection of 
information, MSHA invites comments on: (1) Whether the proposed 
collection of information is necessary for proper performance of MSHA's 
functions, including whether the information will have practical 
utility; (2) the accuracy of MSHA's estimate of the burden of the 
proposed collection of information, including the validity of the 
methodology and assumptions used; (3) ways to enhance the quality, 
utility, and

[[Page 66363]]

clarity of information to be collected; and (4) ways to minimize the 
burden of the collection of information on respondents, including 
through the use of automated collection techniques, when appropriate, 
and other forms of information technology.
    These estimates are an approximation of the average time expected 
to be necessary for a collection of information. They are based on such 
information as is available to MSHA.
Submission
    The Agency has submitted a copy of this proposed rule to OMB for 
its review and approval of these information collections. Interested 
persons are requested to send comments regarding this information 
collection, including suggestions for reducing this burden, to the 
Office of Information and Regulatory Affairs, OMB New Executive Office 
Bldg., 725 17th St. NW., Rm. 10235, Washington, DC 20503, Attn: Desk 
Officer for MSHA. Submit written comments on the information collection 
not later than February 18, 1997.
Description of Respondents
    Those required to provide the information are mine operators and 
individuals who are paid to perform tasks for the mine operator (e.g., 
physicians reporting the results of audiograms to the mine operator).
Description
    The proposal contains information collection requirements in 
Secs. 62.120, 62.130, 62.140, 62.150, 62.160, 62.170, 62.180, 62.190, 
62.200, and 62.210. The following chart presents the paperwork 
requirements by section.

       Net Information Collection Burden Hours by Proposed Section      
------------------------------------------------------------------------
                                Paperwork requirement and               
          Section                   associated tasks            Hours   
------------------------------------------------------------------------
62.120.....................  Evaluate miners' noise            (135,250)
                              exposure; notify miner of                 
                              overexposure; prepare and                 
                              post administrative controls;             
                              give miners copy of                       
                              administrative controls.                  
62.130.....................  Prepare and file a training          10,270
                              certification.                            
62.140.....................  Perform audiograms; notify           69,930
                              miners to appear for testing              
                              and need to avoid high noise.             
62.150.....................  Compile an audiometric test           9,175
                              record; obtain a                          
                              certification.                            
62.160.....................  Provide information and              21,350
                              audiometric test record;                  
                              perform audiometric retests.              
62.170.....................  Perform otological evaluations        1,045
                              and provide information and               
                              notice.                                   
62.180.....................  Prepare a training                      700
                              certification for retrained               
                              miners; review effectiveness              
                              of engineering and                        
                              administrative controls.                  
62.190.....................  Inform miner of test results;         6,300
                              inform miner of STS.                      
62.200.....................  Provide access to records.....        1,255
62.210.....................  Transfer records..............          235
                                                            ------------
      Total................  ..............................     (14,985)
------------------------------------------------------------------------


    These paperwork requirements have been submitted to the Office of 
Management and Budget (OMB) for review under section 3504(h) of the 
Paperwork Reduction Act of 1995 (PRA 95). Respondents are not required 
to respond to any collection of information unless it displays a 
currently valid OMB control number.
    The following chart summaries MSHA's estimates by section in 
tabular form. Data is distributed by commodity. All numbers have been 
rounded.


          Net Information Collection Burden Hours by Commodity          
------------------------------------------------------------------------
                                                                Metal/  
                     Task                           Coal       nonmetal 
------------------------------------------------------------------------
62.120  Limitations on Noise Exposure.........    (140,545)        5,295
62.130  Training..............................        4,000        6,270
62.140  Audiometric Testing Program...........       30,655       39,275
62.150  Audiometric Test Procedures...........        3,930        5,245
62.160  Evaluation of Audiograms..............        9,340       12,015
62.170  Followup Evaluation...................          475          570
62.180  Followup Corrective Measures..........          335          365
62.190  Notification of Results...............        2,715        3,585
62.200  Access to Records.....................          255        1,000
62.210  Transfer of Records...................          100          135
                                               -------------------------
      Total (discrepancies due to rounding)...     (88,740)       73,755
------------------------------------------------------------------------

    Alternatively, the paperwork hours may be distributed between small 
and large mines. The following table provides this analysis. Small 
mines are those with less than 20 employees.

          Net Information Collection Burden Hours by Mine Size          
------------------------------------------------------------------------
                     Task                          Small        Large   
------------------------------------------------------------------------
62.120  Limitations on Noise Exposure.........     (15,510)    (119,740)
62.130  Training..............................        2,965        7,305
62.140  Audiometric Testing Program...........       19,270       50,660
62.150  Audiometric Test Procedures...........        2,885        6,290
62.160  Evaluation of Audiograms..............        6,185       15,170
62.170  Followup Evaluation...................          250          800
62.180  Followup Corrective Measures..........          160          540

[[Page 66364]]

                                                                        
62.190  Notification of Results...............        1,935        4,365
62.200  Access to Records.....................          500          755
62.210  Transfer of Records...................          185           50
                                               -------------------------
      Total (discrepancies due to rounding)...       18,825     (33,805)
------------------------------------------------------------------------

    Metal/nonmetal mines would incur 75,080 burden hours under the 
proposal and coal mines would incur 55,675 hours. For metal/nonmetal 
mines, the existing burden is 1,325 hours as defined and calculated 
under PRA 95; this makes the net burden for metal/nonmetal mines 73,755 
hours. For coal mines, the net burden is 88,740 fewer hours than the 
existing burden as calculated under PRA 95. The proposal would result 
in a net decrease of 14,985 burden hours associated with information 
collection from that associated with the current requirements. It 
should be noted that the existing burden hours are currently approved 
in three separate paperwork packages and reflect burden hours 
calculated under the provisions of the 1980 Paperwork Reduction Act 
(PRA 80). MSHA is in the process of updating and combining these three 
packages. The Agency's official paperwork submission accompanying this 
proposal includes a chart comparing the existing burden hours under PRA 
80, the existing burden hours under PRA 95, and the proposed burden 
hours under PRA 95.
    Additional detail is presented in the charts that follow. These 
charts provide annual and annualized paperwork burden hours as measured 
by PRA 95. Burden hours for tasks which predominantly would occur in 
the first year only, dose determination and notification, are presented 
in annualized form. Proposed Secs. 62.140(b)(3), 62.250 (b) and (c), 
62.160 (a)(1) and (a)(3), 62.170 (b) and (c), 62.180(a), 62.190 (a)(1) 
and (a)(2), 62.200(b) and 62.210(a) are anticipated to require the 
paperwork burden of the mine operator providing instructions to the 
clerical worker. This burden is included in the total hours per 
regulation column.

--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                             Number of                      Maintenance                 
               Regulation                    Number of       Hours per       Number of     responses per    Total hours    and operating    Annualized  
                                            respondents      response        responses      respondent    per regulation       costs       capital costs
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                             Small Metal and Nonmetal Mines                                                             
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                                                        
    62.120(f)(1)........................           6,218            2.00             n/a             n/a           3,530        $597,922      $1,315,604
    62.120(f)(2)........................           6,218            0.08          35,300               6             490           1,253               0
    62.120(c)(1)........................              18            1.75              18               1              25               0               0
    62.120(c)(1)........................              18            0.05             103               5               5              26               0
    62.130(b)...........................           6,218            0.05          35,300               6           2,385           8,825               0
    62.140(b)(1)........................           2,430            1.00          13,779               6          13,780         413,370               0
    62.140(b)(3)........................           2,430            0.08          13,779               6           1,345           3,445               0
    62.150(b)...........................           2,430            0.08          13,779               6           1,345           3,445               0
    62.150(c)...........................           2,430            0.05          13,779               6             930           3,445               0
    62.160(b)(1)........................             300            1.50           1,720               6           2,585          86,000               0
    62.160(a)(1)........................           2,430            0.08          13,779               6           1,345           3,445               0
    62.160(a)(3)........................           2,430            0.05          13,779               6             930           3,445               0
    62.170(a)...........................              15            2.00              90               6             180          22,500               0
    62.170(b)...........................              15            0.08              90               6               9              23               0
    62.170(c)...........................              15            0.08              90               6               9              23               0
    62.180(a)...........................             320            0.05           1,808               6              90             452               0
    62.180(c)...........................              15            2.00              15               1              20               0               0
    62.190(a)(1)........................           2,430            0.08          13,779               6           1,345           3,445               0
    62.190(a)(2)........................             320            0.08           1,812               6             180           1,461               0
    62.200(b)...........................              60            0.10           4,374              12             440           1,094               0
    62.210(a)...........................             361            0.25             361               1             125               0               0
    Monitoring (existing)...............           1,705            2.00             n/a             n/a             970         163,953         360,744
                                                                                                                                                        
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                             Large Metal and Nonmetal Mines                                                             
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                                                        
    62.120(f)(1)........................           1,023            5.00             n/a             n/a           1,455         $98,372        $216,446
    62.120(f)(2)........................           1,023            0.08          75,700              75             875           2,687               0
    62.120(c)(1)........................              40            2.25              40               1              90               0               0
    62.120(c)(1)........................              40            0.05           2,972              70             150             726               0
    62.130(b)...........................           1,023            0.05          75,700              75           3,885          18,925               0
    62.140(b)(1)........................             301            1.00          22,328              75          22,330         669,840               0
    62.140(b)(3)........................             301            0.08          22,328              75           1,820           5,582               0
    62.150(b)...........................             301            0.08          22,328              75           1,820           5,582               0
    62.150(c)...........................             301            0.05          22,328              75           1,150           5,582               0
    62.160(b)(1)........................              40            1.50           2,790              70           4,185         139,500               0
    62.160(a)(1)........................             301            0.08          22,328              70           1,820           5,582               0
    62.160(a)(3)........................             301            0.05          22,328              70           1,150           5,582               0
    62.170(a)...........................               2            2.00             174              85             344          43,500               0
    62.170(b)...........................               2            0.08             174              85              15              44               0

[[Page 66365]]

                                                                                                                                                        
    62.170(c)...........................               2            0.08             174              85              15              44               0
    62.180(a)...........................              50            0.05           3,490              70             175             873               0
    62.180(c)...........................              35            2.25              35               1              80               0               0
    62.190(a)(1)........................             301            0.08          22,328              75           1,820           5,582               0
    62.190(a)(2)........................              40            0.08           2,965              70             240             742               0
    62.200(b)...........................              10            0.10           5,601             560             560           1,400               0
    62.210(a)...........................              10            1.00              10               1              10               0               0
    Monitoring (existing)...............             250            5.00             n/a             n/a             355          24,040          52,895
                                                                                                                                                        
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                    Small Coal Mines                                                                    
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                                                        
    62.120(f)(1)........................           1,255            2.00             n/a             n/a             715        $120,681        $265,533
    62.120(f)(2)........................           1,255            0.08           9,020               7             120             320               0
    62.120(c)(1)........................              20            1.75              20               1              30               0               0
    62.120(c)(1)........................              20            0.05             173               7              10              43               0
    62.130(b)...........................           1,255            0.05           9,020               7             580           2,255               0
    62.140(b)(1)........................             536            1.00           3,851               7           3,851         115,530               0
    62.140(b)(3)........................             536            0.08           3,851               7             360             963               0
    62.150(b)...........................             536            0.08           3,851               7             360             963               0
    62.150(c)...........................             536            0.05           3,851               7             250             963               0
    62.160(b)(1)........................              70            1.50             480               7             720          24,050               0
    62.160(a)(1)........................             536            0.08           3,851               7             360           1,926               0
    62.160(a)(3)........................             536            0.05           3,851               7             250               0               0
    62.170(a)...........................               4            2.00              24               6              48           6,000               0
    62.170(b)...........................               4            0.08              24               6               2               6               0
    62.170(c)...........................               4            0.08              24               6               2               6               0
    62.180(a)...........................              60            0.05             507               8              25             127               0
    62.180(c)...........................              20            1.25              20               1              25               0               0
    62.190(a)(1)........................             536            0.05           3,851               7             360             963               0
    62.190(a)(2)........................              73            0.05             505               7              50             126               0
    62.200(b)...........................              15            0.10             610              40              60             131               0
    62.210(a)...........................             160            0.25             160               1              60               0               0
    Monitoring (existing)...............           1,762            0.50          25,334              14          12,670         357,492         169,434
    Audiograms (existing)...............              35            1.00              74               2              70           2,220               0
    Supplemental Noise Survey...........             420            0.05             840               2           (120)               0               0
    Supplemental Noise Survey...........             420            0.25           5,980              14         (2,990)               0               0
    Written HCP.........................              90            6.00              90               1           (535)               0               0
    Calibration Reports.................           1,762            0.25           1,762               1           (440)               0               0
    Survey Reports......................           1,762            0.05           1,762               1            (90)               0               0
    Monitoring Records..................           1,762            0.10          25,334              14         (2,530)               0               0
    Survey Certificates.................           1,762            0.05           1,762               1            (90)               0               0
                                                                                                                                                        
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                    Large Coal Mines                                                                    
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                                                        
    62.120(f)(1)........................             890            5.00             n/a             n/a           1,265         $85,582        $188,306
    62.120(f)(2)........................             890            0.08          66,667              75             770           2,367               0
    62.120(c)(1)........................              45            2.25              45               1              75           1,309               0
    62.120(c)(1)........................              45            0.05           5,237              75             290               0               0
    62.130(b)...........................             890            0.05          66,667              75           3,420          16,667               0
    62.140(b)(1)........................             334            1.00          25,007              75          25,007         750,210               0
    62.140(b)(3)........................             334            0.08          25,007              75           2,035           6,252               0
    62.150(b)...........................             334            0.08          25,007              75           2,035           6,252               0
    62.150(c)...........................             334            0.05          25,007              75           1,285           6,252               0
    62.160(b)(1)........................              40            1.50           3,126              80           4,690         156,300               0
    62.160(a)(1)........................             334            0.08          25,007              80           2,035           6,252               0
    62.160(a)(3)........................             334            0.05          25,007              80           1,285           6,252               0
    62.170(a)...........................               3            2.00             196              65             392          49,000               0
    62.170(b)...........................               3            0.08             196              65              16              49               0
    62.170(c)...........................               3            0.08             196              65              16              49               0
    62.180(a)...........................             400            0.05           3,908              35             195             977               0
    62.180(c)...........................              40            2.25              40               1              90               0               0
    62.190(a)(1)........................             334            0.05          25,007              75           2,035           6,252               0
    62.190(a)(2)........................              40            0.05           3,322              80             270             831               0
    62.200(b)...........................              10            0.10           1,934             194             195             484               0
    62.210(c)...........................              40            1.00              40               1              40               0               0
    Monitoring existing.................           1,134            0.50         169,424             150          84,710         230,077         239,932
    Audiograms (existing)...............               6            1.00             542              90             540               0               0

[[Page 66366]]

                                                                                                                                                        
    Supplemental Noise Survey...........             293            0.05          43,712             150        (21,860)               0               0
    Supplemental Noise Survey...........             293            0.25             293               1            (40)               0               0
    Written HCP.........................              67            6.00              67               1           (405)               0               0
    Calibration Reports.................           1,134            0.25           1,134               1           (280)               0               0
    Survey Reports......................           1,134            0.05           1,134               1            (60)               0               0
    Monitoring Records..................           1,134            0.10         169,424             150        (16,940)               0               0
    Survey Certificates.................           1,134            0.05           1,134               1            (60)               0               0
--------------------------------------------------------------------------------------------------------------------------------------------------------

(D) Regulatory Flexibility Act

    In accordance with Sec. 605 of the Regulatory Flexibility Act 
(RFA), the Mine Safety and Health Administration certifies that the 
noise proposal does not have a significant economic impact on a 
substantial number of small entities. MSHA considers small mines to be 
mines with fewer than 20 employees. However, for the purposes of the 
RFA and this certification, MSHA has also evaluated the impact of the 
proposal on mines up to and including those with fewer than 500 
employees. No small governmental jurisdictions or nonprofit 
organizations are affected. Under the Small Business Regulatory 
Enforcement Fairness Act (SBREFA) amendments to the RFA, MSHA must 
include in the proposal a factual basis for this certification. The 
Agency also must publish the regulatory flexibility certification 
statement in the Federal Register, along with the factual basis, 
followed by an opportunity for comment by the public. The Agency has 
consulted with the Small Business Administration (SBA) Office of 
Advocacy and believes that this analysis provides a reasonable basis 
for the certification in this case.
    MSHA specifically solicits comment on the Agency's determination in 
this regulatory flexibility certification statement, including cost 
data and data sources. To facilitate the public participation in the 
rulemaking process, MSHA will mail a copy of the proposed rule, 
including the preamble and regulatory flexibility certification 
statement, to every mine operator.
Factual Basis for Certification
    The Agency has used a quantitative approach in concluding that the 
proposed rule does not have a significant impact on a substantial 
number of small entities. The Agency performed its analysis separately 
for two groups of mines: the coal mining sector as a whole, and the 
metal and nonmetal mining sector as a whole. Based on a review of 
available sources of public data on the mining industry, the Agency 
believes that a quantitative analysis of the impacts on various mining 
subsectors (i.e., beyond the 4-digit SIC level) may not be feasible. 
The Agency requests comments, however, on whether there are special 
circumstances that warrant separate quantification of the impact of 
this proposal on any mining subsector, and information on how it might 
readily obtain the data necessary to conduct such a quantitative 
analysis. The Agency is fully cognizant of the diversity of mining 
operations in each sector, and has applied that knowledge as it 
developed the proposal.
    Under the RFA, MSHA must use the SBA definition for a small mine of 
500 employees or fewer or, after consultation with the SBA Office of 
Advocacy, establish an alternative definition for the mining industry 
by publishing that definition in the Federal Register for notice and 
comment. The alternative definition could be the Agency's traditional 
definition of ``fewer than 20 miners,'' or some other definition. As 
reflected in the certification, MSHA analyzed the costs of this 
proposal for small and large mines using both the traditional Agency 
definition, and SBA's definition, as required by RFA, of a small mine. 
The Agency compared the costs of the proposal for small mines in each 
sector to the revenues and profits for each sector for every size 
category analyzed. In each case, the results indicated that the costs 
as a percent of revenue are less than 1%. Further, the costs do not 
appear to have any appreciable impact on profits.
    The following table summarizes the results of this analysis for 
mines which employ fewer than 500 miners, at various sizes.

                                                   Small Mines: Costs Compared to Revenues and Profits                                                  
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                         Total                                          
                                                                Estimated    Estimated     Average     estimated    Estimated    Cost as %    Cost as % 
                                                                  costs       revenue    profit as %    profits      cost per    of revenue   of profit 
                                                                 (thous.)    (millions)   of revenue   (millions)   small mine                          
--------------------------------------------------------------------------------------------------------------------------------------------------------
Coal Mines:                                                                                                                                             
    Small <20................................................        ($45)         $855         3.82          $33        ($26)        -0.01        -0.14
    Large >=20...............................................          332       19,094         3.82          729          293         0.00         0.05
     Small <50...............................................          586        3,542         3.82          135          237         0.02         0.43
    Large >=50...............................................        (300)       16,408         3.82          627        (709)         0.00        -0.05
    Small <100...............................................          832        6,061         3.82          232          309         0.01         0.36
    Large >=100..............................................        (545)       13,888         3.82          531      (2,684)         0.00        -0.10
    Small <250...............................................          677       12,624         3.82          482          240         0.01         0.14
    Large >=250..............................................        (391)        7,326         3.82          280      (5,140)        -0.01        -0.14
    Small <500...............................................          382       19,117         3.82          730          132         0.00         0.05
    Large >=500..............................................         (95)          831         3.82           32      (8,660)        -0.01        -0.30
M/NM Mines:                                                                                                                                             
    Small <20................................................        4,437       11,929         4.55          543          479         0.04         0.82
    Large >=20...............................................        3,600       26,071         4.55        1,186        2,324         0.01         0.30
    Small <50................................................        5,731       18,814         4.55          856          557         0.03         0.67
    Large >=50...............................................        2,306       19,186         4.55          873        4,359         0.01         0.26

[[Page 66367]]

                                                                                                                                                        
    Small <100...............................................        6,323       23,047         4.55        1,049          599         0.03         0.60
    Large >=100..............................................        1,714       14,953         4.55          680        6,418         0.01         0.25
    Small <250...............................................        7,037       29,558         4.55        1,345          655         0.02         0.52
    Large >=250..............................................        1,000        8,442         4.55          384       14,492         0.01         0.26
    Small <500...............................................        7,571       32,134         4.55        1,462          702         0.02         0.52
    Large >=500..............................................          466        5,866         4.55          267       17,249         0.01         0.17
--------------------------------------------------------------------------------------------------------------------------------------------------------

    In determining revenues for coal mines, MSHA multiplied coal 
production data (in tons) for mines in specific size categories 
(reported to MSHA quarterly) by the average price per ton (from the 
Department of Energy, Energy Information Administration, Annual Energy 
Review 1995). For metal and nonmetal mines, the Agency estimated 
revenues for specific mine size categories as the proportionate share 
of these mines' contribution to the Gross National Product (from the 
Department of the Interior, former Bureau of Mines, Mineral Commodity 
Summaries 1996). Average profit as a percent of revenue for both coal 
mines and metal and nonmetal mines comes from Dun & Bradstreet 
Information Services, Industry Norms & Key Business Ratios, 1993-94.
    Based on the information in the Agency's preliminary Regulatory 
Impact Analysis (summarized in the ``costs'' table in the Question and 
Answer section of this preamble), the costs of the proposal for all 
metal and nonmetal mines with fewer than 20 employees would be $4.6 
million; the average cost of the proposal for a small metal and 
nonmetal mine with fewer than 20 employees is about $500. The average 
cost of the proposal for a small metal and nonmetal mine with fewer 
than 500 employees is about $700. For small coal mines with fewer than 
20 employees, the proposal is estimated to result in a small net 
savings of about $30. This savings results from the proposed 
elimination of a substantial paperwork burden that now exists in the 
coal mine sector for monitoring miners' noise exposures. For small coal 
mines with fewer than 500 employees, the proposal is estimated to 
result in a small net cost of about $130.
Regulatory Alternatives Rejected
    The limited impacts on small mines, regardless of size definition, 
reflect decisions by MSHA not to propose more costly regulatory 
alternatives. In considering regulatory alternatives for small mines, 
MSHA must observe the requirements of its authorizing statute. Section 
101(a)(6)(A) of the Mine Act requires the Secretary to set standards 
which most adequately assure, on the basis of the best available 
evidence, that no miner will suffer material impairment of health over 
his/her working lifetime. In addition, the Mine Act requires that the 
Secretary, when promulgating mandatory standards pertaining to toxic 
materials or harmful physical agents, consider other factors, such as 
the latest scientific data in the field, the feasibility of the 
standard and experience gained under the Act and other health and 
safety laws. Thus, the Mine Act requires that the Secretary, in 
promulgating a standard, attain the highest degree of health and safety 
protection for the miner, based on the ``best available evidence,'' 
with feasibility as a consideration.
    As a result of this statutory requirement, MSHA seriously 
considered two alternatives that would have significantly increased 
costs for small mine operators--lowering the PEL to a TWA8 of 85 
dBA, and lowering the exchange rate to 3 dB. In both cases, the 
scientific evidence in favor of these approaches was strong. But in 
both cases, for the purpose of this proposal, MSHA has concluded that 
it may not be feasible for the mining industry to accomplish these more 
protective approaches. The impact of these approaches on small mine 
operators was an important consideration in this regard. Part IV of 
this preamble contains a full discussion of MSHA's preliminary 
conclusions about these alternatives. The public is invited to propose 
other alternatives for consideration.
Paperwork Impact
    In accordance with the Regulatory Flexibility Act and the Paperwork 
Reduction Act of 1995 (PRA 95), MSHA has analyzed the paperwork burden 
for small mines. While the proposal results in a net paperwork burden 
decrease for all mines, it results in an increase in paperwork hours. 
For mines with fewer than 20 miners the proposal would result in an 
increase of about 18,800 hours, and with fewer than 500 miners it would 
result in a decrease of about 14,985 hours. The bulk of the new hours 
(greater than 80%) is derived from the audiometric testing program and 
procedures. While mines with fewer than 20 employees in the coal and 
metal and nonmetal sectors will have extra burden hours associated with 
new requirements, the net burden hours for small coal mines are 
actually reduced, because the proposal would eliminate current 
requirements for biannual noise surveys and other miscellaneous reports 
and surveys in that sector. However, at this size level, there are more 
metal and nonmetal mines than there are coal mines. Thus, at this size 
level, the proposal would result in a net gain in paperwork burdens.
    As required by PRA 95, MSHA has included in its paperwork burden 
estimates the time needed to perform tasks associated with information 
collection. For example, the proposed rule requires a mine operator to 
notify a miner if the miner's noise exposure exceeds the action level. 
In order to determine if notification is necessary, the mine operator 
must perform dose determination monitoring. Although completion of the 
notification would take 0.05 hour on average, the time for dose 
determination must be included in the burden estimate according to the 
new paperwork law. The proposal's average paperwork burden per small 
metal and nonmetal mine is 4.8 hours and per small coal mine is 6 hours 
per year.
Other Relevant Matters
    In accordance with the Small Business Regulatory Enforcement 
Fairness Act (SBREFA), MSHA is taking actions to minimize the 
compliance burden on small mines. As discussed in the ``Questions and 
Answers'' section of this preamble, MSHA is committed to writing the 
final rule in plain English, so that it can be easily understood by 
small mine operators. The proposed effective date of the rule would be 
a year after final promulgation, to provide adequate time for small 
mines to achieve compliance. Also, as stated

[[Page 66368]]

previously, MSHA will mail a copy of the proposed rule to every mine 
operator which primarily benefits small mine operators. The Agency has 
committed itself to issuance of a compliance guide for all mines, and 
has invited comment on whether compliance workshops or other such 
approaches would be valuable.
    MSHA is considering whether to continue to use ``fewer than 20 
miners'' as the definition of a small mine for purposes of the 
Regulatory Flexibility Act (RFA). For this rulemaking's Regulatory 
Flexibility Analysis, the Agency is using fewer than 20 employees, in 
addition to the SBA's definition of fewer than 500, as required by the 
RFA. MSHA presently is consulting with the SBA Office of the Chief 
Counsel for Advocacy in order to determine an appropriate definition to 
propose to the public for comment in the future. For purposes of this 
proposed rule on noise, MSHA has continued its past practice of using 
``under 20 miners'' as the appropriate point of reference, in addition 
to SBA's definition. Reviewers will note that the paperwork and cost 
discussions continue to refer to the impacts on ``small'' mines with 
fewer than 20 employees. The Agency has not established a definition of 
``small entity'' for purposes of the final rule. Based on this 
analysis, MSHA concludes that whatever definition of ``small entity'' 
is eventually selected, the proposed noise rule does not have a 
significant economic impact on a substantial number of small entities.

(E) Unfunded Mandates Act

    MSHA has determined that, for purposes of Sec. 202 of the Unfunded 
Mandates Reform Act of 1995, this proposal does not include any Federal 
mandate that may result in increased expenditures by State, local, or 
tribal governments in the aggregate of more than $100 million, or 
increased expenditures by the private sector of more than $100 million. 
Moreover, the Agency has determined that for purposes of Sec. 203 of 
that Act, this proposed rule does not significantly or uniquely affect 
small governments.
Background
    The Unfunded Mandates Reform Act was enacted in 1995. While much of 
the Act is designed to assist the Congress in determining whether its 
actions will impose costly new mandates on State, local, and tribal 
governments, the Act also includes requirements to assist Federal 
agencies to make this same determination with respect to regulatory 
actions.
Analysis
    Based on the analysis in the Agency's preliminary Regulatory Impact 
Statement (summarized in the ``cost'' table in the Questions and 
Answers section of this preamble), the cost of this proposed rule for 
the entire mining industry is less than $10 million. Accordingly, there 
is no need for further analysis under Sec. 202 of the Unfunded Mandates 
Reform Act.
    MSHA has concluded that small governmental entities are not 
significantly or uniquely impacted by the proposed regulation. The 
proposed rule will impact approximately 14,000 coal and metal and 
nonmetal mining operations; however, increased costs would be incurred 
only by those operations where noise exposures exceed the allowable 
limits. MSHA estimates that approximately 350 sand and gravel or 
crushed stone operations are run by state, local, or tribal governments 
and would be impacted by this rule. MSHA anticipates that these 
entities would be able to reduce noise exposure below the PEL via 
engineering and administrative controls and would not need to use a 
Hearing Conservation Program, thereby minimizing their costs. MSHA 
estimates that increased costs for these entities would be about $500 
per year which would be partially offset by reduced worker compensation 
costs. Other tangible benefits include reduction in the number of cases 
of hearing impairment in these entities.
    When MSHA issues the proposed rule, the Agency will affirmatively 
seek input of any state, local, and tribal government which may be 
affected by the noise rulemaking. This would include state and local 
governmental entities who operate sand and gravel mines in the 
construction and repair of highways and roads. MSHA will mail a copy of 
the proposed rule to approximately 350 such entities.
    Following is MSHA's state-by-state listing of sand and gravel mines 
owned or operated by state or local governments.
    The Agency welcomes any corrections.

         State/County Owned/Operated Sand and Gravel Operations         
                            [As of 12/08/95]                            
------------------------------------------------------------------------
                                                State    County    City 
                    State                       owned    owned    owned 
------------------------------------------------------------------------
ARIZONA......................................        2        2  .......
ARKANSAS.....................................  .......        5  .......
CALIFORNIA...................................  .......        4  .......
COLORADO.....................................        4       27  .......
IDAHO........................................  .......       13  .......
ILLINOIS.....................................  .......        2  .......
INDIANA......................................  .......        5  .......
IOWA.........................................  .......        2  .......
KANSAS.......................................  .......        2  .......
MAINE........................................        5  .......  .......
MARYLAND.....................................  .......  .......        6
MICHIGAN.....................................  .......        8  .......
MISSISSIPPI..................................  .......        5  .......
MISSOURI.....................................  .......        8  .......
MONTANA......................................        8       34  .......
NEBRASKA.....................................  .......        2  .......
NEVADA.......................................  .......        1  .......
NEW MEXICO...................................  .......        4  .......
NEW YORK.....................................  .......       15       95
OKLAHOMA.....................................  .......        2  .......
OREGON.......................................  .......       11  .......
PENNSYLVANIA.................................  .......  .......        1
SOUTH CAROLINA...............................  .......        1  .......
SOUTH DAKOTA.................................  .......       15  .......
TENNESSEE....................................  .......        3  .......
TEXAS........................................  .......        6  .......
UTAH.........................................        1        5  .......
VERMONT......................................  .......  .......       11
WASHINGTON...................................  .......        9  .......
WISCONSIN....................................  .......       20        1
WYOMING......................................  .......        1  .......
                                              --------------------------
      Total 346..............................       20      212      114
------------------------------------------------------------------------

(F) Rulemaking History

    MSHA's noise standards in metal and nonmetal mines (30 CFR 56/
57.5050) and in coal mines (Secs. 70.500 through 70.511, and 
Secs. 71.800 through 71.805) were first published in the early 1970's. 
These standards, derived from the Walsh-Healey Public Contracts Act 
occupational noise standard, adopted a TWA8 PEL of 90 dBA and a 5-
dB exchange rate.
    Because of the differences between the standards for coal mines and 
those for metal and nonmetal mines, members of the mining community 
with operations in coal and metal and nonmetal requested that MSHA 
revise its standards to provide one set of noise standards covering all 
mines. Other mine operators with facilities regulated by both MSHA and 
OSHA suggested that MSHA promulgate noise standards which are generally 
consistent with OSHA standards. The United Mine Workers also requested 
that the Agency reconsider the existing standards to address several 
asserted deficiencies.
    Based on these comments and the incidence of noise-induced hearing 
loss (NIHL) among miners, the Agency published an Advanced Notice of 
Proposed Rulemaking (ANPRM) on December 4, 1989 (54 FR 50209). In this

[[Page 66369]]

ANPRM, the Agency solicited information for revision of the noise 
standards for coal and metal and nonmetal mines. The Agency received 
numerous comments which are reflected in this proposal from mine 
operators, trade associations, labor groups, equipment manufacturers, 
and other interested parties.
    A draft of the proposed rule and accompanying analyses was sent to 
the Office of Management and Budget and to the Chief Counsel for 
Advocacy of the Small Business Administration, in accordance with law 
and Executive Order. Consultations with these two agencies were 
completed within 90 days. No substantive changes to the proposal were 
recommended during these consultations, nor were any made by MSHA. The 
Agency did receive valuable advice on the presentation of its initial 
Regulatory Flexibility Analysis and on displaying the results of its 
paperwork analysis, so as to better highlight the Agency's compliance 
with PRA 95 and SBREFA.
    In the Spring of 1996, the National Institute for Occupational 
Safety and Health (NIOSH) released for peer review a draft criteria 
document for occupational noise exposure to update the one issued in 
1972. As indicated previously (see response to Question 6 in 
``Questions and Answers''), MSHA has determined that it would not be 
appropriate to delay publication of this proposed rule to await the 
issuance of the final NIOSH criteria document.
    A summary of the draft criteria document, prepared by NIOSH, is 
reprinted here verbatim for those in the mining community who have not 
otherwise received copies. This summary should provide ample notice of 
the position NIOSH may be taking in a new criteria document.

April 16, 1996--(NIOSH) Summary of Recommendations, Criteria for a 
Recommended Standard: Occupational Noise Exposure

1. Hearing Impairment and Risk Assessment

    The protection goal incorporated in most definitions of hearing 
impairment has been to preserve hearing at critical audiometric 
frequencies for speech discrimination. Hearing impairment as defined 
by NIOSH in 1972 was an average of the hearing threshold levels 
(HTLs) at the audiometric frequencies of 1000, 2000 and 3000 Hertz 
(Hz) that exceeded 25 decibels (dB). The 4000-Hz audiometric 
frequency has been recognized as being not only sensitive to noise 
but also extremely important for hearing and understanding speech in 
unfavorable or noisy listening conditions. Because listening 
conditions are not always ideal in everyday life, and on the basis 
of the American Speech Language-Hearing Association Task Force's 
proposal made in 1981, NIOSH has modified its definition of hearing 
impairment to include the 4000-Hz audiometric frequency for use in 
assessing the risk of occupational NIHL. Hence, with this 
modification, NIOSH defines material hearing impairment as an 
average of the HTLs at 1000, 2000, 3000 and 4000 Hz that exceeds 25 
dB.
    Because of the prolific occupational use of hearing protectors 
since the early 1980's, new data that can be used to determine dose-
response relationships for NIHL in U.S. workers are not known to 
exist. NIOSH recently conducted a risk assessment on occupational 
noise-induced hearing loss (NIHL) using the original definition of 
hearing impairment and the hearing data from the 1972 criteria 
document. Although the risk model used in the new assessment is 
different from the risk model used in 1972, the excess risk 
estimates derived in the new assessment are comparable to those 
published in 1972. The excess risk at age 60 from a 40-year 
occupational exposure to an average daily noise level of 85 
decibels, a weighted network (dBA) is approximately 14%, versus the 
16% published in 1972. With the new NIOSH definition of hearing 
impairment, and based on the new risk assessment, the excess risk at 
the 85-dBA REL is 8%. Thus, the new risk assessment did not revise 
the excess risk at the 85-dBA REL upward, and although there is 
still evidence of excess risk at exposure levels below 85 dBA, NIOSH 
is recommending that the current REL be retained.

2. Exchange Rate

    Health effect outcomes are dependent on exposure level and 
duration. This relationship is called the ``exchange rate,'' which 
is the increment in decibels that requires the halving of exposure 
time. The most commonly used exchange rates are 3 dB and 5 dB. A 3-
dB exchange rate requires that noise exposure time be halved for 
each 3-dB increase in noise level; likewise, a 5-dB exchange rate 
requires that exposure time be halved for each 5-dB increase. NIOSH 
now recommends the 3-dB exchange rate. The 1972 criteria document 
recommended the 5-dB exchange rate, which is what OSHA and MSHA 
currently enforce. There is more scientific, although not 
unequivocal, support for the 3-dB exchange rate than for the 5-dB 
exchange rate, which is not based on scientific data and is derived 
from a series of over-simplifications of the original criteria. The 
3-dB exchange rate is recommended by the International Organization 
for Standardization (ISO), and it is now enforced by most European 
countries and some provinces of Canada. In the U.S., there have been 
recent ``converts'' to the 3-dB exchange rate: the U.S. Air Force in 
1993; and the American Conference of Governmental Industrial 
Hygienists and the U.S. Army in 1994.

3. Ceiling Limit

    In the 1972 criteria document, NIOSH recommended a ceiling limit 
of 115 dBA, which is retained in this draft criteria document. 
Exposures to noise levels greater than 115 dBA would not be 
permitted regardless of the duration of the exposure. This ceiling 
limit is based on the assumption that above a critical intensity 
level the ear's response to energy no longer has a relation to the 
duration of the exposure, but is only related to the intensity of 
the exposure. Recent research with animals indicates that the 
critical level is between 115 and 120 dBA. Below this critical 
level, the amount of hearing loss is related to the intensity and 
duration of exposure; but above this critical level, the 
relationship does not hold. For a noise standard to be protective, 
there should be a noise ceiling level above which no unprotected 
exposure is permitted. Given the recent data, 115 dBA is a 
reasonable ceiling limit beyond which no unprotected exposure should 
be permitted.

4. Hearing Protectors

    One consideration for selecting a hearing protector would be its 
noise reduction capabilities, which are expressed in terms of a 
noise reduction rating (NRR). The NRR is a single-number, 
laboratory-derived rating required by the Environmental Protection 
Agency (EPA) to be shown on the label of each hearing protector sold 
in the U.S. In the late 1970's and early 1980's, two NIOSH field 
studies found that insert-type hearing protectors in the field 
provided less than one-half the attenuation measured in the 
laboratory, and since the 1970's, 22 additional studies of ``real-
world'' attenuation with a variety of hearing protectors have shown 
similar results.
    In calculating the noise exposure to the wearer of a hearing 
protector, OSHA has implemented the practice of derating the NRR by 
one-half for all types of hearing protectors. In the 1972 criteria 
document, NIOSH recommended the use of the equivalent full NRR 
value, but now it recommends derating the NRR by 25%, 50% and 70% 
for earmuffs, formable earplugs and all other earplugs, 
respectively. This derating scheme is not perfect and is intended 
only as an interim recommendation. If the testing and labeling 
requirements for hearing protectors are to be changed, EPA must 
initiate the rulemaking procedures because it has the statutory 
authority. Given that the funding for EPA's Office of Noise 
Abatement and Control was eliminated in the early 1980's, this 
change is unlikely to occur in the near future.
    The draft also recommends that hearing protectors be worn for 
any noise exposure over 85 dBA, regardless of exposure duration. 
This measure is simplistic but extremely protective because its 
implementation does not require the calculation of time-weighted-
average (TWA) exposures. This ``hard-hat'' approach, as opposed to 
predicating the requirement on TWA exposures, is a departure from 
what was recommended in 1972. It appears to be a prudent policy, 
which the U.S. Army has been using for years, but there are no data 
in the document to support this recommendation.

5. Exposure Level Requiring a Hearing Loss Prevention Program

    In this draft document, the requirement for a hearing loss 
prevention program (HLPP), which includes audiometry, worker 
education, etc., is triggered by the exposure level of 82 dBA, 8-
hour TWA (i.e., \1/2\ of the REL). This level is essentially an 
``action level''--a concept developed in the mid-

[[Page 66370]]

 1970's to address interday exposure variability and later adopted 
in the Standards Completion Program as \1/2\ of an exposure limit. 
In the 1972 criteria document, which preceded the Standards 
Completion Program, the requirement for a HLPP began at the REL of 
85 dBA, 8-hour TWA.

6. Types and Frequency of Audiometric Examinations

    In this draft document, the recommended types (i.e., baseline, 
monitoring, confirmation and exit audiograms) and frequency of 
audiometric examinations are different from those in the 1972 
criteria document. The new recommendations are in line with current 
practices in HLPPs.

7. Significant Threshold Shift

    Significant threshold shift is a shift in hearing threshold 
levels, outside the range of audiometric testing variability 
(5 dB), that warrants follow-up action to prevent 
further hearing loss. NIOSH recommends an improved significant 
threshold shift criterion, which is an increase of 15 dB in hearing 
threshold at 500, 1000, 2000, 3000, 4000, or 6000 Hz that is 
repeated for the same ear and frequency in back-to-back tests. This 
criterion is different from that in the 1972 criteria document, and 
has been selected from among several criteria on the bases of their 
relative sensitivity and specificity. The new criterion has the 
advantages of a high identification rate (identifying those workers 
whose hearing thresholds have shifted toward higher levels) and a 
low false-positive rate.

8. Age Correction on Audiogram

    NIOSH recommends that age correction not be applied to an 
individual's audiogram for the calculation of a significant 
threshold shift. Although many people experience some decrease in 
hearing sensitivity with age, age correction cannot be accurately 
applied to audiograms in determining an individual's significant 
threshold shift because the data on age-related hearing losses 
describe only the statistical distributions in populations. Thus, 
the median hearing loss attributable to presbycusis for a given age 
group will not be generalizable to the presbycusis experienced by an 
individual in that age group. The argument for age correction has 
been that the employer should not be penalized for hearing losses 
due to ageing. In the 1972 criteria document, NIOSH recommended age 
correction but did not provide a rationale for it.

9. Evaluation of Program Effectiveness

    To assess the effectiveness of a HLPP, it is necessary to have 
an evaluation method that can monitor trends in the population of 
workers enrolled in the program and thus indicate program 
effectiveness before many individual shifts occur. In general, NIOSH 
suggests that the success of a smaller HLPP should be judged by the 
audiometric results of individual workers. An overall program 
evaluation becomes critical when the number of workers grows so 
large that one cannot simply look at each worker's audiometric 
results and get an adequate picture of the program's efficacy. At 
the present time, there is not one generally accepted method for the 
overall evaluation of HLPPs. NIOSH recommends a significant 
threshold shift incidence rate of 5% or less as evidence of an 
effective HLPP. This method is currently the simplest procedure 
available, and has no more disadvantages than other potential 
evaluation methods.

10. American National Standards Institute (ANSI)

    In the 1972 criteria document, NIOSH recommended several ANSI 
standards for quality assurance in audiometry and in noise 
measurements. Since then, these standards have been updated several 
times. In the draft document, NIOSH recommends that these standards 
be superseded with the latest versions as they become available. The 
major advantage for this ``blanket'' endorsement is that the revised 
criteria document will stay current with changing technology.

II. The Risks to Miners

    This part of the preamble sets out the evidence collected by MSHA 
to date with respect to whether there is a continuing risk to miners of 
exposure to harmful levels of noise, despite existing standards, and 
evidence on the level of that risk. Based upon this information, MSHA 
has concluded that workplace noise exposure does continue to pose a 
significant risk of material impairment of health and functional 
capacity to miners.
    The data presented in this part provide a profile of the mining 
population at risk at different levels of workplace noise exposure. The 
noise exposure limitations being proposed by the Agency, described in 
part III, would not eliminate the risk of material impairment--although 
they would cut the present risk by two-thirds. (The feasibility of 
further reducing risk is discussed in part IV. The data in this part II 
were utilized by the Agency to assist it in determining the cost to 
industry of reducing risk to various levels, and thus in reaching the 
Agency's conclusions about economic feasibility.)
    There are a number of technical terms used throughout this section. 
Reviewers not familiar with noise terminology should refer to the 
discussion in part III of this preamble concerning proposed 
Sec. 62.110, Definitions.
    All the studies discussed and cited in this part are included in 
the references listed in part V, along with similar studies reviewed by 
the Agency. All constitute part of the Agency's rulemaking record.
    The Agency is interested in receiving additional data with respect 
to the risks of noise exposure.

Defining the Problem

    Noise is one of the most pervasive health hazards in mining. 
Exposure to hazardous sound levels results in the development of 
occupational noise-induced hearing loss (NIHL), a serious physical, 
psychological, and social problem. NIHL can be distinguished from aging 
and medical factors, diagnosed, and prevented.
    The National Institute for Occupational Safety and Health (NIOSH) 
has identified the ten leading work-related diseases and injuries in 
the publication, ``Proposed National Strategies for the Prevention of 
Leading Work-Related Diseases and Injuries, Part 2.'' According to 
NIOSH, NIHL is among these ``top ten'' diseases and injuries.
    For many years, the risk of acquiring an NIHL was accepted as an 
inevitable consequence associated with mining occupations. Miners use 
mechanized equipment and work under conditions that often expose them 
to hazardous sound levels. But MSHA standards, OSHA standards, military 
standards, and others around the world have been established in 
recognition of the controllability of this risk. Quieter equipment, 
isolation of workers from noise sources, and limiting worker exposure 
times are among the many well accepted methods now used to reduce the 
costly incidence of NIHL.
    NIHL can be temporary or permanent depending on the intensity and 
duration of the noise exposure. Temporary hearing loss results from 
short term exposures to noise, with normal hearing returning after a 
period of rest. Generally, prolonged exposure to noise over a period of 
several years causes permanent damage to the auditory nerve: the higher 
the sound level the more rapid the loss. The loss may be so gradual, 
however, that a person may not realize that he or she is becoming 
impaired until a substantial amount of hearing acuity is lost.
    Damage to the inner ear hair cells and auditory nerve makes it 
difficult to hear as well as understand speech. This damage is 
irreversible. Although people with NIHL sometimes can benefit from the 
use of a hearing aid, the aid can never ``correct'' a hearing loss the 
way eyeglasses usually can correct impaired vision. That is because 
hearing aids primarily amplify sound without making it clearer or less 
distorted. Also, they amplify the unwanted noise as well as the wanted 
speech signals.
    People with significant NIHL have difficulty with the perception of 
speech. They are often frustrated by missing information that is vital 
for social or vocational functioning, and can produce workplace safety 
hazards. Also, people around them need to speak louder, and more 
clearly to be understood. In addition, background noise has a much more 
disruptive effect on hearing-

[[Page 66371]]

 impaired individuals because they are less able to differentiate 
between the wanted signal and the unwanted background noise.
    There is a wealth of information on the relationship between noise 
exposure and its auditory (hearing loss) and non-auditory 
(physiological and psychosocial) effects.
    Numerous studies are available which describe the effects of noise 
on hearing as a function of sound level and duration. Dose-response 
relationships have been well established for noise equal to or greater 
than average sound levels of 85 dBA (see, e.g., Lempert and Henderson, 
1973).
    Although the non-auditory effects of noise are more difficult to 
identify, document, and quantify than is hearing loss, recent 
laboratory and field studies have implicated noise as a causative 
factor in cardiovascular problems (Tomei et al., 1992 and Lercher et 
al., 1993) and other illnesses such as hypertension (Talbott, 1990, and 
Jansen, 1991). Decreasing the noise exposure from greater than 85 dBA 
to less than 85 dBA significantly improved both the psychological and 
physiological stress reactions (Melamed and Bruhis, 1996). However, 
these studies of health effects have not been conclusive.
    In Earlog 6, Berger (1981) discussed the adverse non-auditory 
effects of noise exposure. He suggests that effective hearing 
conservation programs may not only prevent NIHL, but also improve 
general employee health and productivity.
    Schmidt, et al. (1980) studied injury rates among workers in a 
North Carolina cotton manufacturer exposed to noise ranging from 92 to 
96 dBA. During the ten year time period studied, a significant 
reduction in injury rates was observed for those workers who were in an 
HCP, compared to those who were not.
    Safety risks can specifically be created because workers harmed by 
NIHL can no longer hear safety signals. Most people with an NIHL have 
reduced hearing acuity at the higher frequencies and lose their ability 
to distinguish consonants on which the intelligibility of speech 
depends. For example, they would have difficulty in distinguishing 
between ``fish'' and ``fist.''
    Although MSHA recognizes that non-auditory effects of noise can be 
significant, they are difficult to quantify; by contrast, the auditory 
risks have a well-established dose-response relationship, and thus 
provide a solid foundation on which to base regulatory action. The 
Agency believes that reducing sound levels and protecting miners from 
hazardous noise exposures will also reduce the non-auditory effects of 
noise.

Definition of Material Impairment

    Section 101(a)(6) of the Mine Safety and Health Act provides that 
in setting standards to protect workers from the risks of harmful 
physical agents, the Secretary ``shall set standards which most 
adequately assure on the basis of the best available evidence that no 
miner will suffer material impairment of health or functional capacity 
even if such miner has regular exposure to the hazards dealt with by 
such standard for the period of his working life.''
    While the material impairment to which the law refers is material 
impairment of ``health or functional capacity'', the term material 
impairment in the literature on noise risk generally refers to a level 
of harm which is considered handicapping or even disabling--a 25 dB 
hearing level (deviation from audiometric zero)--so this had to be the 
basis of MSHA's estimates of the risk of material impairment. The 
scientific community has actually utilized over time at least three 
different definitions of what constitutes ``material impairment'' in 
the case of NIHL. All use a 25 dB hearing level, but each definition 
has used a different set of frequencies. Of these, the Agency believes 
the one developed in 1972 by NIOSH and subsequently used by OSHA is 
most appropriate of the three for evaluating the risks faced by miners 
of developing disabling NIHL. The OSHA/NIOSH definition of material 
impairment of hearing is a 25 dB hearing level averaged over 1000, 
2000, and 3000 Hertz (Hz) in either ear. As noted in the History 
section of this preamble, the Agency is aware that NIOSH is currently 
considering a new definition that also includes hearing loss at 4000 
Hz; but until such an approach is peer reviewed and approved, MSHA 
believes it is not an appropriate basis for evaluating risk.
Background
    Ideally, a definition of material impairment based solely upon 
audiometric tests that measure individual ability to understand speech 
would best characterize the debilitating effects of an NIHL. 
Unfortunately, these tests are complicated, not well standardized, and 
therefore seldom used to determine hearing impairment. For these 
reasons, most definitions of impairment are based solely on pure tone 
audiometry.
    Pure tone audiometric tests utilize an audiometer to measure the 
hearing level threshold of an individual by determining the lowest 
level of discrete frequency tones that the individual can hear. The 
test procedures for conducting pure tone audiometry are relatively 
simple, widely used, and have been standardized. Although there is 
little debate among the scientific community about the usefulness of 
pure tone audiometry in assessing hearing loss, some disagreement 
exists as to the hearing level where hearing impairment begins and the 
range of audiometric frequencies to use in making the assessment.
    In issuing its Hearing Conservation Amendment (46 FR 4078), OSHA 
defined hearing impairment as exceeding a 25 dB ``hearing level'' 
averaged over 1000, 2000, and 3000 Hertz (Hz) in either ear. Hearing 
level is the deviation in hearing acuity from audiometric zero, the 
lowest sound pressure level audible to the average normal-hearing young 
adult. Positive values indicate poorer hearing acuity than audiometric 
zero, while negative values indicate better hearing. Because OSHA based 
its definition on a 1972 recommendation by NIOSH (1972), MSHA refers to 
this definition as the OSHA/NIOSH criteria for hearing impairment.
    NIOSH specifically developed its definition of hearing impairment 
for understanding speech under everyday (noisy) conditions. NIOSH 
concluded that ``the basis of hearing impairment should be not only the 
ability to hear speech, but also to understand speech,'' and this is 
best predicted by the hearing levels at 1000, 2000, and 3000 Hz.
    When OSHA initially published its Hearing Conservation Amendment, 
most medical professionals used the 1959 criteria developed by the 
American Academy of Ophthalmology and Otolaryngology (AAOO), a subgroup 
of the American Medical Association (AMA). This criteria (AAOO 1959) 
defined hearing impairment as exceeding a 25 dB hearing level, 
referenced to audiometric zero, averaged over 500, 1000, and 2000 Hz in 
either ear (1959).
    The American Academy of Otolaryngology Committee on Hearing and 
Equilibrium and the American Council of Otolaryngology Committee on the 
Medical Aspects of Noise (AAO-HNS) has since modified the 1959 criteria 
by adding the hearing level at 3000 Hz to the hearing levels at 500, 
1000, and 2000 Hz (1979).
    Unlike the OSHA/NIOSH criteria, the AAOO 1959 and AAO-HNS 1979 
criteria are for all types of hearing loss, including noise-induced 
hearing loss (NIHL), and were mainly designed for hearing speech under 
relatively quiet conditions.

[[Page 66372]]

    In its ANPRM, MSHA asked for comments on a definition of hearing 
impairment. Many commenters either directly or indirectly endorsed the 
OSHA/NIOSH definition of hearing impairment. One commenter suggested 
defining a significant material impairment as an average permanent 
threshold shift of 25 dB or more at 1000, 2000, 3000, and 4000 Hz in 
either ear. Other commenters supported the AAO-HNS 1979 criteria as the 
level where impairment begins. (Several commenters suggested that MSHA 
separately address a definition of hearing loss for reporting purposes; 
this has been done, as discussed in part III of this preamble in 
connection with proposed Sec. 62.190(b).)
Discussion
    MSHA has determined that with respect to mine safety and health, 
any definition of material impairment of hearing should relate to a 
permanent, measurable loss of hearing which, unchecked, will limit the 
ability to understand speech, as it is spoken in everyday social 
(noisy) conditions. This is because speech comprehension is essential 
for mine safety.
    Measures of hearing impairment depend upon the frequencies used in 
calculating the hearing impairment. At relatively low sound levels 
(between 80 dBA and 90 dBA) the hearing loss is confined to the higher 
audiometric frequencies. In order to show the effect of noise below 90 
dBA on hearing, inclusion of test frequencies above 2000 Hz is 
necessary. MSHA agrees with the many comments and studies cited to show 
that high frequency hearing is critically important for the 
understanding of speech and that every day speech is sometimes 
distorted and often takes place in noisy conditions.
    Therefore, MSHA has determined that for purposes of mine safety and 
health, 3000 Hz should be included in any definition of material 
impairment. In addition, 500 Hz should be excluded from any definition, 
since it is not as critical for understanding speech and least affected 
by noise. Of the three generally utilized definitions of noise--the 
AAOO 1959, the AAO-HNS 1979, and the OSHA/NIOSH criteria--only the 
latter meets this test.
    All three of the aforementioned definitions of noise use a 25 dB 
hearing level. As noted previously, this level of hearing loss relative 
to audiometric zero is actually well beyond that at which there is harm 
to health and also well beyond that at which workers suffer a loss of 
functional capacity. Nevertheless, this is the measure used in almost 
all of the studies of risk of noise exposure that have been done. This 
constrains the definition of material impairment the Agency utilizes to 
evaluate the available risk data.
    Accordingly, solely for the purposes of evaluating the significance 
of the available risk studies for miners, MSHA is adopting the OSHA/
NIOSH criteria, a 25 dB hearing level averaged over 1000, 2000, and 
3000 Hertz (Hz) in either ear, as its definition of material 
impairment.
    With respect to risk evaluations, the number of persons meeting the 
definition of impairment in any noise-exposed population will be higher 
under the OSHA/NIOSH criteria than under the other criteria (AAOO 1959 
and AAO-HNS 1979). This is because noise does not affect hearing acuity 
equally across all frequencies. Typically, NIHL occurs first at 4000 
Hz, then progresses into the lower and higher frequencies. The AAOO 
1959 criteria is weighted toward the lower frequencies and was 
developed to determine an individual's ability to communicate under 
quiet conditions. Recognizing that an individual's ability to hear 
speech in a noisy environment depends upon that person's ability to 
hear sounds in the higher frequency range, the AAO-HNS added 3000 Hz to 
the frequencies used in the AAOO 1959 criteria. The impact of this 
modification is that the number of persons meeting the impairment 
criteria in any noise-exposed population will be higher under the AAO-
HNS 1979 criteria than under the AAOO 1959 criteria. With the 
elimination of the hearing level at 500 Hz from the frequency range 
used, the OSHA/NIOSH definition is weighted even more toward the higher 
frequencies than the AAO-HNS 1979 criteria, and thus even more are 
determined to be impaired.
    Moreover, selection of a criterion places some limitations on 
direct comparisons of data sources available for risk assessment. Data 
compiled using one definition of impairment are not readily 
translatable to the others. Since there is no reliable mathematical 
relationship among the three criteria for hearing impairment, it is not 
possible to accurately predict the impact on a population using the 
other two criteria when only the impact of one criterion is known. The 
ideal way to convert from one hearing impairment criterion to another 
would be to use the hearing level data for individual frequencies (raw 
data), if still available from the individual audiograms. It is also 
possible to crudely estimate the impact of one criterion to another 
provided that summary data on individual frequencies are available. 
Unfortunately, most of the data necessary to complete such conversions 
are no longer available.
    In the discussion of risk that follows in the next section of this 
preamble, sources of data based on all three definitions of impairment 
are presented, so this caveat about translation needs to be kept in 
mind. As it turns out, however, data using all three definitions tend 
to demonstrate the same result.
Risk of Impairment
    The studies of risk reviewed in this section consistently indicate 
that the risk of developing a material impairment (as defined in the 
prior section for purposes of this discussion) becomes significant over 
a working lifetime when workplace exposure exceeds average sound levels 
of 85 dBA. The data indicate that while lowering exposure from an 
average sound level of 90 dBA to one of 85 dBA does not eliminate the 
risk, it does reduce the risk by approximately half.
Measuring Risk
    It is not possible to determine the risk to individual miners of 
particular levels of noise. Some miners will suffer harm long before 
other miners from the same level of noise, and it is not possible to 
measure susceptibility in advance. Risks can, however, be determined 
for entire populations. According to Melnick (1982), professor emeritus 
of audiology at Ohio State University:

    Experts agree that information is available for deriving the 
relationship of noise exposure to hearing loss. This information 
serves as the basis for development of damage risk criteria. * * * 
The relationship of noise to hearing is in the scientific domain. 
The decisions inherent in development of damage risk criteria are 
social, political, and economic. Damage risk criteria are 
statistical concepts. Use of these criteria should be limited to 
considerations of populations. Damage risk criteria are not 
appropriate for use with individuals no matter how tempting such an 
application might be.

    The probability of acquiring a ``material impairment'' of hearing 
in a given population can be determined by extrapolating from data 
obtained from a test population exposed to the same sound levels. Three 
methods are generally used to express this population risk:
    (1) the hearing level of the exposed population;
    (2) the percent of an exposed population meeting the selected 
criteria; and
    (3) the percent of an exposed population meeting the selected 
criteria minus the percent of a non-noise exposed population meeting 
the same criteria, provided both populations are

[[Page 66373]]

similar except for the occupational noise exposure.
    The latter of these expressions is more commonly known as ``excess 
risk''. The excess risk method separates that percentage of the 
population expected to develop a hearing impairment from occupational 
noise exposure from that percentage expected to develop an impairment 
from non-occupational causes--for example, the normal aging process or 
medical problems. Hearing impairment risk data will be presented here 
using the excess risk method, because MSHA has concluded that this 
method provides the most accurate picture of the risk of hearing loss 
resulting from occupational noise exposure. OSHA also used this method 
in quantifying the degree of risk in the preamble to its Hearing 
Conservation Amendment.
    Although studies of hearing loss consistently indicate that 
increased noise exposure (either level or duration) results in 
increased hearing loss, the reported risk estimates of occupational 
NIHL can vary considerably from one study to another. As noted in the 
prior section, the definition of ``material impairment'' used plays a 
role. But two additional factors can be involved: the screening of the 
control group (non-noise exposed group), and the threshold used to 
define that group.
    Some researchers do not screen their study and control populations, 
while others use a variety of different screening criteria. 
Theoretically, screening would not have a significant impact on the 
magnitude of occupational NIHL experienced by given populations as long 
as the same criteria are used to screen both the noise and the non-
noise populations being compared. However, when considering whether the 
subjects have exceeded an established definition of material 
impairment, failure to take into account any non-occupational noise 
exposure and/or presbycusis (loss of hearing acuity due to aging) can 
have a profound effect on the estimates of hearing acuity of an exposed 
population. For example, if both the exposed and control populations 
are screened to eliminate persons with a history of military exposure, 
use of ototoxic medicines, noisy hobbies, conductive hearing loss from 
acoustic trauma or illness, etc., the excess risk would be 
significantly different from that determined using unscreened 
populations.
    The data presented here all use the same threshold. The threshold 
refers to that average sound level below which no adverse effects from 
noise exposure are expected to occur. Although researchers Kryter 
(1970) and Ambasankaran et al. (1981) have reported hearing loss from 
exposure to average sound levels below 80 dBA, most believe that the 
risk of developing a material impairment of hearing from exposure to 
such levels over a working lifetime is negligible. Accordingly, almost 
all noise risk studies consider the population exposed only to average 
levels of noise below 80 dBA as a ``non-noise exposed'' control group. 
In turn, this becomes the baseline from which the excess risk of being 
exposed to noise at higher levels is measured. When OSHA evaluated the 
risk of hearing loss for its hearing conservation amendment, it took 
the position that it was appropriate to consider the non-noise exposed 
control group to those exposed to sound levels below 80 dBA. MSHA, for 
the purpose of this proposal, agrees with OSHA's assessment.
    As a result of these variations, the data available present a range 
of risk estimates. As discussed later in the ``Conclusions'' section of 
this part, for purposes of estimating the risks to miners, the Agency 
has determined it should properly utilize the range of risk in those 
studies based upon the OSHA/NIOSH definition of material impairment. As 
noted in that discussion, however, even using the full range of the 
data presented here would lead to a similar conclusion.
Review of Study Data
    Table 1 is taken from the preamble to OSHA's Hearing Conservation 
Amendment (46 FR 4084). It displays the percentage of the industrial 
population expected to develop a hearing impairment meeting the AAOO 
1959 criteria if exposed to the specified sound levels over a working 
lifetime (40 years). This is a compilation of data developed by the 
U.S. Environmental Protection Agency (EPA) in 1973, the International 
Standards Organization (ISO) in 1975, and NIOSH in 1972. EPA, ISO, and 
NIOSH developed their risk assessments using the AAOO 1959 criteria 
because this was the format used by the original researchers in 
presenting their data. OSHA's risk table was developed primarily from 
studies of noise exposed populations in many sectors of general 
industry.

                      Table II-1.--OSHA Risk Table                      
------------------------------------------------------------------------
                                                  Excess risk (%)       
                                          ------------------------------
            Sound level  (dBA)               ISO                        
                                            (1975)  EPA   NIOSH   Range 
------------------------------------------------------------------------
80.......................................        0    5       3   0-5   
85.......................................       10   12      15  10-15  
90.......................................       21   22      29  21-29  
------------------------------------------------------------------------

    As seen in Table II-1, the excess risk of material impairment after 
a working lifetime at an average noise exposure of 80 dBA is low, at an 
average noise exposure of 85 dBA ranges from 10-15%, and at an average 
noise exposure of 90 dBA it ranges from 21-29%. Table II-2 presents 
further information on the risk assessments developed by NIOSH in their 
criteria document (1972), one portion of which was included in Table 
II-1. In Table II-2, data are based on both the AAOO 1959 criteria and 
the OSHA/NIOSH criteria.

                      Table II-2.--NIOSH Risk Table                     
------------------------------------------------------------------------
                                                     Excess risk (%)    
              Sound level  (dBA)               -------------------------
                                                 OSHA/NIOSH   AAOO 1959 
------------------------------------------------------------------------
80............................................            3            3
85............................................           16           15
90............................................           29           29
------------------------------------------------------------------------

    As shown in Table II-2, NIOSH's risk assessment (1972) found little 
difference using OSHA/NIOSH criteria when compared to AAOO 1959 
criteria. However, as previously noted, NIOSH recommends using the 
OSHA/NIOSH criteria for making risk assessments.
    Several researchers have commented on how adjustments to the 
criteria used would affect such excess risk figures. Suter (1988) 
estimates that the excess risk would be somewhat higher if 500 Hz was 
excluded and 3000 Hz was included in the definition of material 
impairment. Sataloff (1984) also reported on the effect of adding 3000 
Hz into the impairment criteria. He recalculated the effect of 
including hearing loss at 3000 Hz to the AAOO 1959 definition of 
hearing impairment and found that the prevalence of hearing impairment 
increased considerably. After 20 years of exposure to intermittent 
noise that peaked at 118 dBA, 3% of the workers experienced hearing 
impairment according to the AAOO 1959 definition of hearing impairment. 
If the AAO-HNS 1979 definition is used, the percentage increases to 9%. 
Royster et al. (1978) confirmed that the exclusion of 500 Hz and the 
inclusion of 3000 Hz increased the number of hearing impaired 
individuals during a study of potential

[[Page 66374]]

workers' compensation costs for hearing impairment. Using an average 
hearing loss of 25 dB as the criteria, Royster found that 3.5% of the 
industrial workers developed a hearing impairment according to AAOO 
1959, 6.2% according to AAO-HNS 1979, and 8.6% according to OSHA/NIOSH.
    Table II-3, II-4 and II-5 display another set of data on the 
working lifetime risk of material impairment, based upon the three 
different criteria commonly used for defining material impairment. 
Table II-3 is based on the AAO 1959 criteria, Table II-4 is based on 
the AAO-HNS 1979 criteria, and Table II-5 is based on the OSHA/NIOSH 
criteria. MSHA constructed these tables based on data presented in 
Volume 1 of the Ohio State Research Foundation report (Melnick et al., 
1980) commissioned by OSHA. The hearing level data, used to construct 
the tables, were taken from summary graphs in the report. The noise 
exposed population is 65 years old with 40 years of noise exposure. The 
control group was not screened as to the cause of any hearing loss; 
therefore, the high level of non-occupational hearing loss may 
underestimate the excess risk from occupational noise exposure. The 
researchers added the noise-induced permanent threshold shift component 
to the control data. Noise-induced permanent threshold shift (NIPTS) is 
the actual shift in hearing level only due to noise exposure after 
corrections.
    As expected, the three tables produce different results, reflecting 
that, for any given population, the excess risk for material impairment 
will be greater using the AAO-HNS 1979 criteria than using the AAOO 
1959. Likewise, the excess risk for material impairment will be greater 
using the OSHA/NIOSH criteria than using the AAO-HNS 1979. All three 
tables produce a smaller excess risk than did the data presented in 
Table II-1.

Table II-3.--Risk of Impairment Using AAOO 1959 Definition of Impairment
                    Using Melnick, et al., 1980 Data                    
------------------------------------------------------------------------
                                                             Excess risk
                                                  Percent      (%) with 
                   Exposure                         with        noise   
                                                 impairment    exposure 
------------------------------------------------------------------------
Non-noise.....................................         26.8          0.0
80 dBA........................................         26.8          0.0
85 dBA........................................         27.8          1.0
90 dBA........................................         31.4          4.6
------------------------------------------------------------------------


    Table II-4.--Risk of Impairment Using AAO-HNS 1979 Definition of    
               Impairment Using Melnick, et al., 1980 Data              
------------------------------------------------------------------------
                                                             Excess risk
                                                  Percent      (%) with 
                   Exposure                         with        noise   
                                                 impairment    exposure 
------------------------------------------------------------------------
Non-noise.....................................         41.6          0.0
80 dBA........................................         41.8          0.2
85 dBA........................................         44.4          2.8
90 dBA........................................         50.0          8.4
------------------------------------------------------------------------


     Table II-5.--Risk of Impairment Using OSHA/NIOSH Definition of     
               Impairment Using Melnick, et al., 1980 Data              
------------------------------------------------------------------------
                                                             Excess risk
                                                  Percent      (%) with 
                   Exposure                         with        noise   
                                                 impairment    exposure 
------------------------------------------------------------------------
Non-noise.....................................         48.5          0.0
80 dBA........................................         48.7          0.2
85 dBA........................................         51.5          3.0
90 dBA........................................         57.9          9.4
------------------------------------------------------------------------

    Tables II-6 and II-7 present data derived by Melnick in Forensic 
Audiology (1982) for damage risk due to noise exposure. These tables 
use the AAO-HNS 1979 criteria. In these tables, the population is 60 
years old with 40 years of exposure to the specified sound levels. In 
both tables, the data represent NIPTS (noise induced permanent 
threshold shift) calculated by Johnson, but the screening used in the 
two tables is different. Melnick's data in Table II-6 is based upon the 
screened presbycusis data (i.e. screened for non-occupational hearing 
loss) of Robinson and Passchier-Vermeer, whereas Table II-7 is based on 
unscreened non-occupational hearing loss data from the 1960-62 U.S. 
Public Health Survey.
    Overall, the excess risk information presented in these tables is 
closer to that in Table II-1 than to that in Tables II-3, II-4, and II-
5, but still different. Tables II-6 and II-7 directly illustrate the 
effect of screening populations in determining excess risk due to 
occupational noise exposure. As seen in these tables, the percent with 
impairment is greater in the table constructed with an unscreened 
population as the base.

  Table II-6.--Risk of Impairment Using Presbycusis Data of Passchier-  
                          Vermeer and Robinson                          
------------------------------------------------------------------------
                                                             Excess risk
                                                  Percent      (%) with 
                   Exposure                         with        noise   
                                                 impairment    exposure 
------------------------------------------------------------------------
75 dBA........................................            3            0
80 dBA........................................            5            2
85 dBA........................................            9            6
90 dBA........................................           21           18
------------------------------------------------------------------------


Table II-7.--Risk of Impairment Using Non-occupational Hearing Loss Data
                         of Public Health Survey                        
------------------------------------------------------------------------
                                                             Excess risk
                                                  Percent      (%) with 
                   Exposure                         with        noise   
                                                 Impairment    exposure 
------------------------------------------------------------------------
75 dBA........................................           27            0
80 dBA........................................           29            2
85 dBA........................................           33            6
90 dBA........................................           40           13
------------------------------------------------------------------------

    Chart ER1 displays the results of the various models. It should be 
noted that both the P/V/Robinson (data from Table II-6) and the PHS 
model (data from Table II-7) used the AAO-HNS 1979 criteria.
    As noted in the History section of this preamble, the Agency is 
aware that NIOSH is currently working on revising its estimates using a 
different model and taking hearing loss at an additional frequency into 
account; but until such an approach is peer reviewed and finalized, 
MSHA has concluded it should not be considered here.
    As illustrated by Chart ER1, the exact numbers of those at risk 
varies with the study--because of the definition of material impairment 
used, and because of the selection and threshold of the control group. 
Notwithstanding these differences, the data consistently demonstrate 
three points: (1) the excess risk increases as noise exposure 
increases; (2) there is a significant risk of material impairment of 
hearing loss for workers exposed over their working lifetimes to 
average sound levels of 85 dBA; and (3) lowering the exposure from 
average sound levels of 90 dBA to average sound levels of 85 dBA 
reduces the excess risk of developing a material impairment by 
approximately half.

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Related Studies of Worker Hearing Loss

    There is a large body of data on the effects of varying industrial 
sound levels on worker hearing. Some of these studies specifically 
address the mining industry; moreover, MSHA has determined that 
regardless of the industry in which the data were collected, exposures 
to similar sound levels will result in similar degrees of material 
impairment in the workers. These studies are supportive of the 
conclusions reached in the previous section about noise risks at 
different sound levels.
    OSHA's 1981 preamble to its Hearing Conservation Amendment referred 
to studies conducted by Baughn, Burns and Robinson, Martin, et al., and 
Berger et al.
    Baughn (1973) studied the effects of average noise exposures of 78 
dBA, 86 dBA, and 90 dBA on 6,835 industrial workers employed in 
Midwestern plants producing automobile parts. Noise exposures for these 
workers were measured for 14 years and, through interviews, exposure 
histories were estimated as far back as 40 years. The control and the 
noise-exposed groups were not screened for anatomical abnormalities of 
the ear.
    Baughn used his data to provide estimates of the hearing levels of 
workers exposed to 80 dBA, 85 dBA, and 92 dBA and extrapolated the 
exposures up to 115 dBA. Based upon the analysis, the researcher 
constructed an idealized graph which illustrated that 43% of 58-year 
old workers exposed for 40 years to noise at 85 dBA would meet the AAOO 
1959 criteria for hearing impairment. However, 33% of an identical non-
noise exposed population would be expected to meet the same impairment 
criteria. The excess risk from exposure to noise at 85 dBA, therefore, 
would be 10%. Using the same procedure, the excess risk for 80 dBA is 
0% and for 90 dBA it is 19%.
    Burns and Robinson (1970) studied the effects of noise on 759 
British factory workers exposed to average sound levels between 75 dB 
and 120 dB with durations ranging between one month and 50 years. The 
control group consisted of 97 non-noise exposed workers. Thorough 
screening removed the workers with exposure histories which were not 
readily quantifiable, exposure to gunfire, ear disease or abnormality, 
and language difficulty.
    For this study, Burns and Robinson analyzed 4,000 audiograms and 
found that the hearing levels of workers exposed to low sound levels 
for long periods of time were equivalent to other workers exposed to 
higher sound levels for shorter durations. From the data, the 
researchers developed a mathematical model that predicts hearing loss 
between 500 Hz and 6000 Hz in certain segments of the exposed 
population. Using Burns and Robinson's mathematical model, MSHA 
constructed Chart ER2. The chart shows that a noise exposure of 85 dBA 
over a 40-year career is clearly hazardous to the hearing acuity of 60-
year-old workers.

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    Martin et al. (1975) studied the prevalence of hearing loss in a 
group of 228 Canadian steel workers, ranging in age from 18 to 65 years 
of age, by comparing them to a control group of 143 office workers. The 
researchers reported that the risk of hearing impairment (average of 25 
dB at 500, 1000, and 2000 Hz) increases significantly between 85 dBA 
and 90 dBA. Up to 22% of the population would be at risk of incurring a 
hearing impairment with a 90 dBA PEL compared to 4% with an 85 dBA PEL. 
Both the noise exposed and the control groups were screened to exclude 
those workers with non-occupational hearing loss.
    Berger, Royster, and Thomas (1978) studied 42 male and 58 female 
workers employed at an industrial facility. The study included a 
control group of 222 persons that was not exposed to occupational 
noise. Of the 322 individuals included in the study, no one was 
screened for exposures to non-occupational noise from past military 
service, farming, hunting, or shop work, since these exposures were 
common to all. The researchers found that exposure to a daily steady-
state Leq of 89 dBA for 10 years caused a measurable hearing loss 
at 4000 Hz. According to the researchers, the measurable loss was in 
close agreement with the predictions of Burns and Robinson, Baughn, 
NIOSH, and Passchier-Vermeer.
    Passchier-Vermeer (1974) reviewed the results of eight field 
investigations on hearing loss among 20 groups of workers. About 4,600 
people were included in the analysis. The researcher concluded that the 
limit of permissible noise exposure (defined as the maximum level which 
did not cause measurable noise-induced hearing loss, regardless of 
years of exposure) was shown to be 80 dBA. Furthermore, the researcher 
found that noise exposures above 90 dBA caused considerable hearing 
loss in a large percentage of employees and therefore, recommended that 
noise control measures be instituted at this level. The researcher also 
recommended that audiometric testing be implemented when the noise 
exposure exceeds 80 dBA.
    NIOSH (Lempert and Henderson, 1973) published a report in which the 
dose-response relationship for noise-induced hearing loss was 
described. NIOSH studied 792 industrial workers whose average daily 
noise exposures were 85 dBA, 90 dBA, and 95 dBA. The noise-exposed 
workers were compared to a group of controls whose noise exposures were 
lower than 80 dBA. The subjects ranged in age from 17 to 65 years old. 
The exposures were primarily to steady-state noise but the exposure 
levels fluctuated slightly in each category. Both the noise-exposed and 
control groups were screened to exclude those exposed to gunfire as 
well as those who showed some sign of ear disease or audiometric 
abnormality. The report clearly shows that workers whose noise 
exposures were 85 dBA experienced more hearing loss than the controls. 
As the noise exposures increased to 90 dBA and 95 dBA, the magnitude of 
the hearing loss increased.
    NIOSH (1976) published the results from a study on the effects of 
prolonged exposure to noise on the hearing acuity of 1,349 coal miners. 
From this study, NIOSH concluded that coal miners were losing their 
hearing acuity at a faster rate than would be expected from the 
measured environmental sound levels. While the majority of noise 
exposures were less than a TWA8 of 90 dBA, the measured hearing 
loss of the older coal miners was indicative of noise exposures between 
90 dBA and 95 dBA. Only 12% of the noise exposures exceeded a TWA8 
of 90 dBA. NIOSH, however, offered as a possible explanation that some 
miners are exposed to ``very intense noise'' for a sufficient number of 
months to cause the hearing loss.
    Coal miners in the NIOSH (1976) study had a greater percent of 
impairment than the non-occupational exposed group (control group) at 
each age level. Using OSHA/NIOSH definition of impairment, 70% of 60-
year-old coal miners were impaired while only a third of the control 
group were impaired. This would correspond to an excess risk of 37%.
    NIOSH also sponsored a study, conducted by Hopkinson (1981), on the 
prevalence of middle ear disorders in coal miners. As part of this 
study, the hearing acuity of 350 underground coal miners was measured. 
The results of this study corroborated the results of the earlier NIOSH 
study on the hearing acuity of underground coal miners. In both studies 
the measured median hearing levels of the miners were the same. 
However, the study did not present statistics on the percent of miners 
incurring a hearing impairment nor the job classification of the 
miners.

Studies of Harm at Lower Sound Levels

    As our knowledge about the effects of noise increases, there is 
increased need

[[Page 66377]]

to examine data that focuses on the harm that can occur at lower sound 
levels. This section reviews some of the studies, particularly those of 
workers from other countries, available in this regard.
    The most recent data are derived using the International Standards 
Organization's publication ISO 1999 (1990). The information in that 
publication can be used to calculate the mean and various percentages 
of a population's hearing levels. The noise exposures for the 
population can range between 75 dBA and 100 dBA. Table II-8 presents 
the hearing level of a 60-year-old male exposed to noise for 40 years. 
The noise induced hearing permanent threshold shift was combined with 
presbycusis values to determine the total hearing loss. The presbycusis 
values were those from an unscreened population. The unscreened 
population is believed to more accurately represent the mining 
population since people with nonoccupational hearing loss would not be 
excluded from becoming miners.

         Table II-8.--Hearing Level for Selected Noise Exposures        
------------------------------------------------------------------------
                                                Hearing level in dB     
                                         -------------------------------
           Sound Level in dBA               500    1000    2000    3000 
                                            Hz      Hz      Hz      Hz  
------------------------------------------------------------------------
80......................................      12       6      10      30
85......................................      12       6      11      33
90......................................      12       6      16      42
------------------------------------------------------------------------

    Information about the effects on hearing of lower noise exposures 
can be particularly valuable in directing attention to the possibility 
of identifying subpopulations particularly sensitive to noise. The 
Committee on Hearing, Bioacoustics, and Biomechanics of the National 
Research Council (CHABA) (1993) reviewed the scientific literature on 
hazardous exposure to noise. The report, reaffirming many of the 
earlier findings of the Committee, suggests that exposures below 76 dBA 
to 78 dBA are needed to prevent a NIHL based upon temporary threshold 
shift (TTS) studies; moreover, the report suggests that the sound level 
be less than 85 dBA, and possibly less than 80 dBA, to guard against 
any permanent hearing loss at 4000 Hz based upon field studies. But of 
particular interest is the suggestion that therapeutic drugs, such as 
aminoglycoside antibiotics and salicylates, can interact 
synergistically with noise to yield more hearing loss than would be 
expected by either stressor. Given the increasing use of salicylates 
(aspirin) in heart maintenance regimens, the potential synergistic 
effect may warrant further study.
    Few current studies of unprotected U.S. workers exposed to a 
TWA8 between 85 and 90 dBA are available because the OSHA hearing 
conservation standard requires some protection at those levels for most 
industries. The difficulty in constructing new retrospective studies of 
U.S. workers has been noted by Kryter (1984) in his chapter on Noise-
Induced Hearing Loss and Its Prediction. He believes that the 
retrospective studies of Baughn, Burns and Robinson, and the U.S. 
Public Health Service are the best available on the subject of NIPTS. 
Regarding current retrospective studies he states:

    Furthermore, imposition of noise control and hearing 
conservation programs in many industries in many countries over the 
past 10 years or so make somewhat remote the possibility of 
performing a meaningful retrospective study of the effects in 
industry of noise on the unprotected ear.

    Kryter included a formula for deriving the effective noise exposure 
level for damage to hearing. This was used to determine, from a 
population of workers, NIPTS at different percentiles of sensitivity at 
various audiometric test frequencies.
    Studies of workers from other countries can provide information of 
particular value in assessing the consequences of workplace noise 
exposure between 85 dBA and 90 dBA. MSHA has determined that while 
differences in socioeconomic factors (e.g., recreational noise 
exposure, use of ototoxic medicines, otitis media) make it difficult to 
directly apply the results of studies of workers from other countries 
to quantify the risk for U.S. workers, they can be used to establish 
the existence of a risk in the 80 to 90 dBA range.
    Rop, Raber, and Fischer (1979) studied the hearing loss of 35,212 
male and female workers in several Austrian industries, including 
mining and quarrying. The researchers measured the hearing levels of 
workers exposed to sound levels ranging from less than 80 dBA up to 115 
dBA, and arranged them into eight study groups based upon average 
exposures. They assumed that exposure to sound levels less than 80 dBA 
did not cause any hearing loss and workers exposed to these levels were 
assigned to the control group.
    Rop et al. reported that workers with 6 to 15 years of exposure at 
85 dBA had significantly worse hearing than the control group. For the 
five groups exposed between 80 dBA and 103.5 dBA, hearing loss tended 
to increase steadily during their careers, but leveled off after 15 
years. However, for workers exposed to sound levels above 103.5 dBA, 
hearing loss continued to increase beyond 15 years.
    Using the data collected during the study, Rop et al. developed a 
statistical method for predicting hearing loss. The researchers 
predicted that 20.1% of the 55-year old males in the control group with 
15 years of work experience would incur hearing loss. For a comparable 
group of males with exposures at 85 dBA the risk increased to 41.6%; at 
92 dBA the risk increased to 43.6%; and at 106.5 dBA the risk increased 
to 72.3%. Rop et al. concluded that exposure to sound levels at or 
above 85 dBA damaged workers' hearing.
    Schwetz et al. (1980) reported on a study of 25,000 Austrian 
workers. The study concluded that the workers exposed to sound levels 
between 85 dBA and 88 dBA experienced greater hearing loss than workers 
exposed to sound levels less than 85 dBA. Because of this, Schwetz 
recommended 85 dBA as the critical intensity (i.e., PEL). Furthermore, 
the study concluded that a lack of hearing recovery occurs at 85 dBA 
which is the ultimate cause of noise-induced hearing loss (NIHL).
    Stekelenburg (1982) calculated the hearing loss due to presbycusis 
according to Spoor and due to noise according to Passchier-Vermeer. 
Based upon these calculations, Stekelenburg suggested that 80 dBA be 
the acceptable level for noise exposure over a 40 year work history. At 
this exposure, Stekelenburg calculates that impaired social hearing due 
to noise would be expected in 10% of the population.
    Bartsch et al. (1989) studied 537 textile workers. These 
researchers defined hearing loss of social importance as a 40 dB 
hearing level at 3000 Hz. The researchers found that hearing loss 
resulting from exposures below 90 dBA mainly occurs at frequencies 
above 8000 Hz (these frequencies are not normally tested during 
conventional audiometry), and so concluded that this hearing loss was 
not of ``social importance.'' Nevertheless, they recommended a hearing 
loss risk criterion of 85 dBA be used to protect the workers' hearing.
    These results are generally consistent with those of U.S. workers. 
MSHA would, however, note its disagreement with the characterization of 
the amount of hearing loss not being of ``social importance'' as 
expressed in the Bartsch et. al (1989) study. The Agency has concluded 
that a person will encounter hearing difficulty before their hearing 
level reaches 40 dB at 3000 Hz. Studies, discussed earlier in 
Definition of Material Impairment, address the importance of having 
good hearing

[[Page 66378]]

acuity at 3000 Hz in order to adequately understand speech in everyday 
noisy environments.

Reported Hearing Loss Among Miners

    To confirm the magnitude of the risks of NIHL among miners, MSHA 
examined evidence of reported hearing loss among miners--audiometric 
data collected over the years tracking hearing acuity among miners, the 
comments received in response to the Agency's ANPRM, reports of hearing 
loss by mine operators pursuant to 30 CFR part 50, and workers' 
compensation data. Such data could provide a quantitative determination 
of material impairment.
    With respect to audiometric data, MSHA asked NIOSH to examine a set 
of data on coal miners. The analysis (Franks, 1996) supports the data 
from scientific studies. It indicates that 90% of these coal miners 
have a hearing impairment by age 50 as compared with only 10% of the 
general population. Further, Franks stated that miners, after working 
20 to 30 years, could find themselves in life threatening situations 
since safety signals and ``roof talk'' could go unheard. (For the 
purposes of the analysis, NIOSH used the definition of hearing 
impairment it is now considering, an average 25 dB hearing level at 
1000, 2000, 3000, and 4000 Hz; MSHA conducted its own analysis of the 
data without the 4000 Hz, and the results are generally consistent with 
those of NIOSH).
    This section also reviews several other sources of data that might 
provide direct information about the risks of hearing loss to miners: 
the comments received in response to the Agency's ANPRM, the reports of 
hearing loss provided to the Agency by mine operators pursuant to 30 
CFR part 50, and workers' compensation data. In each case, the 
available data are too limited to draw any conclusions. The Agency is 
requesting the public to provide further information along these lines.
Audiometric Data Bases
    Audiometric testing is not currently required in metal and nonmetal 
mining and is only required when an overexposure to noise is determined 
in coal mining. Certain mining companies conduct routine audiometric 
testing on their employees, but the results of these tests are 
confidential and are not published for public use. In addition, summary 
reports of these audiometric tests are generally not available.
    MSHA, however, has obtained an audiometric data base consisting of 
20,021 audiograms conducted on 3,433 individual coal miners, in 
connection with its ongoing efforts to assess the effectiveness of the 
current standards in protecting miner health. The audiometric 
evaluations were conducted between 1971 and 1994 with the bulk of the 
audiograms conducted during the latter years.
    NIOSH (Franks, 1996) has analyzed this data base. Each audiogram 
was reviewed for validity and NIOSH audiologists directly reviewed more 
than 2,500 audiograms. The review reduced the number of audiograms by 
8.8% and the number of miners by 8.3%.
    After deleting those audiograms judged to be invalid, NIOSH's 
analysis indicates that 90% of these miners have a hearing impairment 
by age 50 as compared with only 10% of the general population. Even at 
age 69, only 50% of the non-noise exposed population acquire a hearing 
impairment. Franks defined material impairment as an average 25 dB 
hearing level at 1000, 2000, 3000, and 4000 Hz. This definition differs 
from the MSHA definition of hearing impairment by the inclusion of 4000 
Hz in the average.
    By age 35 the average miner has a mild hearing loss and 20% have a 
moderate loss. By contrast, fewer than 20% of the miners having 
marginally normal hearing by age 64 while the upper 80% have moderate 
to profound hearing loss. The lower 80% of the non-noise exposed 
population will not acquire a hearing loss as severe as the one 
obtained by the average miner regardless of how long they live.

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    Further, Franks stated that miners, after working 20 to 30 years, 
could find themselves in life threatening situations since safety 
signal and roof talk could go unheard.
    MSHA separately conducted an elementary analysis of the data, using 
the definition of material impairment of hearing used throughout the 
analyses in this preamble: an average 25 dB hearing level at 1000, 2000 
and 3000 Hz. For MSHA's analysis, all audiograms were considered to be 
valid (e.g., no contamination from temporary threshold shifts, sinus 
conditions, etc.). Information on years of mining experience, noise 
exposure, use of hearing protectors, and job function was not provided.
    In order to reflect current trends, the percentage of current coal 
miners with a material impairment of hearing was compared to historical 
data (NIOSH's study on coal miners published in 1976). The audiometric 
data were placed into a compatible format, e.g., age and hearing loss 
criteria. Only those coal miners (2,861) whose latest audiogram was 
taken between 1990 and 1994 were included in the analysis. The results 
are shown in Chart R1 along with NIOSH's 1976 results for both the 
noise exposed miners and the non-noise exposed controls.

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The data points for chart R1 are the mean of both ears at 1000, 2000 
and 3000 Hz. The top line connects data points from the 1976 group, and 
the middle line connects points from the 1990-1994 group; the bottom 
line represents the non-noise exposed group.
    As shown in Chart R1, it is obvious that many coal miners who had 
audiograms taken from 1990 through 1994 have a material impairment of 
hearing. These miners were still losing more of their hearing acuity 
than non-noise exposed workers. This remains true even if the analysis 
is limited to miners less than 40 years of age (i.e., those who have 
worked only under the current coal noise regulations). The fact that 
the loss is at a slower rate than shown in the 1976 data may indicate 
some progress under the existing regulations compared with no 
regulation.
    Furthermore, MSHA analyzed the data for the number of standard 
threshold shifts (STS's) and reportable hearing loss cases in order to 
estimate the number of such events that may occur if the proposal is 
adopted. In the proposal, MSHA defines an ``STS'' as a change in 
hearing threshold level relative to the miner's original or 
supplemental baseline audiogram of an average of 10 dB or more at 2000, 
3000, and 4000 Hz in either ear. The importance of an STS is that it 
reveals that a permanent loss in hearing acuity has occurred relative 
to that miner's baseline. This is the type of loss that is deserving of 
mine operator intervention. When the change from the baseline averages 
25 dB or more at the same frequencies, the hearing loss must be 
reported to MSHA so that the Agency can intervene if necessary. (MSHA 
discusses the definition of STS and reportable hearing loss in detail 
in the sections of this preamble dealing with proposed Secs. 62.160 and 
62.190.) In both cases, the data differ from that in Chart R1, which is 
looking at the hearing loss relative to audiometric zero--not the 
individual miner's baseline.
    For a second analysis, the first audiogram was assumed to be the 
baseline. The last audiogram was compared to the baseline. Neither 
audiogram was corrected for presbycusis. Also, because of the lack of 
supporting data, no provision for excluding an STS as being non-
occupational was possible. A total of 3,102 coal miners had a baseline 
and at least a second audiogram. However, only those miners whose 
latest audiogram was conducted between 1990 and 1994 were considered. 
The results are presented in Chart R2.

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    Chart R2 clearly shows that many of the coal miners from 1990 
through 1994 were found to have an STS. The likelihood of acquiring an 
STS generally increases with advancing age. The MSHA analysis was 
conducted in a conservative fashion. Because the intervening audiograms 
were excluded from this analysis, the number of STSs is probably low 
since only a single STS was recorded. There could be several 
explanations for the drop in the percentage of STS's for the 65 year 
old age group in chart R2, including, for example, changed work 
assignments.
    In addition to this privately maintained audiological data, there 
have been two special NIOSH studies of the hearing acuity of coal 
miners. These studies were reviewed in detail in the Risk of Impairment 
section, above. The first study was published in 1976. Even though the 
majority of noise exposures were found to be less than 90 dBA, 
approximately 70% of the 60-year-old coal miners had a material 
impairment of hearing using the OSHA/NIOSH definition. Another NIOSH 
study, conducted by Hopkinson (1981), corroborated the results of the 
earlier NIOSH study on the hearing acuity of coal miners.
Commenter Data
    In its ANPRM, MSHA solicited comments on the number of current 
miners with a hearing loss based on suggested criteria. Two commenters 
provided information on the hearing acuity of miners. The first 
commenter estimated that 45 to 50% of the employed miners have an STS 
and at least 25% have an STS if corrected for presbycusis. Further, 
this commenter estimated that about 25% of the miners have an average 
hearing loss of 25 dB or more at 1000, 2000, and 3000 Hz. However, when 
corrected for presbycusis, the percentage of miners with this level of 
hearing loss decreased to about 15%.
    The second commenter referenced a paper presented by Smith et al. 
at the 1989 Alabama Governor's Safety and Health Conference. This 
commenter stated that Smith et al. reported on the evaluation of serial 
audiograms from 100 workers exposed to sound levels less than 85 dBA. 
Smith et al. had found that 15% of these workers would have some degree 
of hearing impairment using AAO-HNS 1979 impairment criteria. Smith et 
al. also reported that at least 26% of the mining population would have 
some degree of hearing impairment using the same criteria. Smith (1994) 
confirmed the prevalence of material impairment among miners in a 
letter to MSHA.
    MSHA also requested information on hearing loss to individual 
miners in its ANPRM. Specific information was requested on each miner 
who had incurred a hearing loss, including the related noise exposure, 
state workers' compensation award, cost of the award, miner's age, 
occupation and degree of hearing loss. The Agency received few comments 
pertaining to the information requested. The Agency requests additional 
comment on these issues.
Reported Hearing Loss Data
    Another potential body of information about hearing loss among 
miners comes from reports mine operators are required to submit to MSHA 
of such losses. At present, however, there is not a definition of 
``reportable hearing loss'' linking what is reported to some particular 
measurement. Rather, under 30 CFR part 50, mine operators are only 
required to report cases of NIHL to MSHA when it is diagnosed by a 
physician or when the miner receives an award of compensation.
    Nevertheless, between 1985 and 1995 mine operators reported a total 
of 2,402 cases of NIHL--and among these cases were a substantial number 
of miners who began working at a mine after the implementation of the 
current noise regulations.
    Coal mine operators reported 608 cases among surface miners, 1,077 
cases among underground miners, and 14 cases among miners whose work 
positions were not identified. According to coal mine operators, 662 of 
the 1,699 cases began working at a mine after the implementation of 
noise regulations for coal mines (1972 for underground and 1973 for 
surface). Workers with no reported mining experience were excluded from 
this analysis, because their noise exposure history in mining was 
unknown.
    For the same period, metal and nonmetal mine operators reported 555 
cases among surface miners and 148 cases among underground miners. 
According to mine operators, 142 of the 703 cases began working at a 
mine after the implementation of noise regulations for metal and 
nonmetal mines (1975). As with the coal data, workers with no reported 
mining experience were excluded.

[[Page 66381]]

    Comparing the two types of mining, there were significantly more 
reported hearing loss cases at coal mines than at metal and nonmetal 
mines, and a higher proportion of those cases were to workers who began 
working after the implementation of the current standards. This is 
despite the fact that, at the present time, there are more metal and 
nonmetal miners than coal miners employed in the U.S. A possible 
explanation of the differences between reported cases of NIHL among 
coal, metal and nonmetal miners may be the more frequent use of 
engineering noise controls in metal and nonmetal mining.
    MSHA reviewed the narrative associated with each NIHL case to 
determine the degree of hearing loss. Although many narratives 
contained information as to the reason for reporting the NIHL case, 
others only listed the illness as ``hearing loss.'' Approximately half 
the cases had no information on the severity of the hearing loss. Some 
narratives contained information on the severity of the hearing loss, 
such as an STS, OSHA reportable case, or percent disability. Based upon 
the information in the narratives it is not possible to determine an 
average severity for the NIHL cases.
    However, at least 40% of the cases in coal mining were reported to 
MSHA as the result of the miner being compensated for NIHL. Another 7% 
of the cases filed a workers' compensation claim for NIHL. In metal and 
nonmetal, at least 19% of the cases were the result of the miner being 
compensated for NIHL. Nearly another 3% of the cases filed a workers' 
compensation claim for NIHL.
    MSHA contends that the number of cases reported to the Agency are 
low because of the following factors: the lack of a specific definition 
of a NIHL in MSHA's part 50 regulations which may result in confusion 
on the part of mine operators about which cases to report; the lack of 
consistency among the states' requirements for awarding compensation 
for an NIHL and among physicians in diagnosing what constitutes a 
hearing loss caused by noise; and the lack of periodic audiometric 
testing in the mining industry.
    In summary, current hearing loss reported to MSHA under part 50 
cannot be used to accurately characterize the incidence, prevalence or 
the severity of hearing loss in the mining industry. However, the part 
50 data clearly show that miners are incurring NIHL.
Workers' Compensation Data
    Another source of information about hearing loss among miners is 
state workers' compensation agencies and insurance carriers. Many 
states do not keep detailed workers' compensation data themselves; 
categorization of data are inconsistent across the states; and there 
are privacy concerns in obtaining the detailed information needed for 
studies. MSHA would welcome information about studies of hearing loss 
that have been performed by the insurance industry or others based on 
this data.
    Valoski (1994) studied the number of miners receiving workers' 
compensation and the associated indemnity costs of those awards. 
Despite contacting each state workers' compensation Agency and using 
two national data bases, he was unable to obtain data for all states. 
In fact, data were not available from a number of key mining states.
    From the data that were available for study, Valoski reported that 
between 1981 and 1985 at least 2,102 coal miners and 312 metal and 
nonmetal miners were awarded compensation for occupational hearing 
loss. The identified total indemnity costs of those awards exceeded 
12.5 million dollars excluding rehabilitation or medical costs.
    In Niemeier's letter to MSHA, Chan et al. of NIOSH (1995) 
investigated the incidence of NIHL among miners using information from 
the Bureau of Labor Statistics' (BLS) Supplementary Data System. Like 
Valoski, he found the national data to be incomplete. Only 15 states 
participated in the BLS program between 1984 and 1988. In these 15 
states, a total of 217 miners (93 coal miners and 124 metal and 
nonmetal miners) were awarded workers' compensation for NIHL. Chan et 
al. stated that because of differing state workers' compensation 
requirements, it is not possible to directly compare NIHL among the 
states. These factors limit the usefulness of the obtained data.
    MSHA also reviewed reports on workers' compensation in Canada and 
Australia. The noise regulations and mining equipment used in these 
countries are similar to those in the U.S. A recent report on workers' 
compensation awards to miners in Ontario, Canada (1991) revealed that 
between 1985 and 1989, NIHL was the second leading compensable 
occupational disease. Approximately 250 claims for NIHL involving 
miners were awarded annually during that time.
    Lescouflair et al. (1980) studied 278 metal and asbestos miners in 
Quebec, Canada, who claimed compensation for hearing loss. Of the 278 
cases, 28.7% (80) were excluded as cases of non-mining NIHL. 
Approximately 50% (99) of those remaining cases diagnosed as having 
NIHL were shown to have a hearing impairment based upon the AAOO 1959 
criteria and an estimated 63% (125) showed an impairment based upon 
AAO-HNS 1979 criteria. The miners were exposed to noise for 15 to 49 
years and showed a similar occurrence of hearing loss in both surface 
and underground occupations. The researchers also reported that there 
was no significant difference in NIHL among the miners for those 
subjects exposed to a mixture of intermittent-continuous noise versus 
intermittent noise except at 2000 Hz.
    Eden (1993) reported on the Australian mining industry's experience 
with hearing conservation. Eden quoted statistics from the Joint Coal 
Board which revealed that NIHL comprised 59% to 80% of the reported 
occupational diseases from 1982 to 1992. Eden also reported that in New 
South Wales 474 of 16,789 coal miners were awarded compensation for 
NIHL. The incidence rate for the total mining industry in New South 
Wales was about 23 cases per 1,000 workers during 1990-1991. This was 
the highest rate for any industry in New South Wales.
    In conclusion, like reported cases of NIHL, the compensation data 
are too incomplete to be used for quantitative estimates of the 
prevalence of NIHL in the mining industry. But like the reported case 
data, the compensation data that are available do show that numerous 
cases are still being filed each year at considerable cost. Further, 
according to the data reported by mine operators, many miners who 
developed NIHL only worked in mining after the implementation of the 
current noise regulations. While limited, this evidence of continued 
risk supplements and supports the data previously presented from 
scientific studies.
    The Agency would welcome the submission of additional data to 
supplement that which it has been able to gather to date.

Exposures in the U.S. Mining Industry

    In this section MSHA presents information on noise exposure in the 
U.S. mining industry, so as to develop a picture of the mining 
population at a significant risk of incurring material impairment as a 
result of that exposure. The exposure levels are particularly high in 
the coal industry, where hearing protectors, rather than engineering or 
administrative controls, remain the primary means of miner protection 
against NIHL. But the data indicate that exposure levels remain high in 
all sectors of the mining industry even

[[Page 66382]]

though noise regulations have been implemented for some time.
Inspection Data
    The first presentation, Tables II-9 and II-10, reviews noise 
exposure data collected by MSHA inspectors from thousands of samples 
gathered over many years to check compliance with the current permitted 
levels. Because the proposed rule would alter the way a miner's noise 
dose is calculated in one respect, MSHA conducted a special survey to 
obtain data that would reflect this change. The data are presented in 
Tables II-11 and II-12. The survey data are also presented by 
occupation in Tables II-13 and II-14. All the readings are in time-
weighted 8-hour averages.
    Tables II-9 and II-10 display samples which present readings 
exceeding the permissible exposure limit, a TWA8 of 90 dBA.
    Table II-9 shows noise dose trends in metal and nonmetal mines 
based on over 232,500 full-shift samples collected by MSHA from 1974 
through 1995 using personal noise dosimeters.

    Table II-9.--Metal and Nonmetal Noise Dose Trends 1974 to 1995 a    
------------------------------------------------------------------------
                                                                Percent 
                                         Number of  Number of      of   
                  Year                    samples   samples >  samples >
                                                      90 dBA     90 dBA 
------------------------------------------------------------------------
1974...................................        363        139       38.3
1975...................................      3,826      1,661       43.4
1976...................................      9,164      3,725       40.6
1977...................................     13,485      5,047       37.4
1978...................................     17,326      6,415       37.0
1979...................................     21,176      7,638       36.1
1980...................................     15,185      5,203       34.3
1981...................................     11,278      3,651       32.4
1982...................................      3,208        876       27.3
1983...................................      7,628      2,188       28.7
1984...................................      8,525      2,311       27.1
1985...................................      8,040      2,094       26.0
1986...................................      9,213      2,402       26.1
1987...................................     10,145      2,818       27.8
1988...................................     10,514      2,417       23.0
1989...................................     10,279      2,208       21.5
1990...................................     13,067      2,721       20.8
1991...................................     14,936      2,947       19.7
1992...................................     14,622      2,809       19.2
1993...................................     14,566      2,529       17.4
1994...................................     15,979      2,627       16.4
1995...................................     13,865      1,989      14.4 
------------------------------------------------------------------------
a Data from USBOM' MIDAS data base.                                     

    Table II-10 below presents noise dose trends in coal mines based on 
75,691 full-shift samples collected by MSHA from 1986 through 1995 
using personal noise dosimeters. MSHA actually began routine sampling 
in coal mines in 1978; however, its data base did not begin until 1986.

  Table II-10.--Coal Mine Noise Dose Trends, Fiscal Years 1986 to 1995  
------------------------------------------------------------------------
                                                                 Percent
                                         Number of  Number of      of   
              Fiscal year                 samples    samples    samples 
                                                     >90 dBA    >90 dBA 
------------------------------------------------------------------------
1986...................................      2,037        593       29.1
1987...................................     12,774      3,314       25.9
1988...................................     11,888      2,702       22.7
1989...................................     11,035      2,313       21.0
1990...................................     10,861      2,388       22.0
1991...................................      6,898      1,635       23.7
1992...................................      6,636      1,660       25.0
1993...................................      7,223      1,908       26.4
1994...................................      6,339      1,656       26.1
1995...................................      5,407      1,219       22.5
------------------------------------------------------------------------

    The inspection data for the two sectors have also been graphed in 
charts II-9 and II-10 for years in which MSHA collected data for both 
sectors.
    As illustrated by the charts, the metal and nonmetal sector shows a 
gradual, but consistent, downward trend in the percent of samples 
exceeding the current PEL. However, there was no such clear trend for 
coal mines during the same time period. (It should be noted that while 
the data points on these 3-D graphs come from the last column of the 
tables, the shading may make them seem somewhat lower than they are in 
fact.)

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[[Page 66384]]

    There are several factors which must be considered when drawing any 
conclusions from the data. MSHA sampling may be biased towards noisier 
mines and occupations. Additionally, when an overexposure is found 
during an initial survey, the data base includes both the initial 
overexposure and the results of any resampling to determine compliance 
after the mine operator has utilized engineering and/or administrative 
controls. While these biases may tend to offset each other, their 
specific impact cannot be quantified. These factors should, however, 
impact both sectors roughly equally.
Dual Survey Data
    MSHA has concluded that the information contained in Tables II-9 
and II-10 understates the actual noise exposures in the industry 
because the information was collected using a 90 dBA threshold level, 
i.e. sound levels of less than 90 dBA are not integrated into the 
results. As discussed later in part III of the preamble, in connection 
with proposed Sec. 62.120(a), MSHA is proposing to change the threshold 
level to integrate sound levels of between 80 dBA and 130 dBA because 
MSHA has concluded that this is warranted by the weight of scientific 
evidence. Integrating the sound levels between 80 dBA and 90 dBA into 
the noise exposure will generally increase the measured noise dose. The 
greater the amount of noise between 80 dBA and 90 dBA the greater the 
impact on the measured noise dose.
     Accordingly, MSHA conducted a special survey to compare noise 
exposures at different threshold levels. The survey, referred to 
hereinafter as the ``dual-threshold'' survey, involved the collection 
of personal noise dosimeter data by MSHA inspectors in coal mines and 
metal and nonmetal mines. Each sample was collected using a personal 
noise dosimeter with the capability of simultaneously collecting data 
at both a 90 dBA threshold and an 80 dBA threshold. All other dosimeter 
settings were the same as those used during normal compliance 
inspections (the 90 dB criterion level, 5-dB exchange rate, and A-
weighting system which are not now being proposed by MSHA for change). 
The noise doses were mathematically converted to the appropriate 
TWA8 using different criterion levels and threshold values.
    Tables II-11 and II-12 display the dual-threshold data: 
respectively in metal and nonmetal mines, and in coal mines. Table II-
11 specifically shows the dual-threshold data collected for metal and 
nonmetal mines from March 1991 through December 1994 using personal 
noise dosimeters. This data consisted of more than 42,000 full-shift 
samples.

  Table II-11.--M/NM Dual Threshold Samples at or Exceeding Specified TWA8 Sound Levels from March 1991 Through 
                                                  December 1994                                                 
----------------------------------------------------------------------------------------------------------------
                                                                  90 dBA thresholds         80 dBA threshold    
                                                             ---------------------------------------------------
                  TWA8 Sound Level (in dBA)                    Number of    Percent of   Number of    Percent of
                                                                samples      samples      samples      samples  
----------------------------------------------------------------------------------------------------------------
90..........................................................        7,360         17.4       11,150         26.5
85..........................................................  ...........  ...........       28,250         66.9
----------------------------------------------------------------------------------------------------------------

    Note: Two of the boxes in the table do not contain entries. This 
is to avoid the potential for making an inappropriate comparison of 
values. Direct comparison of TWA8 values determined with 
different thresholds is not appropriate if the TWA8 is less 
than one of the thresholds. An example may help to illustrate the 
point. A miner exposed to a constant sound field of 85 dBA for 8 
hours would be determined to have a noise dose of 0%, or a TWA8 
of 0 dBA, if a 90 dBA threshold is used: none of the sound would be 
counted in the computation. If the exposure was measured using an 80 
dBA threshold, the dose would be 50%, or a TWA8 of 85 dBA. 
Contrasting the measures taken with the two thresholds would be 
inappropriate in such a case.

    As indicated in Table II-11, 17.4% of all samples collected by MSHA 
in metal and nonmetal mines during the specified time period equaled or 
exceeded a TWA8 of 90 dBA using a 90 dBA threshold--slightly less 
than the results of inspector sampling in Table II-9. In these 
instances, engineering and/or administrative controls were required to 
be implemented in the metal or nonmetal mines to reduce sound levels to 
the PEL: a requirement that would be retained under the proposed rule. 
When sound levels between 80 dBA and 90 dBA are taken into account, 
however, 26.4% of the readings indicated non-compliance. Thus, changing 
the threshold to properly reflect harmful sound levels indicates 
harmful noise exposures in this industry are more significant than 
revealed by the inspection data in Table II-9. Furthermore, 67% of the 
samples in metal and nonmetal mines exceeded a TWA8 of 85 dBA 
using an 80 dBA threshold.
    MSHA dual-threshold sampling data for coal mines is presented in 
Table II-12. This data consists of over 4,200 full-shift samples 
collected from March 1991 through December 1995 using personal noise 
dosimeters.

   Table II-12.--MSHA Coal Dual Threshold Samples at or Exceeding Specified TWA8 Sound Levels from March 1991   
                                              Through December 1995                                             
----------------------------------------------------------------------------------------------------------------
                                                                  90 dBA threshold          80 dBA threshold    
                                                             ---------------------------------------------------
                  TWA8 Sound Level (in dBA)                    Number of    Percent of   Number of    Percent of
                                                                samples      samples      samples      samples  
----------------------------------------------------------------------------------------------------------------
90..........................................................        1,075         25.3        1,510         35.6
85..........................................................  ...........  ...........        3,268         76.9
----------------------------------------------------------------------------------------------------------------

    As indicated in Table II-12, 25.3% of all samples collected by MSHA 
in coal mines during the specified time period equaled or exceeded a 
TWA8 of 90 dBA using a 90 dBA threshold. This percentage increases 
to 35.6% when an 80 dBA threshold is used. Furthermore, using an 80 dBA 
threshold, almost 77% of the survey samples from the coal

[[Page 66385]]

industry showed noise exposures equaling or exceeding 85 dBA.
    Tables II-13 and II-14 present some of the MSHA dual-threshold 
sampling data by occupation for the most frequently sampled occupations 
in metal and nonmetal mines and coal mines, respectively. A note of 
caution: the only data presented in these tables is 90 threshold data 
at a TWA8 of 90, and 80 threshold data at a TWA8 of 85. 
Accordingly, the columns should not be compared. Perhaps the best way 
to think of this presentation is as two independent analyses at how the 
exposure levels of various job categories compare with each other.

 Table II-13.--Percentage of MSHA M/NM Samples a by Selected Occupation,
                  Exceeding Specified TWA8 Sound Levels                 
------------------------------------------------------------------------
                                                   90 dBA       80 dBA  
                                                 threshold    Threshold 
                                    Number of  -------------------------
            Occupation               samples     Percent of   Percent of
                                                 samples >    samples > 
                                                   90 dBA       85 dba  
------------------------------------------------------------------------
Front-end-loader operator........       12,812         12.9         67.7
Truck driver.....................        6,216         13.1         73.7
Crusher operator.................        5,357         19.9         65.1
Bulldozer operator...............        1,440         50.7         86.2
Bagger...........................        1,308         10.2         65.0
Sizing/washing plant operator....        1,246         13.2         59.7
Dredge/barge attendant...........        1,124         27.2         78.7
Clean-up person..................          927         19.3         71.3
Dry screen operator..............          871         11.7         57.6
Utility worker...................          846         12.4         60.6
Mechanic.........................          761          3.8         43.9
Supervisors/administrators.......          730          9.0         32.2
Laborer..........................          642         17.1         65.7
Dragline operator................          583         34.0         82.5
Backhoe operator.................          546          8.4         52.6
Dryer/kiln operator..............          517         10.5         55.5
Rotary drill operator (electric/                                        
 hydraulic)......................          543         39.6         83.1
Rotary drill operator (pneumatic)          489         64.4        89.0 
------------------------------------------------------------------------
a These occupations comprise about 87 percent of the 42,206 MSHA dual-  
  threshold samples collected in metal and nonmetal mines from March    
  1991 through December 1994. All samples were collected using a        
  personal noise dosimeter over a miner's full-shift.                   


 Table II-14.--Percentage of MSHA Coal Samples by Occupation, Exceeding 
                      Specified TWA8 Sound Levelsa                      
------------------------------------------------------------------------
                                                   90 dBA       80 dBA  
                                                 threshold    threshold 
                                    Number of  -------------------------
            Occupation               samples     Percent of   Percent of
                                                 samples >    samples > 
                                                   90 dBA       85 dBA  
------------------------------------------------------------------------
Continuous miner helper..........           68         33.8         88.2
Continuous miner operator........          262         49.6         96.2
Roof bolter operator (single)....          234         21.8         85.5
Roof bolter operator (twin)......           92         31.5         98.9
shuttle car operator.............          260         13.5         78.5
Scoop car operator...............           94         18.1         74.5
Cutting machine operator.........           22         36.4         63.6
Headgate operator................           20         40.0        100.0
Longwall operator................           34         70.6        100.0
Jack setter (longwall)...........           25         32.0         68.0
Cleaning plant operator..........          107         36.4         77.6
Bulldozer operator...............          225         48.9         94.2
Front-end-loader operator........          244         16.0         76.6
Highwall drill operator..........           83         21.7         77.1
Refuse/backfill truck driver.....          162         13.6         78.4
Coal truck driver................           28         17.9        64.3 
------------------------------------------------------------------------
a Above sampled occupations comprise about 71.0% of the 4,247 MSHA dual 
  threshold samples collected in coal mines from March 1991 to December 
  1995. All samples were collected using a personal noise dosimeter over
  a miner's fullshift.                                                  

    As shown in these tables, the percentage of miners exceeding the 
specified sound levels varied greatly according to occupation. For 
example, Table II-13 shows that only 8.4% of the backhoe operators in 
metal and nonmetal mines had noise exposures exceeding a TWA8 of 
90 dBA using a 90 dBA threshold, while 64.4% of the pneumatic rotary 
drill operators had similar exposures. When reviewing the same two 
occupations, 52.6% of the backhoe operators and 89.0% of the pneumatic 
rotary drill operators would have noise exposures exceeding a TWA8 
of 85 dBA using an 80 dBA threshold.

[[Page 66386]]

Conclusion; Miners at Significant Risk of Material Impairment

    MSHA has prepared an exposure profile of miners based on the data 
presented in this part; the methodology is summarized in the following 
paragraphs and described in detail in the Agency's preliminary RIA. 
Based on this profile, MSHA has concluded that despite many years under 
existing standards, noise exposures in all sectors of mining continue 
to pose a significant risk of material impairment to miners over a 
working lifetime.
    Specifically, MSHA estimates that 15% of coal miners will incur a 
material impairment of hearing under present exposure conditions, or 
18,947 coal miners. The figures are 13% of metal and non-metal miners 
(26,977 metal and nonmetal miners) and 14% of miners as a group (45,924 
miners). (The figures include contract miners but exclude certain 
office workers.)
    To derive this information, MSHA began with the 80 dBA exposure 
data discussed in the prior section. The sampling data were sorted by 
exposure range: e.g., samples with a TWA8 of between 80-84.9 dBA, 
those between 85-89.9 dBA, those between 90-94.9 dBA, and so on.
    The sampling data were then adjusted by subtracting 5 dBA from the 
exposure readings for all samples that had a TWA8 of 90 dBA at the 
90 threshold. These are the samples that would be above the current 
PEL. MSHA assumed that mine operators currently issue personal HPDs to 
miners exposed at or above the PEL, that miners are using the HPDs, and 
that such protection reduces the miner's equivalent TWA8 noise 
exposure by about 5 dBA. (There is an extended discussion in part III 
of this preamble about hearing protector effectiveness, and appropriate 
references, that shed further light on these assumptions.)
    Then the percentage of adjusted samples within each range was 
multiplied by MSHA's estimates of the total number of mine employees. 
Those estimates are based on information gathered by the former USBOM 
(and are presented in part IV of this preamble as part of the Agency's 
industry profile).
    Finally, to establish the number of miners expected to incur a 
material impairment of hearing, the Agency multiplied the number of 
miners in each exposure range by the risk of impairment of exposure at 
that range for a lifetime. For this purpose, the Agency used the 1972 
NIOSH risk estimates discussed earlier in this part. (The Agency is 
aware that NIOSH is currently working on revising its estimates using a 
different model and taking hearing loss at an additional frequency into 
account; but until such an approach is peer reviewed, MSHA has 
concluded it should rely upon the 1972 estimates.)
    Based on these assumptions, Table II-15 presents MSHA's profile of 
the projected number of miners currently at significant risk of 
developing a material impairment of NIHL under existing exposure 
conditions.

                Table II-15.--Projected Number of Miners Likely To Incur NIHL Impairment under Existing Standards and Exposure Conditions               
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                   <80        80-84.9      85-89.9      90-94.9      95-99.9     100-104.99  105     Total*  
--------------------------------------------------------------------------------------------------------------------------------------------------------
Coal.........................................            0          599       11,956        5,622          643          111             16        18,947
M/NM.........................................            0        1,225       16,910        7,580        1,190           62             10        26,977
                                              ----------------------------------------------------------------------------------------------------------
    Total *..................................            0        1,825       28,866       13,201        1,833          173             26       45,924 
--------------------------------------------------------------------------------------------------------------------------------------------------------
* Includes contractor employees. Does not include office workers. Discrepancies are due to rounding.                                                    

    When MSHA promulgated noise standards in 1971 for underground coal 
mines, in 1972 for surface coal mines, and in 1974 for metal and 
nonmetal mines, compliance with the requirements was thought to be 
adequate to prevent the occurrence of NIHL in the mining industry. 
Since that time, however, there have been numerous awards of 
compensation for hearing loss among miners.
    Moreover, MSHA's requirements are dated in light of the Agency's 
experience, that of other domestic and foreign regulatory agencies, and 
the recommendations of experts on what it takes to have an effective 
prevention program. NIOSH, for example, currently recommends a 
comprehensive program which includes the institution of an HCP to 
prevent NIHL; MSHA's current standards do not include such protection.
    In light of current scientific evidence demonstrating that NIHL 
constitutes a serious hazard, the evidence of continuing harm to 
miners, and the fact that MSHA standards no longer reflect experience 
and expert advice, MSHA has concluded that there is a need to replace 
its existing noise standards with new standards that would provide 
additional protection to miners. Section 101(a)(6)(A) of the Federal 
Mine Safety and Health Act of 1977 (Mine Act), states that MSHA's 
promulgation of health standards must:

* * * [A]dequately assure on the basis of the best available 
evidence that no miner will suffer material impairment of health or 
functional capacity even if such miner has regular exposure to the 
hazards dealt with by such standard for the period of his working 
life.

Significant NIHL clearly is the type of material impairment of health, 
which Congress has directed the Secretary of Labor (Secretary) to 
prevent. MSHA has concluded that the new requirements in this proposal 
are necessary to prevent large numbers of miners from suffering 
material impairment of health resulting from exposure to noise. 
Compliance will reduce NIHL among miners and the costs associated 
therewith.
    Based on these studies and MSHA's own calculations and analysis 
presented above, the Agency has concluded that regulatory action is 
necessary to address the continued excess risk of NIHL resulting from 
mining employment.

III. Discussion of Proposed Rule

Summary

    This part of the Supplementary Information reviews the provisions 
of the proposed rule, along with the information, comments and 
alternatives considered by MSHA in developing each feature of the 
proposal.
    While the Agency is seeking to present a complete picture of the 
basis for its preliminary decisions, so as to facilitate comment, space 
considerations preclude a full presentation of all of the sources 
reviewed by the Agency. Part V is a complete reference list of those 
sources. Among other things, part V contains a list of publications by 
the former USBOM that were reviewed by the Agency. Many of these 
describe methods for controlling noise for particular types of mining 
equipment or facilities, and thus supplement the discussion in this 
part about feasible engineering controls. All constitute part of the 
Agency's rulemaking record.

[[Page 66387]]

    In addition to the materials cited in part V, the Agency researched 
the noise regulatory codes of a number of other jurisdictions--
including those of the military and of other countries. While these 
codes are noted in this part in a few summary tables, and discussed in 
connection with certain key requirements being proposed by the Agency, 
the Agency has determined there is no need to elucidate their 
requirements in each and every section of this part. Nevertheless, 
these codes also constitute part of the Agency's rulemaking record.

Section 62.100  Purpose and Scope; Effective Date

Purpose

    The purpose of the standards in proposed part 62 is the prevention 
of occupational noise-induced hearing loss among miners. It is 
important to clearly state the purpose of the regulations: to clarify 
it to the regulated public and Agency personnel, and so that the 
effectiveness of the regulations over time can be measured consistent 
with principles under the Government Performance Results Act.
Scope
    Part 62 would set forth health standards for all coal, metal and 
nonmetal mines, both surface and underground, subject to the Federal 
Mine Safety and Health Act of 1977. MSHA currently has four sets of 
noise standards: for surface metal and nonmetal mines (30 CFR 56.5050), 
for underground metal and nonmetal mines (30 CFR 57.5050), for 
underground coal mines (30 CFR part 70, subpart F), and for surface 
coal mines and surface work areas of underground coal mines (30 CFR 
part 71, subpart I). In fact, however, there are really two groups of 
standards: those applicable to coal mines and those applicable to metal 
and nonmetal mines. This is because the surface and underground 
standards for noise in metal and nonmetal mines are identical; the same 
is true of the surface and underground standards for noise in coal 
mines. The differences between the standards applicable in the coal 
industry and in other mining industries are discussed in detail in the 
following pages.
    Part 62 would establish a single, uniform noise standard applicable 
to all mines. This approach is favored by many. Those who responded to 
MSHA's ANPRM generally agreed that consolidation and simplification of 
multiple standards into one may help to facilitate understanding of, 
and thus compliance with, regulatory requirements. Such an approach is 
also traditional with noise: OSHA's standards apply uniformly to 
hundreds of industries.
    The proposed standard is not identical to the existing coal 
standard nor to the existing metal and nonmetal standard. Nor is the 
proposal identical to the noise standard which has been applicable to 
most other industries since 1983 pursuant to the Occupational Safety 
and Health Act (29 CFR 1910.95). Conditions in the mining industry, 
experience with the current standards, MSHA's review of the latest 
scientific information, the comments submitted in response to the 
ANPRM, and the requirements of the Mine Safety and Health Act have led 
the Agency to propose a standard that is unique in some respects. 
Nevertheless, many key features in the proposal are identical to 
features in one or more of the existing noise standards.
    Several charts comparing the features of the proposed standard to 
the features of existing MSHA and OSHA noise standards are included in 
the ``Question and Answers'' in part I of the Supplementary Information 
accompanying this notice.
Effective Date
    MSHA recognizes that successful implementation of these new and 
uniform health rules will require new training of MSHA personnel and 
guidance to employees and mine operators, particularly small mine 
operators. Accordingly the Agency is proposing that the new standards 
take effect one year after the date of publication of the final rule. 
An alternative would be to phase in the new requirements. The Agency 
believes some could be phased in quickly, but wants to avoid confusion. 
The Agency requests comment on whether a phased-in approach is 
appropriate and how it might most effectively be designed.

Section 62.110  Definitions

    The proposal would include some definitions to facilitate 
understanding.
    The definitions include some technical terms universally used in 
noise measurement, e.g., criterion level.
    The definitions also include some terms used in the mining industry 
in a way that differs from usage in other contexts, e.g., usage under 
the OSHA standard. One example is the term ``hearing conservation 
program'' or ``HCP.'' Under the proposal, requirements for hearing 
protectors and training are not always linked to audiometric testing 
results as they are under the OSHA standard. To avoid confusion, the 
proposal defines a hearing conservation program as a generic reference 
to those sections of the proposal that set forth the requirements for 
an audiometric testing program. Another example is the definition of 
``qualified technician''.
    The definitions also include some terms which are non-standard. In 
particular, the Agency is proposing to use the term ``supplemental 
baseline audiogram'' instead of the more commonly used ``revised 
audiogram''; MSHA believes its terminology will make it easier for the 
mining industry to understand the requirements of the proposal.
    The discussion which immediately follows summarizes the salient 
features of the definitions. A more detailed discussion of the 
definitions is contained in those sections of the preamble which review 
the context in which each definition is to be used.
Access
    Access is the right to examine and copy records. This is consistent 
with the use of this term in several of MSHA's and OSHA's existing 
health standards.
Audiologist
    A professional, specializing in the study and rehabilitation of 
hearing, who is certified by the American Speech-Language-Hearing 
Association or licensed by a state board of examiners. MSHA has 
included this definition primarily to indicate which organizations 
certify or license audiologists. MSHA has decided that all practicing 
audiologists should be either licensed or certified by one or both of 
the above organizations. This term is considered in the section of this 
preamble that discusses proposed Sec. 62.140 Audiometric testing 
program.
Baseline Audiogram
    The audiogram against which future audiograms are usually compared. 
By comparing an annual audiogram to the baseline audiogram the 
progression of noise-induced hearing loss can be determined. This term 
is considered in the section of this preamble that discusses proposed 
Sec. 62.140, Audiometric testing program.
Criterion Level
    This refers to the sound level which if applied for 8 hours results 
in a dose of 100% of that permitted by the standard. Under proposed 
Sec. 62.120(a), the criterion level would be a sound level of 90 dBA. 
If applied for 8 hours, this sound level would result in a dose of 100% 
of the permissible exposure limit (PEL), established by proposed 
Sec. 62.120(c) as an 8-hour-time-weighted average of 90 dBA. The PEL 
and the

[[Page 66388]]

criterion level are not the same thing. While the PEL is a sound level 
of 90 dBA for 8 hours, it is also a sound level of 95 dBA for 4 hours; 
the criterion level is always a constant, derived from what the PEL is 
at 8 hours of exposure.
Decibel (dB)
    Unit of measurement of sound. Decibel is used to describe 
environmental/occupational sounds and hearing acuity.
Decibel, A-weighted (dBA)
    Sound levels measured using the A-weighting network. There are 
several frequency response networks which have been developed, as noted 
in the section of the preamble discussing proposed Sec. 62.120(a). A-
weighting refers to the frequency response network closely 
corresponding to the frequency response of the human ear. This network 
attenuates sound energy in the upper and lower frequencies (<1000 and 
>5000 Hz) and slightly amplifies those frequencies between 1000 and 
5000 Hz. The characteristics of the A-weighting network are found in 
ANSI S1.25-1991, ``Specification for Personal Noise Dosimeters''.
Designated Representative
    A designated representative is an individual or organization to 
whom a miner gives written authorization to exercise a right of access 
to records, pursuant to proposed Sec. 62.200.
Exchange Rate
    The amount of increase or decrease in sound level which would 
require halving or doubling the allowable exposure time to maintain the 
same noise dose. In this proposal, a 5-dBA increase in the sound level 
would correspond to a halving of the allowable exposure time. Exchange 
rate is discussed in detail in the section of this preamble discussing 
proposed Sec. 62.120 Noise exposure levels.
Hearing Conservation Program (HCP)
    An HCP is designed to detect early changes in a miner's hearing 
acuity so that corrective action can be instituted to minimize future 
hearing loss. In general parlance, an HCP is a system of audiological 
examinations that provide guidance for the use of hearing protectors, 
other controls, and training. In the proposed rule, however, hearing 
protector use and training linked to audiological examinations are only 
a limited subset of the hearing protector and training requirements. 
Accordingly, to avoid confusion, the term ``hearing conservation 
program'' in the proposed rule is defined as a generic reference to the 
requirements of Secs. 62.140 through 62.190 of part 62, the 
requirements dealing with audiological examinations and the corrective 
actions linked thereto.
Hearing Protector
    The purpose of this definition is to clarify that not all devices 
or materials inserted in or that cover the ear to reduce the noise 
exposure can qualify as a hearing protector. For example, MSHA does not 
consider a hearing aid as a hearing protector.
    A hearing protector must meet two requirements. First, to be a 
hearing protector a device must be sold wholly or in part on the basis 
of its ability to reduce the level of sound entering the ear. Thus, 
cotton would not be an acceptable hearing protector. Second, the device 
must have a scientifically accepted indicator of noise reduction value.
    MSHA's definition encompasses that used in the Environmental 
Protection Agency's (EPA) labeling standards for hearing protectors (40 
CFR Sec. 211.203(m)). The EPA defines a hearing protector as:

* * * any device or material, capable of being worn on the head or 
in the ear canal, that is sold wholly or in part on the basis of its 
ability to reduce the level of sound entering the ear. This includes 
devices of which hearing protection may not be the primary function, 
but which are nonetheless sold partially as providing hearing 
protection to the user.

    EPA requires that all hearing protector manufacturers include 
labeling information with their products that indicate their Noise 
Reduction Rating (NRR). Thus, if a hearing protector has such a label, 
the mine operator can be confident that it meets MSHA's definition of a 
hearing protector. As noted in the discussions of proposed 
Sec. 62.120(a), MSHA does not believe the NRR ratings are meaningful in 
workplace situations; moreover, other organizations have recommended 
that the EPA reconsider the rating system it uses. MSHA is therefore 
not proposing to delimit the range of hearing protectors that may be 
offered to only those with an NRR as such; rather, any scientifically 
accepted indicator of noise reduction value will be acceptable evidence 
of the product's purpose.
    The Agency is interested in comments on this definition.
Hertz (Hz)
    A unit of measurement of frequency, numerically equal to cycles per 
second. The range of audible frequencies is 20 to 20,000 Hz.
Medical Pathology
    A condition or disease affecting the ear. The term is used in the 
proposed rule in contexts which do not require actual diagnosis and 
treatment; see specifically the discussion of proposed Secs. 62.125 and 
62.170. Medical conditions of this type should ultimately be diagnosed 
and treated by a physician specialist, e.g., an otolaryngologist.
Qualified Technician
    A technician who has been certified by the Council for 
Accreditation in Occupational Hearing Conservation (CAOHC) or by 
another recognized organization offering similar certification. MSHA 
has decided that requiring a technician to be certified would ensure 
that audiometric tests are administered by a competent person. The 
definition of ``qualified technician'' is discussed in connection with 
proposed Sec. 62.140 Audiometric testing program.
Reportable Hearing Loss
    This defines the extent of hearing loss which must be reported to 
MSHA so the Agency can intervene to prevent further hearing loss. Such 
reporting is already required pursuant to 30 CFR part 50. This 
definition clarifies how the requirements of 30 CFR part 50 apply in 
the case of noise.
    The definition in the proposed rule would require that hearing loss 
be calculated by subtracting the current hearing levels from those on 
the baseline audiogram at 2000, 3000, and 4000 Hz; when the permanent 
hearing losses at each frequency are averaged (added up and divided by 
three), the hearing loss must be reported if the average loss in either 
ear has increased by 25 dB. In making this calculation, a supplemental 
baseline audiogram would be used in lieu of the baseline audiogram in 
those cases in which the supplemental audiogram was created because of 
a significant improvement in hearing acuity, in accordance with the 
provisions of proposed Sec. 62.140(d)(2).
    The definition of reportable hearing loss is discussed in 
connection with proposed Sec. 62.190, Notification of results; 
reporting requirements. As discussed therein, the Agency is 
specifically seeking comment on two points: (a) an appropriate 
definition of reportable hearing loss in those cases in which operators 
lack an audiometric test record; and (b) the nature of the hearing loss 
that MSHA should capture through its part 50 reporting system.

[[Page 66389]]

Sound Level (in dBA)
    The sound pressure level measured in decibels using the A-weighting 
network and exponential time averaging. Pursuant to proposed 
Sec. 62.120(a)(3)(iv), sound pressure levels would be measured using 
the A-weighting network and the slow-response time constant. Sound 
consists of pressure changes in air caused by vibrations. These 
pressure changes produce waves that move out from the vibrating source. 
The sound level is a measure of the magnitude of these pressure changes 
and is generally perceived as loudness.
Standard Threshold Shift (STS)
    This defines the extent of hearing loss which requires intervention 
by a mine operator pursuant to proposed Sec. 62.180.
    An STS is a measure of permanent change for the worse--relative to 
a miner's baseline audiogram, or relative to the most recent 
supplemental audiogram where one has been established pursuant to 
proposed Sec. 62.140(d). The definition in the proposed rule would 
require that hearing loss be calculated by subtracting the current 
hearing levels from those measured by the baseline (or supplemental) 
audiogram at 2000, 3000, and 4000 Hz; when the hearing losses at each 
frequency are averaged (added up and divided by three), the hearing 
loss would be considered an STS if the average loss in either ear has 
reached 10 dB.
    MSHA discusses this definition in detail in connection with 
proposed Sec. 62.160, Evaluation of audiogram.
    By contrast with an STS, a temporary threshold shift (TTS) is a 
temporary change in hearing acuity, which corrects itself after sound 
levels are decreased and does not permanently impair hearing. The 
latter term is used frequently in the preamble, but is not needed in 
the proposed rule.
Supplemental Baseline Audiogram
    This is an annual audiogram used in certain specific cases in lieu 
of the baseline audiogram to measure reportable hearing loss or 
standard threshold shift. Some professionals prefer the term 
``revised'' baseline audiogram; in this proposal, ``supplemental'' is 
used to ensure mine operators are clear that the integrity of the 
original ``baseline'' audiogram must be preserved.
    A supplemental baseline audiogram is established under the 
circumstances set forth in proposed Sec. 62.140(d)(1) or 62.140(d)(2). 
See the discussion of those sections in this preamble, as well as the 
related discussions of ``reportable hearing loss'' and ``standard 
threshold shift.''
Time-Weighted Average-8 Hour (TWA8).
    That sound level, which if constant over an 8-hour time period, 
would result in the same noise dose as is measured. This yardstick 
measurement is used in the rule in connection with various limitations; 
for example, the proposed PEL would be a TWA8 of 90 dBA.
    Not all noise measurement instruments give readouts in terms of 
time-weighted 8-hour averages. Many personal noise dosimeters, for 
example, measure noise as a percentage of permitted dosage, with the 
PEL equated to 100%. Mine operators therefore need to convert noise 
dose to an equivalent TWA8 to determine if the action level or the 
PEL has been exceeded, and to evaluate the impact of engineering 
controls. Accordingly, MSHA has provided a list of TWA8 conversion 
values in Table 62-2, included in proposed Sec. 62.120. The table has 
been compiled by equating a dose of 100% to the proposed PEL. For 
example, a dose of 50% equals a TWA8 of 85 dBA--the level at which 
some protective action must be taken under the proposal.
    The TWA8 and the dose are to be used interchangeably. Since 
the noise exposure will be measured for the entire shift, compliance 
with the noise standard will be based upon the measured dose. If the 
measured dose exceeds 100%, regardless of the length of the workshift, 
the miner will be considered to be overexposed to noise. It would thus 
be improper to adjust a TWA8 reading for an extended work shift.
    Care should be taken not to assume that those models of personal 
noise dosimeters which give readouts in both the noise dose and the 
``average sound level'' in dBA are giving a TWA8 readout. The 
``Lavg'', or average sound level, is the constant sound level 
which equals the dose over the measurement period. The value of the 
TWA8 is the same as the Lavg if the measurement period is 8 
hours.
    It should be noted that the TWA8 is a term used in the context 
of a 5-dB exchange rate. In the context of a 3-dB exchange rate, the 
equivalent term is the ``Leq,8''. The latter term is used 
occasionally in the preamble--in discussing the possible use of a 3-dB 
exchange rate, and in those studies performed with data from countries 
using a 3-dB exchange rate.

Section 62.120  Limitations on Noise Exposure

Introduction
    The provisions of this section of the proposed regulation deal with 
some critical subjects: how to compute a miner's noise dose; the 
hierarchy of controls at different noise exposure doses; and the 
monitoring of noise exposure.
    Specifically, paragraph (a) of proposed Sec. 62.120 provides the 
parameters for computing the amount of noise to which a miner is 
exposed--a miner's noise dose. Paragraphs (b) through (d) establish a 
series of noise exposure limitations, and the specific mine operator 
actions required if noise exceeds that level. Paragraph (e) establishes 
a ceiling on sound levels to which a miner may be exposed. Paragraph 
(f) establishes a mine operator's obligation to evaluate each miner's 
noise exposure to determine if it exceeds any of the limitations 
established by this section, and to notify miners at risk.
    A short summary of each subsection follows. Thereafter, a more 
detailed presentation is provided.
Sec. 62.120(a)
    Proposed paragraph (a) sets forth a formula for dose computation 
which corresponds to the measurements made by most current personal 
noise dosimeters. It further specifies that: all sound levels from 80 
dBA to at least 130 dBA be integrated into the dose measurement, 
including impact/impulse noise in that range; noise be measured over a 
full shift; a 5-dB exchange rate be used; and that measurements be made 
using the A-weighting network and slow response instrument settings. 
This paragraph also clarifies that measurement of noise dosage is to be 
made without regard for the effect of a hearing protector.
    The exchange rate is the measure that reflects how much of a 
decrease in exposure time is required when the sound level increases. 
The proposed 5-dB exchange rate is the same as under current standards. 
Using that rate, the exposure permitted at a sound level of 90 dBA is 
half that permitted at a sound level of 85 dBA--a miner gets the same 
noise dose in 4 hours at 90 dBA as at 8 hours at 85 dBA.
    The Agency currently uses a 5-dB exchange rate. There appears to be 
a consensus in the recent literature for an exchange rate of 3-dB. 
Moreover, the current 5-dB exhange rates incorporates an assumption 
that there is significant time for hearing to recover from high sound 
levels. MSHA has concluded that

[[Page 66390]]

noise exposure under mining conditions does not warrant such an 
assumption. A 3-dB exchange rate does not incorporate this assumption.
    Nevertheless, the Agency is proposing to retain the existing 5-dB 
exchange rate because of feasibility considerations. Changing to a 3-dB 
rate from a 5-dB rate would significantly reduce the amount of time 
that miners could be exposed to higher sound levels without exceeding 
the permissible exposure limit. For example, MSHA estimates that the 
percentage of miners whose exposure would be in violation of a PEL set 
at a Leq,8 of 90 dBA would be just about double that of a PEL set 
at a TWA8 of 90 dBA. This means mine operators would have to 
utilize controls to reduce exposures to the PEL more frequently--and 
the controls required to reduce exposures that much would be more 
expensive. Furthermore, it is extremely difficult to reduce the noise 
exposures to below a Leq,8 of 90 dBA using currently available 
engineering or administrative noise controls or a combination thereof. 
Accordingly, moving the industry to a 3-dB exchange rate may be 
infeasible at this time. (Part IV contains a further discussion of 
feasibility issues.)
    Two features proposed with respect to noise measurement of 
particular significance are: lowering the threshold at which sound 
levels are integrated into a miner's noise dose, and prohibiting the 
adjustment of noise measurements to provide credit for hearing 
protector attenuation.
    MSHA is proposed that the threshold for integrating noise into dose 
measurements be expanded to cover sounds as low as 80 dBA. This 
decision is based on strong evidence that such exposures do contribute 
to hearing impairment. While more protective than the present threshold 
of 90 dBA, this change will generally result in higher dose readings in 
both the coal and metal and nonmetal sectors than at present. For 
example, MSHA's dual-threshold survey indicated that in the metal and 
nonmetal industry, the percentage of samples above the PEL increased 
from 17.4% at a 90 dBA threshold to 26.4% at an 80 dBA threshold; in 
coal the figures increased from 25.3% to 35.6%.
    Moreover, the proposed regulation would not allow dose measurements 
to be adjusted in those cases in which miners are wearing hearing 
protectors. This is consistent with the thrust of the proposal to 
establish for all mining sectors a hierarchy of controls for noise in 
which primary reliance will be upon engineering and administrative 
controls.
Sec. 62.120(b)
    Proposed paragraph (b) establishes an ``action level'' at a 
TWA8 of 85 dBA.
    The need for an action level reflects two facts: (1) There is a 
significant risk of material impairment to miners from a lifetime of 
exposure to noise at this level; and (2) the Agency believes it may not 
be feasible at this time to lower the PEL to this level, since that 
would require that mine operators use all feasible engineering and 
administrative controls to reduce noise exposures to this level.
    The proposal would require that all miners exposed above the action 
level be provided special instruction in the hazards of noise and 
protective methods. The training is to be provided annually for as long 
as exposure exceeds the action level. (The nature of this instruction, 
how it is to be provided, and how it can be coordinated with other 
required miner training are subjects discussed in connection with 
proposed Sec. 62.130.)
    If a miner's exposure exceeds the action level but is below the 
PEL, an operator will also be required to enroll a miner whose exposure 
exceeds the action level in a hearing conservation program (HCP). While 
enrollment in the HCP would require the operator to make annual 
audiometric testing available to the miner, miners exposed to noise 
below the PEL would have the right to decline taking any annual 
audiometric testing. The requirements for such testing are discussed in 
connection with proposed Sec. 62.140, audiometric test procedures. MSHA 
is seeking comments on how to minimize the burden on mine operators of 
providing audiometric examinations for those miners with only a 
temporary attachment to the mining work force (e.g., summer employees), 
while recognizing the importance of detecting and tracking hearing loss 
among those who switch jobs.
    In addition, the operator must provide properly fitted hearing 
protection--before the initial hearing examination, if a significant 
threshold shift in hearing acuity is detected, and at any other time 
upon miner request. Should it take more than 6 months to provide the 
initial hearing examination because of the need to wait for a mobile 
test van, or should a significant threshold shift in hearing acuity be 
detected, the operator would also be required to ensure that the miner 
wear the hearing protection--even if the miner's noise exposure remains 
under the PEL. (A discussion of the timeframes for audiometric tests, 
and the use of mobile test vans, is included in the discussion of 
proposed Sec. 62.140, audiometric test program. The definition of a 
significant threshold shift is discussed in connection with proposed 
Sec. 62.160, evaluation of audiogram).
    An action level currently exists under OSHA but would be new to the 
mining industry. As discussed herein, MSHA proposes to build upon the 
requirements which have been used by OSHA while giving due regard to 
implementation approaches appropriate to the circumstances of the 
mining community.
Sec. 62.120(c)
    Proposed paragraph (c) would establish the permissible exposure 
limit (PEL) to noise for a miner as a TWA8 of 90 dBA during any 
workshift. (This is also referred to as a dose measurement of 100%; the 
action level TWA8 of 85 dBA is half this dose of noise.) The 
proposal further provides that if the PEL is exceeded, in addition to 
the controls required at the action level, the mine operator shall use 
all feasible engineering and administrative controls to reduce the 
miner's noise exposure to the PEL. The mine operator has a choice of 
whether to use engineering controls, administrative controls, or both; 
but if administrative controls are utilized, a copy of the procedures 
involved must be posted, and copies given to the affected miners.
    If reducing the dose to this level with such controls is not 
feasible, the proposal requires the mine operator to use such controls 
to lower the noise exposure as much as is feasible.
    In addition, in such cases, the proposal requires that the operator 
take extra steps to protect miner hearing. The operator must ensure all 
miners so exposed take the annual hearing examinations, must provide 
properly fitted hearing protection to all miners so exposed, and must 
ensure the hearing protection is used by all miners so exposed.
    Under the proposal, a consistent hierarchy of controls is 
established for all mines. Mine operators must first utilize all 
feasible engineering and administrative controls to reduce sound levels 
to the PEL before relying on other controls to protect against hearing 
loss. This approach is consistent with that currently in place for 
metal and nonmetal mines, but would be a change for coal mines. As 
discussed herein (in connection with proposed Sec. 62.125, hearing 
protectors), MSHA has considerable evidence that primary reliance upon 
hearing protectors, as is the current case in the coal industry, is 
misplaced.
    As under the present standards, the proposal would require a mine 
operator

[[Page 66391]]

to use only such engineering controls as are technologically feasible, 
and to use only such engineering and administrative controls as are 
economically feasible for that mine operator.
    As noted, the proposed rule provides for supplemental controls in 
those cases in which the Agency concurs with a mine operator that the 
use of all feasible engineering and administrative controls cannot 
reduce noise to the PEL. MSHA believes that when a miner is exposed to 
such high levels of noise, these supplemental obligations are necessary 
to protect miner hearing. Hearing protectors are not without their 
discomforts; but the risk of hearing loss at such exposure levels ought 
to be the controlling factor. While audiometric testing is not an 
invasive procedure, the Agency is concerned that there may be economic 
pressures and personal reasons that may lead miners to decline to take 
hearing examinations. The information generated by these tests is 
necessary, however, to trigger investigation of potentially serious 
flaws in the layers of noise controls required at these high exposure 
levels. In addition, the Agency believes that miners operating under 
such high noise conditions should be aware of the severity of any 
hearing loss; in a mining environment, this knowledge could have 
implications for the safety of the miner and the safety of others. 
Comments on this provision are specifically solicited.
Sec. 62.120(d)
    Proposed paragraph (d) provides that should a miner's noise 
exposure exceed a TWA8 of 105 dBA during any workshift, a dose of 
800% of the PEL, the mine operator shall, in addition to taking all of 
the actions required when exceeding the PEL, require the miner to use 
dual hearing protection--i.e. both a plug type and a muff type hearing 
protector. In this context, the Agency presents information about the 
mining jobs at which the exposures of this level are occurring; and 
requests comment on whether there should be an absolute dose ceiling, 
regardless of the feasibility of control by an individual mine 
operator.
Sec. 62.120(e)
    Proposed paragraph (e) would provide that at no time shall a miner 
be exposed to sound levels exceeding 115 dBA.
Sec. 62.120(f)
    Proposed paragraph (f) consists of two parts. First, it would 
require mine operators to establish a system of monitoring which 
effectively evaluates each miner's noise exposure. This will ensure 
that mine operators have the means to determine whether a miner's 
exposure exceeds any of the limitations established by this section, as 
well as to assess the effectiveness of noise controls. The proposed 
rule is performance oriented in that the regularity and methodology 
used to make this evaluation are not specified. Specific requirements 
for periodic monitoring now applicable to the coal sector would be 
revoked.
    Proposed paragraph (f) would also require that miners be notified 
in writing should their exposure exceed any of the levels specified by 
this section--whether based on operator or MSHA evaluations of noise. 
Notice would be required within 15 calendar days.
    The proposal has been designed to ensure that miners are made aware 
of the hazards they currently face. Miners exposed above the action 
level should be notified of that fact so, for example, they can 
consider the importance of using provided, properly fitted and 
maintained hearing protectors. On the other hand, the proposal does not 
require notification of a particular miner if an exposure measurement 
indicates that the miner's exposure has not changed and the miner has 
within the last year been apprised of the same information.
    The proposal has no provision for requiring the posting of warning 
signs.
Dose Computation
    Proposed Sec. 62.120(a) sets forth important technical 
specifications on computing noise dose. These specifications were 
utilized in the establishment of the limitations set forth in this 
section; they therefore must be utilized in dose measurements taken to 
determine compliance.
Using a Personal Dosimeter
    The dose itself is usually read directly from a personal noise 
dosimeter. The dosimeter is set to the specifications required by the 
proposed standard (e.g. 80 dB threshold), attached to the miner, and 
the total dose read out at the end of the full work shift.
Using a Sound Level Meter
    Some operators may prefer to take a series of individual readings 
with sound level meters, and derive the dose from these readings. 
Accordingly, the proposal also sets forth the formula for determining 
the dose in this fashion.
    Proposed Sec. 62.120(a)(1) would specify that noise dose is to be 
computed by combining the sound levels during various periods of time 
during the miner's measurement period, in accordance with the formula:

D=100(C1/T1 + C2/T2+ * * * +Cn/Tn),

where:

D=the percent of permissible exposure,
Cn=the total time of exposure at a specified sound level, and
Tn=the reference duration of exposure at that level, as listed in 
Table 62-1.

    Table 62-1 contains reference durations for sound levels from 85 to 
115 dBA. The sound levels to be integrated into the dose measurement 
pursuant to this proposal actually range from 80 to 130 dBA. Reference 
durations for sound levels not in the table can be calculated pursuant 
to the formula in the table note. (For a detailed discussion of this 
topic see the section of this preamble entitled Threshold and range of 
integration.)
    As noted, current personal noise dosimeters automatically compute a 
miner's noise exposure essentially using the above formula. In fact, 
noise dose is relatively simple to compute when the sound level is 
constant throughout the work shift. For example, a miner is exposed to 
95 dBA for 2 hours and has no additional noise exposure. The reference 
duration, from Table 62-1, for 95 dBA is 4 hours. Substituting the 
values into the above formula yields:

D=100 (\2/4\) or equivalently 50%.

    When a miner is exposed to fluctuating sound levels, the total 
noise dose can be computed using the same formula. For example, a miner 
is exposed to 90 dBA for 1 hour, 95 dBA for 2 hours and 100 dBA for 1 
hour. The reference durations from Table 62-1 are 8 hours, 4 hours, and 
2 hours, respectively. Substituting the values into the above formula 
yields:

D=100 (\1/8\+\2/4\+\1/2\ ) or 100 (0.125+0.50+0.50) or equivalently 
112.5%.
Conversion of Dose to TWA8
    Table 62-2, included in proposed Sec. 62.120(a)(2), has been 
constructed to permit dosage measurements to be converted readily into 
time-weighted average 8-hour (TWA8) measurements.
    The TWA8 is the sound level which if constant over an 8-hour 
time period, would result in the same noise dose as is measured. This 
yardstick measurement is the one used to establish the action level, 
PEL, and double-hearing protection supplemental control level in the 
proposed regulation. Since personal noise dosimeters measure noise as a 
percentage of permitted dosage, with the permissible exposure limit 
(PEL) equated to 100%, this table allows for ready conversion of

[[Page 66392]]

those measurements into a form that measures compliance.
    As stated previously, the TWA8 and the dose are to be used 
interchangeably. It is intended that the TWA8 not be adjusted for 
extended work shifts. Since the noise exposure will be measured for the 
entire shift, compliance with the noise standard will be based upon the 
measured dose. If the measured dose exceeds 100%, regardless of the 
length of the workshift, the miner will be considered to be overexposed 
to noise. MSHA requests commenters to review the proposed rule and 
offer suggestions to help the Agency ensure that this intention is 
clearly conveyed in the rulemaking language.
    The table has been constructed by equating the proposed PEL to a 
dose of 100%. More specifically, the TWA8 conversion values in 
Table 62-2 are based on the use of a 90 dBA PEL, 80 dBA threshold, and 
a 5-dB exchange rate. Interpolation for values not found in this table 
can be determined from the following formula: TWA8=16.61 
log10(D/100)+90, where D is the percent dose.
    It is important to understand that the exposure is interpreted as 
if averaged over 8 hours. Thus, if a miner only works for 5 or 6 hours, 
the sound levels can be higher during those hours than if the miner 
works for 8 hours. Conversely, if a miner works an extended shift 
(greater than eight hours), the sound levels would need to be lower. 
Some current models of personal noise dosimeters will provide readings 
in both dose and the average sound level (Lavg) over the sampling 
period. Although the Lavg is useful in some circumstances, it is 
only equal to the TWA8 when the period sampled is 8 hours.
Consideration of Hearing Protector Attenuation
    Proposed Sec. 62.120(a)(3)(i) would require that when determining a 
miner's noise dose, the attenuation of hearing protectors not be 
considered. This provision would supplement the intent of proposed 
Sec. 62.120(c) to preclude the current practice in the coal industry of 
not issuing a citation based upon a noise exposure that exceeds the PEL 
when the miners are wearing hearing protection.
    Several commenters recommended that no credit be given for hearing 
protector attenuation in determining the miner's noise dose. These 
commenters believed that engineering or administrative controls should 
be given primacy over hearing protectors.
    Other commenters, however, supported an allowance for hearing 
protector attenuation. Their recommendations varied from allowing the 
full NRR value, to allowing only a 5 decibel attenuation for all makes 
and models of hearing protectors.
    Field studies in mining by Giardino and Durkt (1996), Kogut and 
Goff (1994), Giardino and Durkt (1994), Durkt (1993), Goff, et. al. 
(1986), Durkt and Marraccini (1986), and Goff and Blank (1984) have 
shown that the measured hearing protector attenuation at mines is far 
less than the attenuation measured in the laboratory and is in some 
cases minimal. Furthermore, the measured attenuations were highly 
variable. These two factors make it virtually impossible to accurately 
predict the in-mine effectiveness of hearing protectors in reducing 
noise exposures. A more detailed discussion of hearing protector 
performance and attenuation rating methods is presented in the Hearing 
protector effectiveness section of this preamble.
    Table III-1 presents three types of information from various 
jurisdictions. These items are--
    (1) the consideration of hearing protector attenuation when 
determining the occupational noise exposure;
    (2) the weighting network used for measuring occupational noise 
exposure; and
    (3) the instrument response time for measuring non-impulse/impact 
occupational noise.

           Table III-1.--Features of Selected Legislation or Guidelines for Evaluating Non-Impulse/Impact Noise Tabulated for Various Entities          
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                     Credit for hearing protector                                                                                       
              Entity                         attenuation                Weighting network                            Response times                     
--------------------------------------------------------------------------------------------------------------------------------------------------------
U.S. Army........................  No.............................  A-weighting..............  Slow.                                                    
U.S. Navy........................  Implied........................  A-weighting..............  Slow.                                                    
U.S. Air Force...................  No.............................  A-weighting..............  Slow.                                                    
Canada (consensus)...............  Not addressed..................  A-weighting..............  Slow (SLM only).                                         
EEC..............................  No.............................  A-weighting..............  Slow or fast.                                            
Australia (consensus)............  No.............................  A-weighting..............  Fast (integrating SLM) or slow (SLM)                     
Australia (national).............  No.............................  A-weighting..............  Fast (integrating SLM) or slow (SLM).                    
Western Australia................  No.............................  A-weighting..............  Fast (integrating SLM) or slow (SLM).                    
South Africa.....................  Implied no.....................  A-weighting..............  Slow.                                                    
ISO (consensus)..................  Implied no.....................  A-weighting..............  Fast (SLM).                                              
ACGIH (consensus)................  Implied no.....................  A-weighting..............  Slow.                                                    
--------------------------------------------------------------------------------------------------------------------------------------------------------

    In reviewing the procedures for exposure measurement in regulations 
and codes of practice (mandatory or recommended) from the selected 
branches of the U.S. armed services, international communities, the 
ISO, and the ACGIH, MSHA found that some diversity exists among the 
methods used (See Table III-1). Nearly all of the entities either 
specify or imply that attenuation provided by hearing protectors should 
not be considered in determining a worker's noise exposure.
    Based on this information, MSHA has concluded that it would be 
inappropriate to consider the attenuation of hearing protectors in 
determining a miner's noise dose. As computed, the noise dose provides 
a measurable foundation upon which can be built a noise control 
program: including, as discussed herein, the use of hearing protectors 
to attenuate that noise dose.
    This provision would supplement the intent of proposed 
Sec. 62.120(c) to preclude MSHA's current practice in the coal industry 
of not issuing a citation based upon a noise exposure that exceeds the 
PEL when the miners are wearing hearing protection. This is consistent 
with the thrust of the proposal to establish for all mining sectors a 
hierarchy of controls for noise in which primary reliance will be upon 
engineering and administrative controls. These issues are discussed at 
length in connection with proposed Sec. 62.120(c) under Hierarchy of 
controls and Hearing protector effectiveness.
Threshold and Range of Integration
    Proposed Sec. 62.120(a)(3)(ii) would require that all sound levels 
from 80 dBA to 130 dBA be integrated into the

[[Page 66393]]

miner's noise dose for determining compliance with the PEL. Sound 
levels less than 80 dBA would not be included in the noise exposure 
computation. By not excluding any particular types of sound from the 
requirement, MSHA intends that the term ``all sound levels'' include, 
but is not limited to, continuous, intermittent, fluctuating, impulse, 
and impact noise.
    MSHA currently uses a threshold of 90 dBA for all purposes. OSHA, 
however, uses a dual threshold: a 90 dBA threshold for measuring 
whether a dose exceeds its PEL (TWA8 of 90 dBA), and an 80 dBA 
threshold for determining whether a dose exceeds its action level 
(TWA8 of 85 dBA).
    Many of the commenters to MSHA's ANPRM supported a threshold of 80 
dBA. Some specifically supported a single threshold. One of these 
commenters stated the following:

    It was an undue burden on employers when OSHA adopted a dual 
threshold level (90 dBA when sampling for PEL and 80 dBA when 
sampling for a Hearing Conservation Program). Few employers in our 
practice understand the difference, and in fact, very few service 
providers in our area understand the dramatic differences these two 
threshold levels can create. MSHA has the opportunity to correct 
this [oversight] by OSHA, and would be wise to adopt the 80-dBA 
threshold.

    Another commenter stated:

    MSHA should use an 80-dBA threshold for integrating noise on 
dosimeters for both compliance with the PEL and the action level. 
The exposure characterization of levels between 80 dBA and 130 dBA 
would be more accurate using an 80-dBA threshold dosimeter versus a 
90-dBA integrating dosimeter.

    A third commenter recommended the following:

    One threshold level should be used for all measurements--80 dBA. 
A single threshold level of 80 dBA, as compared to separate 
thresholds of say, 90 dBA and 80 dBA, would greatly simplify and 
reduce the costs of measuring noise exposure levels and would 
provide an additional margin of safety.

    Several commenters recommended that the current threshold of 90 dBA 
be retained. One of these commenters stated the following:

    * * * multiple thresholds would be extremely burdensome and 
costly and would require companies to purchase and use meters that 
integrate at different levels. * * * the requirement that more than 
one threshold be used is unsupported by reliable and widely accepted 
scientific data and is unnecessary for protection of the health of 
miners.

    Two commenters supported the use of a dual threshold consistent 
with OSHA's current standard, while another commenter recommended a 
threshold of 75 dBA, because EPA had said that 75 dBA equates to no 
risk.
    One mining association commented that a member company had 
collected about 4,500 samples between 1985 and 1988 using personal 
noise dosimeters set at an 80 dBA threshold and found that about 20% of 
the measurements equalled or exceeded the PEL. MSHA notes these results 
are comparable to the results of the dual-threshold survey conducted by 
the Agency and reviewed in part II.
    According to ACGIH (1994) all sound levels exceeding 80 dBA should 
be integrated into the daily noise exposure. Because permissible 
durations are presented for sound levels up to 139 dBA, the range of 
integration can be inferred to be 80 to 139 dBA.
    ANSI S1.25-1991, ``Specification for Personal Noise Dosimeters'', 
recommends that the threshold level be set at least 5 dB below the 
criterion level. Although ANSI S1.25-1991 specifies personal noise 
dosimeters to have an operating range of at least 50 dB, most currently 
manufactured personal noise dosimeters have an operating range greater 
than 50 dB. In addition, these personal noise dosimeters will integrate 
sound levels up to 140 dBA to include impulse/impact noise at pre-
selected thresholds of 80 dBA, 85 dBA, and 90 dBA.
    There is general agreement among the EEC, the ISO, the 
international community, and selected branches of the U.S. armed 
services that all types of noise be integrated in the worker's noise 
dose; however, a threshold is not always specified.
    Moreover, based on its review of the available evidence, MSHA has 
determined that the use of a single 80 dBA threshold for determining a 
miner's noise exposure is necessary for miner protection. Its many 
advantages include:
    (1) it would address the risk of hearing impairment from prolonged 
exposure (greater than 8 hours) above 80 dBA;
    (2) it would improve the accuracy of exposure measurements, 
ensuring that at-risk miners would be accurately identified;
    (3) it is consistent with OSHA's 80 dBA threshold for HCP 
requirements, allowing for comparison data;
    (4) it would be less burdensome than using dual thresholds, 
allowing the use of a single, less complex personal noise dosimeter to 
collect the required information rather than a more expensive 
instrument or two separate instruments; and
    (5) a single threshold is appropriate in as much as MSHA's proposed 
approach to hearing conservation is linked closely to other parts of 
its proposal.
    Several consequences should be noted of switching to a threshold of 
80 dBA from the present threshold of 90 dBA. As noted in part II of 
this preamble, MSHA inspectors conducted comparative sampling for 
several years, simultaneously collecting readings at both the 90 dBA 
and 80 dBA thresholds. Tables II-11 and II-12, located in part II of 
the Preamble, show the effect of using an 80 dBA threshold versus a 90 
dBA threshold with a criterion level of 90 dBA. Of the more than 42,000 
samples collected in metal/non-metal mines, for example, 7,360 (17.4%) 
exceeded a criterion of 90 dBA using a 90 dBA threshold; whereas, 
11,150 (26.4%) exceeded the 90 dBA criterion using an 80 dBA threshold. 
Hence, the use of an 80 dBA threshold will result in a higher 
proportion of samples exceeding the PEL. Also, an 80 dBA threshold 
means that in the case of an extended workshift of more than 8 hours, 
sound levels that average below 90 dBA can result in a dose that 
exceeds the PEL. For example, the PEL for a 16-hour workshift is 85 
dBA, which equates to a TWA8 of 90 dBA.
    Further, based upon research conducted by MSHA, the Agency has 
determined that the effect of switching to a lower threshold is not 
linear. Sound levels just under 90 dBA will have a much greater impact 
on the dose computation than those nearer 80 dBA.
Full-Shift Sample
    Proposed Sec. 62.120(a)(3)(ii) would also require that compliance 
with the PEL or action level be based on the determination of a miner's 
full-shift noise exposure. Typically, a full-shift measurement would be 
taken with a personal noise dosimeter. This procedure would be 
consistent with MSHA's existing noise standards and sampling 
procedures.
    OSHA's noise standard does not specify a sampling duration, other 
than to require personal monitoring where circumstances such as high 
worker mobility, significant variation in sound level, or a significant 
component of impulse noise make area monitoring generally 
inappropriate. OSHA does require that the sample be representative of 
the worker's exposure.
    In response to MSHA's ANPRM, numerous commenters addressed sampling 
duration, including the question of novel work shifts (work shifts 
differing from 8 hours). Many commenters stated that the noise 
measurement should encompass the entire work shift regardless of 
duration. For those shifts which exceed 8 hours,

[[Page 66394]]

a number of commenters suggested that the PEL be adjusted to account 
for the longer work shift. Others suggested that the noise exposure be 
adjusted.
    Several commenters advocated the use of a 40-hour noise exposure 
instead of a daily 8-hour noise exposure because of the widely varying 
noise exposure of miners. These commenters believed that the 40-hour 
exposure would present a better representation of the noise exposure.
    A few commenters addressed partial shift sampling. At many small 
mines, miners may be involved with several different jobs with 
different noise exposures. Because of this, one commenter believed that 
partial-shift sampling was more representative of a miner's noise 
exposure. The commenter did not want the highest partial-shift noise 
exposure projected to a full-shift and reported as the typical exposure 
for that shift. Another commenter suggested that the survey duration 
encompass at least two-thirds of the shift in order to represent a 
full-shift sample.
    Lancaster (1986), in a study of noise exposure of British coal 
miners, reported that the variation in the day-to-day occupational 
noise exposure of compressed air drillers and electricians had a range 
that exceeded 30 dBA. The smallest range for any of the fifteen 
occupations was 8 dBA. Lancaster reported that five-shift samples 
greatly reduced the chance of getting an unrepresentative high or low 
result. Further, Lancaster concluded that a five-shift sample was not a 
reliable routine method for determining the long-term noise exposure. 
In order to determine the long-term average noise exposure to within an 
accuracy of 2 dBA, Lancaster stated that 4 to 57 samples are needed 
depending upon the occupation.
    MSHA concurs with the majority of commenters that full-shift 
sampling is more representative of the noise exposure than partial-
shift sampling. Therefore, MSHA has determined that a full-shift 
measurement is necessary because partial-shift noise surveys do not 
account for such factors as: variable work tasks, worker mobility, and 
no set production pattern for many mining situations. These occurrences 
are commonplace in the mining industry.
    The Agency did not include a long-term sampling requirement in the 
proposal. Such a requirement would be burdensome to the mining industry 
and is not relevant to compliance with the proposed standard, which 
will be based upon a single full-shift sample by the Agency. (For 
further consideration of MSHA compliance policy in this regard, see the 
last of the Questions and Answers in part I.)
Impulse/Impact Noise
    MSHA's proposal does not include a specific limit on impulse or 
impact noise. Rather, it provides that all noise in the range from 80 
dBA to 130 dBA be integrated into a miner's noise dose, including any 
impulse/impact noises measured in those ranges. Most personal noise 
dosimeters cover this range of sound levels. MSHA has concluded that, 
currently, there is not a sufficient scientific consensus to support a 
separate impulse/impact noise standard. Further, existing procedures, 
for identifying and measuring such sound, lack the practicality to 
enable its effective enforcement: for example, many personal noise 
dosimeters do not permit use of the fast response settings needed to 
isolate sounds of this type. Since industrial impulses are almost 
always superimposed on a background of moderate-to-high levels of 
continuous noise, and since both may be harmful, MSHA has determined 
that it is only reasonable to consider their effect together, rather 
than to treat each separately. As indicated below, there is ample 
justification for this approach in the studies reviewed by MSHA and 
comments submitted to the record.
    MSHA's existing noise standards for coal mines do not include a 
limit for impulse/impact noise. Both OSHA's and MSHA's Metal and 
Nonmetal existing noise standards limit impulse/impact noise to a peak 
level of 140 dB. Neither standard, however, specifically defines 
impulse/impact noise nor procedures to measure it.
    OSHA, in its Hearing Conservation Amendment, determined that 
impulse noise should be combined with continuous noise to calculate 
employee noise exposure for purposes of the HCP. OSHA's standard, 
however, retains the 140 dB peak limit on impulse and impact noise. The 
OSHA preamble to its Hearing Conservation Amendment (46 FR 4099) 
stated:

    Since industrial impulses are almost always superimposed on a 
background of moderate to high levels of continuous noise * * * and 
since both may be harmful, it is only reasonable to consider their 
effects together rather than to treat each separately * * *. The 
decision to measure all noise exposures for purposes of the hearing 
conservation program is a pragmatic approach to the whole problem of 
impulse noise. For, while there is some dispute as to the precise 
definition and effect of impulse noise, there is general agreement 
that impulse noise is damaging.

    Impulse/impact noise is typically characterized by a rapid rise 
time, high peak value of short duration, and rapid decay.
    In 1974, OSHA proposed the following definition for impulse noise 
(39 FR 37775):

* * * a sound with a rise time of not more than 35 milliseconds to 
peak intensity and a duration of not more than 500 milliseconds to 
the time when the level is 20 dB below the peak. If the impulses 
recur at intervals of less than one-half second, they shall be 
considered as continuous sound.

    At that time, OSHA proposed to limit exposure to impulses at 140 dB 
to 100 per day, and to permit a tenfold increase in the number of 
impulses for each 10-dB decrease in the peak pressure of the impulse. 
OSHA stated that this proposal was in accordance with the criterion 
proposed by McRobert and Ward (1973). OSHA's proposal on impulse noise 
exposure limits was identical to that recommended by the ACGIH (1986).
    Currently, there is no uniformly accepted definition of impulse or 
impact noise. ANSI S12.7-1986, ``Methods for Measurement of Impulse 
Noise'', defines impulse noise as ``a single short burst or a series of 
short bursts of sound pressure. The pressure-time history of a single 
burst includes a rise to a peak pressure, followed by a decay of the 
pressure envelope.''
    The ACGIH (1986) states that:

    Impulsive or impact noise is considered to be those variations 
in noise levels [sound levels] that involve maxima at [time] 
intervals of greater than one per second. Where the intervals are 
less than one second, it should be considered continuous.

    Integrating impulse/impact noise into the miner's noise dose is 
broadly supported by many of the commenters. One commenter stated that 
currently there is not enough scientific information to promulgate a 
separate standard on impulse/impact noise. Several commenters advocated 
retaining the current MSHA Metal and Nonmetal 140 dB peak limit. 
However, two commenters indicated that exposure to this peak be limited 
to 100 occurrences per work shift. One commenter on this issue 
recommended that MSHA adopt the measurement methods described in ANSI 
S12.7-1986, ``Methods for Measurement of Impulse Noise''. This ANSI 
document, however, does not specify a criterion level for such noise. 
Another commenter stated that 156 dB is most likely the critical point 
at which the sensory components of the human ear disintegrate.
    Defining impulse/impact noise, and setting an appropriate limit, 
has proven to be an arduous task mainly because of the difficulty in 
measuring such sound and differentiating it from non-impulse/impact 
noise that may occur simultaneously. Impulse/impact noise

[[Page 66395]]

seldom occurs alone in the mining environment. Several commenters on 
this issue indicated that current instrumentation, including in 
particular the personal noise dosimeter, cannot distinguish between 
impulse/impact and continuous noise occurring simultaneously. Some 
commenters stated that although personal noise dosimeters cannot 
distinguish between impulse/impact noise and continuous noise, newer 
models of personal noise dosimeters are capable of accurately 
integrating the two types of noise into a single combined dose.
    The studies reviewed by MSHA and discussed below indicate that even 
though there is no consensus as to a definition of impulse/impact 
noise, all researchers and regulators agree that this type of noise is 
damaging to hearing.
    Ward (1990) stated that both impulse and impact noises involve high 
sound pressure levels and short durations, so in a sense, they jointly 
represent an extreme type of intermittent noise. He believed, however, 
that there is considerable evidence that a distinction should be made 
between impulse noise and impact noise, and that they should be treated 
separately. Ward characterized impulse noise as ``A-duration,'' such as 
that from gunfire. Whereas he characterized impact noise as ``B-
duration,'' having multiple, nearly equal peaks and a sustained 
reverberation that may endure for a second or even longer.
    Ward believed that recent research tends to support the conclusion 
that impact noise can reasonably be expected to behave in a manner 
similar to that of intermittent exposure to short bursts of otherwise 
continuous but high-intensity noise. He stated that any predictive 
scheme that accurately estimates the hazard of intermittent noise in 
the range of time-weighted averages (TWA8) or Leq,8 of 110 
dBA to 130 dBA also would be successful in predicting the hazard from 
impact noise, and no ``correction for impulsiveness'' should be 
necessary. He further stated, the same is true of impulse noise as long 
as the level of the pulse does not exceed some ``critical'' value. If 
the impulse exceeds this critical level, however, Ward believed that 
the hazard increases rapidly with further increases in level or in the 
number of impulses.
    Ward stated that the most hazardous impulse would be one that has 
its maximum energy in the most sensitive region of the human auditory 
system: namely 2000 to 3000 Hz. This occurs when the A-duration is 
around 0.2 milliseconds (ms). For pulses whose A-duration is in this 
vicinity, he believed the critical level to be around 150 dB for the 
average individual and around 140 dB for the most susceptible ears. He 
believes, however, that his limit results in overprotection against 
pulses whose A-duration is short (as in the case of cap guns) or long 
(as with cannons or sonic booms).
    Ward concluded that impulse noise may be the most important cause 
of NIHL in the general population, not by a gradual erosion of auditory 
sensitivity through repeated daily exposure, but rather by a single 
event causing acoustic trauma. He emphasized, however, that the 
determination of valid exposure limits for specific impulses is still a 
major problem.
    In the American Industrial Hygiene Association (AIHA) Noise & 
Hearing Conservation Manual, Ward (1986) also expressed concern 
regarding an impulse/impact noise limit. He stated:

    Just where, if anywhere, this type of limit should be placed is 
still undecided. Although the present OSHA regulations state: 
``Exposure to impulsive or impact noise should not exceed 140 dB 
peak sound pressure'' (Anon., 1971), this number was little more 
than a guess when it was first proposed in the CHABA document 
(Kryter et. al., 1966), and no convincing supportive evidence has 
since appeared. While 140 dB may be a realistic ceiling for impact 
noises, it is inappropriate for impulses, so exposure limits in 
which the permitted peak level increases as the duration of the 
pulses becomes shorter should continue to be used (Anon., 1968).

    Volume II of the Ohio State University Research Foundation report 
(Melnick et al., 1980) discussed the effects of single, high-level 
impulses and stated:

    There are insufficient data to develop distributions of hearing 
loss as the function of the parameters of single, high-intensity 
impulses. The very nature of the stimulus makes these effects on man 
difficult to quantify.

    This report, however, stated the following regarding single impulse 
levels that could cause damage:

* * * In experiments with laboratory animals, impulses having peak 
levels in the range of 150 to 160 dB were capable not only of 
producing damage to the inner ear but also showed evidence of trauma 
to the structures of the middle ear, including perforation of the 
tympanic membrane (Eames et al., 1973). Pfander (1975) reports that, 
in humans, perforations of the tympanic membrane were observed when 
the peak level for an explosive impulse was in the range of 180 dB. 
In his experiments with the effects of sonic booms on mice using 
peak levels that range from 126 to 146 dB, with durations in excess 
of 100 msec, Reinis (1976) reported that five such booms delivered 
at the rate of 1 every 10 seconds are capable of producing bleeding 
in the cochlea of the experimental animals.

    The Committee on Hygiene Standards of the British Occupational 
Hygiene Society (1976) developed standards for impulse noise. Their 
recommendation referenced a study by Kryter and Garinther which 
``showed that temporary hearing loss after exposure to 100 impulses 
increased rapidly at sound pressure levels exceeding 170 dB.'' Kryter 
and Garinther, however, recommended limiting instantaneous sound 
pressure levels to 150 dBA, because special measurement techniques and 
instruments would be needed to measure levels in excess of 150 dBA.
    Shaw (1985) recommended, in the interest of simplicity and in 
keeping with ISO/DIS 1999-1984, that the use of hearing protectors be 
mandatory where there is exposure to noise at the work place with 
instantaneous peak sound pressures exceeding 200 pascals (140 dB 
relative to 20 micropascal). Shaw stated, however, that exposure to 
many simple non-reverberant impulses (``clicks'') at that level would 
be required to produce significant temporary threshold shift even in 
the most sensitive ears. Shaw further discussed the concept of 
``critical level'' and stresses that ``the relationship between peak 
sound pressure level and mechanical or physiological stress * * * is 
exceedingly complex.'' Shaw quoted McRobert and Ward (1973) who urged 
that ``* * * damage risk criteria incorporate a more complicated 
criterion for impulse and impact noise than a simple ceiling or peak 
level * * *.''
    ISO/DIS 1999-1990 (1990) also supported combining continuous noise 
with impulse/impact noise in conjunction with the use of a 3-dB 
exchange rate.
    In discussing the combined effects of continuous and impulse/impact 
noise, the ACGIH (1986) stated that:

    Some studies have shown that the effects of combined impulse and 
continuous noise are additive [Okada et al., Int. z Angew. Physiol., 
30:105-111 (1972)]. Other studies have shown that rapidly repeated 
impulses [Coles and Rice, Occupational Hearing Loss, pp. 71-77 
(1971)] and simultaneously continuous noise [Cohen et al., J. 
Acoust. Soc. Am., 40:1371-1379 (1966)] in some cases provide up to 
10 dB of protection.

    Evans and Ming (1982) and Sulkowski and Lipowczan (1982), however, 
supported the theory that impulse noise superimposed on steady-state 
noise is more hazardous than the same levels of either separately. 
Cluff (1982), professor of audiology at Arizona State University, 
believed that the combined

[[Page 66396]]

continuous/impulse noise dose procedure should be approached with a 
degree of caution. He stated that:

    The procedure involves some knotty issues; not the least of 
which is the issue of equal energy (3-dB doubling rule) vs 
equinocivity (the principle embodied in the 5-dB doubling rule). One 
other issue deserves mention also. What is impact/impulse noise? It 
is a simple matter to describe impact/impulse noise in terms of its 
source when the source is obvious and individual events are spaced 
far apart temporally. It is quite another matter to describe it 
differentially from continuous noise when the source is not obvious 
and when individual events are repeated rapidly (as with the case of 
gear trains, pneumatic chisels, conveyor belts, grinders, internal 
combustion engines, etc.). Indeed, this difficulty may be central to 
the heretofore tendency to class it as continuous noise when the 
repetition rate exceeds one or two events per second. Were it not 
that the weight of evidence appears to argue against this approach, 
the simple thing would be to call it continuous noise and treat it 
as such.

    As shown in Tables III-4 and III-5 (in the section entitled 
Permissible exposure level (PEL), discussing proposed Sec. 62.120(c)), 
the majority of international communities and selected branches of the 
U.S. armed services have adopted 140 dB peak as the upper limit for 
sound levels in their respective regulations. However, there is no 
consensus among these regulators as to a definition of impulse/impact 
noise.
    In reviewing the literature on impulse/impact noise, MSHA found 
that such noise frequently is divided into two general categories: ``A-
duration'' impulses are short duration (measured in microseconds) and 
non-reverberant in that they usually occur outside or in a sound 
deadening environment; and ``B-duration'' impacts are of longer 
duration (measured in milliseconds) and are reverberant mainly because 
they occur inside where the sound is augmented by reflections from hard 
surfaces. MSHA's experience indicates that there is seldom impulse 
noise of A-duration in mills and underground mines, because of the 
reverberant field. Scheduled blasting at surface mines would not be 
impulse noise of A-duration because of the multiple detonations several 
milliseconds apart in a semi-reverberant field when considering the 
rock walls and floor.
    MSHA is concerned about the practicality of enforcing an impulse/
impact noise limit in mining. Distinguishing impact/impulse noise from 
continuous noise, according to most of the definitions discussed above, 
would require sophisticated, delicate laboratory instrumentation. This 
equipment is: cumbersome, not intrinsically safe, not readily 
available, and not capable of withstanding the harsh mining 
environment.
    As pointed out by some commenters, there have been many 
technological advances in the capabilities of noise measuring 
instruments, and equipment now exists that can integrate impulse/impact 
noise into the dose. The ability of personal noise dosimeters to 
accurately integrate sound levels above 130 dBA into the noise dose, 
however, may be questionable. ANSI S1.25-1991, ``Specification for 
Personal Noise Dosimeters'', specifies that personal noise dosimeters 
must have an operating range of 50 dB. ``Operating range'' is defined 
by ANSI as the range between threshold and an upper sound level within 
which a personal noise dosimeter operates within stated tolerances. 
Accordingly, if an 80 dBA threshold is used, current personal noise 
dosimeters would be required to meet ANSI tolerances up to 130 dBA.
    As stated previously, MSHA has determined that there is little 
noise in mining that could be characterized as impact or impulse given 
their prevailing definitions. One source of impact noise that may 
exceed the existing 140 dB criteria is that caused by blasting in 
underground mines. MSHA has determined that noise from blasting in 
underground mines would be considered impact noise rather than impulse 
noise because of the highly reverberant environment.
    In Volume II of the Ohio State University Research Foundation 
report (Melnick et al., 1980), Melnick et al. states the following with 
regard to measuring impulse/impact noise, such as that produced by 
blasting:

    Under conditions sufficient to produce measurable hearing loss, 
it would be extremely fortuitous if measuring instruments were in 
place to permit the assessment of the actual exposure of the single 
impulsive event. Generally, these exposures are accidental in 
nature.

    Because blasting occurs at irregular intervals, with most miners 
removed from the blast site prior to its initiation, it would be 
difficult for MSHA to measure such exposures and to enforce a limit 
designed to protect against such exposures.
    MSHA considered many factors in determining the merit of proposing 
an impulse/impact noise limit for the mining industry. Although there 
is much evidence in the literature on the harmful effects of impulse/
impact noise, MSHA concluded that, currently, there is not a sufficient 
scientific consensus to support a separate impulse/impact noise 
standard. Further, existing procedures for identifying and measuring 
such sound lack the practicality to enable its effective enforcement. 
This is due, in part, to the complexity of the phenomena, where 
consideration must be given to such factors as: the peak sound pressure 
level; the wave form and crest factor; the rise and decay time; whether 
it is A-duration or B-duration; the number of impulses per day; the 
presence or absence of steady-state sound; the frequency spectrum of 
the sound; and the protective effect of the middle ear acoustic reflex.
    In conclusion, studies discussed above indicate that when impulse/
impact noise is combined with continuous noise, hearing loss is 
exacerbated. Therefore, MSHA has determined that, for purposes of this 
proposal, impulse/impact noise should be combined with continuous noise 
for purposes of calculating a miner's noise exposure. Since industrial 
impulses are almost always superimposed on a background of moderate-to-
high levels of continuous noise, and since both may be harmful, it is 
only reasonable to consider their effect together, rather than to treat 
each separately. There is ample justification for this approach in the 
studies reviewed by MSHA and comments submitted to the record.
    MSHA, however, requests further comment on this issue, particularly 
on impulse/impact noise sources in mining which may not be integrated 
adequately into the miner's noise dose. Additionally, MSHA requests 
data addressing a critical level to prevent traumatic hearing loss; 
what this critical level should be; whether it should be based on a 
single event; and a practical scientifically validated method for its 
discrete measurement.
Exchange Rate
    The exchange rate is another factor which is involved in the 
determination of noise dose. The exchange rate is the change in sound 
level which corresponds to a doubling or a halving of the exposure 
duration. For example, using a 5-dB exchange rate, a miner who receives 
the maximum permitted noise dose over an 8-hour exposure to 90 dBA 
would be determined to have accumulated the same dose as a result of 
only a 4-hour exposure at 95 dBA. If the exchange rate were reduced to 
3-dB, the same dose would be received with a 4-hour exposure at only 93 
dBA. Other terms for exchange rate include ``doubling rate,'' ``trading 
ratio,'' and ``time-intensity tradeoff.''
    The Agency currently uses a 5-dB exchange rate. There appears to be 
a concensus in the recent literature for an exchange rate of 3-dB, 
although the Agency is seeking additional

[[Page 66397]]

information on this point. Moreover, the current 5-dB exchange rates 
incorporates an assumption that there is significant time for hearing 
to recover from high sound levels. MSHA has concluded that noise 
exposure under mining conditions does not warrant such an assumption. A 
3-dB exchange rate does not incorporate this assumption.
    Nevertheless, the Agency is proposing to retain the existing 5-dB 
exchange rate because of feasibility considerations. Changing to a 3-dB 
rate from a 5-dB rate would significantly reduce the amount of time 
that miners could be exposed to higher sound levels without exceeding 
the permissible exposure limit. For example, MSHA estimates that the 
percentage of miners whose exposure would be in violation of a PEL set 
at a Leq,8 of 90 dBA would be just about double that of a PEL set 
at a TWA8 of 90 dBA. This means mine operators would have to 
utilize controls to reduce exposures to the PEL more frequently--and 
the controls required to reduce exposures that much would be more 
expensive. Furthermore, it is extremely difficult to reduce the noise 
exposures to below a Leq,8 of 90 dBA using currently available 
engineering or administrative noise controls or a combination thereof. 
Accordingly, moving the industry to a 3-dB exchange rate may be 
infeasible at this time. (Part IV contains a further discussion of 
feasibility issues.)
    OSHA, in its 1974 proposed noise standard (39 FR 37774), stated the 
following regarding its decision to use a 5-dB exchange rate:

    EPA recommended [in response to OSHA's proposal] a doubling rate 
[exchange rate] of 3 dB. While the 3-dB doubling rate is 
hypothetically correct for uninterrupted noise exposure, noise 
exposure in industry is normally interrupted since there are several 
breaks in the day's work. OSHA agrees with the Advisory Committee 
[Standards Advisory Committee on Noise, appointed by the Assistant 
Secretary for OSHA] that the doubling rate should be adjusted to 
take into account the various breaks which occur in a workday. 
Therefore, OSHA believes that a doubling rate of 5 dB is more 
appropriate than the 3 dB.

    MSHA received numerous comments regarding this particular issue. 
Many refer to scientific studies showing the ability of the ear to 
recover from temporary shifts (temporary threshold shifts, or TTS) 
incurred during noise exposure. TTS should not be confused with PTS, 
which refers to permanent theshold shifts--i.e., loss of hearing 
acuity. Whether TTS and PTS are inexorably linked is a subject of 
debate, as noted below.
    Many commenters advocated retaining the existing 5-dB exchange 
rate. Two of these commenters believed that there is sufficient support 
in the scientific literature for a 3-dB exchange rate, but recommended 
that MSHA retain using the 5-dB exchange rate so as to maintain 
consistency between MSHA and OSHA.
    A number of commenters, however, recommended a 3-dB exchange rate. 
Several stated that it has greater scientific and technical validity. 
Others supported the 3-dB exchange rate because it would be in 
agreement with regulations in many countries outside the United States 
and with the recently issued international standards [International 
Standards Organization, ISO 1999.2] which the U.S. endorsed. One 
commenter asserted that the ``use of the 3-dB, rather than a 5-dB, 
exchange rate facilitates the calibration/characterization and the 
interpretation of the performance of such [noise measuring] 
instruments.'' Another commenter criticized the theory that the 3-dB 
exchange rate only applies to steady state noise, stating the 
following:

    First, steady and intermittent noise merely identifies the 
extremes of episodes of noise and quiet that most workers experience 
in the course of a day. It is the rare exception to find workers who 
experience either continuous or steady state noise. Recovery from 
noise-induced damage, therefore, is unpredictable in the real world. 
Second, the hypothesis of recovery during intermittent noise 
exposure has not been empirically verified.

    Other commenters stated that the use of the 3-dB exchange rate is 
not appropriate in mining because exposures in the mining industry are 
intermittent and, therefore, miner recovery from temporary threshold 
shifts occurs during the working day. Finally, two commenters stated 
that if the exchange rate were lowered, many of the personal noise 
dosimeters currently in use would become obsolete and would have to be 
replaced.
    MSHA reviewed several recent studies relating to the selection of 
an exchange rate. Kryter (1984) in his discussion of interruptions in 
and durations of daily noise exposures, asserts that even short periods 
of reduced noise exposure during the workday facilitate recovery, and 
that a 5-dB exchange rate is thus appropriate to take this into 
account. He states:

* * * it does not matter whether the off time is continuous or 
interrupted during the 8-hour day. In either case, the recovery 
process continues and is equally effective. For example, the level 
of a noise of 8 hours duration per workday could be increased by 6 
dB and cause no additional PTS provided its duration is decreased to 
4 hours, either by reducing the total work period by 4 hours or by 
introducing ``off'' periods (longer than 10 sec each) which total 4 
hours. This, of course, is in reasonably close agreement with the 
``5 dB exchange'' that would be allowed in some noise assessment 
procedures, such as the U.S. Department of Labor Occupational Safety 
and Health Administration (OSHA) regulations.

    Dear (1987) supported retaining the 5-dB exchange rate based upon 
the studies of Sulkowski (1980), Gosztonyi (1975), Scheiblechner 
(1974), Schneider (1970) and Pell (1973). Further, Dear believed that 
the studies of Passchier-Vermeer (1973) and Burns and Robinson (1970), 
which formed the basis for Shaw's recommendation to adopt a 3-dB 
exchange rate (discussed below), were critically flawed and furthermore 
the findings of Passchier-Vermeer did not agree with those of Burns and 
Robinson. Dear asserted that Shaw discounted other studies which showed 
that the 5-dB exchange rate correlated well with hearing loss. Dear 
claimed that for every study which supports the 3-dB exchange rate, 
another supports the 5-dB exchange rate. Dear further contended that a 
3-dB exchange rate was valid only for workplaces with no intermittent 
noise exposure, which is a condition that rarely exists in American 
workplaces.
    Sataloff et al. (1984) studied the effect of intermittent noise 
exposure on the hearing acuity of workers. This study corroborates an 
earlier report, done by Sataloff et al. (1969) on the hearing acuity of 
rock-drilling miners, that intermittent noise is not as hazardous as 
continuous noise of the same intensity. In the more recent study, 295 
industrial workers who did not use hearing protectors were exposed to 
non-impact sound levels from 99 dBA to 118 dBA with quiet periods less 
than 90 dBA. Most of the workers were exposed to the higher sound 
levels. The researchers concluded that intermittent noise exposure 
produced little hearing loss at frequencies below 3000 Hz; however, it 
produced substantial damage at the higher frequencies. The pattern of 
damage, exhibited by workers exposed to continuous noise, was also 
realized at the lower audiometric frequencies. The researchers 
attributed the difference in patterns of damage to the recovery of the 
hair cells in the cochlea during quiet periods in the workers exposure 
to intermittent noise.
    Sataloff et al. (1984) also compared the hearing loss of a 
population of 295 workers exposed to intermittent noise to other 
studies on workers exposed to continuous noise conducted by Royster et 
al., Botsford, and Johnson and Harris'

[[Page 66398]]

review of Baughn's findings. Sataloff et al. asserted that the 
comparison indicated that workers exhibited more hearing loss when 
exposed to continuous noise than from exposures to intermittent noise. 
Although research showed that the loss caused by intermittent noise 
differs substantially from the effects of continuous noise of the same 
intensity, Sataloff et al. did not state an opinion as to which 
exchange rate is most appropriate.
    Hodge and Price (1978), in their review of damage risk criteria, 
summarized that the 3-dB exchange rate was proposed to account for 
variations in exposure time to both intermittent and continuous noise 
and that the 5-dB exchange rate was proposed to account for the 
``beneficial effect of recovery'' during quiet periods between such 
exposures. They stated, however, that the sound level would need to 
fall below 60 dBA to effect recovery. They concluded that neither the 
3-dB nor 5-dB exchange rate fits the hearing loss at all frequencies or 
under all conditions and there will be controversy in this area for 
many years to come.
    Cluff (1982), professor of audiology at Arizona State University, 
states that:

* * * while equinocivity (the principle embodied in the 5-dB 
doubling rate) may be an applicable basis for determining noise dose 
for lower levels of noise, its credibility suffers as the level of 
the noise increases above 90 dBA. * * * The only justification for 
equinocivity, in lieu of equal energy [3-dB exchange rate], is that 
on-the-job exposure to noise will probably be intermittent. * * * 
Applying the above logic to very high noise levels [sound levels], 
intermittent exposure may be claimed for noise levels of 115 dBA, 
for instance, only if the duration of each individual exposure is 
substantially shorter than the approximately two minute maximum that 
would be allowed under equal energy.

    Bies and Hansen (1990) developed an equation fitting a 6-dB 
exchange rate to the ISO 1999: 1990(E) data, instead of the 3-dB 
exchange rate as presented by ISO. Essentially, they showed that the 
mathematical solution fitting an equation to the hearing loss data 
contained in ISO 1999: 1990(E) is not unique.
    Macrae (1991) published an article which refutes Bies and Hansen's 
findings. Macrae studied people with a sensorineural hearing loss at 
4000 Hz to determine the progression of the loss in relation to 
presbycusis. Macrae's data supported ISO 1999 which uses a 3-dB 
exchange rate. Macrae believed that Bies and Hansen erred by assuming 
that hearing loss, due to presbycusis and noise exposure, was additive 
on an antilogarithmic basis at 4000 Hz. Because the progression of 
hearing loss at other frequencies was not studied, Macrae could not 
reach any definite conclusions as to the progression of hearing loss at 
frequencies other than 4000 Hz.
    According to the Committee on Hearing, Bioacoustics, and 
Biomechanics of the National Research Council (CHABA) (1993), the data 
for specifying an exchange rate were not conclusive.
    Compared to steady-state noise data, little data exist on the 
effect of intermittent or time varying noise exposure. Depending upon 
the length of time of the exposure, an exchange rate of between 0-dB 
and 8-dB is appropriate. Each of these single number exchange rates is 
valid for a limited set of exposure conditions. Therefore, CHABA did 
not recommend an exchange rate. Additionally, CHABA concluded that the 
maximum sound level for effective quiet is approximately 80 dBA at most 
frequencies.
    NIOSH (1995) recommends a 3-dB exchange rate based upon the latest 
scientific data. This recommendation represents a change in NIOSH's 
position on exchange rate from that included in the 1972 Criteria for 
Recommended Standard * * * Occupational Exposure to Noise.
    NIOSH presents many reasons for this change in position. In their 
1972 criteria document, NIOSH based the recommendation for a 5-dB 
exchange rate on earlier recommendations of CHABA (Kryter et al., 
1966). CHABA's 1966 recommendations were predicated on three 
postulates, which included--
    (1) TTS2 (temporary threshold shift measured two minutes after 
cessation of the noise exposure) is a valid predictor of permanent 
threshold shift (PTS);
    (2) equivalent TTS2's obtained from exposures were equally 
hazardous; and
    (3) TTS2 is a consistent measure of the effects of a single 
day's exposure to noise.
    Since that time, NIOSH believes that more recent scientific studies 
have proven these postulates to be erroneous. Another assumption that 
NIOSH found for justifying the 5-dB exchange rate was that 
interruptions will be of ``equal length and spacing so that a number of 
identical exposure cycles are distributed uniformly throughout the 
day.''
    Although NIOSH found that intermittent noise exposure is less 
harmful than continuous noise exposure, NIOSH has determined that the 
beneficial effects of intermittency which allow for recovery from TTS 
are not found in industry today. The quiet periods are too loud and too 
short to permit recovery of TTS before the next exposure to harmful 
noise.
    NIOSH cites field studies by Sataloff et al. (1969), Holmgren et 
al. (1971), Johansson et al. (1973), and Institut National de Recherche 
et de Securite (1978), to show the beneficial effect of intermittency 
of noise exposure in mining and forestry. Studies by NIOSH (1976), 
NIOSH (1982), Passchier-Vermeer (1973) and Shaw (1985), not supporting 
this finding were also cited. NIOSH, however, concludes that ``the 
ameliorative effect of intermittency does not support the use of the 5-
dB exchange rate.''
    The Shaw study (1985) supports the 3-dB exchange rate based on the 
premise that a 3-dB exchange rate better fits the epidemiological data 
on the relationship between noise exposure and hearing loss. Shaw also 
criticizes the use of the 5-dB exchange rate because it was based upon 
the assumption that a permanent threshold shift (PTS) is related 
directly to temporary threshold shift (TTS). Shaw believes that no 
researcher has adequately demonstrated a relationship between PTS and 
TTS. Furthermore, he states that the 5-dB exchange rate does not take 
into account variations in the temporal pattern of exposure.
    Suter (1983) conducted a comprehensive review of the literature on 
exchange rate. She concluded that the 5-dB exchange rate is under-
protective in many situations and that the 3-dB exchange rate is more 
firmly supported by the scientific evidence for assessing hearing 
impairment as a function of sound level and duration. Suter, however, 
stated that:

    The situation becomes more complex when noise becomes truly 
intermittent, in other words, when there are large differences 
between high and low levels, and levels in between occur rarely. The 
studies of forestry workers and miners [Sataloff et al. 1969; 
Holmgren 1971; Johansson 1973; and Institute National de Recherche 
et de Securite 1978] indicate that the frequent periods of quiet 
between noise bursts can in some circumstances, ameliorate the 
effects of noise exposure.

    Regarding the literature review, Suter explained that the 
researchers' findings have been refuted by two NIOSH studies of 
intermittently exposed coal miners (NIOSH, 1976) and firefighters 
(NIOSH, 1982). In addition, the researchers' studies suffer from 
various methodological problems such as inadequate characterization of 
exposure, sporadic wearing of hearing protectors, small sample size, 
etc. Nevertheless, Suter believed that these studies show a valid 
trend, in that the intermittency of exposure can offset the effects of 
noise exposure, especially in view of

[[Page 66399]]

some of the animal studies (Ward and Turner, 1982). Suter further 
stated that:

    The logical consequence of such a trend [intermittent noise 
exposure being less hazardous than continuous noise exposure] would 
be to allow an adjustment to the maximum permissible exposure limit 
for outdoor, intermittent noise exposure. This is by contrast to a 
5-dB exchange rate, for which there is virtually no scientific 
justification * * *.

    Suter suggested using a 3-dB exchange rate along with an adjustment 
of 2 dB to the PEL for outdoor noise. She stated that ``The exact 
amount of such an adjustment should await clarification by further 
scientific evidence.''
    According to Sliney (1993), chair of the ACGIH Physical Agents TLV 
Committee, (ACGIH) revised its exchange rate from 5-dB to 3-dB, on the 
basis that the use of a 5-dB exchange rate is not wise for short 
exposure periods. The ACGIH stated that allowable durations for high 
sound levels which are permitted with a 5-dB exchange rate are 
excessive. In addition, ACGIH believed that, with a 3-dB exchange rate, 
an upper limit for the TLV was capped by a 140 dBC impulse peak sound 
pressure level. Both the 1971 and 1990 versions of the ISO 1999 
standard employ the 3-dB exchange rate.
    Evans and Ming (1982) studied five groups of employees in noisy 
occupations using personal noise dosimeters which integrated sound 
levels based on a 3-dB exchange rate. The noise exposures ranged from 
80 dBA to 102 dBA. They used a mathematical model developed by Robinson 
and Shipton based upon a 3-dB exchange rate for predicting hearing loss 
among exposed workers. Evans and Ming stated that the observed noise-
induced hearing loss (NIHL) of workers in the spinning, weaving, and 
bottling industries agreed with those predicted by Robinson and 
Shipton's model. The hearing loss of workers in the metal-work 
industry, however, tended to be greater than those predicted. The 
authors believed that the significant amount of impulse noise 
contributing to the noise exposures in this industry explained the 
difference. Evans and Ming concluded that the use of Robinson and 
Shipton's prediction method is valid for predicting the hearing loss 
risk for various noise exposures.
     As will be displayed later in Tables III-4 and III-5, the 3-dB 
exchange rate is also used by many international communities and 
selected branches of the U.S. armed services.
    Although occupations in the mining industry are typically exposed 
to varying sound levels, most miners are continuously exposed to noise 
above 80 dBA. Because the majority of exposures are continuously above 
80 dBA, little or no time is available to permit ``recovery time'' from 
TTS. Thus, miners experience little recovery from the effects of these 
noise exposures. ``Recovery time'' is a basic tenet of the current 5-dB 
exchange rate; thus, the Agency has concluded the continuous nature of 
noise exposure in the mining industry is more realistically 
characterized by the 3-dB exchange rate.
    Although the Agency has reached this conclusion, and although there 
appears to be a growing consensus supporting the use of a 3-dB exchange 
rate among the scientific community, international regulators, and the 
U.S. armed services, MSHA has chosen to retain a 5-dB exchange rate for 
its proposal because there are significant feasibility implications of 
adopting a 3-dB rate--both economic and technological.
    With respect to economic feasibility, MSHA conducted a study of the 
effect of a 3-dB exchange rate on the measured noise exposure of U.S. 
metal and nonmetal miners. The mine inspectors collected measurements 
during the course of their regular inspections using personal noise 
dosimeters which collected data using 5-dB and 3-dB exchange rates 
simultaneously. These data are presented in Table III-2.

  Table III-2.--M/NM Samples a Exceeding Specified Sound Levels Collected by MSHA From May 1995 to October 1995 
----------------------------------------------------------------------------------------------------------------
                                                                 5-dB exchange rate        3-dB exchange rate   
                                                             ---------------------------------------------------
                    Sound level (in dBA)                       Number of    Percent of   Number of    Percent of
                                                                samples      samples      samples      samples  
----------------------------------------------------------------------------------------------------------------
90..........................................................          491         16.5         1483         49.9
85..........................................................  ...........  ...........         2543         85.5
----------------------------------------------------------------------------------------------------------------
a Total of 2974 samples. Two of the boxes in the table do not contain entries. This is to avoid the potential   
  for making an inappropriate comparison of values. Direct comparison of TWA8 values determined with different  
  thresholds is not appropriate if the TWA8 is less than one of the thresholds. An example may help to          
  illustrate the point. A miner exposed to a constant sound field of 85 dBA for 8 hours would be determined to  
  have a noise dose of 0%, or a TWA8 of 0 dBA, if a 90 dBA threshold is used: none of the sound would be counted
  in the computation. If the exposure was measured using an 80 dBA threshold, the dose would be 50%, or a TWA8  
  of 85 dBA. Contrasting the measures taken with the two thresholds would be inappropriate in such a case.      

    The measurements in Table III-2 for a 5-dB exchange rate were made 
using a 90-dBA threshold while the 3-dB exchange rate data were 
obtained without a threshold. To get a better picture of the impact of 
moving from a 5-dB exchange rate to a 3-dB exchange rate if, as 
proposed, the Agency adopts an 80-dBA threshold, Table III-3 has been 
constructed. The data for the 5-dB exchange rate comes from the 
Agency's dual-threshold survey for metal and nonmetal mines, presented 
in Table II-11. This also allows for the analysis of data at values 
below a TWA8 of 90 dBA, something which is not possible with a 90 
dBA threshold. The data for the 3-dB exchange rate come from Table III-
2--switching to an 80 dB threshold does not significantly change the 3-
dB readings in Table III-2.

Table III-3.--Metal/Nonmetal Samples Exceeding Specified Sound Levels at
                        Different Exchange Rates                        
------------------------------------------------------------------------
                                   5-dB                                 
-------------------------------------------------      3-dB percent     
  Sound level (in dBA)            Percent                               
------------------------------------------------------------------------
90.....................              26.9                     49.9      
85.....................              67.6                     85.5      
------------------------------------------------------------------------

    As indicated in Table III-3 the selection of an exchange rate 
substantially affects the measured noise

[[Page 66400]]

exposure. The percentage of miners whose noise exposure would exceed a 
PEL set at a TWA8 of 90 dBA (or an LEq,8 of 90 dBA in the 
case of a 3-dB exchange rate) increases from 26.9% to 49.9% when the 
exchange rate changes from 5-dB to 3-dB. Looking at the numbers another 
way, as compared with using a 5-dB exchange rate, using a 3-dB exchange 
rate would result in the need to utilize engineering or administrative 
controls to limit the exposure of twice as many miners. Moreover, the 
engineering controls required would be more expensive since it would 
take a more stringent control to bring down, to the PEL, exposures that 
double every 3-dB. The table also reveals that to switch to a 3-dB 
exchange rate and setting the PEL at an Leq,8 of 85 dBA would 
increase the percentage of miners whose exposure is out of compliance 
with the PEL from 67.6% to 85.5%.
     MSHA has not compiled similar data for coal mining, although the 
consequences would be similar. Accordingly, MSHA believes that using a 
3-dB exchange rate would have significant implications for the U.S. 
mining industry.
    With respect to technological feasibility, it is extremely 
difficult to reduce the noise exposures to a Leq,8 of 90 dBA using 
currently available engineering or administrative noise controls or a 
combination thereof. For many pieces of existing equipment it is not 
practical to apply engineering controls without seriously compromising 
the equipment's operational capacity.
    Accordingly, as discussed in part IV of this preamble, moving the 
industry to a 3-dB exchange rate may be infeasible at this time.
    MSHA believes that the determination of an appropriate exchange 
rate is one of the more noteworthy issues in the proposed rule. 
Accordingly, MSHA requests further comment and data on this issue. In 
particular, MSHA notes that the studies supportive of a 5-dB rate are 
generally dated, and requests information about any more current study 
supporting that exchange rate.
A-weighting, slow-response
    Proposed Sec. 62.120(a)(3)(iv) requires that the instruments used 
for measuring noise exposures be set for the A-weighting network and 
slow-response (exponential time averaging). This is identical to the 
existing MSHA regulations for exposures to non-impulse/impact noise. 
OSHA also uses the A-weighting network and the slow-response time for 
evaluating exposure to noise.
    Weighting networks were designed to approximate the response of the 
human ear to tones of equal loudness. The human ear does not respond to 
all levels of tones in the same way. At low sound pressure levels 
(e.g., 50 dB) the ear discriminates against low-frequency and high-
frequency tones. At higher sound pressure levels (e.g., 90 dB), the ear 
no longer discriminates against low- and high-frequency tones. Although 
the human ear does not discriminate against low-frequency tones at high 
sound levels, the low-frequency tones are less damaging to hearing than 
mid-frequency tones.
    Several weighting networks have been developed to take these 
differences into account: known as A, B, and C. Early researchers 
suggested using them all in combination: the A-weighting network when 
the sound pressure level was less than 55 dB, the B-weighting network 
between 55 and 85 dB, and the C-weighting network for sound pressure 
levels exceeding 85 dB (Scott, 1957). Since that time, however, 
concensus has developed on the use of the A-weighting network.
    Response time, also known as a time constant, refers to the speed 
at which the instrument responds to a fluctuating noise.
    There are five responses defined in ANSI S1.4-1983, ``Specification 
for Sound Level Meters''. They are fast, slow, impulse, exponential, 
and peak. The quickest response is the peak response and the slowest is 
the slow. Originally the slow response (1000 milliseconds) was used to 
characterize occupational noise exposure. This response was used since 
it was easier to read the needle deflections on a meter in rapidly 
fluctuating noise. For this type of noise the needle deflections using 
the fast response (125 milliseconds) were too difficult for the human 
eye to follow. ANSI S1.25-1991, ``Specification for Personal Noise 
Dosimeters'', prescribes only the slow and the fast responses for 
personal noise dosimeters. Many of the older, but not obsolete, 
personal noise dosimeters only have the slow response. Furthermore, the 
slow response was used for characterizing the noise exposure when most 
damage risk criteria were developed.
    Many commenters suggested that MSHA adopt OSHA's instrumentation 
requirements. This would imply that noise is to be measured on the A-
weighting network and the slow response. However, one commenter 
suggested that MSHA use the fast response for evaluating noise 
exposure, because ``Use of fast response will result in a more accurate 
assessment of employee exposure.''
    Prior to the adoption of the A-weighting network to evaluate noise 
exposure, the scientific community used more complex methods (e.g., 
octave bands and speech interference levels).
    ACGIH (1986) reports that:

    * * * Botsford demonstrated that A-weighted levels are as 
reliable as octave band levels in the prediction of effects on 
hearing in 80% of the occupational noises considered, and slightly 
more conservative in 16% of the cases. Passchier-Vermeer and Cohen 
et al. similarly demonstrated that A-weighted levels provide a 
reasonable estimate of the hazard to hearing in most industrial 
environments.

    The National Safety Council's Book, Fundamentals of Industrial 
Hygiene, Fourth Edition (Plog et al., 1995) states that:

    The A-weighted sound level measurement has become popular in the 
assessment of overall noise hazard because it is thought to provide 
a rating of industrial broadband noises that indicates the injurious 
effects such noise has on the human ear.

    NIOSH (1972) recommended the continued use of the A-weighted sound 
level measurement in its criteria document for a recommended standard 
on occupational noise exposure. In this criteria document they state:

    As a result of its simplicity and accuracy in rating hazard to 
hearing, the A-weighted sound level was adopted as the measure for 
assessing noise exposure by the American Conference of Governmental 
Industrial Hygienist (ACGIH) and by Intersociety Committee 
consisting of representatives from the American Academy of 
Occupational Medicine, American Academy of Ophthalmology and 
Otolaryngology, ACGIH, Industrial Hygiene Association, and the 
Industrial Medical Association. A-weighted sound level measurement 
was adopted by the U.S. Department of Labor as part of the 
Occupational Safety and Health Standards and by the British 
Occupational Hygiene Society in its Hygiene Standards for Wide-Band 
Noise.

    In reviewing the procedures for exposure measurement in regulations 
and codes of practice (mandatory or recommended) from the EEC, the ISO, 
the international community, and selected branches of the U.S. armed 
services (see Tables III-4 and III-5), MSHA found that there is general 
agreement among these groups that measurements be taken using the A-
weighting network and most agree to use the slow-response instrument 
settings. ISO 1999 (1990) recommends that if sound level meters are 
used to measure noise exposure, then the instrument should be set on A-
weighted, fast-response. In Australia, integrating sound level meters 
should be

[[Page 66401]]

set to fast-response while other sound level meters should be set to 
slow-response.
    The scientific community and most regulatory entities around the 
world accept the A-weighting network and slow-response time as 
appropriate measurement parameters for characterizing noise exposures. 
These parameters have been used by the U.S. Department of Labor, since 
the adoption of the Walsh-Healey Public Contracts Act noise regulations 
of 1969.
    Based upon comments and the good correlation between hearing loss 
and A-weighted noise exposures, MSHA proposes to continue using A-
weighting and slow-response when determining a miner's noise exposure.
Action Level
    Proposed Sec. 62.120(b) establishes an ``action level'' at a 
TWA8 of 85 dBA.
    The need for an action level reflects two facts: 1) there is a 
significant risk of material impairment to miners from a lifetime of 
exposure to noise at this level; and 2) the Agency believes it may not 
be feasible at this time to lower the PEL to this level, since that 
would require that mine operators use all feasible engineering and 
administrative controls to reduce noise exposures to this level.
    The proposal would require that all miners exposed above the action 
level be provided special instruction in the hazards of noise and 
protective methods. The training is to be provided annually for as long 
as exposure exceeds the action level. (The nature of this instruction, 
how it is to be provided, and how it can be coordinated with other 
required miner training are subjects discussed in connection with 
proposed Sec. 62.130.)
    If a miner's exposure exceeds the action level but is below the 
PEL, an operator will also be required to enroll a miner whose exposure 
exceeds the action level in a hearing conservation program (HCP). While 
enrollment in the HCP would require the operator to make annual 
audiometric testing available to the miner, miners exposed to noise 
below the PEL would have the right to decline taking any annual 
audiometric testing. MSHA's proposed testing requirements related to 
the action level are consistent with those of the OSHA HCP. The 
requirements for such testing are discussed in connection with proposed 
Sec. 62.140, audiometric testing program.
    MSHA is seeking comments on how to minimize the burden on mine 
operators of providing audiometric examinations for those miners with 
only a temporary attachment to the mining work force (e.g. summer 
employees), while recognizing the importance of detecting and tracking 
hearing loss among those who switch jobs.
    In addition, the operator must provide properly fitted hearing 
protection--before the initial hearing examination, if a significant 
threshold shift in hearing acuity is detected, and at any other time 
upon miner request. Should it take more than 6 months to provide the 
initial hearing examination because of the need to wait for a mobile 
test van, or should a significant threshold shift in hearing acuity be 
detected, the operator would also be required to ensure that the miner 
wears the hearing protection--even if the miner's noise exposure 
remains under the PEL. (A discussion of the time frames for audiometric 
tests, and the use of mobile test vans, is included in the discussion 
of proposed Sec. 62.140, audiometric testing program. The definition of 
a significant threshold shift is discussed in connection with proposed 
Sec. 62.160, evaluation of audiogram.)
    An action level currently exists under OSHA but would be new to the 
mining industry. As discussed herein, MSHA proposes to build upon the 
requirements which have been used by OSHA while giving due regard to 
implementation approaches appropriate to the circumstances of the 
mining community.
Comments on Action Level
    Several commenters recommended an action level of 85 dBA for 
triggering the requirements of an HCP.
    Many of those who commented in response to MSHA's ANPRM discussed 
hearing protection and audiometric testing. Some of these comments shed 
light on the relationship and comparative benefits of these approaches.
    Some commenters supported the use of hearing protectors as an 
integral part of an HCP, while other commenters recommended that 
hearing protectors be supplied even when not required so as to afford 
greater protection. Other commenters expressed three common concerns 
over the use of hearing protectors--
    (1) difficulty with speech communication and the masking of warning 
signals (roof talk, backup alarms, etc.), especially for those miners 
with a pre-existing hearing loss;
    (2) miner acceptance, including comfort; and
    (3) personal hygiene.
    The latter two issues of miner acceptance and personal hygiene are 
discussed in detail in the sections of the preamble entitled Selection 
of hearing protectors and Maintenance of hearing protectors, 
respectively (in connection with proposed Sec. 62.125).
    Several commenters suggested alternatives for dealing with 
communication problems associated with the use of hearing protectors by 
those with a hearing loss or in the presence of background noise. These 
alternatives included use of a ``buddy'' system, visual warnings, 
communication headsets, vitro-tactile warning systems, flat-frequency 
response hearing protectors, and notch-amplification earmuffs.
    Many commenters specifically mentioned the problem of miner 
acceptance of hearing protectors. One of these commenters stated: ``* * 
* there is anecdotal reporting to suggest that miners resist wearing 
hearing protective devices.''
    One commenter stated: ``Another [usage] problem may be the use of 
muffs with additional safety equipment, e.g. hard hats and safety 
glasses, that may be required for use by the miners.'' Other commenters 
either had no problems with hearing protectors or felt that any 
problems could be overcome with the proper training.
    In addition to the comments received in response to MSHA's ANPRM on 
this issue, several researchers and organizations have taken a position 
in regard to the use of hearing protectors.
    Shaw (1985) reviewed much of the same literature as OSHA when the 
1983 Hearing Conservation Amendment was prepared. Shaw's study supports 
requiring both hearing protectors and an HCP for exposures exceeding 85 
dBA.
    In Communication in Noisy Environments (Coleman et al., 1984), the 
authors state that:

    * * * excessive attenuation needs to be minimized and the 
frequency response of the protector is of particular importance in 
this respect. * * * (S)everal authors * * * suggest that a protector 
which passed relatively more low frequencies could increase remote 
masking and produce potential communication difficulties for some 
members of the population. This effect has been demonstrated to be 
of practical significance for coal mining conditions * * * A flat 
frequency response for a protector is necessary to counter the 
effect.

    Michael (1991) recommends that the hearing protector attenuate the 
noise with an adequate margin of safety; however, the hearing protector 
should not unnecessarily reduce important aural communications. To 
accomplish this goal, the hearing protector's attenuation 
characteristics should be matched to the noise exposure spectra as 
close as possible. This way the hearing protector will minimally change

[[Page 66402]]

the worker's perception of the noise. Michael also points out that 
overall noise reduction achieved by a hearing protector can be 
substantially influenced by the spectra of the noise.
    Chiusano et al. (1995) reported that a communication headset, 
without gain limiters, can expose communication workers to hazardous 
sound levels. The noise exposures ranged from 79.9 dBA to 103.8 dBA, 
with the average exposure being 87.0 dBA. Furthermore, the peak sound 
pressure levels ranged from 119.2 dB to 148.8 dB, with the average 
being 140.8 dB. Some recommendations presented by the authors to 
control the noise exposure were to include peak clipping, bandwidth 
limitations, signal compression, computerized gain control, and 
improving the signal to noise ratio.
    In the CAOHC Manual, Miller (1985) states that many authorities 
consider OSHA's requirement on who must wear hearing protectors to be 
``unwieldy.'' This manual states further that ``A more practical and 
workable approach is to require all workers exposed to levels of 85-dBA 
or higher to use PHPD's [personal hearing protection devices] 
regardless of whether the audiograms show an STS.''
    According to Suter (1986): ``Because hearing loss may occur in 
people chronically exposed to levels of 85-dBA and above, it is wise to 
use protectors that attenuate to 85-dBA in all cases.''
    The U.S. Armed Services, as well as the European Economic Community 
and other foreign countries, require the use of hearing protection when 
sound levels exceed 85 dBA.

General Discussion of Action Level and Requirements

    The Agency has concluded that there is a significant risk of 
material impairment to miners from a lifetime of exposure to noise at a 
TWA8 of 85 dBA. In mining, the first line of defense against risks 
has always been training. Accordingly, the proposal provides for annual 
instruction--to enhance awareness of noise risks, operator 
requirements, and available controls. This training would be required 
for any miner whose exposure is above the action level.
    MSHA's requirements for this training, and a discussion of how it 
can be coordinated with existing training requirements, are in proposed 
Sec. 62.130. As discussed below in connection with that section, MSHA 
received many comments in response to its Advance Notice of Proposed 
Rulemaking that supported the value of an annual training requirement. 
Studies have shown that the effectiveness of a hearing protection 
program is highly dependent on the proper use of hearing protectors and 
the commitment of both management and employees, and annual training is 
critical to reinforce both the knowledge and commitment.
    The Agency believes it may not be feasible at this time to require 
mine operators to reduce noise exposures to a TWA8 of 85 dBA. A 
detailed discussion on this point can be found in Part IV of this 
preamble. Thus, for exposures between a TWA8 of 85 dBA (the action 
level), and a TWA8 of 90 dBA (the PEL), the available tools to 
supplement training are limited to hearing protectors and annual 
audiometric examinations.
    Hearing protectors offer only limited noise protection. As 
discussed in detail in connection with proposed Sec. 62.125, studies 
indicate that hearing protectors may provide significantly less than 
their rated protection under actual mining conditions. Nevertheless, 
MSHA believes that if hearing protection is properly utilized--that is, 
if the requirements under proposed Sec. 62.125 are implemented--they 
generally can be relied on to provide at least 5 dBA attenuation, and 
thus could realistically protect the majority of miners whose noise 
exposure falls between the action level and the PEL.
    The comments that MSHA received in response to its ANPRM, however, 
suggest that ensuring the protectors are properly fitted, maintained 
and utilized may continue to prove difficult--even once the proposed 
new standards in this regard (see the discussion of proposed 
Sec. 62.125) are taken into account. For example:
    (1) The mining environment presents hazards which require a miner 
to be aware of his/her surroundings. Many underground miners claim that 
the use of hearing protectors interferes with their ability to hear 
warning signals or roof talk. This interference may be particularly 
pronounced among miners who already have a significant degree of 
hearing loss, and such miners may justifiably be reluctant to use 
hearing protectors;
    (2) Hearing protectors (earmuffs and earplugs) are difficult to 
keep clean in the mining environment which can lead to irritation or 
infection of the ear(s);
    (3) Earmuffs are often uncomfortable when worn in hot environments 
(e.g., surface mines during periods of extreme heat or some deep 
underground mines);
    (4) Hearing protectors experience a degradation of attenuation when 
moved from their original position. This condition can occur often when 
hearing protectors are worn by a miner operating vibrating equipment 
(e.g., pneumatic drills, continuous mining machines, mobile equipment), 
wearing certain types of personal protective gear (e.g., safety 
glasses, hardhats, respirators, welder's hood, etc.), or sweating;
    (5) The effectiveness of hearing protectors is highly dependent 
upon proper fit and use by the miner. While the amount of protection 
afforded by engineering controls can be easily measured, the 
attenuation of hearing protectors under actual working conditions can 
only be estimated; and
    (6) Generally, hearing protectors are not effective in reducing low 
frequency noise. As most mining machinery emits predominantly low 
frequency noise, the use of hearing protectors may have a negligible 
effect in reducing the overall sound level.
    To alleviate these problems, both operators and miners must be 
committed to working through individual concerns about hearing 
protection. MSHA believes that the best way to facilitate this 
process--at exposure levels between the action level and the PEL, and 
with a few exceptions--is to have operators provide instruction and 
make suitable hearing protectors available to miners upon request. If 
protectors are requested, they would have to be provided in accordance 
with the requirements of Sec. 62.125--i.e. a choice of plug or muff 
type, properly fitted, maintained, and replaced under certain 
conditions. An operator would generally not, at such exposure levels, 
have an obligation to enforce the use of hearing protection. MSHA 
believes that the combination of knowledge, availability, and properly 
selected, fit and maintained equipment may be the best way to encourage 
hearing protector use.
    MSHA would require an operator to provide a miner with a hearing 
protector while awaiting a baseline audiometric examination; but with 
the exception noted below, the operator would not have to enforce the 
use of the protector as long as the miner's exposure does not exceed 
the PEL.
    In two cases, however, MSHA proposes to require operators to 
enforce hearing protector use at exposures below the PEL. The first 
case would be in the event a miner exposed above the action level has 
to wait more than 6 months for a baseline audiometric examination. As 
noted in proposed Sec. 62.140, the baseline examination is normally to 
take place within 6 months of a determination that a miner is at risk 
because his or her exposure exceeds the action level; however, the time 
frame can be extended for an additional 6 months if the operator has to 
wait for a

[[Page 66403]]

mobile test van. In such cases, the miner is exposed to harm for an 
extended period of time without the benefit of audiometric test data, 
and MSHA believes it would be appropriate to require protection to be 
worn. This is the approach taken under OSHA's noise requirements.
    In addition, an operator would be obligated to ensure the miner 
uses provided hearing protection when audiometric examinations indicate 
a significant threshold shift (STS) in hearing acuity has occurred and 
the miner's exposure exceeds the action level. (The evaluation of 
audiograms, and the determination of whether or not there is an STS, is 
the subject of proposed Sec. 62.160.) MSHA believes that once there is 
evidence from the tests that the miner is incurring hearing loss, it is 
appropriate to require that hearing protectors be worn as long as 
exposure exceeds the action level.
    Annual audiometric examinations cost more than providing hearing 
protection--but as already recognized by many in the mining industry, 
and all the industries which operate under OSHA's requirements, such 
examinations provide important information, especially in an 
environment in which hearing protector use has the problems noted 
previously. The act of enrolling miners in a ``hearing conservation 
program'' (HCP) can help emphasize to those individuals that they 
should pay more attention to the training and available controls. It 
also helps miner representatives, operators, and MSHA focus available 
resources on those miners who have actually suffered an STS at lower 
noise exposures. While MSHA is not proposing to require operators to 
compel miners to take the annual examinations at exposure levels below 
the PEL, and expects that many miners may be reluctant to take 
examinations out of concern about how the information would be used, 
MSHA anticipates that over time the required training would lead to 
growing use of such examinations within the mining industry. (MSHA's 
preliminary RIA assumes only limited participation at such exposure 
levels during the initial years of the rule's implementation.)
Participation in an HCP
    MSHA has no standards addressing hearing conservation plans or 
programs in its existing metal and nonmetal regulations. However, an 
indeterminate number of mines have voluntarily established HCP's. MSHA 
estimates that 5% of small mines, and 20% of large mines, have such 
programs.
    Existing MSHA coal noise standards require mine operators to submit 
``* * * a plan for the administration of a continuing, effective 
hearing conservation program,'' within 60 days following the issuance 
of a notice of violation [citation] for subjecting a miner to a noise 
exposure exceeding the PEL. This plan must include provisions for pre-
employment and periodic audiograms. The regulation, however, does not 
specify the procedures nor the time frame for obtaining these 
audiograms. Additionally, due to coal's policy of considering hearing 
protector attenuation in determining compliance with the PEL, few 
miners are found overexposed.
    OSHA's noise standard requires that all employees exposed above the 
action level (TWA8 of 85 dBA) be enrolled in an HCP. OSHA's HCP 
requirements include provisions addressing exposure assessment, 
training, audiometric testing, hearing protectors, notification, and 
recordkeeping.
    Several commenters recommended requiring an HCP whenever a miner's 
exposure exceeds a TWA8 of 85 dBA, or equivalently a noise dose of 
50%.
    Under MSHA's proposal, participation in an HCP would be provided by 
the mine operator at no cost to the miner. OSHA also specifies that 
audiometric testing and hearing protectors be provided at no cost to 
the employees. MSHA intends that the audiometric testing be given 
during normal working hours (on-site or off-site) and that miners 
participating in these activities receive wages for the time spent in 
their involvement. If the audiometric testing is provided off-site, 
MSHA intends the mine operator to compensate the miners for the 
additional costs, such as mileage, meals, and lodging, that they may 
incur.
Elements of an HCP
    Some of the elements often considered to be part of an HCP are 
handled through separate, free-standing requirements under MSHA's 
proposal. These include hearing protection and training, and an 
employer's obligation to evaluate the noise to which miners are exposed 
to determine if specified levels are exceeded. Accordingly, the 
proposal uses the term HCP to refer essentially to annual audiometric 
testing and required follow up examinations and actions.
    Under OSHA's noise standard, the elements of an HCP include:
    (1) monitoring employee noise exposure;
    (2) wearing hearing protectors;
    (3) education and training; and
    (4) audiometric testing and medical evaluation.
    In its ANPRM, MSHA requested information concerning the elements 
which would be appropriate for inclusion in an HCP for mining. MSHA 
received numerous comments concerning this issue. Of these, many 
supported MSHA's adoption of HCP requirements similar to OSHA's, 
including:

* * * Assessment, monitoring, engineering and/or administrative 
controls, hearing protective devices, employee education, 
audiometric testing, interpretation of audiometric tests and follow-
up, and appropriate record keeping.

    Although there was a consensus among commenters on the elements of 
an HCP, there was considerable variation in the substantive aspects of 
these elements. Commenters ranged from wanting more performance 
oriented requirements to wanting more specific requirements with fewer 
exceptions than in the existing OSHA rule.
    One commenter wanted ``* * * a more stringent program than the 
present OSHA HCP * * *''. Another felt that no program should be 
implemented until ``* * * sufficient evidence and testing demonstrates 
a need for the program to protect the hearing of miners.'' Another 
commenter believed that audiograms were a needless expense, but that 
hearing protectors should be required for all miners exposed to 
hazardous sound levels. Several commenters believed that HCP's were of 
no value, stating ``Our experience with HCP's indicates they are wasted 
bureaucratic red tape and present no benefit to the employees.''
    ``Guidelines for the Conduct of an Occupational Hearing 
Conservation Program'' (1987) developed by the American Occupational 
Medical Association's Noise and Hearing Conservation Committee of the 
Council on Scientific Affairs presents the basic elements of an HCP. 
They recommend that each program include: (1) measurement of exposure; 
(2) engineering controls; (3) use of hearing protectors; (4) 
audiometric testing and medical evaluation; (5) education and training; 
(6) assessment of program effectiveness; and (7) management support.
    MSHA agrees with the majority of the commenters to the ANPRM. 
However, as noted, MSHA proposes to require some of these elements 
through free-standing requirements. Accordingly, the proposal uses the 
term HCP to refer essentially to annual audiometric testing and 
required follow up examinations and actions. Overall, the requirements 
of MSHA's proposal are generally

[[Page 66404]]

consistent with OSHA's current HCP requirements and with the 
requirements of the U.S. armed services and the international 
community.
    MSHA reviewed HCPs in effect at a variety of organizations. The 
HCPs consist mainly of monitoring employee noise exposure, controlling 
the noise, training employees, and conducting audiometric testing. The 
Agency believes that when engineering and administrative controls are 
not able to reduce a miner's exposure to within the PEL, annual 
audiometric testing and medical evaluation would enable mine operators 
and miners to take proper precautions to identify early hearing loss 
and thereby prevent further deterioration of hearing. This is discussed 
in more detail in those sections of the preamble reviewing the proposed 
HCP requirements (proposed Sec. 62.140 et. seq.).
Effectiveness of HCP's
    Although many commenters to MSHA's ANPRM stated that an HCP is 
needed, only a few commenters specifically addressed the effectiveness 
of an HCP.
    One commenter referenced a study (ANSI, 1990; Royster and Royster, 
1988) which indicated that the HCP at five out of 17 companies, or less 
than 30%, could be considered effective/adequate. This inadequacy, 
however, could be attributed to a lack of commitment by the companies 
in carrying out all of the necessary components of the HCP. This study 
found that, for the HCP to be successful, it is critical that a single 
individual have control over the program and its implementation. 
Furthermore, management must make a commitment to ensure that the 
program is fully implemented.
    Another commenter, representing nonmetal mining companies, 
indicated that its members have not experienced large numbers of claims 
for hearing loss and this may be a reflection of program effectiveness.
    In addition to the above comments, MSHA reviewed several studies 
regarding the effectiveness of HCP's. Villeneuve and Caza (1986) 
reported on the HCP for a Canadian mining company. Under this HCP, 
miners undergo audiometric evaluations, receive training, and wear 
hearing protectors. After ten years, the incidence of workers' 
compensation claims for hearing loss has diminished.
    After obtaining audiometric data from three Ontario employers who 
had HCP's, Abel and Haythornthwaite (1984) investigated the progression 
of NIHL. Workers for the first employer (public utility) had their 
maximum hearing loss between 2000 and 6000 Hz. Further, 78% of the 
workers who reported never wearing their hearing protectors experienced 
25 dB of hearing loss at 4000 Hz. For those workers who wore their 
hearing protectors at least half of the time, 38% had the same degree 
of hearing loss.
    At the second employer (mining company) about half the drillers 
incurred a hearing loss of 1 dB per year or more at 4000 Hz. Motorman 
chute blasters incurred an average change of hearing of a little over 1 
dB per year. This compares to a hearing loss of 0.5 dB per year for the 
control group. Further, in subjects who were over 50 years of age, 
100%, 88% and 38% of the drillers, the motorman chute blasters, and the 
controls respectively had a hearing loss that exceeded 25 dB at 4000 
Hz.
    Finally, workers at a foundry and steel mill showed a 0.13 dB per 
year hearing loss at 1000 Hz and 1.3 dB per year at 4000 Hz. Their 
hearing loss was similar to the miners.
    Abel (1986) reported on the progression of NIHL among three groups 
of workers, including miners. All noise-exposed workers had exposures 
exceeding 85 dBA and were enrolled in an HCP. One requirement of the 
HCP was mandatory use of hearing protectors. At 4000 Hz, the noise-
exposed workers lost their hearing acuity at 1.5 dB per year compared 
to 0.5 dB per year for the control group, who were office workers.
    Despite mandatory use of hearing protectors, most workers in the 
Abel study admitted to wearing their hearing protectors less than 50% 
of the time. Further, many modified their hearing protectors to provide 
greater comfort. Many of the modifications had a deleterious effect on 
the attenuation.
    Gosztonyi (1975) reported on his evaluation of an HCP at a large 
manufacturing plant. The study covered a 5-year period (1969-1974) 
shortly after the passage of the Walsh-Healey Public Contracts Act 
noise regulations. The study covered 213 employees with a median age of 
43 years. The workers were divided into three groups based on their 
noise exposure. These were: (1) 71 office workers exposed to sound 
levels of 50 to 70 dBA; (2) 71 workers in the machine shop exposed to 
sound levels of 80 to 85 dBA; and (3) 71 workers (wearing hearing 
protectors) in the chipping and grinding areas of the iron and steel 
foundry exposed to sound levels of 100 to 110 dBA. Gosztonyi found 
that, over a 5-year period, the hearing loss incurred by workers in 
group (3) were no greater than the losses exhibited by the other groups 
at each frequency, regardless of the baseline hearing thresholds. He 
concluded that an HCP (consisting of periodic noise exposure 
assessments, annual audiometric testing, and the mandatory use of 
hearing protectors) instituted when noise exposures exceed a hearing 
conservation criterion of approximately 90 dBA adequately protects the 
hearing of noise-exposed workers.
    Pell and Dear (1989) reported the following:

    Two longitudinal studies of changes in hearing threshold levels 
and one study of the prevalence of hearing impairment in noise 
exposed and non-exposed workers have clearly indicated that DuPont's 
hearing conservation program has been effective in preventing 
occupationally noise-induced hearing loss [NIHL].

    Several reports on the effectiveness of DuPont's HCP have been 
published. DuPont's HCP requires the wearing of hearing protectors in 
high noise areas, audiometric testing, and monitoring of noise 
exposure. In the first study Pell (1972) showed, via a retrospective 
study, that the hearing of workers was being protected. The hearing 
levels of workers in high noise areas were compared to the hearing 
levels of workers in quieter areas (below approximately 90 dBA). Both 
groups of workers had comparable hearing levels at frequencies between 
500 and 2000 Hz. At higher frequencies the median hearing level of 
quieter area workers was slightly better than the median hearing level 
of high noise area workers. Although the differences were statistically 
significant, the author believed that the small differences lacked 
practical importance. Moreover, the difference was much less than the 
hearing loss which occurred due to presbycusis and other non-
occupational factors. Comparing the results to a study published by 
Nixon and Glorig (1961) on unprotected workers, Pell concluded that the 
DuPont workers experienced much less hearing loss.
    Later, Pell (1973) published the initial results of a 5-year 
longitudinal study on the same workers. The sound level to which 
workers were exposed in the quiet areas could approach 90 dBA, but most 
exposures were between 50 and 70 dBA. The workers in the highest noise 
areas were required to wear hearing protectors and most of the workers 
in the moderate noise areas chose to wear hearing protectors. A 
comparison of workers' hearing levels at 3000, 4000, and 6000 Hz 
revealed that there was no increased hearing loss among workers who 
wore hearing protectors in high noise areas versus the workers in the 
quiet areas. The researcher concluded that:


[[Page 66405]]


    The analysis of changes in hearing threshold levels over a 5-
year period has clearly indicated that persons who work in areas 
where noise levels (sound levels) exceeded 90 dBA showed hearing 
losses that were no greater than those experienced by persons who 
worked in areas where the noise levels (sound levels) were less than 
90 dBA. It is evident, therefore, that a hearing conservation 
program in which the hearing conservation criterion is approximately 
90 dBA can successfully protect the hearing of noise-exposed 
workers.

    Pell believed that his study confirmed the earlier conclusion that 
DuPont's HCP was effective in preventing occupational hearing loss. 
Pell emphasized, however, that this study cannot reveal the effects of 
these sound levels on hearing acuity but is intended only to evaluate 
the effectiveness of the HCP. The third study is a continuation of the 
second study. In this study, Pell and Dear (1988) evaluated the 
effectiveness of DuPont's HCP over 20 years. However, the study did not 
involve the same workers over the entire time frame for many reasons. 
Furthermore, the researchers divided the workers into three categories: 
workers exposed to noise under 85 dBA; between 85 to 94 dBA; and 95 dBA 
or higher. The mean differences, over a 3-year period between workers 
in noisy (over 85 dBA and wearing hearing protectors) and quiet areas, 
were small. Evaluating the prevalence of hearing impairment using the 
AAO-HNS 1979 definition showed that the high noise areas had slightly 
higher prevalence rates of hearing impairment. After adjusting for 
presbycusis, only 7.1% of the workers in the high noise areas developed 
a hearing impairment. Pell and Dear concluded that presbycusis was by 
far the major factor in developing a hearing impairment. Furthermore, 
independent clinical evaluations of the non-presbycusis cases revealed 
that socioeconomic factors, (e.g., differences in off-the-job noise 
exposures and otological disease), may account for much of the excess 
hearing impairment of the noise-exposed workers. Pell and Dear 
attributed the effectiveness of DuPont's HCP to educating the workers 
to the hazards of noise, hearing protector fitting, and supervision. 
Because of these components, DuPont workers received greater noise 
reduction from foam earplugs than did workers in other industries. Pell 
and Dear believe that effective use of hearing protectors is the 
overwhelming factor in approaching avoidance of problem hearing loss. 
In addition, Pell and Dear believe that employees exposed above 90 dBA 
are better protected by using appropriate hearing protectors rather 
than implementing engineering controls to reduce the noise to 89 dBA or 
even 84 dBA.
    Savell and Toothman (1987) studied the HCP at a factory. The 
workers whose time-weighted average noise exposures ranged from 86 to 
103 dBA were required to wear hearing protectors as a condition of 
employment which was strictly enforced. These workers were employed 
between 8 and 12 years. Only the employees with more than 25 months off 
the job during the course of the study were excluded in order to obtain 
a large sample (265 workers). The group mean hearing levels from the 
latest audiograms were compared to the initial audiograms. Savell and 
Toothman did not find any significant change in hearing acuity over the 
course of the study. Therefore, they concluded that mandatory use of 
hearing protectors in an HCP can protect the hearing acuity of workers.
    Bruhl and Ivarsson (1994) conducted a longitudinal study of the HCP 
at an automobile stamping plant over a 15-year period. The researchers 
evaluated workers' hearing levels over the frequency range of 2000 to 
8000 Hz. Workers' hearing levels were compared to the hearing levels of 
a ``highly screened'' non-noise exposed male population. For sheet 
metal workers, the HCP reduced the noise-induced permanent threshold 
shift. Bruhl and Ivarsson concluded that the HCP, which included 
effective use of hearing protectors and reduction of sound levels, can 
eliminate occupational NIHL.
    Franks et al. (1989) examined the hearing conservation records of a 
large printing company with multiple facilities. They examined the 
records for factors associated with the development of an STS. Franks 
et al. indicated that ``* * * statistically significant factors 
associated with Standard Threshold Shift [STS] were from medical and 
non-occupational noise exposure histories, and not occupational noise 
exposure.'' In other words, the HCP was effective since the hearing 
loss developed by the workers was from non-occupational exposures.
    Moretz (1990), reporting on the work of the ANSI S12.12 working 
group, stated that ``A pilot analysis of industry's audiometric data 
found that fewer than 20 percent of the programs [HCP's] are 
effective.'' Moretz further reported that Alice Suter, a member of this 
ANSI working group, had stated that ``the actual percentage of 
companies with effective programs is probably even lower * * *,'' 
because the ANSI working group had looked at data from relatively large 
companies. Suter thought that smaller companies are less likely to have 
the resources necessary to operate an effective HCP.
    The National Institutes of Health (NIH), in its Consensus Statement 
on Noise and Hearing Loss (1990), states that ``many existing hearing 
conservation programs remain ineffective due to poor organization and 
inadequately trained program staff.''
    Although evidence indicates that a properly supervised and operated 
HCP can provide effective protection, in many instances, HCP's have 
failed due to the lack of necessary supervision and adherence to proper 
procedures and principles. Furthermore, the studies which showed HCP's 
to be effective were mainly of short term durations (five years or 
less). There is a lack of evidence that long term HCP's protect the 
hearing acuity of workers. Pell and Dear's 20 year study (1988) was in 
actuality two shorter longitudinal studies covering a five-year period 
at the beginning of the study and a three-year period at the end. In 
both of these shorter studies the hearing level of the participants did 
not change at a rate different from the non-noise exposed controls.
    The two other long-term studies, Bruhl and Ivarsson (1994) and 
Bruhl et al. (1994) demonstrated that HCP's were effective in reducing 
noise-induced permanent threshold shift. At the plant both engineering 
noise control and hearing protectors were utilized to reduce worker's 
exposure to noise. Therefore, these studies indicate engineering noise 
control is a necessary component of an effective long-term HCP.
    Rink (1996) studied the hearing loss of workers enrolled in HCPs. 
Between 1991 and 1995 nearly 590,000 audiograms were given. During the 
years the percentage of STSs decreased each year--from 4.69% to 1.22%. 
Further, Rink reported that about 50% of the STS consistent with noise 
exposure were persistent (confirmed STSs). The remainder were not 
permanent. Rink concluded that aggressively adhering to and enforcing 
the hearing conservation policies proposed by OSHA in 1983 can reduce 
and effectively control NIHL.
    Many of the above studies indicate that an HCP can be effective in 
preventing hearing loss, but only if management and workers strictly 
adhere to its requirements. Several of these studies also concluded 
that engineering controls were a necessary part of an effective HCP. 
This is not inconsistent with MSHA's conclusions about the

[[Page 66406]]

importance of commitment by both operators and miners.
Evaluation of HCP Effectiveness
    MSHA has not included a methodology or a requirement for mine 
operators to test the effectiveness of their HCP's. Currently, both 
MSHA's Coal and OSHA's noise standards require an effective HCP, but do 
not specify a procedure for evaluating the effectiveness of the 
program. Further, Metal and Nonmetal's noise standard has no 
requirement for an HCP.
    In its ANPRM, MSHA also requested information concerning 
appropriate methods or requirements for evaluating the effectiveness of 
HCP's. One commenter felt that evaluation criteria are unnecessary and 
that the HCP is effective if exposures are reduced. Another commenter 
stated that uniform evaluation criteria have not been adopted. Another 
suggested that NIOSH be given the task of evaluating the effectiveness 
of HCP's for the mining industry.
    A number of commenters believed that it was essential for MSHA to 
address procedures for evaluating the effectiveness of HCP's. Several 
of these commenters suggested that MSHA monitor the activities of the 
ANSI S12.12 Working Group for Evaluation of HCP's and consider using 
the guidelines established by this group, once they were finalized. 
ANSI has published a draft standard, ANSI S12.13-1991 Audiometric 
Database Analysis (ADBA), which describes techniques for evaluating the 
effectiveness of the HCP's.
    Adera et al. (1993) studied the effect of using ADBA to determine 
the effectiveness of a utility company's HCP which had 2,317 
participants. The hearing acuity of the utility workers was compared to 
the hearing acuity of tobacco company employees (control population). 
The tobacco company employees were one of the control populations used 
in developing the draft ANSI standard S12.13-1991. The control 
population's noise exposure was approximately 87 dBA and they wore 
hearing protectors consistently. While the ADBA method deemed the HCP 
acceptable, epidemiological techniques showed the workers to be at risk 
of developing a hearing loss. The age-adjusted risk of developing a 
hearing loss was 2.3 times that of the control population.
    Simpson, Stewart, and Hecksel (1992) studied HCP's at 28 small 
companies representing 2,183 employees of which 865 qualified for ANSI 
analysis. The researchers concluded that companies with less than 100 
employees may have difficulty in meeting ANSI S12.13-1991 data 
requirements for more than two consecutive years of data analyses due 
to employee turnover and absenteeism. Sample sizes smaller than 30 
employees are likely to be more sensitive to outlier scores. Smaller 
sample sizes were also more likely to be rated marginal or unacceptable 
due to biasing effects of sample size. For 1990, the percent of STS's 
ranged from 0% to 3.8% at the individual plants. The rate of STS's 
across all 28 plants was 1.5%.
    Simpson, Stewart and Kaltenbach (1994) investigated early 
indicators of HCP performance. A total of 27,047 employees (3,245 
controls and 23,802 subjects) in 21 HCP's were included in the study. 
The rate of STS in the control groups ranged from 2.5 to 5.7% while the 
exposed groups had a rate between 4.6 and 28%. Comparing the incidence 
of STS's with ANSI S12.13-1991 indicators, the researchers concluded 
that the incidence of STS's was as good as the ANSI test criteria as an 
early indicator of the effectiveness of an HCP from the first two 
audiograms.
    NIOSH (1995) recommended a simple method of determining the 
effectiveness of an HCP. According to NIOSH, if less than 5% (1 out of 
20) of the noise-exposed workers enrolled in an HCP incur an 
occupationally-induced STS, the HCP is deemed effective. According to 
NIOSH, this method should be used to continually monitor the results of 
audiometric testing to indicate the effectiveness of the HCP before 
many individuals incur permanent shifts in hearing acuity.
    While MSHA recognizes that the ADBA technique may be promising, the 
Agency is concerned that it may not be practical for the majority of 
mine operators. The ADBA technique may not be applied reliably to 
populations of fewer than 30 individuals and about 90% of the 15,000 
mines under MSHA's jurisdiction employ less than 30 miners. Even if 
every miner was placed in an HCP, regardless of noise exposure, less 
than 10% of the mines could consider using the ANSI draft ADBA 
procedures to evaluate their HCP. ADBA analysis also may not be 
appropriate if the workforce being analyzed is not stable, exhibiting a 
high turnover rate. MSHA has determined that this may be the case for 
many small mines which operate seasonally, are portable, or change 
geographic locations. Currently, the annual turnover rate in mining 
ranges from 2% in large coal mines to 11% in small metal and nonmetal 
mines.
    In addition, ADBA requires several years of data before the 
analysis can be conducted. Consequently, ADBA cannot be used to 
immediately determine the effectiveness of an HCP unless audiograms 
were collected prior to the effective date of the rule.
    Finally, existing procedures for conducting ADBA call for the use 
of audiograms taken without observing a quiet period. Both OSHA's 
existing standard and this proposal require a 14-hour quiet period 
before conducting a baseline audiogram. These standards, however, do 
not address a quiet period for annual audiograms, leaving the choice to 
the employer or the mine operator. Consequently, where a quiet period 
is used, those audiograms could not be used in conducting ADBA.
    MSHA also is concerned that the statistical methods employed by 
ADBA require the use of a computer, which many small mine operators may 
not have. Consequently, many mine operators may need to employ outside 
consultants to conduct this analysis. Because the ADBA techniques are 
relatively new, a sufficient number of consultants, who fully 
understand and can utilize this analytical technique, may not be 
available. Despite the problems with ADBA analysis for the mining 
industry, MSHA recognizes that it may be a valuable tool for 
identifying and correcting problems in an HCP before an STS occurs. 
MSHA does not wish to discourage mine operators from using this 
technique.
    The analysis of an HCP's effectiveness can be as simple as 
comparing a current audiogram with prior audiograms. This simple 
approach, however, can be extremely time consuming and may not identify 
trends among miners.
    Further, international communities and selected branches of the 
U.S. armed services require the effectiveness of the HCP's to be 
evaluated even though they do not include specific methods for the 
evaluation.
    MSHA, however, is not specifying a methodology to determine the 
effectiveness of an HCP for several reasons. First, there is not a 
consensus among researchers and commenters as to a method even though a 
draft ANSI standard (ADBA) has been published on this issue. Secondly, 
the techniques for evaluating the effectiveness of an HCP that have 
been developed are not appropriate to an HCP with few participants. 
MSHA estimates that most HCP's in the mining industry would not have a 
sufficient number of participants to be tested. Further, MSHA contends 
that there are few consultants and fewer mine operators with the 
expertise to evaluate the effectiveness of an HCP.
    MSHA requests specific suggestions on practical methods which could 
be used in the mining industry, particularly among small mine

[[Page 66407]]

operators, to evaluate the effectiveness of HCP's. MSHA also requests 
comments on NIOSH's above stated recommendations.
Temporary or Seasonal Miners
    The proposal would not provide any exemption from the requirements 
to provide audiometric examinations for temporary or seasonal miners.
    OSHA has no such explicit requirement. Moreover to create such an 
exemption would mean that workers who change jobs--within a single 
industry, or between industries--might end up never having a check on 
hearing loss even if working in very noisy conditions.
    The proposal does include certain provisions that might in practice 
exclude some miners from examinations otherwise required. A mine 
operator has up to 6 months to conduct a baseline audiogram--up to 12 
months if a mobile van is used. Thus in practice, the operator's 
obligation to provide examinations does not extend to those miners who 
leave employment before this time and who do not subsequently return to 
work for the same operator. Many summer employees might fall into this 
category.
    MSHA solicits further comment on this issue.
Permissible Exposure Level (PEL)
    Proposed Sec. 62.120(c) provides as follows:

    No miner shall be exposed to noise in excess of a TWA8 of 
90 dBA (PEL) during any workshift, or equivalently a dose of 100%.
    (1) If a miner's noise exposure exceeds the PEL, the operator 
shall, in addition to taking the actions required under paragraph 
(b) of this section, use all feasible engineering and administrative 
controls to reduce the miner's noise exposure to the PEL. When 
administrative controls are used to reduce a miner's exposure, the 
operator shall post these procedures on the mine bulletin board and 
provide a copy to affected miners.
    (2) If a miner's noise exposure exceeds the PEL despite the use 
of the controls required by paragraph (c)(1) of this section, the 
operator shall take the actions required by this paragraph for that 
miner.
    (i) The operator shall use the controls required by paragraph 
(c)(1) of this section to reduce the miner's noise exposure to as 
low a level as is feasible.
    (ii) The operator shall ensure that a miner whose exposure 
exceeds the PEL takes the hearing examinations offered through 
enrollment in the hearing conservation program.
    (iii) The operator shall provide hearing protection to a miner 
whose exposure exceeds the PEL and shall ensure the use thereof. The 
hearing protection shall be provided and used in accordance with the 
requirements of Sec. 62.125.

    This paragraph would establish the permissible exposure limit (PEL) 
to noise for a miner as a TWA8 of 90 dBA during any workshift. 
(This is also referred to as a dose measurement of 100%; the action 
level TWA8 of 85 dBA is half this dose of noise.)
    The PEL is a time-weighted average sound level to which a miner may 
be exposed that establishes the maximum dose of noise permitted. Under 
the proposal, this is established as a TWA8 of 90 dBA--the same as 
at present. TWA8 refers to a time-weighted-8-hour average, a term 
defined in proposed Sec. 62.110. The exposure needed to reach the PEL 
varies by sound level and time. For example, the PEL would be reached 
as a result of exposure to a sound level of 90 dBA for 8 hours, but 
also reached by exposure to a sound level of 95 dBA for only 4 hours or 
92 dBA for 6.1 hours.
    The Agency considered proposing a different PEL. As noted in part 
II of the preamble, MSHA has concluded that there is a significant risk 
of material impairment from noise exposures at or above a TWA8 of 
85 dBA. MSHA considered setting the PEL at this level, but as discussed 
in part IV of this preamble believes that this may not be feasible at 
this time for the mining industry. Accordingly, the Agency is proposing 
to keep the PEL at a TWA8 of 90 dBA--the level in effect for the 
mining industry and under OSHA. The PEL is a dose twice that which 
would be received at the level at which there is a significant risk of 
material impairment.
    While the PEL would not change, the actions required if noise 
exposure exceeds the PEL would in many cases be different from those 
currently required.
    Under the proposal, a hierarchy of controls is established for all 
mines. Mine operators must first utilize all feasible engineering and 
administrative controls to reduce sound levels to the PEL. This 
approach is more consistent with MSHA's existing noise standards for 
metal and nonmetal mines than for coal mines. Under the current metal 
and nonmetal regulations, mine operators have to utilize either 
engineering or administrative controls to reduce noise to the PEL or as 
close thereto as feasible. In the coal industry, MSHA inspectors do not 
cite for noise without first deducting the attenuating value of hearing 
protectors being worn by the miners subjected to excessive exposures of 
noise. In practice, this means personal protective equipment is in most 
cases accepted as a substitute for engineering and administrative 
controls.
    As under the present standards, the proposal would require a mine 
operator to use only such engineering controls as are technologically 
feasible, and to use only such engineering and administrative controls 
as are economically feasible for that mine operator.
    Moreover, the proposed rule spells out explicit requirements that 
will supplement these controls in those cases in which the Agency 
concurs with a mine operator that the use of all feasible engineering 
and administrative controls cannot reduce noise to the PEL. All sectors 
of the mining industry will, in such cases, have to provide all miners 
exposed above the PEL with a properly fitting hearing protector, ensure 
the miners use those protectors, and ensure that miners take their 
annual hearing examinations.
Existing Standards
    MSHA's existing metal and nonmetal noise standards require the use 
of feasible engineering and administrative controls when a miner's 
noise exposure exceeds the PEL. Hearing protectors are also required if 
the exposure cannot be reduced to within the PEL. The existing metal 
and nonmetal standards do not, however, require the mine operator to 
post the procedures for any administrative controls used, to conduct 
specific training, or to enroll miners in hearing conservation 
programs.
    MSHA's existing noise practices for coal mines are significantly 
different from those for metal and nonmetal mines. The difference stems 
from the circumstances under which the Agency is authorized to issue 
citations. In metal and nonmetal mines, a citation is issued based 
exclusively on the exposure measurement--when MSHA measures an exposure 
at a TWA8 of 90 dBA. But in coal mines, a citation is not issued 
in such a case if the miners are wearing hearing protection judged to 
be appropriate. The appropriateness is based on the EPA noise reduction 
rating minus 7 dB; in practice, most hearing protectors have ratings 
which meet this official test for many coal mine exposures. 
Accordingly, citations are seldom issued.
    When coal mine operators do receive a citation for a miner's noise 
exposure exceeding the PEL, they are required to promptly institute 
administrative and/or engineering controls to assure compliance. 
Additionally, within 60 days of receiving a citation, coal mine 
operators are required to submit to MSHA a plan for the administration 
of a continuing, effective hearing conservation program, including 
provisions for--
    (1) Reducing environmental noise levels;

[[Page 66408]]

    (2) Making personal ear protective devices available to miners;
    (3) Conducting pre-placement and periodic audiograms; and,
    (4) Instituting engineering and administrative controls to ensure 
compliance with the standard (underground only).
    With regard to MSHA's existing noise standard, the Federal Mine 
Safety and Health Review Commission (Commission) has addressed the 
issue of what MSHA must consider, when determining what is a feasible 
noise control for enforcement purposes, at a particular mine. According 
to the Commission, a control is considered feasible when: (1) the 
control reduces exposure, (2) the control is economically achievable, 
and (3) the control is technologically achievable. See Secretary of 
Labor v. Callanan Industries, Inc., 5 FMSHRC 1900 (1983), and Secretary 
of Labor v. A. H. Smith, 6 FMSHRC 199 (1984).
    In determining technological feasibility of a regulation, the 
Commission has ruled that a control is deemed achievable if through 
reasonable application of existing products, devices, or work methods 
with human skills and abilities, a workable engineering control can be 
applied to the noise source. The control does not have to be ``off-the-
shelf''; but, it must have a realistic basis in present technical 
capabilities.
    In determining economic feasibility, the Commission has ruled that 
MSHA must assess whether the costs of the control are disproportionate 
to the ``expected benefits,'' and whether the costs are so great that 
it is irrational to require its use to achieve those results. The 
Commission has expressly stated that cost-benefit analysis is 
unnecessary in order to determine whether a noise control is required. 
According to the Commission, an engineering control may be feasible 
even though it fails to reduce exposure to permissible levels contained 
in the standard, as long as there is a significant reduction in 
exposure. Todilto Exploration and Development Corporation v. Secretary 
of Labor, 5 FMSHRC 1894 (1983). No guidance has been provided by the 
Commission as to what level of reduction is considered significant. 
However, the Commission has accepted the Agency's determination that a 
3 dBA reduction is significant.
    MSHA has interpreted the ``expected benefits'' to be the amount of 
noise reduction achievable by the control. MSHA generally considers a 
reduction of 3 dBA or more to be a significant reduction of the sound 
level because it represents at least a 50% reduction in sound energy. 
Consequently, a control that achieves relatively little noise reduction 
at a high cost could be viewed as not meeting the Commission's test of 
economic feasibility.
    Consistent with the case law, MSHA considers three factors in 
determining whether engineering controls are feasible at a particular 
mine: first, the nature and extent of the overexposure; second, the 
demonstrated effectiveness of available technology; and third, whether 
the committed resources are wholly out of proportion to the expected 
results. Before a violation of these requirements of the standard could 
be found, MSHA would have to determine that a worker has been 
overexposed; that administrative or engineering controls are feasible; 
and that the mine operator failed to install or maintain such controls. 
(See also the discussion of enforcement policy in the last of the 
Questions and Answers in part I.)
    OSHA's PEL is a TWA8 of 90 dBA, computed using a 90 dBA 
threshold. The standard requires the use of feasible engineering or 
administrative controls when a citation for exceeding the PEL is 
issued. Under OSHA policy (CPL 2.45A CH-12), however, if an effective 
HCP is in place, no STS has been detected, and adequate hearing 
protectors are utilized, no citation will be issued for noise exposures 
up to a TWA8 of 100 dBA if the costs to implement the HCP are less 
than those of engineering or administrative controls. In determining 
the appropriateness of hearing protection for this purpose, OSHA 
reduces the EPA rating by 7; but it then further reduces effectiveness 
by halving the result of that calculation. (A more detailed discussion 
of hearing protector derating approaches can be found in the section on 
Hearing Protector Effectiveness, part of the discussion of proposed 
Sec. 62.125.)
Comments and Studies on PEL
    Several commenters to MSHA's ANPRM recommended a PEL of 85 dBA. One 
of these stated the following:

    The current PEL provides inadequate protection for miner's 
hearing. The 90 dB(A) PEL is excessive and permits noise exposure 
that will result in significant hearing loss among exposed miners. 
Specifically, 21 to 29% of workers exposed to 90 dBA for 40 years 
will suffer material impairment of hearing. Material impairment of 
hearing, defined by OSHA in this case, is 25 dBA or more loss for 
the frequencies 1, 2, and 3 kHz. Based on this risk of damage, OSHA 
adopted a hearing conservation program that is required when noise 
exposure reaches 85 dBA TWA.

    Another of these commenters recommended a PEL of 85 dBA with an 80 
dBA action level. This commenter stated that:

    Both OSHA and the National Institute for Occupational Safety and 
Health (NIOSH) have recommended a PEL of 85 dBA. This level seems to 
be an appropriate PEL for mining as well, since the numbers of 
miners with hearing loss continues to be a problem. Obviously a more 
conservative approach would be to utilize 80 dBA as the action level 
to trigger the implementation provisions of an HCP. Although more 
costly, the benefits for prevention of NIHL would certainly be 
substantial.

    Many commenters on this issue, however, believe that MSHA's current 
PEL of 90 dBA should be retained and that it is adequate to protect 
miners. One commenter referenced Bartsch (see Related Studies in the 
III. Nature of the Hazard section of this preamble) as supporting 
evidence for retaining the PEL of 90 dBA. Three commenters cited lack 
of compensable noise-induced hearing loss (NIHL) cases among miners in 
their geographical area as a positive indication that the current PEL 
is adequate and they questioned the benefit of reducing the PEL to 85 
dBA. These commenters also stated that about 20% of the miners in their 
area were exposed to average sound levels above 85 dBA, but under 90 
dBA.
    In addition to the comments received in response to its ANPRM, MSHA 
also reviewed numerous studies and standards relating to the 
establishment of a PEL.
    The Physical Agents Threshold Limit Value Committee of American 
Conference of Governmental Industrial Hygienists (ACGIH) (1993) has 
adopted a Threshold Limit Value (TLV) of 85 dBA Leq,8. The 
committee believed that there was a clear consensus that an 85 dBA TLV 
was valid and needed to protect the hearing acuity of workers at the 
higher audiometric frequencies of 3000 and 4000 Hz.
    Stekelenburg (1982) suggests that 80 dBA be the acceptable level 
for noise exposure over a 40 year work history. Moreover, the 
researcher suggests that extra precautions are necessary for sensitive 
individuals and that these people need to be identified during the 
first five years of exposure to noise.
    Embleton (1994) summarized the occupational noise regulations 
(pertaining to: PEL, exchange rate, and the upper limit for noise 
exposure) from 17 countries and selected branches of the U.S. armed 
services. His summary table (absent the recommendations in his report) 
is reproduced below as Table III-4.

[[Page 66409]]



                                       Table III-4.--Some Features of Legislation Tabulated for Various Countries*                                      
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                          Limit for                                                                     
                                LAeq 8-hour exposure                   engineering or    Limit for monitoring                                           
    Country (jurisdiction)              rate           Exchange rate   administrative          hearing                Upper limit for sound level       
                                                                          controls                                                                      
--------------------------------------------------------------------------------------------------------------------------------------------------------
Australia (varies by state)..  85 dB................  3 dB..........  85 dBA..........  85 dBA...............  140 dB lin, peak.                        
Brazil.......................  85 dB................  5 dB..........  90 dBA, no        85 dBA...............  130 dB peak.                             
                                                                       exposure >115                                                                    
                                                                       dBA if no                                                                        
                                                                       protection.                                                                      
Canada:                                                                                                                                                 
    (Federal)................  87 dB................  3 dB..........  87 dB...........  84 dBA...............  140 dB peak.                             
    (ON, QU, NB).............  90 dB................  5 dB..........  90 dBA..........  85 dBA (a)...........                                           
    (AB, NS, NF).............  85 dB................  5 dB..........  85 dBA..........                                                                  
    (BC).....................  90 dB................  3 dB..........  90 dBA..........                                                                  
China........................  70-90................  3 dB..........  ................  .....................  115 dBA.                                 
Finland......................  85 dB................  3 dB..........  85 dB...........                                                                  
France (b)...................  85 dB................  3 dB..........  90 dBA or 140 dB  85 dBA...............  135 dB peak.                             
                                                                       peak.                                                                            
Germany (b), (c).............  85 dB................  3 dB..........  90 dBA..........  85 dBA...............  140 dB peak.                             
Hungary......................  85 dB................  3 dB..........  90 dBA..........  .....................  125 dBA or 140 dB peak.                  
Israel.......................  85 dB 5 dB...........  ..............  ................  115 dBA or 140 dB                                               
                                                                                         peak..                                                         
Italy........................  85 dB................  3 dB..........  90 dB...........  85 dB................  140 dB peak.                             
Netherlands..................  80 dB................  3 dB..........  85 dB...........  140 dB peak..........                                           
New Zealand..................  85 dB................  3 dB..........  85 dBA +3 dB      115 dBA slow or 140                                             
                                                                       exchange rate.    dB peak..                                                      
Norway.......................  85 dB................  3 dB..........  ................  80 dBA...............  110 dBA.                                 
Spain........................  85 dB................  3 dB..........  90 dBA..........  80 dBA...............  140 dB peak.                             
Sweden.......................  85 dB................  3 dB..........  90 dBA..........  80 dBA...............  115 dBA or 140 dBC.                      
United Kingdom...............  85 dB................  3 dB..........  90 dBA..........  85 dBA...............  140 dB peak.                             
USA (d)......................  90 dB (TWA8).........  5 dB..........  90 dBA but no     85 dBA...............  115 dBA or 140 dB peak.                  
                                                                       exposure >115                                                                    
                                                                       dBA.                                                                             
USA Army and Air Force)......  84 dB................  3 dB..........  ................  85 dBA...............  140 dB peak.                             
--------------------------------------------------------------------------------------------------------------------------------------------------------
*Embleton (1994).                                                                                                                                       
Information for countries not represented by Member Societies participating in the Working Party is taken from Ref. 15.                                 
(a) A more complex situation is simplified to fit this tabulation.                                                                                      
(b) These countries require the noise declaration of machinery, the use of the quietest machinery where reasonably possible, and reduced reflection of  
  noise in the building, regardless of sound or exposure levels.                                                                                        
(c) The noise exposure consists of LAeq and adjustments for tonal character and impulsiveness.                                                          
(d) TWA is Time Weighted Average. The regulations in the U.S. are unusually complex because different thresholds are used to compute levels to initiate 
  hearing programs (85 dBA), noise exposure monitoring (80 dBA), and noise reduction measures (90 dBA), each using a 5-dB exchange rate.                

    Embleton included recommendations based upon current practice taken 
from the various jurisdictions:

----------------------------------------------------------------------------------------------------------------
                                              Limit for engineering                                             
   LAeq 8-hour ex-         Exchange rate        or administrative     Limit for monitoring     Upper limit for  
     posure rate                                     controls               hearing              sound level    
----------------------------------------------------------------------------------------------------------------
85 dBA...............  3 dBA................  Use quietest machines  On hiring and at       140 dB peak.        
                                               and room absorption    intervals thereafter.                     
                                               in workplaces.                                                   
----------------------------------------------------------------------------------------------------------------

    He stated that:

    The primary goal of this report and its recommendations is to 
reduce the risk of long term hearing damage and expose people to a 
practical minimum. . . . Each feature recommended had been 
considered to be practicable by at least one national jurisdiction 
and there may be some experience of its usefulness. Much current 
legislation was enacted several years ago, before the more recent 
scientific evidence was available and before it was integrated into 
current understanding of this complex scientific topic.

    The U.S. armed services and possibly some international communities 
do not go through a public rulemaking process in establishing their 
respective noise regulations. Nevertheless, MSHA has included these 
sources to show that a consensus exists on noise legislation. Table 
III-5 lists information similar to that included in Table III-4 for 
several additional entities. Furthermore, there was a discrepancy found 
in Table III-4 as per the information provided for the U.S. armed 
services. The corrected information is included in Table III-5 
(compiled by MSHA).

                                        Table III-5.--Features of Noise Exposure Criteria for Additional Entities                                       
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                   Limit for                                                            
                                        LAeq 8- hour                            exgineering or          Limit for                                       
      Country or jurisdiction          exposure rate        Exchange rate       administrative      monitoring hearing     Upper limit for sound level  
                                                                                   controls                                                             
--------------------------------------------------------------------------------------------------------------------------------------------------------
American Conference of              85 dBA.............  3-dB..............  ....................  85 dBA.............  140 dBC peak.                   
 Governmental Industrial                                                                                                                                
 Hygienists (ACGIH).                                                                                                                                    

[[Page 66410]]

                                                                                                                                                        
European Economic Community (EEC).  85 dBA.............  3-dB..............  90 dBA..............  85 dBA.............  140 dB peak.                    
South Africa......................  85 dBA.............  3-dB..............  85 dBA..............  85 dBA.............  115 dBA or 150 dB.              
U.S. Air Force....................  85 dBA.............  3-dB..............  85 dBA..............  85 dBA.............  115 dBA or 140 dB.              
U.S. Army.........................  85 dBA.............  3-dB..............  85 dBA..............  85 dBA.............  140 dB.                         
U.S. Navy.........................  84 dBA.............  4-dB..............  84 dBA..............  84 dBA.............  140 dB.                         
State of Western Australia........  90 dBA.............  3-dB..............  90 dBA..............  ...................  140 dB.                         
--------------------------------------------------------------------------------------------------------------------------------------------------------

    Because the information contained in Tables III-4 and III-5 does 
not include every jurisdiction, MSHA solicits additional information on 
features of noise legislation for comparison purposes.
Hierarchy of Controls
    The proposal would require mine operators to use all feasible 
engineering or administrative controls or a combination of these 
controls to reduce a miner's daily noise exposure to the PEL. If these 
controls do not reduce the exposure to the PEL, then they shall be used 
to reduce the exposure as low as feasible. The proposal does not place 
preference on the use of engineering controls over administrative 
controls; but all feasible controls of both types must be implemented 
to reduce noise exposure to the PEL or as close thereto as is possible 
when all feasible controls are utilized.
    MSHA's proposed requirements for either feasible engineering or 
administrative controls or a combination of these controls are closer 
to MSHA's existing noise standards for metal and nonmetal mines than to 
the standards for coal mines.
    In metal and nonmetal mines, engineering or administrative controls 
are required to the extent feasible when exposures exceed a TWA8 
of 90 dBA. Current metal and nonmetal enforcement requirements equate 
engineering and administrative controls and do not accept hearing 
protectors in lieu of such controls. Mine operators in these 
industries, which have a significant percentage of small employers, 
generally opt to use engineering controls over administrative controls, 
citing practical difficulties with the implementation of the latter. 
Administrative controls reduce exposure by limiting the amount of time 
that a miner is exposed to noise, through such actions as rotation of 
miners to areas having lower sound levels, rescheduling of tasks, and 
modifying work activities.
    The hierarchy of noise control for coal mines is significantly 
different. In determining whether the mine operator is in violation of 
the PEL, MSHA deducts from noise exposure measurements the corrected 
attenuation of hearing protectors being worn by the miners. Given 
normal conditions in these mines, when hearing protectors are being 
worn, no citation is issued.
    OSHA's standard requires the use of feasible engineering or 
administrative controls. As discussed above, however, current OSHA 
policy allows employers to rely on a combination of other controls--
enrollment in an HCP, no STS, and adequate hearing protectors (measured 
in accordance with specifications adjusted for the purpose of the 
policy)--up to a noise exposure of 100 dBA, provided that the cost is 
less than that of the engineering and/or administrative controls.
    A number of commenters responding to MSHA's ANPRM, specifically 
supported the primacy of engineering controls. One commenter supported 
the primacy of engineering controls citing anecdotal evidence that 
miners resist wearing hearing protectors. Another commenter stated that 
engineering controls for mining are far more available than commonly 
thought.
    Several commenters stated that administrative controls can be 
effective but are often impractical. One commenter stated that 
administrative controls are effective but are of limited use at small 
operations because there are not enough people to rotate through the 
various jobs. Another commenter stated that although the use of 
administrative controls may lower the exposure of an individual miner 
such controls have the disadvantage of increasing overall exposure to a 
larger population. A third commenter stated that administrative 
controls should be the least preferred control method.
    A significant number of commenters specifically requested that MSHA 
allow the use of hearing protectors in lieu of engineering or 
administrative controls, as long as the hearing protector provided 
adequate attenuation. These commenters believed that hearing protectors 
were equally as effective as engineering and administrative controls.
    Many commenters recommended that MSHA allow the mine operator a 
choice or combination of controls, including the use of an HCP. Several 
commenters stated the following:

    There is no logical reason to handcuff operators by limiting 
flexibility and freedom of choice in selecting the most appropriate 
method of noise protection for the particular application; 
providing, of course, the method is effective.
    For some reason HPD's (hearing protection devices) have been 
regulated to be a third class behind administrative, and engineering 
controls. It is our experience the HPD's provide more effective, 
less costly, and more reliable protection than engineering or 
administrative controls in many circumstances. The employee 
acceptance is also good to excellent. Therefore the discrimination 
against HPD's should be removed in any future regulations.

    Dear (1987) contends that employers can manage the risk of hearing 
impairment by encouraging all employees to participate in the HCP and 
that an HCP can be as effective, in many cases, as the use of other, 
more costly controls. He believes that some workers are better served 
by wearing hearing protectors than reducing the noise via engineering 
controls to the PEL. He contends that removing the hearing protectors 
when the sound levels are reduced to 90 dBA [by engineering controls] 
would expose workers to at least 90 dBA; whereas, use of hearing 
protectors would reduce exposures much lower. Dear cites studies 
conducted by DuPont on their employees to show the effectiveness of 
hearing protectors. Employees in the DuPont HCP, which includes hearing 
protectors and begins at approximately 90 dBA, had not developed 
hearing impairment during the study period.
    Pell and Dear (1988) believe that employees exposed above 90 dBA 
are better protected by using appropriate hearing protectors, rather 
than implementing engineering controls to

[[Page 66411]]

reduce the noise to 89 dBA or even 84 dBA.
    Berger (1983) states the following regarding engineering controls 
versus hearing protectors:

    When one compares engineering noise controls to HPDs [hearing 
protectors], it must be remembered that the same types of problems 
which afflict HPD performance in the RW [real world], will tend to 
reduce the effectiveness of noise control measures as well. For 
example, one of the most commonly used treatments is an enclosure. 
If it is not well fitted, or left partially ajar, or circumvented by 
an inconvenienced employee, or its gaskets and seals age, 
deteriorate, or break in any way, then its performance will be 
degraded in a manner similar to that which has been observed for 
poorly fitted and misused HPDs. When noise control is achieved by 
improved adjustments and lubrication, there must be a trained and 
dedicated employee to monitor the maintenance schedule, just as 
employees must care for and maintain their HPDs. In fact most 
engineering noise control procedures, except for some source noise 
control accomplished through equipment redesign, require maintenance 
and periodic adjustment or replacement to continue functioning 
properly. And except for enclosures, noise reductions of 10 dB or 
more are often difficult to achieve and maintain. Thus HPDs remain 
one of the most important protective methods for a hearing 
conservationist to consider, and can provide an effective adjunct to 
engineering noise controls in the majority of industrial noise 
environments.

    Nilsson et al. (1977) studied hearing loss in shipbuilding workers. 
The workers were divided into two groups. In the first group, the 
workers were exposed to 94 dBA with 95% of the workers using hearing 
protectors. In the second group, the workers were exposed to 88 dBA and 
90% of them wore hearing protectors. Both groups were subjected to 
impulse noise up to 135 dB. Despite the fact that the vast majority of 
the workers in both groups wore hearing protectors, cases of noise-
induced hearing loss (NIHL) were common. The mean pure tone audiograms 
showed the typical noise dip at 4000 Hz. For increased exposure 
durations, the amount of NIHL increased. Workers exposed to 94 dBA 
exhibited more hearing loss than those exposed to 88 dBA. Nilsson 
concluded that 58.1% of all of the workers had some degree of hearing 
impairment, and only 1.8% was caused by factors other than noise after 
excluding hearing loss due to heredity, skull injury, or ear disease. 
According to Nilsson et al., the hearing protectors should have 
attenuated the noise by at least 13 dBA. This study concluded that 
reliance on hearing protectors alone is not sufficient to protect the 
hearing acuity of the workers.
    NIOSH's position regarding the hierarchy of controls is stated in 
their December 16, 1994 comments to MSHA (NIOSH 1994). According to 
NIOSH there are three elements of an effective hierarchy of controls. 
They are--
    1. Prevent or contain hazardous workplace emissions at their 
source;
    2. Remove the emissions from the pathway between the source and the 
worker; and
    3. Control the exposure of the worker with barriers between the 
worker and the hazardous work environment.
    NIOSH further states that the essential characteristics of specific 
control solutions are--
    1. The levels of protection afforded workers must be reliable, 
consistent, and adequate;
    2. The efficacy of the protection for each individual worker must 
be determinable during use throughout the lifespan of the system;
    3. The solution must minimize dependence on human intervention for 
its efficacy so as to increase its reliability; and
    4. The solution must consider all routes of entry into worker's 
bodies and should not exacerbate existing health or safety problems or 
create additional problems of its own.
    NIOSH (1988), in its publication entitled ``Proposed National 
Strategy for the Prevention of Noise-Induced Hearing Loss'' 
(Publication No. 89-135), encouraged OSHA to rescind its policy of 
accepting HCP's in lieu of either feasible engineering and/or 
administrative controls and states:

    It is extremely foolhardy to regard hearing protection as a 
preferred way to limit noise exposures because most employees obtain 
only half the sound attenuation possible from hearing protectors. 
Even with training, some workers fail to obtain maximum benefit from 
these protectors because they have difficulty adjusting them 
properly, or they refuse to wear them because they fear such devices 
will impair their ability to perform their jobs properly or hear 
warning signals. If, however, noise is reduced by engineering and/or 
administrative controls, the limitations of hearing protectors are 
of less concern.

    In the report, ``Preventing Illness and Injury in the Workplace,'' 
the Office of Technology Assessment (1985) found that health 
professionals rank engineering controls as the priority means of 
controlling exposure, followed by administrative controls, with 
personal protective equipment as a last resort.
    The National Hearing Conservation Association (NHCA) in a letter 
from their President, Susan Cooper Megerson (1994), to Joseph Dear, 
Assistant Secretary of Labor for Occupational Safety and Health, urged 
OSHA to rescind its policy of accepting an HCP in lieu of engineering 
noise controls for exposures up to 100 dBA. NHCA contends that feasible 
engineering controls should be the preferred method of controlling the 
noise. Further, NHCA states that ``Most hearing protectors, as they are 
worn in the field, do not provide sufficient attenuation to bring 
workers' exposures from 100 dB(A) to safe noise levels.''
    Suter (1994) in a letter to Sue Andrei of OSHA's Policy Directorate 
urged OSHA to rescind its policy of accepting an HCP in lieu of 
engineering and/or administrative controls for exposures up to 100 dBA. 
Suter contends that most HCPs are ineffective due to hearing protectors 
providing only a fraction of their laboratory attenuation. Further, 
Suter urges OSHA to re-emphasize engineering noise controls.
    MSHA understands that the two letters to OSHA were sent in response 
to an OSHA request for comment on how to design a priority scheme for 
OSHA standards. No responses were issued, and the priority scheme is 
still pending. MSHA has also reviewed a recent letter to the EPA from 
the American Industrial Hygiene Association questioning the rating 
system used to label hearing protectors with attenuation values; this 
is discussed above in the section on Hearing protector effectiveness 
(in connection with proposed 62.125).
    In summary, commenters and researchers on this issue were divided 
as to whether engineering/administrative controls should have primacy 
over the use of hearing protectors or an HCP. Most of the international 
community, U.S. armed services, and NIOSH, however, discourage the use 
of hearing protectors and an HCP as the primary means of control and 
accept their use only when engineering and administrative controls 
failed to achieve a significant reduction in the worker's exposure.
    Administrative controls reduce exposure by limiting the amount of 
time that a miner is exposed to noise, through such actions as rotation 
of miners to areas having lower sound levels, rescheduling of tasks, 
and modifying work activities. Many mine operators have demonstrated 
that administrative controls can be as effective and less costly than 
the installation of engineering controls. However, the use of 
administrative controls may be limited by labor/management agreements, 
limitations on the number of qualified miners capable of handling a 
specific task, or difficulty in ensuring that miners adhere to the

[[Page 66412]]

administrative controls. Additionally, administrative controls have the 
potential draw back of exposing multiple workers to high sound levels 
for designated time periods. Because the effectiveness of 
administrative controls is based on adherence to these strict time 
periods, mine operators may find it difficult to verify compliance with 
the administrative procedures.
    Although there are some disadvantages to using administrative 
controls, the Agency has determined that in certain circumstances they 
can be as effective as engineering controls. MSHA, therefore, believes 
that the mine operator should have the option to choose which method of 
control to use--provided that all feasible controls must be utilized if 
needed to reduce sound levels to or below the PEL. This would give mine 
operators maximum flexibility when considering the intricacies of their 
operation in complying with the regulation. Administrative controls, 
utilized properly, spread the risk over a larger population although at 
a lower risk to each individual.
    A related type of control would be the transfer of miners to other 
assignments. The Mine Safety and Health Act provides for the Agency to 
prescribe such an approach in certain cases. MSHA considered proposals 
to do so in cases in which an STS is detected. Discussion of this topic 
is covered by the section of the preamble that reviews proposed 
Sec. 62.180.
    Based upon its review of the available evidence, MSHA concludes 
that a reduction of a miner's risk of material impairment due to 
occupational NIHL noise can best be achieved through the use of all 
feasible engineering or administrative controls or a combination 
thereof. The use of engineering controls inherently provides the most 
consistent and reliable protection because such controls do not depend 
upon individual human performance or intervention to function. MSHA's 
proposal would, however, allow mine operators to use either engineering 
or administrative controls. This would provide the mine operator with 
the flexibility to select the most appropriate control for the 
situation. These methods would be given clear primacy over personal 
protective controls. While MSHA is aware that NIOSH is seeking to 
develop an approach that would more accurately derate hearing 
protectors in actual workplace use, the prospects for this remain 
uncertain; moreover, the issues associated with the consistency and 
reliability of personal protective equipment use would remain.
Engineering Noise Controls for Mining Equipment
    Engineering noise controls reduce exposure by modifying the noise 
source, noise path or the receiver's environment thereby decreasing the 
miner's exposure to harmful sound levels. Examples of these three types 
of engineering controls are exhaust mufflers, barriers, and 
environmental cabs, respectively. Exposures may also be controlled by 
substituting quieter mining equipment. For example, a diamond wire saw 
can be substituted for a conventional hand-held channel burner in the 
dimension stone industry.
    MSHA has listed feasible engineering controls for the major 
classifications of equipment used in metal and nonmetal mines in its 
Program Policy Manual, Volume IV. The engineering controls referenced 
in this manual have been evaluated by MSHA Technical Support and proven 
feasible and effective in the mining industry. This document is 
currently used by MSHA inspectors and others to assist in determining 
if engineering controls are feasible. Following are some examples of 
the feasible controls covered in that manual.
    1. Acoustically treated cabs. For mining equipment such as haul 
trucks, front-end-loaders, bulldozers, track drills, and underground 
jumbo drills, acoustically treated cabs are among the most effective 
noise controls. Such cabs are widely available, from the original 
equipment manufacturer and the manufacturers of retrofit cabs, for 
machines manufactured within the past 20 years. The noise reduction of 
factory installed acoustically treated cabs is generally more effective 
than that of retrofit cabs. According to some manufacturers, sound 
levels at the mine operator's position inside factory cabs are often 
below 90 dBA and in some cases below 85 dBA.
    Occasionally, underground mining conditions are such that full-
sized surface haulage equipment can be used. Where this is possible, 
such equipment can be equipped with a cab as described above. 
Additionally, some manufacturers offer cabs for lower profile 
underground mining equipment such as scoop-trams, shuttle cars, and 
haul trucks. The use of cabs on such underground mobile haulage 
equipment generally is feasible provided it does not create a safety 
hazard due to impaired visibility.
    The former USBOM has published two how-to manuals entitled 
``Bulldozer Noise Controls'' (1980), and ``Front-End Loader Noise 
Controls'' (1981) that describe in great detail how to install a 
retrofit cab and install acoustical materials.
    2. Barrier shields. For some equipment, generally over 20 years 
old, an environmental cab may not be available from the original 
equipment manufacturer or from manufacturers of retrofit cabs. In such 
cases, a partial barrier with selective placement of acoustical 
material can generally be installed at nominal cost to block the noise 
reaching the equipment operator. These techniques are also demonstrated 
in ``Bulldozer Noise Controls'' (1980).
    Barrier shields and partial enclosures can also be used on track 
drills where full cabs are not feasible. Such shields and enclosures 
can be either free standing or attached to the drill. Typically, 
however, they are not as effective as cabs and usually do not reduce 
the miner's noise exposure to within MSHA's current 90 dBA PEL. This 
barrier can be constructed at minimal cost from used conveyor belting.
    3. Exhaust mufflers. In addition to an environmental cab or barrier 
shield, diesel powered equipment can be equipped with an effective 
exhaust muffler. The end of the muffler's exhaust pipe should be 
located as far away from the equipment operator as possible, and the 
exhaust directed away from the operator. For underground mining 
equipment, exhaust mufflers are generally not needed where water 
scrubbers are used. A water scrubber offers some noise reduction and 
the addition of an exhaust muffler may create excessive back pressure 
or interfere with the proper functioning of the scrubber. However, 
exhaust mufflers can be installed on underground equipment where 
catalytic converters are used.
    Exhaust mufflers can also be installed on pneumatically powered 
equipment. For example, exhaust mufflers are offered by the 
manufacturers of almost every jackleg drill, chipping hammer, and jack 
hammer. In the few cases where such exhaust mufflers are not available 
from the factory, they can be easily constructed by the mine operator. 
MSHA has a videotape available showing the construction of such an 
exhaust muffler for a jackleg drill. This muffler can be constructed at 
minimal cost from a section of rubber motorcycle tire.
    4. Acoustical materials. Various types of acoustical materials can 
be strategically used to block, absorb, and/or dampen sound. Generally 
such materials are installed on the inside walls of equipment cabs or 
operator compartments and in control rooms and booths. For example: 
barrier and

[[Page 66413]]

absorptive materials can be used to reduce noise emanating from the 
engine and transmission compartments; and acoustic material can be 
applied to the firewall between the employee and transmission 
compartment. Noise reduction varies depending upon the specific 
application. Care must be taken to use acoustical materials that will 
not create a fire hazard.
    5. Control rooms and booths. Acoustically treated control rooms and 
booths are frequently used in mills, processing plants, or at portable 
operations, to protect miners from noise created by crushing, 
screening, or processing equipment. Such control rooms and booths 
typically are successful in reducing exposures of employees working in 
them to below 85 dBA.
    6. Substitution of equipment. In a few cases, where sound levels 
are particularly severe, and neither retrofit nor factory controls are 
available, the equipment may need to be replaced with a quieter type. 
For example, hand-held channel burners had been used for many years to 
cut granite in dimension stone quarries. These were basically small jet 
engines on a pole, fueled by diesel fuel and compressed air. The pole 
was held by the channel burner operator and the flame was directed 
against the granite. The intense heat caused the granite to spall and 
by moving the flame back and forth a channel could be created. Sound 
levels typically exceeded 120 dBA at the operator's ear.
    Several years ago, alternative and quieter methods of cutting the 
granite were developed. These included replacing the channel burner 
with either a diamond wire saw, hydraulic or pneumatic slot drill, or 
water jet. Dimension stone operators were notified by MSHA of the 
availability of these alternatives and given time to phase out the use 
of diesel-fueled, hand-held burners and replace them with one of the 
quieter alternatives. MSHA also has a videotape describing these 
various alternatives.
    7. New equipment design. Using the channel burners as an example, a 
new design of channel burner was engineered which automated the 
process. The hand-held channel burners can be replaced with automated 
channel burners using liquid oxygen. The automated design does not 
require the operator to be near the channel burner, thereby using 
distance to attenuate the noise.
    In addition to the noise controls described in MSHA's Program 
Policy Manual, Volume IV, a number of other documents are available 
describing effective noise controls for coal, metal and nonmetal 
mines--controls for underground equipment and controls for surface 
equipment.
    The MSHA document entitled, ``Summary of Noise Controls for Mining 
Machinery,'' (Maraccini et al., 1986) provides case histories of 
effective noise controls installed on specific makes and models of 
mining equipment. The case histories describe the controls used, their 
cost, and the amount of noise reduction achieved. MSHA believes that 
the controls utilized in these specific cases can be extended to other 
pieces of mining equipment.
    Furthermore, the former USBOM, which has been responsible for 
conducting research leading to improved equipment and methods for 
controlling safety and health hazards in mining, published a handbook 
entitled, ``Mining Machinery Noise Control Guidelines, 1983.'' 
(Bartholomae and Parker, 1983) This handbook describes engineering 
noise controls for coal, metal and nonmetal mining equipment. The 
former USBOM also published numerous documents describing noise 
controls for mining machinery. Many of these research reports are 
listed in the USBOM publication IC9004, ``The Bureau of Mines Noise-
Control Research Program--A 10-Year Review.'' (Aljoe et al., 1985) Part 
V of this preamble contains a list of USBOM publications dealing with 
particular types of equipment.
    In particular, these include noise control methods for coal cutting 
equipment, longwall equipment, conveyors, and diesel equipment. 
Underground coal mining equipment may require some unique noise 
controls. However, for coal cutting machines such as continuous miners 
and longwall shears, the use of remote control is the single most 
significant noise control. The installation of noise dampening 
materials and enclosure of motors and gear cases can be used to aid in 
controlling noise of coal transporting equipment such as conveyors and 
belt systems. Diesel equipment used underground can use controls 
similar to those used on surface equipment. Mufflers, sound controlled 
cabs, and barriers will provide much of the needed noise control for 
this type of equipment.
    Finally, while MSHA is not making any assumptions about the 
development of new technologies, it would be interested to learn of any 
processes under development that could further assist mine operators in 
controlling noise. For example, the former USBOM (Burks and 
Bartholomae, 1992) has developed a variable speed chain conveyor which 
can be used to reduce the noise exposure of continuous miner operators 
and loading machine operators in particular. An empty conveyor is 
noisier than a full one because the coal covering the conveyor inhibits 
the radiation of noise. The variable speed chain conveyor only operates 
when necessary to convey coal. To date the manufacturers of mining 
machines have apparently not adopted this technology, despite the fact 
that it has the added benefits of reduced dust emissions, reduced power 
consumption, and reduced maintenance costs.
    Although most of the USBOM noise control documents are not 
specifically discussed in this section, MSHA has reviewed them. The 
reviewed documents are listed in the references and are available to 
the mining community. For additional information on USBOM noise control 
projects contact: Mr. Edward D. Thimons, U.S. Department of Energy, 
Pittsburgh Research Center, P.O. 18070, Pittsburgh, PA 15236, (412) 
892-6683, Fax (412) 892-4259.
Posting of Administrative Control Procedures
    The proposal would require that the mine operator post a copy of 
any administrative controls in effect on the mine bulletin board, and 
provide affected miners with a copy. As required by Section 109 of the 
Mine Act, a mine operator must have a bulletin board. Documents 
containing pertinent mine information are required to be posted by 
various mandatory standards (e.g., training plan, emergency 
communication numbers, MSHA citations, etc.). This is an ideal place to 
require the administrative procedures to be posted, since most miners 
are familiar with its location and the importance of documents placed 
on it.
    The existing MSHA coal noise regulations do not require written 
administrative controls, unless these controls are part of a hearing 
conservation plan. Further, if written, the administrative controls are 
not required to be posted. However, the affected miner would be 
informed of the administrative procedures as part of his/her required 
part 48 training. Neither MSHA's current metal and nonmetal nor OSHA's 
noise regulations require that administrative controls, if used, be in 
writing and posted.
    MSHA did not receive any comments on this issue.
    MSHA has concluded that it is important that administrative 
controls be posted, since miners must actively comply for the controls 
to be effective. Posting would facilitate informing miners of work 
practices necessary for

[[Page 66414]]

reducing their noise exposures, especially when temporarily assigned to 
a different job. Since the administrative controls must be in writing 
to be posted on the mine bulletin board, MSHA believes that providing 
the affected miners with copies would not be a significant burden as 
compared to other possible methods of notification and is likely to be 
more much more effective in ensuring miners are on notice of their 
obligation to comply.
Supplementary Controls
    Under proposed Sec. 62.120(b), any miner exposed above the action 
level will receive special training in noise protection, and be 
enrolled in a hearing conservation program in which annual audiometric 
tests are offered. Any miner exposed above that level is to receive 
hearing protection upon request, as is any miner who incurs an STS or 
who is waiting for a baseline audiogram. The operator must ensure 
hearing protection is worn, however, in only two cases: if there is an 
STS, and if it will take more than 6 months to get the baseline 
audiogram because of the need to wait for a mobile test van.
    Under proposed Sec. 62.120(c), if exposures exceed the PEL, and 
cannot be feasibly reduced to the PEL through the use of all feasible 
engineering and administrative controls, a few additional requirements 
would be applicable. All miners so exposed must be provided hearing 
protection, and required to use the hearing protection. In addition, 
the operator would be required to ensure that miners take the scheduled 
audiometric examinations.
    The circumstances under which hearing protection must be worn are 
discussed more fully in connection with proposed Sec. 62.125.
    MSHA is proposing that mine operators require miners enrolled in an 
HCP to participate in audiometric testing once exposures exceed the 
PEL. This is not the case under OSHA; however, MSHA believes this 
approach is warranted in the mining industry.
    The information generated by these tests can serve as triggers for 
both the mine operator and the Agency to investigate more thoroughly 
the implementation of noise controls. If an employee incurs a standard 
threshold shift, at the very least a hearing protector needs to be 
provided or changed. The audiological information can provide useful 
clues to the noise causing the problem, and point to an undetected 
failure of various controls: engineering controls, administrative 
controls, or the failure to properly fit, maintain or utilize hearing 
protectors. If an employee incurs a reportable hearing loss, it is an 
indication that despite regular MSHA inspections, some serious problem 
has not been detected or resolved and a more thorough analysis is 
probably required. If the required audiological examinations are not 
taken, standard threshold shifts and cases of reportable hearing loss 
will go unreported.
    In addition, the Agency wants to ensure that miners are aware of 
the severity of any hearing loss; in a mining environment, this 
knowledge could have implications for the safety of the miner and the 
safety of others. Miners who do not recognize that they have a hearing 
problem--and hearing loss occurs gradually and is often hard for 
individuals to accept--may be less willing than those who have been 
advised they have a problem to pay attention to the problem. The 
proposed regulation provides for annual training, but a notification of 
a detectable change in hearing acuity would certainly help to focus 
attention.
    The Agency is concerned that unless such participation is 
mandatory, the cost of the examinations, however limited, might create 
an incentive for mine operators to encourage miners to waive the 
examinations. Concern about the implications of health examinations on 
their job security may likewise discourage miners from taking 
examinations. The voluntary X-ray surveillance program currently 
offered to coal miners has a poor record of participation. This is not 
an unusual situation in the mining industry, where retention of good, 
well-paying jobs is a priority for most workers.
    Finally, it should be noted that audiometric testing is not an 
invasive procedure. No damaging radiation is involved, nor is there any 
penetration with a needle or other device.
    Comments on this provision are specifically solicited. In 
particular, experience from companies in which such examinations are 
mandated would be welcome. The Agency recognizes there may be concern 
on the part of some miners that if mine operators are provided with 
audiometric information, it could lead to the discharge of miners who 
are developing hearing loss problems so as to minimize potential 
workers' compensation claims.
Dual Hearing Protection
    Proposed Sec. 62.120(d) would require that, in addition to the 
controls required for noise exposure that exceed the PEL, a mine 
operator provide dual hearing protectors to a miner whose noise 
exposure exceeds a TWA8 of 105 dBA during any workshift, a dose of 
800% of the PEL. The mine operator must also ensure that they are worn. 
An earplug type protector would be worn under an earmuff type 
protector.
    Currently, neither MSHA nor OSHA specifically mandate the use of 
dual hearing protection. In practice, however, existing rules require 
dual hearing protection under some circumstances.
    Under current Coal and Metal and Nonmetal noise policy, dual 
hearing protection would be required whenever the attenuation of a 
single hearing protector does not reduce the miner's noise exposure to 
within the PEL.
    Also, due to MSHA's current procedures for determining the 
attenuation of hearing protectors (discussed under Hearing protector 
effectiveness of this preamble), dual hearing protection would almost 
always be required when miners are exposed to sound levels above 112 
dBA. As discussed below, the attenuation provided by dual hearing 
protectors is less than the sum of their individual attenuations. MSHA 
policy currently specifies that 6 dB be added to the attenuation of the 
hearing protector having the higher attenuation.
    OSHA requires that ``adequate'' hearing protection be provided to 
and worn by workers. Employers would thus have to utilize dual hearing 
protection in some cases to get the needed attenuation. However, no 
specific dose level triggering dual hearing protection level has been 
established by OSHA.
    No commenter addressed the exposure above which dual hearing 
protection would be required. One commenter suggested that MSHA 
consider dual hearing protection to provide 5 dB more attenuation than 
the hearing protector with the higher attenuation. Another commenter, 
disagreed with current MSHA Metal and Nonmetal policy and believed that 
more than 6 dBA credit should be given above the attenuation of the 
higher component (earplug or earmuff) when dual hearing protectors are 
worn. This commenter did not, however, specify how much credit should 
be given.
    Research has demonstrated that dual hearing protection affords the 
wearer greater attenuation than either earplugs or earmuffs alone. 
Berger in EARLOG 13 (1984) has shown that the use of dual hearing 
protectors provides greater attenuation. The attenuation of the dual 
hearing protection is at least 5 dB greater than the attenuation of 
either hearing protector alone. This attenuation, however, is much less 
than the sum of the individual Noise Reduction Rating (NRR) values and 
is dependent on the frequency. Dual hearing protectors are especially 
important for noise which is dominated

[[Page 66415]]

by low to middle frequency sounds. The performance of dual hearing 
protectors is not influenced greatly by the selection of the earmuff; 
however, the selection of the earplug has a strong influence on the 
attenuation below 2000 Hz. For noises which are dominated by sounds 
above 2000 Hz, the attenuation of dual hearing protectors is limited by 
flanking bone conduction paths to the inner ear. Berger recommends dual 
hearing protectors whenever the TWA8 exceeds 105 dBA.
    Michael (1991) believes that, because of complex coupling factors, 
the attenuation from wearing both earplugs and earmuffs cannot be 
predicted accurately. If the attenuation of the earplug and earmuff is 
about the same at a given frequency, then the resultant attenuation 
should be 3 to 6 dB greater than the higher of the two individual 
attenuations. However, if one attenuation is much greater than the 
other, then the resultant attenuation will be slightly more than the 
higher attenuation.
    Nixon and Berger (1991) report that earplugs, worn in combination 
with earmuffs or helmets, typically provided more attenuation than 
either hearing protector alone. The gain, in attenuation at individual 
frequencies, varies between 0 to 15 dB. At or above 2000 Hz, the 
attenuation of the combination is limited by bone conduction to 
approximately 40 to 50 dB. Below 2000 Hz, the selection of the earplug 
is critical for increasing the attenuation. There is little change in 
the attenuation of different types of earmuffs at frequencies below 
2000 Hz.
    Bertrand and Zeiden (1993) determined that miners exposed to sound 
levels of 118 dBA were afforded protection consistent with a sound 
level of 98 dBA by the use of earmuffs. The earmuff had an NRR of 24 
dB. Consequently, the earmuff alone could not provide attenuation 
sufficient to protect the miner's hearing acuity.
    Research has clearly demonstrated that dual hearing protection 
provides greater attenuation than either hearing protector alone. 
Further, the U.S. armed services require dual hearing protection for 
workers exposed to high sound levels. MSHA concurs that the additional 
attenuation afforded by the use of dual hearing protection is necessary 
to protect miners who are exposed to high sound levels. Furthermore, 
MSHA has concluded that a TWA8 of 105 dBA (800%) is a prudent 
level above which dual hearing protection should be required. This 
level of noise exposure can quickly damage the hearing acuity of the 
exposed miner.
Dose Ceiling
    Although the statement of the PEL in Sec. 62.120(c) is absolute 
that no miner shall be exposed to noise above a TWA8 of 90 dBA, 
the remainder of that paragraph and paragraph (d) deal with situations 
where in fact miners are going to be exposed to noise in excess of the 
PEL for some period of time--due to the economic feasibility of 
administrative and engineering controls for a particular mine operator, 
or due to the technological feasibility of engineering controls as to a 
particular operation. The seriousness of this situation for miners is 
indicated by the fact that MSHA is proposing that dual hearing 
protectors be required at a TWA8 of 105 dBA: a noise dose of 800%.
    The Agency is interested in comments on whether there is some noise 
dose which should be established as an absolute dose ceiling by the 
regulation, regardless of the implications for a particular mine 
operator or operation. The circumstances in which this might pose a 
problem for the mining industry appear to be very limited. While coal 
inspection data over the years have indicated some exposures over 800%, 
MSHA believes these are anomolies for which well-known controls are 
available. If there are problems, they are likely to be in the metal 
and nonmetal sector.
    On the one hand, the dual-survey data indicate that using the 80 
dBA threshold level, only about one-quarter of one percent (0.28%) of 
metal and non-metal exposures exceed a noise dose of 800%. The data 
indicate, however, that there remain a few specific job categories in 
the metal and nonmetal sector which experience a significant problem 
with noise exposures of this dimension, as indicated in Table III-6. 
The sample size is provided to illustrate that in some cases, the 
percentages are based on limited data.

   Table III-6: Metal/Nonmetal Job Categories in Which More Than 1% of  
       Recorded Exposures Are Over a TWA8 of 105 dBA (800% of PEL)      
------------------------------------------------------------------------
                                              No. >    No. of    Percent
      Code              Job category           105     sample     > 105 
------------------------------------------------------------------------
134............  Jet-piercing channel              5         9        56
                  operator.                                             
234............  Jet-piercing drill                1         3        33
                  operator.                                             
058............  Drift miner..............        15        55        27
057............  Stope miner..............         9        39        23
534............  Jackleg or stopper drill          7        31        23
                  operator.                                             
434............  Churn drill operator.....         1         7        14
334............  Wagon drill operator.....         3        30        10
034............  Diamond drill operator...         3        46         7
046............  Rock or roof bolter......         2        38         5
734............  Rotary (pneumatic) drill         20       478         4
                  operator.                                             
634............  Rotary (electric or              11       544         2
                  hydraulic) drill                                      
                  operator.                                             
934............  Jumbo percussion drill            2       111         2
                  operator.                                             
399............  Dimension stone cutter            3       301        1 
                  and polisher; rock sawer.                             
------------------------------------------------------------------------
Notes: Miscellaneous job categories where less than 1% of recorded      
  exposures exceeded TWA8 of 105 dBA are not displayed. Numbers are for 
  four year period, 1991-1994.                                          

    The job descriptions do not necessarily indicate the equipment in 
use; for example, the stope miners and drift miners may well have been 
using the same equipment as the jackleg drill operators. Based on the 
Agency's experience, there are only a few pieces of equipment used in 
mining for which no control other than multiple hearing protectors is 
currently available.
    The data illustrate that many exposures at this level are 
preventable. Even with the jackleg drills more than 75% of the 
exposures were controlled to less than a TWA8 of 105 dBA. The data 
base from which the above information was drawn found nine bulldozer 
operators and three truck drivers

[[Page 66416]]

exposed to noise above 800% of the PEL; and while these constituted 
only a small fraction of the samples of those job categories, 0.7% and 
0.05% respectively, the Agency is disturbed to find any such samples at 
all given that the metal and nonmetal industry has for some years been 
operating under a requirement to use engineering and administrative 
controls to bring sound levels down to the PEL or as close thereto as 
is feasible.
    Accordingly, MSHA requests comment on whether there should be an 
absolute dose ceiling, regardless of the economic feasibility of 
control by an individual mine operator, and what that should be. MSHA 
also requests comment on whether such a dose ceiling should be 
technology forcing--i.e. apply regardless of the technological 
feasibility of currently available controls.
Ceiling Level
    Proposed Sec. 62.120(e) would retain MSHA's current 115 dBA ceiling 
level for continuous and intermittent noise. The 115 dBA ceiling level 
is intended to protect individuals from high sound levels which last 
longer than those typically characterized by impulse/impact noise.
    The 115 dBA ceiling level originated out of the Walsh-Healey Public 
Contracts Act which formed the basis of current Department of Labor 
noise regulations. OSHA, in its 1974 proposed noise standard (39 FR 
37775), specified that the 115 dBA limit was a maximum steady state 
sound level which was not to be exceeded regardless of the time-
weighted average dose computation.
    In its ANPRM, MSHA did not specifically request comments on the 115 
dBA ceiling limit. One commenter, however, presented a view on the 115 
dBA level. This commenter stated that ``Few professionals would allow a 
worker to remain unprotected while exposed to 115 dBA for 15 minutes.''
    MSHA's review of available literature found a diversity of opinions 
on the choice of a ceiling level for exposures to continuous and 
intermittent noise.
    At the 93rd Meeting of the Acoustical Society of America, Johnson 
and Schori (1977) reported that 115 dBA for 15 minutes may be grossly 
under protective, while an upper limit of 115 dBA, regardless of the 
time of the exposure, is unduly restrictive. For example, they found 
significant temporary threshold shift from exposure to 115 dBA for only 
2.7 minutes. On the other hand, they found virtually no such shift from 
exposure to 130 dBA for 10 seconds and minimal shift (median of 2 dB) 
when exposed to 120 dBA for 40 seconds--although MSHA would point out 
it knows of no mining tasks taking such a limited time. In any event, 
this shows that the ceiling limit is dependent upon both time and 
intensity.
    Cluff (1984) stated that ``The selection of 115 dBA for 15 minutes 
is arbitrary and represents several contradictions.'' He agreed with 
Johnson, however, that exposures to 115 dBA for 15 minutes is 
dangerous. Cluff stated that ``this danger is magnified by extending 
the 5 dB rule to 130 dBA'' and suggested that a 3-dB or 4-dB exchange 
rate may have merit as a solution.
    Others discussed different ceiling limits to prevent temporary 
threshold shift which may lead to a permanent NIHL. The U.S. Army's 
Technical Memorandum 13-67, ``Criteria for Assessing Hearing Damage 
Risk from Impulse-Noise Exposure'' (Coles, 1967) stated that:

    It has been customary in steady-state noise DRC [damage risk 
criteria] * * * to include an upper limit of about 135 dB for 
unprotected noise exposure for any duration, however short. In most 
cases it is understood by implication only, rather than by direct 
statement, that this restriction is not intended to apply to impulse 
noise * * *

    The technical memorandum, however, stated further that:

    The relationship between TTS [temporary threshold shift] 
resulting from a single noise exposure and permanent threshold shift 
(PTS) to be expected from habitual exposure is not known with 
certainty even for steady-state noise.

    In Acoustic Parameters of Hazardous Noise Exposures, however, 
Henderson (1990) discussed a critical level above which damage by 
acoustic trauma begins. He stated that:

    At levels above 120 dB SPL [sound pressure level] the cochlea 
begins to be damaged by direct mechanical destruction, i.e., the 
organ of Corti can be lifted off the basilar membrane, tight-cell 
junctions can be ripped apart, and the tympanic membrane can be 
ruptured. The level at which mechanical damage occurs has been 
called the ``critical level,'' but it is important to recognize that 
there is not a critical level but rather a transition point that is 
related to the spectrum and temporal pattern of the exposure.

    CHABA (1993) believed that single exposure to sound levels above 
140 dBA can permanently damage hearing. Furthermore, the threshold for 
pain is dependent upon the frequency of the noise. This threshold lies 
between 135 and 140 dB.
    Ward (1990) stated that:

    * * * a ``critical exposure'' for production of immediate severe 
loss, presumably associated with structural failure in the cochlea 
rather than with metabolic fatigue, is dependent not on the energy 
in the exposure (p2t) but on a different quantity given by 
integrating the fourth power of the pressure over time. * * * The 
best estimate for the critical exposure in man is around 1011 
Pa4-sec for a median value, although individual differences in 
susceptibility and vulnerability mean that the range will be very 
great.

    NIOSH (1995) recommends that the 115 dBA ceiling limit be retained. 
Citing recent medical research, NIOSH believes that the critical level 
is between 115 and 120 dBA. Above the critical level, immediate 
structural damage to the ear occurs. This structural damage causes a 
loss of hearing acuity.
    ACGIH (1994) recommended that exposures to occupational noise 
should not be permitted above 139 dBA. Further, for sound levels equal 
to or exceeding 103 dBA, ACGIH believes that the exposure be ``limited 
by the noise source--not by administrative control.''
    As illustrated by the above discussed studies, there is no 
consensus among the scientific community as to a sound level above 
which permanent damage occurs (regardless of the duration of exposure). 
However, many researchers believe the critical level is slightly above 
115 dBA and is time dependent with an allowable duration of less than 
15 minutes.
    International communities and selected branches of the U.S. armed 
services specify a ceiling level; however, there is no agreement among 
these groups either.
    There are relatively few noise sources in the mining industry that 
produce sound levels exceeding 115 dBA (e.g., unmuffled pneumatic rock 
drills and hand-held channel burners). However, these sources often 
operate during most of the work shift with resulting full-shift noise 
exposure considerably over the PEL. Currently, MSHA surveys these noise 
sources by taking spot readings with Type 2 sound level meters rather 
than conducting full-shift sampling with a personal noise dosimeter. 
The requirements for Type 2 sound level meters are in ANSI S1.4-1983, 
``Specification for Sound Level Meters.'' MSHA intends to continue 
sampling these sources using a sound level meter.
    Even though this proposal has retained the 115 dBA ceiling level 
for noise exposure, sound levels above 115 dBA are to be included in 
the determination of the noise dose. The Agency has determined that it 
is important to include sound levels above 115 dBA in the noise dose so 
that the miner's noise exposure is accurately assessed. By having an 
accurate assessment, the mine operator will be

[[Page 66417]]

able to provide hearing protectors with maximum attenuation and take 
steps to ensure that the hearing protectors are effectively fitted and 
properly worn.
    MSHA believes that exposure to sound levels exceeding 115 dBA, 
regardless of duration, may potentially result in acute hearing loss 
among susceptible individuals. Although there is a lack of scientific 
consensus on the exact time of safe exposure, the majority believe that 
15 minutes is hazardous. Accordingly, MSHA believes retention of the 
current ceiling is warranted. The Agency, however, welcomes additional 
comment on this issue.
Exposure Determination by Operators
    Proposed Sec. 62.120(f)(1) would require mine operators to 
establish a system of monitoring which effectively evaluates each 
miner's noise exposure. This will ensure that mine operators have the 
means to determine whether a miner's exposure exceeds any of the 
limitations established by this section, as well as to assess the 
effectiveness of noise controls. The proposed rule is performance 
oriented in that the regularity and methodology used to make this 
evaluation are not specified. Specific requirements for periodic 
monitoring by qualified persons now applicable to the coal sector would 
be revoked.
    Under the approach proposed, mine operators may design a monitoring 
program suitable for each specific mine site. Mine operators would be 
expected to utilize survey methods and instrumentation which are 
scientifically valid and based on sound industrial hygiene practice.
    Although calibration requirements are not specifically mandated in 
the proposal, good industrial hygiene practice dictates that any 
instrumentation used for determining a worker's occupational exposure 
to a contaminant, in this case noise, be calibrated. The calibration 
program should be composed of three phases--type testing of 
instruments, laboratory calibration of the instruments, and field 
calibration. Seiler and Giardino (1996) discussed the importance of 
each of these classes of calibrations.
    Briefly, type testing is an exhaustive testing of a model of 
instrument to ascertain that it complies with a standard, such as the 
ANSI standard for personal noise dosimeters. Laboratory calibration is 
an extensive calibration that ascertains that an individual instrument 
meets factory specifications. Finally, field calibration is a brief 
procedure conducted before and after a survey to ascertain that an 
instrument is operating properly.
    The mine operator has the responsibility of accurately determining 
a miner's noise exposure. In order to do this properly the type of 
instrumentation needs to be considered. In the cramped quarters of an 
underground mine and on mobile mining equipment, it may not be possible 
to accurately evaluate a miner's noise exposure without endangering the 
technician if a sound level meter is used. Other occupations cannot be 
sampled with a sound level meter because the most exposed ear is not 
accessible to the technician. For the above occupations, a personal 
noise dosimeter would need to be used. An analysis of noise exposures 
collected from 1986 through 1992 by the MSHA coal inspectorate revealed 
that 21.8% of the occupations could only be sampled using personal 
noise dosimeters. These occupations comprised nearly 60% of the surveys 
conducted by the inspectors.
    A program would be expected to evaluate noise exposure in adequate 
detail to enable the mine operator to reasonably determine which miners 
work in areas requiring the institution of the controls that may be 
required. Sufficient evidence of a noise monitoring program must be 
available during mine inspections to permit the evaluation by MSHA of 
the program's effectiveness. The Agency will also take its own surveys 
of noise exposure during inspections to ascertain miner exposure and to 
evaluate the effectiveness of the mine operator's monitoring program.
    MSHA believes that this proposal affirms a mine operator's 
obligation to take the action needed to determine whether or not a 
miner is in compliance with the exposure limitation requirements of the 
proposed regulation. At the same time, it allows mine operators maximum 
flexibility for determining a miner's noise exposure.
    MSHA believes that mine operators have a number of incentives to 
monitor sound levels on a regular basis to ensure they can:
    (1) Avoid the costs associated with needlessly including or 
retaining a miner in an HCP or providing special noise training;
    (2) Assess the effectiveness or need for either engineering or 
administrative controls or a combination of these controls to meet the 
TWA8 of 90 dBA;
    (3) Document the miner's exposure for workers' compensation 
purposes;
    (4) Provide information to health professionals evaluating miners' 
health and audiograms; and
    (5) Avoid citations and penalties during the regular Agency 
inspections in the mining industry for failure to comply with the 
standard's requirements.
    The results of operator monitoring will not be sent to MSHA, nor 
will monitoring results be used to determine compliance with the 
applicable noise standard. Mine operators are, however, under an 
obligation to take certain actions based upon any noise measurements 
they conduct. Proposed Sec. 62.120 requires mine operators to take 
specific corrective action when a miner's noise exposure exceeds the 
various limitations set forth in the section. It also requires that 
miners be notified whenever a mine operator determines that their noise 
exposure exceeds the action level.
    The requirements of proposed Sec. 62.120(a), as to how noise is to 
be measured for the purposes of this proposal, would need to be 
followed by mine operators in their monitoring. These requirements 
include: disregarding the attenuation of any hearing protector worn by 
the miner, integrating all sound levels from 80 dBA to at least 130 dBA 
during a miner's full workshift, using a 90 dBA criterion level and a 
5-dB exchange rate, and using an A-weighting and slow-response 
instrument setting. Mine operators would, of course, be free to take 
any additional measurements that they deem appropriate: for example, 
taking peak-response readings to measure any impact/impulse noise.
    MSHA current coal noise standards (30 CFR Secs. 70.500/71.800) 
require mine operators to monitor each miner's noise exposure twice a 
year and certify the results to MSHA. These standards also specify when 
and how to sample, who is qualified to sample, and reporting 
requirements.
    MSHA's noise standards (30 CFR Secs. 56/57.5050) for metal and 
nonmetal mines do not contain any operator sampling requirements, 
although they do require that mine operators maintain exposures in 
compliance with the PEL. In order to do this effectively, many metal 
and nonmetal mine operators conduct their own monitoring.
    OSHA's noise standard requires employers to implement a monitoring 
program when information indicates that any employee's noise exposure 
may equal or exceed the action level (TWA8 of 85 dBA). OSHA allows 
employers to use representative personal or area sampling; however, in 
areas with significant variations in sound level or high worker 
mobility, the employer would have to show that area sampling produces 
results equivalent to personal sampling. OSHA also requires the

[[Page 66418]]

employer to repeat the monitoring in specific situations.
    MSHA's ANPRM solicited comments on the frequency of monitoring, the 
sampling strategy, and the use of the information obtained. The ANPRM 
also asked whether specification-oriented or performance-oriented 
requirements would be more appropriate. At that time, the Agency 
solicited comments based on the premise that the proposed rule would 
include a detailed monitoring requirement and the commenters responded 
accordingly. However, since MSHA has decided not to propose detailed 
monitoring requirements, the Agency has not addressed specific issues 
regarding area versus personal monitoring, instrumentation 
specifications, calibration requirements, or other related monitoring 
issues.
    Many commenters preferred performance-oriented standards, similar 
to OSHA's, that would allow mine operator discretion in when and how to 
sample. One of these commenters stated:

    The goal of the monitoring effort should not be simply to 
collect noise exposure data, but rather to accomplish the goal of 
eliminating job-related noise induced hearing loss. With this goal 
in mind, the operator would need to have collected noise exposure 
information on the jobs that he had reason to believe were above the 
85 dBA action level. This information would be necessary to identify 
those workers that should be included in the HCP as well as areas 
and equipment where noise controls are needed.
    If the operator does not choose to monitor for noise, he should 
have an alternate plan that accomplished the same goal: i.e., 
includes all non-office workers in the HCP regardless of noise 
exposure, perform a sound level survey to identify mandatory hearing 
protection areas and equipment, etc. It is recommended that MSHA 
adopt the logic outlined in the OSHA noise standard, 29 CFR 
1910.95(d) (1), (2) and (3).

    Conversely, two commenters recommended a specification-oriented 
rule. One of these recommended personal monitoring on an annual basis 
and the other simply recommended personal or area monitoring.
    Finally, two commenters had a different view on monitoring. They 
recommended that MSHA, rather than the mine operator, conduct all 
monitoring for the purpose of this proposed standard. In response to 
these commenters, the Agency would point out that it is the 
responsibility of mine operators to ensure the safety and health of 
their miners. MSHA sampling programs are to audit the mine operators to 
ensure the protection of miners. Moreover, MSHA does not have the 
resources to sample every miner annually. Metal and Nonmetal has 
specific health sampling guidelines which require periodic sampling of 
selected mining occupations. MSHA currently conducts over 20,000 full-
shift noise exposure surveys in the mining industry annually. Although 
MSHA intends to continue measuring the noise exposure of miners in 
order to determine compliance, it can only sample a small percentage of 
the exposed mining population annually. Mine operators are responsible 
for knowing at all times when their employees exceed applicable limits 
so that appropriate action can be taken.
    The Agency, however, is willing to share its sampling results and 
analyses of these results with the mining industry. Mine operators who 
do not conduct their own monitoring could use the MSHA data along with 
information from equipment manufacturers to estimate a miner's noise 
exposure. This could be beneficial to all mine operators, particularly 
small mine operators with limited resources. If, however, as a result 
of this proposal, MSHA changes the threshold, prior sampling conducted 
by the Agency may not provide an accurate indication of whether a 
miner's noise exposure exceeds the new standard.
    Although a mine operator could use prior MSHA sampling results, and 
information from equipment manufacturers, such use would not relieve 
the mine operator of responsibility to appropriately determine a 
miner's noise exposure. Therefore, it would behoove mine operators to 
determine a miner's noise exposure by methods comparable to those which 
would be used by MSHA, as outlined in Sec. 62.120(a).
    Although numerous commenters and organizations supported the need 
for monitoring, most favored a performance-oriented approach and did 
not specify a procedure to be followed. MSHA agrees. The Agency 
believes that the focus of the noise standard should be on preventing 
NIHL and reducing miners' noise exposures and that it would be 
counterproductive to specify detailed monitoring requirements or 
procedures. Also, the Agency does not want to stifle improvements in 
monitoring technology or methodology.
    Moreover, the Agency believes that the current specification-
oriented coal operator monitoring produces results that in fact are not 
representative of miners' noise exposure. For example, in FY 1994, coal 
mine operators conducted approximately 180,000 noise surveys (two per 
miner) and found 36 miners to be overexposed (their exposures exceeded 
132%). However, MSHA does not know the extent to which mine operators 
may be including credit for the wearing of hearing protection in the 
determination of the miner's exposure. Conversely, MSHA conducted 6,339 
surveys in coal mines and found 857 exposures exceeding the 132%. 
However, only 62 of these surveys resulted in a violation due to credit 
being given for use of hearing protection. This indicates that despite 
having specification-oriented monitoring requirements, current operator 
sampling in coal mines may not be providing results consistent with 
those found by MSHA.
    For monitoring compliance with this proposal, the Agency intends to 
use validated scientific methodology. Current MSHA sampling procedures 
and policies are listed in MSHA's Program Policy Manual and its Coal, 
and Metal and Nonmetal, Health Inspection Procedures Handbooks. Copies 
of these documents are available for review and copying in MSHA 
offices. MSHA's sampling procedures, however, would be modified to be 
consistent with Sec. 62.120(a) of this proposal once the rule is 
finalized.
    Currently, MSHA bases its noise exposure compliance determinations 
on personal full-shift sampling with a personal noise dosimeter. The 
calibration of the personal noise dosimeters is checked before and 
after each survey. Additionally, annual laboratory calibration is 
conducted to assure measurement accuracy. The personal noise 
dosimeter's microphone is positioned on the top of the miner's 
shoulder, midway between the neck and the end of the shoulder, with the 
microphone diaphragm pointing in a vertical upward direction. The 
microphone is placed on the shoulder that is normally between the 
principal noise source and the miner's ear. Sampling is conducted while 
the miner performs his/her normal duties.
    In the development of this proposal, MSHA also reviewed the noise 
monitoring programs of the U.S. Armed Services and other jurisdictions.
    Although MSHA has described its current noise sampling procedures, 
the Agency may decide to modify or change these procedures based upon 
new or improved sampling methods, instrumentation, or technology.
Employee Notification
    Proposed Sec. 62.120(f)(2) would require that within 15 calendar 
days of determining that a miner's exposure exceeds the action level, 
the permissible exposure level, the dual hearing protection level, or 
the ceiling level established by this section, the mine

[[Page 66419]]

operator notify the miner in writing of the overexposure and the 
corrective action being taken. If the miner's exposure has not changed 
from one of these levels to another, and the miner has been notified of 
his exposure at that level within the past year, no notification needs 
to be provided; if the level has changed, or there has been no 
notification in the past year, notification is to be provided. The 
proposal specifically states that these notifications are triggered by 
exposure evaluations conducted either by the operator or by an MSHA 
inspector.
    At the present time, MSHA does not require notification, though it 
is implied in those cases in which a coal miner is enrolled in an HCP 
for having exceeded the PEL. OSHA's standard requires that employees be 
notified in writing of monitoring results that exceed the action level 
within 21 days of the monitoring.
    The proposed requirement is consistent with Section 103(c) of the 
Mine Act. Section 103(c) of the Mine Act states in pertinent part that:

    Each operator shall promptly notify any miner who has been or is 
being exposed to * * * harmful physical agents * * * at levels which 
exceed those prescribed by an applicable mandatory health or safety 
standard promulgated under section 101 * * * and shall inform the 
miner who is being thus exposed of the corrective action being 
taken.

    Many commenters supported miner notification of all sampling 
results and stated that such is current company policy. Several of 
these commenters recommended that the specific method of notification 
be left to the discretion of the mine operator. One commenter 
specifically stated that through notification, ``the employee could 
help facilitate a solution to the problem and be more committed to 
following safety procedures.'' This commenter also stated that 
``requiring written notification is not effective when dealing with 
persons who cannot read or do not have the background to understand the 
meaning of the notification's contents.''
    A mining association commented ``* * * that miners should be made 
aware when their exposure exceeds allowable limits * * *'' and that ``* 
* * employees should have knowledge of their exposure and any 
subsequent hearing loss. * * *'' This association suggested, however, 
that notification ``* * * be in the form of entry into the HCP. * * *'' 
Several other commenters recommended that MSHA's requirements be the 
same as OSHA's.
    After reviewing the comments and the regulations from the U.S. 
Armed Forces and international organizations, MSHA concludes that 
notification should be provided for exposure at any level defined in 
the proposed regulation. At the action level, there is a significant 
risk of material impairment (as discussed in part II of this preamble). 
Notification will be needed at this level because under the proposal, 
if the noise exceeds that level, the mine operator would be required to 
take protective action (hearing protectors and enrollment in an HCP). 
Notification at this level would explain to the miners the reason why 
it is necessary for them to wear their hearing protectors. Moreover, 
since the harm occurs at this level, notification is required under 
Sec. 103(c) of the 1977 Mine Act. Notification at the permissible 
exposure level and dual hearing protection level--exposures 
respectively 2 and 16 times the dose at the action level--is necessary 
to ensure the miner understands the rationale for added protection and 
the actions being taken by the mine operator to lower noise exposures. 
The same is true for any exposures exceeding the ceiling level.
    MSHA believes there is no need to notify a miner of every exposure 
determination, as long as the miner is cognizant of the general level 
of his or her exposure--so that the miner pays attention to noise 
exposure and noise abatement efforts (including the use of properly 
fitted and maintained hearing protectors). If an exposure measurement 
for a miner demonstrates a change in that miner's situation--e.g., from 
below the PEL to over the PEL, or from over the PEL to above the dual-
hearing protector level--the miners should be made aware of this fact.
    Moreover, even if the miner's situation has not changed, the miner 
should be reminded of his or her overexposure when it is measured if 
notification has not been made recently. MSHA welcomes comment on the 
proper balance to strike between the need for notification and 
nonproductive paperwork.
    MSHA has concluded that the notification should be in writing. This 
would ensure that the miner does not misconstrue the measured level nor 
the actions being taken.
Warning Signs
    The proposed rule has no provision for requiring the posting of 
warning signs. While MSHA acknowledges the value of posting warning 
signs, the process is inherently complicated in the ever changing 
mining environment, and MSHA believes the training requirements it is 
proposing should ensure miners are apprised of noise hazards to which 
they may be exposed.
    Section 101(a)(7) of the Mine Act requires that health or safety 
standards promulgated by MSHA:

    * * * prescribe the use of labels or other appropriate forms of 
warning as are necessary to insure that miners are apprised of all 
hazards to which they are exposed, * * *

Existing MSHA noise standards do not exercise this authority with 
respect to noise, and do not require the posting of warning signs.
    When OSHA promulgated its Hearing Conservation Amendment, it did 
not include a requirement for warning signs. OSHA stated in the 
preamble to the final rule, that the use of warning signs to warn 
employees about noise hazards in high noise areas should be left to the 
discretion of the employer. In so doing, OSHA stated that noise is more 
readily discernible than other harmful physical agents and therefore a 
specific warning sign requirement may not be necessary to protect 
employees, and that in certain circumstances such signs might confuse 
rather than serve a useful educational purpose. OSHA also recognized 
that the employer is more familiar with the workplace environment and 
will be in a better position to determine if the posting of signs in a 
given situation will aid in the success of the company's HCP. Further, 
OSHA stated that other methods, such as training, may be more 
appropriate for apprising employees of the hazards of noise.
    In its ANPRM, MSHA asked whether it should require warning signs in 
areas exceeding a specified sound level, and what this sound level 
should be. Numerous commenters specifically addressed the issue of 
warning signs and were about equally divided over whether such a 
requirement is necessary. Those commenters supporting the use of 
warning signs varied considerably on criteria for their use. For 
example, one commenter indicated that warning signs should only be 
posted in areas where an immediate threat of injury exists, such as 
areas with impact noise above 140 dB or constant noise above 115 dBA. 
Other commenters said that warning signs should only be required on 
non-mobile equipment, or in areas where the use of hearing protectors 
is mandatory.
    Among those commenters that did not support the use of warning 
signs, several stated that MSHA's standard should be performance-
oriented and allow the mine operator to decide how to warn its 
employees, such as through training, safety meetings, notification of 
exposure results, etc. One commenter

[[Page 66420]]

stated that in the mining environment it would be difficult to 
illuminate signs to the point they could be read and understood, and 
that they would be difficult to maintain in most mining situations. 
This commenter also believed that the nature of certain mining 
operations does not lend itself to the use of signs because the work 
area is constantly changing. Another commenter agreed, stating that 
warning signs would be difficult to keep current in mobile operations.
    Warning signs could provide an indication to miners that they are 
entering an area where the wearing of hearing protectors is required. 
Some mine operators have voluntarily placed warning signs in high noise 
areas such as preparation facilities and on surface mobile equipment.
    MSHA believes, due to the dynamic nature of mining (advancing 
underground faces, changing quarry perimeters, a mobile workforce, 
etc.), that a requirement for the installation of fixed warning signs 
may be difficult to implement. Warning signs may also be inappropriate 
where miners do not work a fixed period of time in the area covered by 
the sign. For example, a miner in an area with a 90 dBA sound level for 
less than four hours, with no significant noise exposure for the rest 
of the day, would not be required to wear hearing protectors under 
MSHA's proposal, whereas a miner who spends more than four hours in 
that area would.
    After careful analysis of the literature and review of regulatory 
requirements from international communities and the U.S. Armed 
Services, MSHA believes that training may be a more appropriate vehicle 
to inform workers of the hazards of noise to their hearing. Further, 
the Agency believes that the posting of warning signs for noise should 
be optional and left to the discretion of the mine operator. The 
proposed rule would require initial and annual training for all miners 
exposed above the action level as discussed under Sec. 62.130 Training 
of this preamble.
    Though MSHA is not proposing to require warning signs for noise, it 
expects that many mine operators will voluntarily post such signs to 
indicate to miners locations where hearing protectors must be worn. If, 
however, mine operators choose to use administrative controls to reduce 
a miner's noise exposure, the proposal would require that the affected 
miner be informed of the administrative procedures and that such 
controls be posted on the mine bulletin board. Such procedures may 
provide notification of sound levels in specific work locations.

Section 62.125  Hearing Protectors.

    Whenever hearing protectors are required to be provided by the 
proposed regulations, they must be provided in accordance with the 
requirements of this section.
    The miner is to have a choice from at least one earplug type and 
muff type protector; and, in the event dual hearing protection is 
required, a choice of one of each. The mine operator is to ensure that 
in those cases when hearing protection is required to be worn, it is 
worn by miners exposed to sound levels required to be integrated into 
the miner's dose measurement: i.e., sound levels above 80 dBA. The 
hearing protector is to be fitted and maintained in accordance with the 
manufacturer's instructions. Hearing protectors and necessary 
replacements are to be provided by the mine operator at no cost to the 
miner. Finally, should the hearing protector cause or aggravate a 
medical pathology of the ear, the miner is to be allowed to select a 
different hearing protector from among those offered by the mine 
operator.
Selection of Hearing Protector
    The proposal requires that if hearing protectors are required to be 
provided to miners for any reasons, the mine operator shall provide a 
choice of one earplug type and one muff type, and ensure proper fit. 
Earmuffs include both active and passive; earplugs include disposable 
earplugs, pre-molded earplugs, custom-molded earplugs, and canal caps. 
The proposal also requires that the training in hearing protection 
specified in proposed Sec. 62.130(a) be received at least once before 
the miner has to make a choice: to ensure the miner understands the 
choices available.
    While these requirements are limited, they will help to 
significantly encourage hearing protector use and effectiveness. The 
proposal does not seek to constrain mine operator selection of 
protectors. As noted herein, hearing protectors come in a wide variety, 
for different purposes, and with different attenuation values. MSHA 
believes that mine operators have an incentive to provide a wide 
variety of types to encourage safe and effective use.
    MSHA's existing noise standards require mine operators to provide 
adequate hearing protectors, but do not specify that a variety of 
hearing protectors be offered. OSHA's noise standard requires that 
employees be given the opportunity to select from a variety of suitable 
hearing protectors provided by the employer; however, the variety is 
not defined. OSHA states in the 1981 preamble to its Hearing 
Conservation Amendment (46 FR 4152) that ``The company must make a 
concerted effort to find the right protector for each worker-one that 
offers the appropriate amount of attenuation, is accepted in terms of 
comfort, and is used by the employee.''
    In its ANPRM, MSHA asked whether mine operators should be required 
to make available a selection of hearing protectors. Almost all of the 
commenters on this issue were in favor of this provision. Some 
specifically recommended that the mine operator provide a choice of at 
least three different models, including at least one earmuff and one 
earplug. One commenter suggested that the selection should include at 
least six models. Most commenters indicated that the need to provide a 
variety of hearing protectors is more related to fitting and comfort 
than on the labeled attenuation per se.
    One commenter recommended against providing a variety of hearing 
protectors, stating that ``It is the responsibility of the mine 
operator to evaluate the various noise exposures, and to select the 
appropriate HPDs [hearing protectors].'' The commenter maintained that 
the mine operator should only have to provide an alternative hearing 
protector when the individual has a specific condition which precludes 
the use of the selected hearing protector.
    Several commenters addressed the need to allow the miner to choose 
a hearing protector that is comfortable. One commenter stated that:

    The most effective hearing protector is one that is worn and 
worn properly. If the hearing protector is not comfortable or the 
employee cannot wear a certain type of plug or muff, then the 
hearing protector will not be worn and the HCP will not be 
effective.

Another commenter maintained that ``* * * the principal usage problem 
with HPD's is that because of discomfort, interference with necessary 
communication, and interference with normal work routines, many HPD's 
are not worn.'' While another commenter stated:

    The performance of hearing protectors in the field (including 
the manners in which they are used, not used, or misused by workers 
in situations in which HPDs are needed, but are uncomfortable, 
unsafe, or otherwise inconvenient) is frequently inferior to their 
performance when tested in idealized laboratory conditions and there 
are substantial variations among individual susceptibilities to 
noise-induced hearing loss [NIHL].

    The National Hearing Conservation Association's Task Force on 
Hearing Protector Effectiveness (Royster, 1995)

[[Page 66421]]

recommends that the employer consider many criteria when selecting the 
variety of hearing protectors from which workers are to choose. The 
most important criterion for choosing a hearing protector is ``the 
ability of a wearer to achieve a comfortable noise-blocking seal which 
can be maintained during all noise exposures.'' Other criteria include 
hearing protector's noise reduction, wearer's daily noise exposure, 
variations in sound level during a work shift, user preference, 
communication needs, hearing acuity of the wearer, compatibility with 
other safety equipment, wearer's physical limitations, and climate and 
working conditions. Physical limitations (missing fingers, arthritis, 
limited hand strength) may restrict users from properly inserting 
compressible foam earplugs in their ears.
    Berger (1986) stated that comfort must be considered when selecting 
hearing protectors. If the laboratory attenuation of a hearing 
protector is very high, but it is uncomfortable to wear, the actual in-
use attenuation may be reduced or even nonexistent. Conversely, a 
comfortable hearing protector with less attenuation may be worn 
consistently, thereby providing greater effective protection.
    In EARLOG 8, Berger (1981) asserted that an employee should have 
two weeks to try out an adequate hearing protector and select another 
one if the original selection does not perform satisfactorily.
    In the report, Communication in Noisy Environments (Coleman et al., 
1984), the authors stated that:

    Although acceptability is in part governed by the comfort of the 
devices, there are other factors such as concern with hygiene, 
belief in (real or presumed) communication difficulties, and social 
constraints which can influence the extent to which workers will use 
the protection provided. * * * Sweetland (1981) found concern about 
communication difficulties to be a major factor in mine workers 
acceptance of protectors.

The authors further stated that:

    In general, ear inserts [earplugs] appear less attractive than 
circumaural protectors [earmuffs] for mining conditions. A helmet 
mounted circumaural protector is to be preferred on grounds of 
comfort, ease of fitting and removal, reliability of attenuation, 
and acceptability in terms of hygiene; whereas ear inserts of the 
compressible foam type may produce marginally less interference with 
communication and they will impair localization less, they are 
likely to be more comfortable in hot and humid conditions.

    Pfeiffer (1992) suggested that greater care be exercised when 
selecting hearing protectors for workers experiencing hearing loss. 
Pfeiffer stated that it is important not to overprotect the worker 
which can cause difficulty in communicating. If this happens, the 
worker will be reluctant to wear the hearing protector.
    MSHA recognizes that local mine conditions such as dust, 
temperature, and humidity can cause one type of hearing protector to be 
more suitable than another. For example, under normal mining 
conditions, some miners may experience problems with earmuffs because 
of a buildup of perspiration under the seals.
    Based on such factors and on comments received in response to the 
ANPRM, MSHA concluded that the minimum selection appropriate to offer 
miners with normal hearing consists of at least one type of earmuff and 
one type of earplug. MSHA expects that each hearing protector in the 
selection would provide adequate attenuation. Further, a consensus of 
the U.S. armed services and international communities agrees that 
workers should choose from a selection of several hearing protectors.
    If miners are allowed to choose from a selection of hearing 
protectors, particularly if given appropriate training as is required 
under this proposal, they will be more apt to wear and care for them in 
such a manner as to obtain the maximum amount of protection. Providing 
miners with a choice from a selection of hearing protectors will foster 
greater acceptance and use. Further, MSHA recognizes that a trial 
period may be necessary for the miner to determine if using the 
selected hearing protector for a prolonged period causes significant 
discomfort. If significant discomfort occurs, MSHA encourages the mine 
operator to allow the miner an opportunity to select an alternate 
hearing protector. Selection of an alternative hearing protector is 
mandatory under the proposal if required by a medical condition.
    There are several factors which the affected miner needs to 
consider before choosing a hearing protector from the selection 
offered, and which miners will learn about through the training 
specified under proposed Sec. 62.130(a). These factors include--
    (1) Hearing protectors must fit properly to provide the estimated 
amount of protection;
    (2) People have all shapes and sizes of ear canals, and fitting 
commonly used earplugs to an unusually shaped ear canal may be 
uncomfortable or harmful to the individual. For those earplugs which 
need to be fitted to the size of the ear canal, all available sizes of 
that earplug should be available for fitting and use. Some employees 
may need a different size for each ear when their ear canals are of a 
different size or configuration; and
    (3) Hearing impaired miners may need special hearing protectors 
which provide adequate attenuation, yet permit auditory reception.
    With regard to the latter, MSHA is not at this time proposing that 
any special type of hearing protector be provided, nor any type of 
protector be excluded, for those miners who are already hearing 
impaired. However, MSHA will endeavor to ensure operators understand 
that special care should be taken in providing a hearing protector for 
the safety of a miner with a significant hearing loss. Most earplugs 
and earmuffs attenuate sound unequally across all frequencies and are 
most effective at attenuating high frequency sounds. Hearing loss due 
to noise and aging reaches its peak at the higher audiometric 
frequencies. Because of these factors, a miner wearing a hearing 
protector, without specific accommodation for any significant hearing 
loss, would hear distorted auditory signals which would significantly 
hamper communication. A miner, with a significant hearing loss and 
wearing hearing protectors, could be placed in a hazardous situation 
because he/she could not hear or comprehend an audible warning.
    Although some commenters have recommended the use of communication 
type hearing protectors for hearing impaired miners, MSHA will caution 
mine operators against their use in very high noise areas because the 
sound level produced under the cup may be hazardous. Some manufacturers 
of communication type hearing protectors, however, have placed limiters 
in the electronics to protect against the speaker in the cup producing 
hazardous sound levels.
    Even though some researchers have indicated that using a hearing 
protector may cause communication problems for an impaired miner, 
commenters have presented many practical ways of resolving this 
problem. Consequently, MSHA chose not to propose specific requirements 
regarding hearing protectors for impaired miners to allow the mine 
operators maximum flexibility.
    MSHA solicits comments on whether mine operators should be required 
to provide an additional type of hearing protector, such as flat 
response, level dependent or active noise control earmuff, for miners 
with a hearing impairment, or whether any type of protector should be 
explicitly excluded for such miners.

[[Page 66422]]

Hearing Protector Effectiveness
    MSHA received many comments on the attenuation, or effectiveness, 
of hearing protectors. The issue arises in a number of contexts, 
including what role a hearing protector's attenuating characteristics 
should play in the selection of the most appropriate hearing protector 
in those cases requiring hearing protection.
    While MSHA recognizes the importance of proper selection, MSHA has 
decided not to incorporate specific procedures into its proposal on 
rating the effectiveness of hearing protectors. Based on the 
information presented herein, MSHA has concluded there is not presently 
a generally acceptable method of predicting hearing protector 
attenuation in the field. Moreover, MSHA has determined that there are 
other factors which are equally or more important than a hearing 
protector's attenuation for ensuring that a miner is protected from 
NIHL. These factors include: (1) comfort, (2) training, (3) fit, (4) 
maintenance, and (5) consistent use.
    Nevertheless, MSHA realizes the merits of having a valid 
methodology for determining the attenuation of hearing protectors--for 
a variety of reasons, including facilitation of the selection of the 
most appropriate hearing protector when selection and use is required. 
The Agency, therefore, solicits comments on a scientifically based, yet 
practical, method for determining the effectiveness of hearing 
protectors as used under mining conditions. In addition, comments on 
field estimates of hearing protector attenuation, especially the NIOSH 
(1995) derating scheme, are encouraged.
    Current MSHA regulations do not explicitly address this issue. MSHA 
policy, however, specifies a procedure for calculating a hearing 
protector's effective attenuation based upon the Noise Reduction Rating 
(NRR) provided by the manufacturer. Manufacturers currently determine 
an NRR for each hearing protector from laboratory testing in accordance 
with EPA regulations (40 CFR Sec. 211.206 and Sec. 211.207). The NRR is 
intended to provide an estimate of the noise reduction achievable under 
optimal conditions and was designed to be used with C-weighted sound 
levels. Because MSHA measures noise exposure with A-weighting instead 
of C-weighting, it adjusts the NRR by subtracting 7 dB. As reported by 
Maraccini (1987), this 7-dB adjustment accounts for the average 
difference between the C-weighted and A-weighted sound levels in 
mining.
    OSHA's standard does specify the hearing protector attenuation 
required. Under OSHA's standard, attenuation must be sufficient to 
reduce an employee's noise exposure to a TWA8 of 90 dBA; except 
that if the worker is experiencing an STS, then the hearing protector 
must reduce the noise exposure to a TWA8 of 85 dBA. Employers are 
required to use one of four methods to determine the noise exposure 
beneath the hearing protector. These methods are NRR and NIOSH methods 
1, 2, or 3 as described in the ``List of Personal Hearing Protectors 
and Attenuation Data,'' HEW Publication No. 76-120, NIOSH 1975, pp. 21-
37. The NRR is the most convenient method to use and is a 
simplification of NIOSH method 2. In addition, when the NRR is to be 
used with A-weighted sound levels, OSHA requires that 7 dB be 
subtracted from the NRR.
    As noted in connection with the discussion of proposed 
Sec. 62.120(c), where an employer wishes to take advantage of OSHA's 
policy of not citing overexposures when, among other factors, adequate 
hearing protection is being used, a more stringent method of 
determining the effectiveness of hearing protectors is used by OSHA. In 
evaluating hearing protector effectiveness in this context, OSHA also 
subtracts 7 dB from the hearing protector's stated NRR to adjust for 
the difference in weighting systems, but further derates the NRR by 
50%. All types of hearing protectors are treated the same way. The 
derating is done to account for the significant reductions, which 
various researchers have found, in hearing protector attenuation under 
industrial conditions when compared to laboratory conditions.
    One commenter to MSHA's ANPRM indicated that laboratory protocols 
have been developed and are being tested which may be more 
representative of the actual field performance of hearing protectors, 
but noted that validated and agreed upon standardized procedures are 
still some years away. This commenter stated:

    The real-world attenuation data which form the basis for our 
criteria are taken from Berger's summary (1983) of 10 field studies, 
utilizing 1551 employees, wearing seven different types of earplugs 
and greater than nine different types of earmuffs, in over 50 
different industries, and his more recent paper (Berger, 1988) which 
discusses additional current studies. Although the data can be 
separated by plugs and muffs, the variability within the plug 
category is such that some of the better attenuating earplugs 
overlap with the earmuffs. Therefore, for a general regulatory 
guideline, the data averaged across all HPDs and employee subjects 
is taken from the two papers. This results in an NRR84 of 
approximately 10 dB (i.e., the NRR computed with a one-standard 
deviation correction which estimates the protection at the 84th 
percentile).
    Since the NRR is meant to be subtracted from the C-weighted 
sound level, and the regulation is formulated in terms of A-weighted 
levels, an indicator of representative C-A values for the mining 
industry is then required. The 100 NIOSH noises (NIOSH, 1975) which 
have often been taken to be representative of general industry have 
median C-A of about 2 dB, and 90% have C-As of <6.5 dB. However, 
mining noises may exhibit greater low-frequency energy. For example 
the data in Kogut (1990) which represent 17 different types of 
equipment in the metal/nonmetal mining industry (coal excluded), 
show a mean C-A of 6.7 dB, but the Kogut values are not a 
statistically representative sample of the mining industry. For our 
purposes we will average the two estimates and presume a median C-A 
for mining of 5 dB.
    With an NRR for 84% of the users of 10 dB, and C-A value for 
typical mining noises of 5 dB, the credit for HPD attenuation for 
most of the users in the typical mining noises is 10-5=5 dB. Adding 
this value of 5 dB to the PEL of 90 dBA sets the second cutoff level 
of 95 dBA.

This commenter also stated that NRR's do not provide a good indication 
of either relative or absolute field performance; thus, ``there is no 
good way to accurately derate existing lab data to predict field 
performance.''
    In The NIOSH Compendium of Hearing Protection Devices (1994) 
several sets of laboratory measured attenuations, besides the NRR, are 
listed. These data were obtained using different standardized methods. 
NIOSH presents examples of using each method to estimate the sound 
level beneath the hearing protector. In addition, NIOSH presents 
physical features (i.e., number of flanges, composition, compatibility 
with other personal safety equipment, etc.) of the hearing protectors.
    NIOSH (1995) recommends a derating scheme based upon the type of 
hearing protector. NIOSH acknowledges that hearing protector wearers do 
not attain the laboratory attenuation in industrial situations. 
Accordingly, they recommend that to ascertain the effectiveness of a 
hearing protector in workplace use, the NRR for an earmuff, formable 
earplugs, and all other earplugs would be derated by 25%, 50%, and 70%, 
respectively.
    The National Hearing Conservation Association's Task Force on 
Hearing Protector Effectiveness (Royster, 1995) recommends that the 
EPA's NRR for hearing protector attenuation be replaced with a new 
NRR(SF), which the researchers felt more realistically reflects the 
field performance of hearing protectors. The NRR(SF)'s are determined 
by laboratory testing for hearing protector attenuation after the

[[Page 66423]]

subject fits the hearing protector to his/her head. This differs from 
the EPA's NRR value which is determined after the researcher fits the 
hearing protector to the subject. Regardless of the method used, the 
amount of attenuation provided by a hearing protector will vary among 
the individual subjects resulting in a range of attenuation values. The 
Task Force stresses that it is not possible to predict the field 
attenuation of a given hearing protector for an individual; it 
concluded, however, that the NRR(SF) would be a more realistic 
estimate. In addition, small differences (less than 3 dB) in the NRR or 
NRR(SF) are not believed to be of practical consequence. The Task Force 
recommends continued audiometric testing whenever hearing protectors 
are used.
    MSHA notes that the American Industrial Hygiene Association (AIHA, 
1995) recently sent the EPA a letter requesting that the EPA revise its 
rule on noise labeling requirements for hearing protectors. The reasons 
cited for requesting a revision of EPA's NRR rating system included--
(1) the current method of rating hearing protectors overestimates the 
actual workplace protection from 140 to almost 2000 percent; (2) the 
inability to predict absolute levels of protection from labeled values; 
(3) the labeled values are a poor predictor of relative performance of 
one hearing protector versus another; (4) there are no provisions for 
retesting the hearing protectors on a recurring basis; and (5) there is 
no requirement for quality assessment or accreditation of the test 
laboratory.
    Michael (1991) believed that the simplification needed to obtain a 
single number rating (NRR) caused it to be inaccurate. Instead of the 
NRR, the researcher recommended using the spectra of the noise in 
conjunction with the attenuation characteristics to select the most 
appropriate hearing protector. This is even more important when the 
wearer has sensorineural hearing loss.
    Many field studies on the attenuation of hearing protectors have 
been conducted in the mining industry by Giardino and Durkt (1996), 
Kogut and Goff (1994), Giardino and Durkt (1994), Bertrand and Zeiden 
(1993), Durkt (1993), Goff et. al. (1986), Durkt and Marraccini (1986), 
Goff and Blank (1984), and Savich (1979). With the exception of 
Bertrand and Zeiden (1993), these researchers reported that hearing 
protectors provided much less attenuation than that measured in the 
laboratory. Some researchers tested new earmuffs while others tested 
old earmuffs. In many instances attenuation was minimal and highly 
variable. These studies indicate that hearing protector attenuation 
cannot be reliably predicted under actual use conditions and is 
substantially less than that indicated by the NRR from the 
manufacturer.
    Bertrand and Zeiden (1993) determined the effectiveness of hearing 
protectors by measuring the hearing level of miners exposed to sound 
levels exceeding 115 dBA. These researchers found that although the 
hearing protectors provided less attenuation, the difference was not 
significant. For example, miners exposed to 118 dBA had hearing levels 
consistent with exposure to 98 dBA. Therefore, the hearing protector 
whose NRR was 24 provided 20 dBA of attenuation.
    Durkt (1993) studied the effectiveness of 11 models of new earmuffs 
using miniature microphones inside and outside the cups. At surface 
mines, 107 tests were conducted on operators of equipment, including 
bulldozers, front-end-loaders, and overburden drills. Durkt concluded 
that the effectiveness of the earmuff was related to the noise 
spectrum. Moreover, the measured noise reduction was much less than the 
NRR when the noise spectrum contained significant amounts of low 
frequency noise. Most diesel-powered equipment generate noise which is 
primarily in the low frequency range.
    Kogut and Goff (1994) studied the effectiveness of earmuffs being 
used in both surface and underground mines. A total of 540 tests were 
conducted on miners wearing their normal earmuffs. The procedure was 
similar, but not identical, to the procedure used by Durkt (1993). Like 
Durkt, the researchers concluded the noise reduction afforded by 
earmuffs was related to the spectrum of the noise. According to the 
researchers, ``The earmuffs' effectiveness in reducing noise exhibited 
great variability and frequently fell far short of the NRR.'' 
Furthermore, a simple method of reliably predicting the effectiveness 
of earmuffs eluded the researchers. A complex method was developed for 
predicting the effectiveness of earmuffs; however, it lacks 
practicality.
    Giardino and Durkt (1996) and Giardino and Durkt (1994) expanded on 
the previous two discussed studies. A total of 1,265 tests were 
performed on 545 different machines (20 different machine types). 
According to the researchers, earmuffs provided minimal noise reduction 
for the operators of equipment powered by internal combustion engines. 
The researchers concluded that the NRR was a poor predictor of earmuff 
performance under actual mining conditions. Furthermore, they reported 
that the NRR is not a good indicator for comparing different models of 
earmuffs.
    Numerous research studies performed in other industries by Pfeiffer 
(1992), Hempstock and Hill (1990), Green et al. (1989), Behar (1985), 
Lempert and Edwards (1983), Crawford and Nozza (1981), and Regan (1975) 
indicate that hearing protector effectiveness is substantially less 
than the NRR value indicated by the manufacturer.
    Furthermore, Regan (1975) found that earmuff type protectors yield 
the most attenuation and custom molded earplugs the least. Behar (1985) 
found that the measured NRR, in industrial situations, averaged 14.9 dB 
lower and reached 25 dB lower than the manufacturer's nominal value. 
Green et al. (1989) reported workers, who were using earplugs, were 
receiving one-third to one-half of the laboratory based NRR value and 
workers enrolled in an effective HCP obtain greater attenuation from 
their hearing protectors. Crawford and Nozza (1981) reported that the 
average attenuations of the earplugs were typically 50% of the 
manufacturer's values, except for user-molded earplugs whose field 
attenuation was near the laboratory values.
    Lempert and Edwards (1983) reported, ``In the majority of cases, 
workers received less than one-half of the potential attenuation of the 
earplugs'' and concluded, ``Regardless of the type of earplug used by a 
particular plant, a large portion of the workers received little or no 
attenuation.''
    Hempstock and Hill (1990) reported that the workplace performance 
of earmuffs more closely approximated the laboratory performance than 
earplugs. For both earmuffs and earplugs, the measured workplace 
attenuations were lower and the standard deviations higher than those 
measured in the laboratory. The researchers attributed these results to 
the ease of fitting an earmuff compared to fitting an earplug. Their 
study revealed that the degradation was dependent upon the model of 
hearing protector and even differed between sites. Another result was 
that safety glasses substantially degraded the performance of earmuffs. 
Workers wearing safety glasses received approximately one-half of the 
laboratory attenuation. However, the researchers did not find that 
headband tension was a factor in the attenuation of earmuffs.
    Royster et al. (1996) found that the wearing of safety glasses 
reduced the attenuation of earmuffs by about 5 dB at all frequencies.
     Pfeiffer (1992) reported on studies of hearing protector 
effectiveness in

[[Page 66424]]

German industry. According to Pfeiffer earplugs provided between 10 and 
15 dB less attenuation and earmuffs about 6 dB less in industry than in 
the laboratory. As part of the study, used muffs, which were not 
obviously defective (e.g., missing liners, headbands stretched out of 
shape, cushions missing or broken), were tested against new ones. The 
older earmuffs provided significantly less attenuation than new ones. 
The degradation of attenuation was dependent upon the model and 
frequency tested and exceeded 7 dB for some frequencies.
    Abel and Rokas (1986) reported that the attenuation of earplugs 
decreases as a function of wearing time and that head and jaw movement 
hastened the decrease. At Noise-Con 81, Berger (1981) also concluded 
that the performance of hearing protectors decreased as a function of 
wearing time. Kasden and D'Aniello (1976, 1978) found that the custom 
molded earplugs retained their attenuation after three hours of use 
during normal activity; however, typical earplug performance degraded 
over the three hours of use. Krutt and Mazor (1980) reported that the 
attenuation of mineral down earplugs decreased over a three-hour 
wearing period. These researchers did not observe any degradation of 
the attenuation of expandable foam earplugs. Cluff (1989) investigated 
the effect of jaw movement on the attenuation provided by earplugs and, 
determined the change in attenuation was dependent on type of earplug. 
The self-expanding viscose foam earplugs retained more of their 
attenuation than multi-flanged or glass-fiber earplugs. Casali and 
Grenell (1989) tested the effect of activity on the attenuation 
provided by an earmuff and found that only at 125 Hz was there a 
significant degradation in attenuation. Furthermore, the attenuation of 
an earmuff was highly dependent upon the fit.
    Royster and Royster (1990) report that the noise reduction rating 
(NRR) cannot be used to determine, or rank order, the real world 
attenuation of hearing protectors. Two individuals, using the same 
model of hearing protector, can obtain vastly different levels of 
attenuation. Royster and Royster stated that ``Products that are more 
goof-proof (earmuffs and foam earplugs) provided higher real-world 
attenuation than other HPDs.''
    Casali and Park (1992) reported that the noise attenuation at 500 
or 1000 Hz showed a high correlation with the total noise attenuation 
of hearing protectors. Therefore, the researchers believe that models 
can be developed to predict the total attenuation of hearing protectors 
based upon the measured attenuation at a single frequency. This would 
eliminate the need to derate the NRR so that it accurately reflects the 
field attenuation. The prediction method, they believe, will provide 
information on the adequacy of the worn hearing protector and can be 
used in objectively fitting the hearing protector.
    Berger (1992) reported on the progress of the ANSI Working Group 
S12/WG11, ``Field Effectiveness and Physical Characteristics of Hearing 
Protectors'', on developing or identifying laboratory and/or field 
procedure(s) which yield useful estimates of field performance of 
hearing protectors. The Working Group was established to address the 
clearly demonstrable divergence between laboratory and field 
attenuations of hearing protectors.
    Berger also summarized the results of 16 studies involving over 
2,600 subjects on the field attenuation of hearing protectors. Earplug 
attenuation averaged about 25% of the published U.S. laboratory 
attenuations (range 6 to 52%) and earmuff attenuations averaged about 
60% of the laboratory attenuations (range 33 to 74%).
    Royster et al (1996) reported on the progress of the American 
National Standards Institute Working Group (S12/WG11) charged with 
developing a laboratory methodology of rating hearing protectors which 
reflects the attenuation obtained by workers. Hearing protector 
attenuation measured using this methodology reflects the attenuation 
achieved by workers in a well managed hearing conservation program. The 
Working Group has developed a methodology and is in the process of 
drafting an ANSI standard around it. However, it will be some time 
before the standard is adopted. Even if the standard is adopted, there 
will be some legal ramifications, as the EPA would have to append their 
regulations to adopt this standard as the method for rating hearing 
protectors. As part of the testing of the methodology, the researchers 
found that the instructions which manufacturers include with their 
hearing protectors may be inadequate. Some of the test subjects could 
not properly don the earplug, from simply reading the manufacturer's 
instructions.
    As demonstrated above, many researchers have developed standardized 
methods of measuring the attenuation of hearing protectors in a 
laboratory setting. In addition, many researchers have compared the 
results of laboratory attenuations to estimated or measured field 
attenuations. However, based on a review of the major studies, MSHA 
notes that researchers have yet to develop standardized tests for 
measuring the field attenuation of hearing protectors.
    MSHA is cognizant of the potential for increased use of diesel 
equipment in mines in coming years. Diesel engine noise, a common 
mining noise control problem, is predominantly low frequency noise. In 
this regard, the Agency notes that hearing protectors are generally 
more effective in reducing high frequency noise than low frequency 
noise. Thus, noise from diesel engines contains the frequencies where 
hearing protectors are least able to attenuate the noise. The 
consequence is that hearing protectors poorly protect workers from 
excessive noise exposure when the source of the noise is a diesel 
engine.
    Some special hearing protectors, notably flat response hearing 
protectors, attenuate the sound across all frequencies the same. In 
developing a flat response hearing protector, the manufacturer degraded 
the attenuation at the high frequency instead of enhancing the low 
frequency attenuation.
    MSHA has concluded that at this time there is not a consensus among 
the scientific community as to a reliable method of predicting the 
actual attenuation received from hearing protectors in the mining 
environment. Additionally, experience indicates that miners do not 
receive the full attenuation measured in the laboratory (NRR). Research 
data indicate that many workers receive only a small fraction of the 
NRR. Therefore, the Agency has determined that one cannot rely solely 
on the EPA's NRR value.
    Because of the lack of an acceptable method of predicting hearing 
protector attenuation in the field, MSHA chose not to include a method 
for determining the adequacy of hearing protectors in the proposed 
noise regulations.
    It should be noted that in order to ensure hearing protection 
devices have undergone testing to ensure quality, MSHA is proposing 
that the definition of ``hearing protector'' permit only devices having 
a ``scientifically accepted indicator of noise reduction value.'' The 
Agency solicits comments as to alternatives to the NRR that could be 
used in this regard.
Wearing of Hearing Protectors
    Proposed Sec. 62.120 would require that hearing protectors must be 
worn in certain cases: if noise exceeds the action level and a baseline 
audiogram has not taken place within 6 months after the exposure is 
determined; if an STS has been detected; and whenever a miner is

[[Page 66425]]

exposed to noise levels above the PEL. In such cases, proposed 
Sec. 62.125 would provide that the hearing protectors must be worn when 
the miner is ``exposed to sound levels which are required to be 
integrated into a miner's noise exposure measurement.'' This means that 
if a miner is required to wear hearing protectors, those protectors 
must be worn when that miner is exposed to sound levels above 80 dBA; 
sounds above that level have been demonstrated to be harmful, while 
such a demonstration has not been made for sound levels less than 80 
dBA.
    MSHA recognizes that mine operators may want to develop particular 
policies on exactly when hearing protectors can be removed, and sees no 
need to delimit how this might be done. This practical approach, when 
taken together with the proposed requirements for employee training 
about hearing protectors and ensuring selection and proper fit of 
hearing protectors should facilitate the appropriate use of hearing 
protectors.
    Both MSHA's and OSHA's existing standards require that hearing 
protectors be worn when the employee's noise dose exceeds permissible 
levels. Neither standard, however, specifies a sound level below which 
workers could remove their hearing protectors. Although MSHA received 
general comments on levels above which hearing protectors should be 
worn, MSHA did not receive any specific comments addressing wearing 
practices or under what conditions it would be safe to remove a hearing 
protector.
    As has been emphasized, hearing protectors are only effective if 
they are worn. Chart NR1 illustrates that the amount of attenuation 
provided is highly dependent upon the duration a hearing protector is 
worn.

BILLING CODE 4510-43-P
[GRAPHIC] [TIFF OMITTED] TP17DE96.008


    Chart NR1 demonstrates that if a hearing protector with an NRR of 
29 dB is worn only half the time, the wearer will effectively obtain 
only about 5 dB of attenuation. Thus, it is critical for mine operators 
to ensure that the hearing protectors provided are worn. An NRR of 29 
dB is among the highest NRR values reported by hearing protector 
manufacturers.
    Although MSHA did not ask a specific question in its ANPRM on 
monitoring effective usage of hearing protectors, several commenters 
recommended that MSHA require mine operators to supervise the proper 
wearing of hearing protectors.
    Despite mandatory use of hearing protectors, most workers in the 
Abel (1986) study admitted to wearing their hearing protectors less 
than 50% of the time. Further, many modified their hearing protectors 
to provide greater comfort. Many of the modifications had a deleterious 
effect on the attenuation.
    In EARLOG 8, Berger (1981) contends that persons, who are more 
prone to otitis externa (infections), would need to be monitored more 
closely for failure to wear their hearing protectors. Persons with a 
medical pathology of the ear are more likely to resist wearing a 
hearing protector because of pain or extreme discomfort associated with 
its use.
    Based on the comments received and MSHA's experience, one critical 
factor impacting on miner use is their concern that wearing hearing 
protectors can, under some circumstances, create serious safety risks. 
Apart from the information previously noted in connection with the 
discussion of the proper selection of a hearing protector by miners 
already suffering hearing loss, there is the issue whether hearing 
protectors diminish the ability of even miners with good hearing to 
hear ``roof talk.'' Prout et al. (1973) stated that:

    Personal ear protectors do not generally prevent a miner from 
hearing and analyzing roof talk when the noise level [sound level] 
is sufficiently high as to require the use of ear protectors. 
However, the ability to interpret roof warning signals is degraded 
by the use of ear protectors in quiet. Consequently, ear protectors 
should be removed when the noisy machines are shut down.

    MSHA is reviewing its own records for further information on the 
effect of hearing protectors on safety, and welcomes further 
information from commenters. Of course, MSHA recognizes that failure to 
wear hearing protectors may accomplish nothing in some cases. For 
example, if some surface haulage fatal accidents result because high 
sound levels from mining machinery mask the backup alarms, taking off 
hearing protectors is not going to make the working environment any 
safer. Indeed it is more likely that the miner would suffer a temporary 
threshold shift which would make it

[[Page 66426]]

even more likely the backup alarm was missed.
    MSHA's review of the literature and codes revealed that the U.S. 
armed services and many international communities have specified sound 
levels above which hearing protectors must be worn.
    MSHA believes proposing specific trigger levels for hearing 
protectors in specific circumstances would be burdensome and require 
mine operators to conduct a comprehensive survey on each piece of 
equipment. A more practical approach would be for mine operators to 
ensure through their policies that hearing protectors are worn whenever 
noise producing equipment is operating in the miner's work area, and 
permit miners to remove their hearing protectors in areas with low 
sound levels (below 80 dBA). This would minimize the miner's feeling of 
isolation and communication difficulties caused by the wearing of 
hearing protectors in such areas. As previously presented, most 
researchers have indicated that sound levels below 80 dBA are not 
hazardous.
    The Agency, however, requests additional comment on this issue, 
and, as noted above, on the specific issue of whether hearing 
protection can be a safety hazard.
Fitting of Hearing Protectors
    The proposal would require that mine operators ensure that hearing 
protectors be fitted in accordance with manufacturer's instructions.
    MSHA's existing noise standards do not address requirements for 
fitting hearing protectors. OSHA's existing standards require that 
employers ensure proper initial fitting and supervise the correct use 
of all hearing protectors.
    Many commenters on this issue recommended fitting.
    Most of these specified use of the manufacturer's instructions for 
fitting. A few of these specifically recommended that miners be fitted 
by individuals trained in the fitting of hearing protectors. Other 
commenters did not recommend fitting per se, but recommended that mine 
operators provide a variety of types and sizes of hearing protectors to 
ensure proper fit.
    Several commenters indicated that some types of hearing protectors 
do not require fitting. One commenter recommended use of Audiometric 
Data Base Analysis (ADBA) to determine hearing protector effectiveness. 
Other than ADBA, this commenter believed that there was insufficient 
data at this time to recommend a criterion for proper fitting.
    In EARLOG 17, Berger (1985) recommends that ``Prior to issuing HPDs 
the fitter should visually examine the external ear to identify any 
medical or anatomical conditions which might interfere with or be 
aggravated by the use of the protector in question.''
    In Communication in Noisy Environments, Coleman et al. (1984) 
stated:

    If a protector cannot be removed or fitted easily and quickly, 
it may be either left on when not needed, possibly impairing 
communication * * * or not fitted when needed, reducing the 
protection from noise exposure. Ease of fitting is therefore a 
desirable attribute for coal mining conditions.
    Sweetland (1981) found that circumaural protectors were removed 
and replaced more often than earplugs in mining conditions, which 
could be taken as an indication that the former devices were easier 
to fit and use. * * * Factors, such as the time required to hold a 
compressible foam plug in position for it to achieve its design 
performance, and the procedure required to fit inserts correctly, 
which involves reaching around the back of the head to grasp the 
earlobe, can reduce their acceptability for mining conditions.

    At Noise-Con 81, Berger (1981) reported that the attenuation was 
greater when noise was used to help in the fitting of hearing 
protectors although the variability was not significantly greater.
    Carter and Upfold (1993) investigated methods of determining the 
attenuation provided by foam earplugs. Both an earmuff with an earphone 
and a cushion with an earphone gave results comparable to the standard 
laboratory method and could be used to estimate the group attenuation 
of foam earplugs. However, the results of the measured attenuation for 
individuals were not as good as that for the group. The researchers, 
therefore, concluded that neither method with earmuffs or cushions 
could be used to determine the attenuation provided by a foam earplug 
to an individual, although the methods could be used to check the 
effectiveness of fitting and training of a group.
    Merry et al. (1992) reported that subjects obtained greater 
attenuation from earplugs if an experimenter directs the fitting using 
the subject's response to noise when compared to subjects simply 
reading the manufacturer's instructions and inserting their own 
earplugs.
    Chung et al. (1983) reported that the major factor affecting the 
earmuff performance was the fit which is dependent upon headband 
tension. Adequate tension is necessary for good attenuation. However, 
high headband tension generally caused discomfort. The same occurred 
when the earmuff seal was cracked. However, no effect of the age of the 
earmuffs was observed. Chung et al. concluded that training and proper 
fitting can increase the effectiveness of earmuffs, thus protecting 
workers from incurring noise-induced hearing loss (NIHL).
    Phoon and Lee (1993) studied workers who developed NIHL in 
Singapore. For 103 of 156 earplug users (66%) who developed NIHL, there 
was a mismatch between the earplug and the size of both ear canals. In 
13.5% of these workers, the mismatch occurred in one ear.
    Royster et al. (1996) reported the manufacturer's instructions were 
not always adequate in describing the procedures for donning a hearing 
protector. Several subjects improperly inserted earplugs during a 
laboratory experiment of hearing protector attenuation. The 
inappropriately inserted earplugs would be considered improperly fitted 
hearing protectors.
    ANSI S3.19-1974, ``Method for the Measurement of Real-Ear 
Protection of Hearing Protectors and Physical Attenuation of 
Earmuffs'', recommends that 60 to 70 dB white noise be used when the 
subject fits a hearing protector. White noise has essentially a random 
spectrum with equal energy per unit frequency bandwidth over a 
specified bandwidth.
    As described above, researchers have identified several techniques 
for both subjectively and objectively evaluating the fit of hearing 
protectors. While many of the techniques show promise, there is no 
consensus as to which method is best. Most techniques are applicable to 
a specific type of hearing protector and are not practical for use by 
many mine operators. These techniques are discussed further under the 
Hearing Protector Effectiveness section of this preamble.
    MSHA also considered the use of ADBA (Audiometric Data Base 
Analysis) to determine the effectiveness of hearing protectors in lieu 
of subjective fitting requirements. Since ADBA does not provide 
immediate feedback as to the fit of a hearing protector, MSHA has 
concluded that ADBA is inappropriate for determining the fit of a 
hearing protector. ADBA analysis requires multiple subjects, not an 
individual, before a conclusion of adequacy is determined. Besides ADBA 
determines the adequacy of the HCP (protecting the hearing acuity of a 
group of workers), not the adequacy of protecting an individual. 
Moreover, MSHA believes that ADBA is not practical for most mining 
operations as discussed under the Evaluation of HCP effectiveness 
section of this preamble. Furthermore, ADBA requires several audiograms 
which are conducted on an

[[Page 66427]]

annual basis. In the interim, the hearing acuity of a miner could be 
irreversibly damaged.
    As supported by the researchers and many commenters, MSHA agrees 
that proper fitting is necessary to ensure optimal effectiveness of 
hearing protectors and that it should not be left solely up to the 
individual miner to determine if the hearing protector fits properly. 
Further, MSHA is concerned that some manufacturer's instructions are 
not adequate to ensure the proper fitting of a hearing protector. 
Although comfortable hearing protectors should be provided, MSHA is 
also concerned that some miners may choose hearing protectors that are 
too loose or otherwise improperly fit, and consequently not achieve 
adequate noise reduction.
    In light of the wide variety of hearing protectors available, the 
broad range of subjective fitting procedures, and the lack of consensus 
on an objective fitting method, MSHA concluded that the manufacturer's 
instructions are the best criteria for fitting. MSHA encourages 
commenters to provide information on any standardized methods of 
testing the fit of hearing protectors.
Maintenance of Hearing Protectors
    MSHA's proposal would also require mine operators to ensure that 
hearing protectors are maintained in accordance with manufacturer's 
instructions. Neither MSHA's nor OSHA's existing noise standards 
address requirements for maintaining hearing protectors.
    MSHA recognizes that it is difficult to keep hearing protectors 
clean in the mining environment. Using contaminated hearing protectors, 
however, may contribute to a medical pathology of the ear. Once the 
skin has been abraded or inflamed, it is easier for microorganisms 
normally found in the ear to invade the skin. When hearing protectors 
are implicated as the cause of inflammation of the external ear canal 
(otitis externa), often the hearing protector is contaminated with an 
irritating or abrasive substance. This situation can be corrected with 
proper cleaning of the hearing protector before use.
    MSHA's proposal is designed to ensure that miners not develop 
medical problems while they are attempting to protect themselves from 
the hazard of noise. If an earplug cannot be adequately cleaned, then 
the mine operator would have to replace it.
    In addition to providing guidance on the fitting of hearing 
protectors, manufacturers also provide instructions on the proper care 
and cleaning of their hearing protectors. Many recommend soap, warm 
water, and careful rinsing. Solvents and disinfectants generally are 
discouraged as cleaning agents because they can cause skin irritation 
and some can damage the hearing protector. In most cases, the proper 
insertion technique for earplugs would just be a matter of applying 
common sense, i.e., cleaning the hands before rolling and/or inserting 
earplugs.
    Several commenters addressed hygiene problems when the hearing 
protectors become dirty. One of these commenters stated that miners 
would need to clean their permanent hearing protector daily and that 
irritation due to sweating and skin contact with the hearing protector 
can be a problem associated with its use.
    In EARLOG 5, Berger (1980) states that permanent [non-disposable] 
hearing protectors should be replaced between two and 12 times per 
year. The constant wearing of hearing protectors causes them to lose 
their effectiveness. For example, headbands on earmuffs can lose their 
compression ability; the soft seals surrounding the ear cup on earmuffs 
can become inflexible; and plastic earplugs can develop cracks, can 
shrink, or can lose their elasticity.
    As referenced in EARLOG 17 (Berger, 1985), Forshaw and Cruchley 
studied the effects of washing the hearing protectors worn by long-
range patrol aircraft crews. The crews were divided into three groups: 
one group wore pre-molded earplugs; the second group wore foam earplugs 
washed after each use; and the third group wore foam earplugs which 
were washed weekly. Examinations by medical officers revealed no fungal 
or clinically significant bacterial infections among the three groups.
    MSHA also reviewed standards from the U.S. Armed Forces and the 
international community on the topic of hearing protector maintenance. 
The consensus of the standards was that damaged or deteriorated hearing 
protectors must be replaced.
    Miners have also been known to alter the hearing protection 
provided to make them more comfortable. Such alterations have included 
cutting off the end of earplugs or stretching out the head-band on 
earmuffs. These alterations can significantly decrease the hearing 
protector's attenuation.
    Hearing protectors can also be damaged from exposure to heat, cold, 
ozone, chemicals, or dirt. Such conditions are common in the mining 
industry, and mine operators must periodically check the hearing 
protectors provided and replace them when damage is found.
Hearing Protectors Provided at No Cost to Miner
    The proposal would also require the mine operator to provide 
necessary replacements at no cost. This is intended to ensure that the 
mine operator repairs or replaces a miner's hearing protector when it 
becomes damaged or deteriorated to the point that the required 
protection is compromised.
    MSHA believes that it is essential for mine operators to replace 
worn-out or damaged hearing protectors in order to maintain their 
effectiveness. This is in agreement with the international community 
and the U.S. armed services. Damaged or deteriorated hearing protectors 
do not provide their designed optimum amount of protection. Further, 
MSHA believes that the manufacturer's instructions are the best source 
of information as to the proper procedures for maintaining a particular 
protector.
    MSHA's existing noise standards do not specifically address the 
replacement of hearing protectors. OSHA's noise standards simply 
require that hearing protectors be replaced as necessary.
    MSHA received no direct comments to its ANPRM on the issue of mine 
operators supplying commercially available hearing protectors at no 
cost to the miner. However, several commenters supported adopting 
requirements similar to OSHA's which includes provisions for providing 
hearing protectors at no cost to the worker.
    Replacement of hearing protectors would be based on the 
manufacturer's instructions, upon finding any deterioration that could 
adversely affect the hearing protectors attenuation, or upon a need for 
the miner to choose a different hearing protector due to a medical 
pathology caused or aggravated by the initial hearing protector 
provided (see following section which discusses medical pathology). For 
example, manufacturers of disposable earplugs may state in their 
instructions that they should be replaced after each use.
Replacement of Hearing Protector Due to Medical Pathology
    MSHA's proposal would also require the mine operator to provide an 
individual miner with a different, more acceptable, type of hearing 
protector when presented with evidence of a medical pathology (e.g., 
otitis externa or contact dermatitis). The definition of ``medical 
pathology'' is intended to be broad enough to cover injuries. If, for 
example, a miner would suffer a burn in the ear canal which would 
preclude the wearing of earplugs, an employee who

[[Page 66428]]

elected earplugs should have the opportunity to now select a muff.
    MSHA does not intend to require that the evidence of a medical 
pathology be a diagnosis by a physician specialist--nor to require mine 
operator action without any evidence whatsoever. The goal here is a 
practical one: exchange the hearing protector if there appears to be a 
medical problem. A preliminary diagnosis of medical pathology by a 
family physician or nurse should be accepted by an employer for the 
purposes of this requirement.
    In EARLOG 17, Berger (1985) discusses some predisposing factors for 
otitis externa. These include allergy to chemicals or hair dyes and 
sprays; dermatitis; chronic draining middle ear infections; excessive 
cerumen (ear wax); and systemic conditions which lower the body 
resistance, such as anemia, vitamin deficiencies, diabetes, and 
endocrine disorders. Disposable hearing protectors may be warranted for 
those individuals prone to infections. The researcher reported that the 
prevalence of otitis externa is approximately 2% in both users and 
nonusers of hearing protectors. He stated that:

    Although hearing protection devices should not be worn in the 
presence of some preexisting ear canal pathologies, and care must be 
exercised regarding selection and use under certain environmental 
conditions, regular wearing of HPDs does not normally increase the 
likelihood of contracting otitis externa.

    Furthermore, Royster and Royster in EARLOG 17 (Berger, 1985) 
reported on a situation in which underground miners in a warm and humid 
environment were experiencing otitis externa. Switching from a pre-
molded vinyl earplug to a foam earplug decreased the incidence of this 
condition.
    Although documented cases of hearing protectors causing infections 
in the ear canal or on the skin surrounding the ear are not prevalent, 
MSHA is aware of at least one reported case of an ear infection in the 
mining industry specifically attributed to the use of hearing 
protectors.
    MSHA's existing noise standards do not specifically address the 
replacement of hearing protectors. OSHA's noise standards simply 
require that hearing protectors be replaced as necessary.
    Based upon the research and several international standards, MSHA 
believes that hearing protectors need to be replaced whenever a medical 
pathology is present. Such replacements would also be at no cost to the 
miner.

Section 62.130  Training

Summary
    Proposed Sec. 62.130 would provide the specifications for 
instruction and certification of training required by the proposed 
rule. Proposed Sec. 62.120 requires such training for all miners 
exposed above the action level, and annually thereafter if still 
exposed above that level. Proposed Sec. 62.180 requires retraining for 
every miner who incurs an STS.
    Miners would receive instruction in the value of hearing 
protectors, selection and fitting of protectors, and proper use of such 
protectors. Miners would also receive instruction as to the operation 
of an operator's hearing program and in the mine operator's noise 
control efforts. There are no special qualifications for instructors, 
nor any specifications on the hours of instruction. Training is 
required to be provided without cost to the miner. The mine operator 
would be required to certify the completion of any training required by 
this part, and maintain the most recent certification for a miner at 
the mine site for as long as the miner is required to use hearing 
protectors or be enrolled in an HCP, and at least 6 months thereafter.
    MSHA considered whether the requirements of part 48, ``Training and 
Retraining of Miners,'' were adequate to ensure the training required 
under this part. The requirements of part 48 specify the initial and 
annual retraining of all miners in a list of subjects, many specified 
in the law itself (section 115 of the Mine Safety and Health Act). The 
importance of this training is emphasized by statutory requirements for 
the submittal of training plans, on the specification of the hours to 
be devoted to the training, and on the qualifications of instructors. 
Training is required on noise, but it is in general terms, covering the 
purpose of taking exposure measurements and on any health control plan 
in effect at the mine. Mine operators may provide additional training, 
but the topics that need to be covered often make this impracticable 
within the prescribed time limits.
    After considering the available information about the importance 
and prevalence of training requirements, and based upon its experience 
in implementing the requirements of part 48, MSHA has determined that 
the requirements of part 48 do not provide adequate noise training for 
those miners for whom exposure is clearly a problem. Part 48 training 
is neither comprehensive enough to provide such miners with the level 
of education needed for the proper use of hearing protection devices, 
nor, in the case of noisy mines, detailed enough on methods to reduce 
sound levels.
    Nevertheless, MSHA believes compliance with this proposal can in 
many cases be fulfilled at the same time as scheduled part 48 training. 
The Agency does not believe special language in proposed part 62 is 
required to permit this action under part 48, but welcomes comment in 
this regard. Mine operators who can do so are free to fulfill their 
training requirements under Sec. 62.120 by covering the topics in 
initial and annual part 48 training, and so certify on the separate 
form required by this part. If incorporated into part 48, mine 
operators would, however, be required to submit a revised training plan 
to the local district office for approval. Some mine operators may not 
have room in their part 48 plans, however, to be able to incorporate 
these topics. Moreover, some training required under the proposal will 
clearly not fit within a regular schedule: e.g., the training required 
by Sec. 62.180 whenever a standard threshold shift in hearing acuity is 
detected.
    MSHA has endeavored to make the training requirements as simple as 
possible. If conducted separate from part 48, there are no 
specifications on trainer qualifications, no minimal training time, nor 
any training plans. If however the training is incorporated into part 
48, then all applicable part 48 requirements will have to be met.
Background
    Training requirements are a mainstay of mine safety and health. 
Although MSHA has no training requirements in its existing noise 
regulations, the general training requirements set forth in part 48 
require basic training as to the purpose of taking noise measurements, 
and in any health (noise) control plans that are in effect at the mine.
    Numerous commenters responding to MSHA's ANPRM, expressed 
considerable support for miner training on noise and its effects and 
believed that it is an essential element of any effective HCP. Many of 
these commenters specifically supported annual refresher training. 
Commenters differed, however, in their opinions as to how training 
could best be accomplished. Several commenters recommended that MSHA 
incorporate any training requirements related to this standard into 
MSHA's existing training requirements under 30 CFR part 48--Training 
and Retraining of Miners. A few commenters believed that the training 
requirements in MSHA's part 48 were adequate and that no additional 
instruction was needed.

[[Page 66429]]

    One commenter suggests that the initial training class be limited 
to less than 10 individuals (Berger, 1988; Royster and Royster, 1985). 
Although training may best be accomplished in small groups, MSHA's 
proposal would not limit the size of any training classes.
    There is considerable precedent for requiring training as part of 
noise control programs.
    OSHA's noise standard has training requirements which are similar 
to those in MSHA's proposed noise standard with a few exceptions. These 
exceptions are discussed later in this section.
    In OSHA's 1981 preamble (46 FR 4157), Morrill stresses the 
importance of worker education in overcoming workers objections to 
wearing hearing protectors. This document quotes a Dr. Maas as saying 
that, ``Supervisors must sell employees on the need and value of 
hearing protection devices. When employees understand what the 
protective measure is for, it will be accepted because the employee 
realizes it is for his own good.'' A number of comments to OSHA's 
Hearing Conservation Amendment (46 FR 4157) indicated that workers are 
reluctant to appear weak or ridiculous as a result of wearing hearing 
protectors. Suter (1986) states, ``Workers who understand the mechanism 
of hearing and how it is lost will be more motivated to protect 
themselves.'' Other researchers concur with this opinion (Wright, 
(1980) and Royster et al., (1982)).
    CAOHC (Miller, 1985) states the following regarding the need for 
training as part of an effective program (HCP):

    A critical component of the OHC [Occupational Hearing 
Conservation] program is the employee education program (EEP). In 
many respects, the EEP is the most important aspect of the OHC 
program since it is designed to increase the auditory consciousness 
of the employee regarding the hazardous effects of noise exposure 
and by so doing to get him to use effective forms of PHPD's 
[personal hearing protective devices] conscientiously and 
consistently. Such use of PHPD's will actually protect the worker's 
hearing, while the other aspects of the program, important as they 
are, will not do so. No amount of noise monitoring or audiometric 
testing, for example, will protect hearing.

    MSHA also reviewed the training requirements set forth in 
international standards and those of the U.S. Armed Services. The 
consensus was that training was necessary; however, the training 
interval was not always specified.
Training About Hearing Protector Selection and Use
    Section 62.130(a) specifically provides that the training is to 
include instruction in--
    (1) the effects of noise on hearing;
    (2) the purpose and value of wearing hearing protectors;
    (3) the advantages and disadvantages of the hearing protectors to 
be offered;
    (4) the care, fitting, and use of the hearing protector worn by the 
miner;
    (5) the general requirements of the regulation;
    (6) the operator's and miner's respective tasks in maintaining mine 
noise controls; and
    (7) the purpose and value of audiometric testing and a summary of 
the procedures.
    OSHA requires annual training on the same elements except it does 
not require training on the requirements of its noise standard. It is 
MSHA's view, however, that some training on the requirements of the 
standard is necessary in order for employees to understand the role 
hearing protection plays in a broader protection scheme.
Purpose, Advantages, and Disadvantages of Hearing Protectors Offered
    Instruction on this topic would help the miner make an informed 
choice as to which hearing protector to use. This basic instruction 
would be initially required when the mine operator first determines the 
miner's noise exposure exceeds the action level. Moreover, pursuant to 
proposed Sec. 62.125, this instruction must be provided at least once 
before the miner must make a selection of a hearing protector. 
Furthermore, it would need to be repeated annually thereafter, because 
hearing protectors should be replaced periodically.
    MSHA anticipates the training would address specific advantages and 
disadvantages of earmuffs, earplugs, and canal caps as they relate to 
the needs of the miner and the specific conditions at the mine. For 
example, an electrician who opts to use an earmuff must understand the 
need to use one with dielectric properties to minimize the chance of 
incurring an electrical shock when working around energized equipment. 
An over-the-head earmuff is unsuited for those miners required to wear 
hardhats: the earmuff would interfere with the wearing of the hardhat 
as the hardhat could not be placed over the headband. In addition, the 
mine operator should discuss the specific advantages and disadvantages 
of any special hearing protectors offered such as active noise 
reduction, level-dependent, flat-response, and notch-amplification 
hearing protectors, or a communication headset. For example, a miner 
with a sensorineural hearing loss in the higher frequencies may require 
a different type of hearing protector than a miner with a conductive 
hearing loss across all frequencies. Accommodating the hearing loss may 
require a level-dependent, active noise reduction, or notch-
amplification hearing protector to improve the miner's ability to 
communicate and hear warning signals in a noisy environment. All miners 
need to understand the relative advantages and disadvantages of 
earmuffs and earplugs as they are not at all obvious: hence, the 
necessity for training.
    Some advantages of earmuffs (circumaural hearing protectors) 
include: they are easily donned and removed by the miner when working 
in intermittent noise; they offer protection against dust in the ear 
canal; they are not easily misplaced or lost; they fit people with 
unusually shaped ear canals; and they can be worn over earplugs. Berger 
in EARLOG 3 (1980), and Coleman et al. (1984) reported that one major 
disadvantage of earmuffs is that they hinder a miner's ability to 
localize the direction of sounds. If the miner's safety depends on the 
ability to localize sounds, then this disadvantage would preclude the 
use of earmuffs. Other potential disadvantages of earmuffs include: 
discomfort; headache; a feeling of claustrophobia; excessive warmth and 
perspiration under the muff seal; and skin irritation. Earmuffs may 
present problems if the miner wears safety glasses or earrings. 
Eyeglass temples reduce the attenuation afforded by earmuffs.
    In EARLOG 19, Berger (1988) states that the use of eyeglasses with 
an earmuff can break the seal of the earmuff and cause a loss of 
attenuation of up to 6 dB depending on the frequency of the noise.
    Royster et al. (1996) tested the effect of wearing two different 
safety glasses on the attenuation of an earmuff. The researchers found 
that the attenuation was reduced by about 5 dB across all frequencies.
    Barham et al. (1989) investigated the effects of safety glasses and 
hair on the effectiveness of earmuffs. The wearing of safety glasses 
decreased the noise reduction up to 4 dB depending upon the frequency. 
The glasses had slender and flexible wire-reinforced side frames so 
that the side frames would fit close to the head. Not only did the 
safety glasses decrease the average noise reduction, they also reduced 
the variability (standard deviation) of the

[[Page 66430]]

noise reduction realized among the individuals. The type of hair and 
its length influenced the noise reduction provided by earmuffs. 
Individuals with short hair realized up to 5 dB more protection, 
depending upon the frequency, than individuals with long or curly hair 
and beards.
    Michael (1991) asserts that glasses with plastic temples may cause 
a loss of attenuation from 1 to 8 dB, due to breaking the seal of the 
earmuff. In some cases, this loss can be substantially reduced if 
small, close fitting wire temples are employed.
    Nixon and Berger (1991) report that temples of eyeglasses reduce 
the efficacy of earmuffs normally by 3 to 7 dB provided the cushions of 
the earmuffs are in good shape. This effect varies among earmuffs and 
it also depends upon the style and fit of the eyeglasses. To minimize 
the effect of wearing eyeglasses, the temples should be as thin as 
possible and fit close to the side of the head.
    Savich (1979) measured the noise attenuation of earmuffs. Because 
of long hair and safety glasses, the earmuffs provided less attenuation 
than expected based upon laboratory tests. Furthermore, head size has a 
significant influence on the attenuation because of different clamping 
forces. Increased clamping force increases the attenuation.
    Some advantages of earplugs include: they are cooler, if the miner 
has to work in a hot, humid environment; they are more easily worn with 
safety glasses, hardhats, and other personal safety equipment (e.g., 
air-purifying or welding helmets); and they fit miners who have 
extremely large external ears. One disadvantage of an earplug is that 
inserting it into the ear canal could present a personal hygiene 
problem if the miner removes and reinserts it several times during the 
day. A miner who is susceptible to ear infections or secretes 
significant amounts of ear wax may be better suited for using earmuffs.
    As noted earlier in this section, training is critical to miner 
cooperation. MSHA has concluded, after reviewing the scientific 
literature, U.S. Armed Forces regulations, and standards from the 
international community, that requiring the mine operator to instruct 
each miner required to wear hearing protectors on the purpose, 
advantages, and disadvantages of the choices available will facilitate 
hearing protector use and effectiveness.
Care, Fitting, and Use of the Hearing Protector Selected
    In response to MSHA's ANPRM, many commenters supported the need to 
train employees on the proper fitting, care, and use of hearing 
protectors.
    Merry et al. (1992) studied the effect of fitting instructions on 
the resulting attenuations of earplugs. Novice subjects were given 
earplugs. The difference in their hearing thresholds between the 
unoccluded and occluded conditions was the attenuation of the earplug. 
The subjects obtained greater attenuation whenever the experimenter 
assisted the subject in fitting the earplug than when the subject 
merely read the manufacturer's instructions before donning the earplug. 
Furthermore, the researchers noted that the attenuations obtained by 
the subject when just the manufacturer's instructions were read is 
comparable to the attenuations measured under industrial conditions.
    Casali and Lam (1986) reported that the proper design and 
presentation of user insertion/donning instructions are critical to the 
amount of attenuation afforded by hearing protectors. They found that 
in some cases, the magnitude of protection afforded by the use of 
earplugs exhibited greater than a twofold increase when training ranged 
from no instruction to detailed and model instruction. Their study also 
showed that the attenuations afforded by earmuffs and earcaps were not 
as influenced by the level of instruction as were earplugs. Casali and 
Lam concluded that any instruction technique provided an improvement in 
attenuation over no instruction at all. However, they found no 
statistically significant differences among the type of instruction 
used. They also stated that regardless of the insertion/application 
instruction type selected, it is imperative that workers be retrained 
periodically in hearing protector insertion practices, hearing 
protector sizing, and hearing protector care to maintain optimal 
hearing conservation.
    Royster et al. (1996) had novice users of hearing protectors don 
the protectors after reading the manufacturer's instructions. Since 
some users failed to properly don the hearing protectors, the 
researchers concluded that the instructions provided by the 
manufacturer were not always adequate. Consequently, additional 
instruction should be provided to assure the proper donning of hearing 
protectors.
    Barham et al. (1989) reported that the noise reduction achieved by 
an earmuff improved by approximately 4 dB for a group and up to 6 dB 
for an individual following instruction on its use. Not only did the 
attenuation increase but also the standard deviation (a measure of 
variability) decreased. Therefore, instruction significantly improved 
the noise reduction achieved by the wearer of an earmuff.
    Park and Casali (1991) studied the effects of two levels (minimal 
and detailed) of instruction on the measured attenuation obtained by 
regular hearing protector users. The users were tested using different 
hearing protectors from the ones they normally wore. The amount of 
noise attenuation increased and the standard deviations decreased when 
the investigators presented the instructions and demonstrated the 
proper manner to don and doff hearing protectors as compared to the 
employees simply reading the instructions. The efficiency of earplugs 
was found to be highly sensitive to the degree of instruction while 
earmuffs and canal caps were not.
    MSHA believes that training is critical to the effective use of 
hearing protectors, and that miners must be shown how to use, fit, and 
care for their hearing protectors if they are to be effective. Further, 
the instructions should be repeated at yearly intervals to maintain 
effectiveness. Simply instructing the miner to read manufacturer's 
directions on the hearing protector container would not be adequate. 
MSHA is concerned that some manufacturer's instructions are inadequate 
for the proper fitting of hearing protectors. The effectiveness of 
hearing protectors can be highly dependent on how they fit the 
individual wearer. Not all people will achieve the same degree of fit 
or effectiveness from the same hearing protector.
Training About Hearing Conservation Program and Operator Noise Controls
    OSHA's noise standard has similar training requirements with the 
exception that they do not require training on the respective 
responsibilities of the employer and employee in maintaining controls.
    MSHA has determined that training miners enrolled in an HCP on the 
respective responsibilities of mine operator and miner is necessary to 
obtain maximum effectiveness from an HCP. Miner cooperation and support 
is required, for example, to ensure:
    (1) The hearing protector provided fits properly each time it is 
donned;
    (2) The hearing protector is worn whenever the miner is exposed to 
hazardous sound levels;
    (3) Exposure to high sound levels is avoided for at least 14 hours 
before taking the baseline audiogram;
    (4) Participation in the audiometric testing;
    (5) Cooperation with any administrative control(s) instituted by 
the mine operator; and

[[Page 66431]]

    (6) Use and maintenance of the engineering noise controls provided 
by the mine operator.
    MSHA believes that a miner's understanding and motivation would be 
enhanced by conducting initial and annual training in these areas. The 
rationale for retraining miners who suffer an STS is discussed in 
connection with Sec. 62.180, Follow-up corrective measures when STS 
detected.
    MSHA believes that a miner must also be trained to understand the 
audiometric tests. This will enable miners to understand their own 
results and determine the effect of wearing hearing protectors.
    Effectiveness. MSHA has endeavored to make the training 
requirements as simple as possible. If conducted separate from part 48, 
there are no specifications on trainer qualifications, no minimal 
training time, nor any training plans. If however the training is 
incorporated into part 48, then all applicable part 48 requirements 
will have to be met.
    While this approach reduces the burden on those mine operators who 
cannot incorporate part or all of the noise training into part 48 
training, it also means that certain safeguards in effect for part 48 
training will not be directly applicable to that noise training not 
provided during part 48 training. There would be no review of a noise 
training plan, for example, to ensure that the instruction is adequate 
or that the training is to be given in the language spoken by most of 
the miners. Comments on this point are solicited.
    The Agency believes it can ensure the noise requirements have been 
fulfilled by checking with exposed miners to ensure that the required 
training elements have been covered and that the certifications are 
valid.
    Certification. Section 62.130(b) of the proposal would require 
that, upon completion of any training required under this part, the 
mine operator certify the date and type of training (initial or annual) 
given each miner. The certification would be signed by the person 
conducting the training.
    It is standard practice in the mining industry to require 
certification of training, as a way of facilitating compliance. 
Training received under part 48 must be certified. The certification 
form used for part 48 does not have a separate line on which to 
indicate that the training required under the proposed noise standard 
has been completed; moreover, this would not be suitable in any event 
for noise training given independently of part 48 training as may often 
be the case.
    MSHA believes that it is important to record the type and date of 
any training conducted under its proposed noise regulations. A written 
record, together with miner interviews, provide the Agency necessary 
checks to ensure the training is provided as required with only a 
minimal burden.
    An optional approach on which MSHA would welcome comment is to 
simply require that a mine operator must, upon request, give an MSHA 
inspector copies of all materials related to the employer's noise 
training program. This is the approach taken by OSHA.
    Retention. Section 62.130(b) of MSHA's proposal would require the 
mine operator to retain the most recent certification at the mine site 
for as long as the miner is exposed to noise above the level which 
initiated the training and for at least six months thereafter.
    MSHA has a retention requirement for part 48 training. Part 48 
training records are to be retained for two years for currently 
employed miners or for 60 days after the termination of employment. 
OSHA has no retention requirement for training records.
    The Agency believes it is important to retain training records in 
order to verify that the required training has been provided, as with 
the certification requirements. The retention requirement is short and 
not burdensome: only the most recent record must be retained, and then 
only until the miner's exposure drops beneath the level which initiated 
the training (or 6 months after cessation if employment should that 
come before the exposure level has dropped).

Section 62.140  Audiometric Testing Program

    This section of the proposal would establish basic procedures for 
the audiometric testing program in which those miners enrolled in a 
hearing conservation program (HCP) will participate. It includes 
provisions for: qualifications of personnel performing the audiograms, 
baseline audiograms, annual audiograms, and supplemental baseline 
audiograms.
    MSHA is seeking explicit comment on a number of points. What 
follows is a brief summary of some key features of this section of the 
proposal.
    With respect to qualifications of personnel, MSHA would require 
that an ``audiologist'' be certified by the American Speech-Language-
Hearing Association or licensed by a state board of examiners. 
``Qualified technicians'' would be required to have been certified by 
the Council for Accreditation in Occupational Hearing Conservation 
(CAOHC) or another recognized organization offering equivalent 
certification. CAOHC or equivalent certification would assure that the 
technicians are qualified. MSHA is not proposing to require 
qualifications for physicians.
    It is critical to obtain a baseline audiogram before exposure to 
hazardous noise. If this is not possible, then the baseline is to be 
obtained as soon as is reasonably possible. Due to remote locations and 
intermittent operations of many mines, MSHA determined that allowing 
six months (or 12 months if a mobile test van is used) for obtaining 
the baseline audiogram was reasonable. The 12 month period would allow 
mine operators to schedule many baseline and annual audiograms 
simultaneously, and thus, substantially reduce the cost when mobile 
test vans are used. Pursuant to proposed Sec. 62.120(b), miners would 
be provided hearing protection until such time as the baseline 
audiogram is conducted; and in the event the miner has to wait for more 
than 6 months to get a baseline audiogram because a mobile test van is 
used, the operator would be required to ensure the use of hearing 
protection.
    MSHA has also determined that a 14-hour quiet period should precede 
the baseline audiogram to ensure a valid result: hearing protectors 
will not be considered a substitute for a quiet period under the 
proposal, and miners are to be notified of the importance of compliance 
with the quiet period.
    MSHA has concluded that audiograms need to be provided annually for 
miners enrolled in an HCP. MSHA is not proposing to require this quiet 
period for annual audiograms, though it may be in the mine operator's 
interest to do so.
Background
    Under existing standards for coal mines, MSHA requires pre-
employment and periodic audiograms at those mines under a hearing 
conservation plan, but includes no specific procedures or time frames 
for obtaining these audiograms. Moreover, at present, less than 1% of 
the coal miners are covered by a hearing conservation plan. MSHA 
currently does not have any requirements addressing audiometric testing 
for metal and nonmetal mines.
    OSHA's noise standard also contains requirements for qualifications 
of personnel and for baseline, annual, and supplemental baseline 
audiograms. The limited number of differences between the OSHA standard 
and the MSHA proposal are noted in the discussion that follows.

[[Page 66432]]

Qualifications of Personnel
    Section 62.140(a) of MSHA's proposal would require that audiometric 
tests be conducted by a physician, an audiologist, or a qualified 
technician who is under the direction or supervision of a physician or 
an audiologist.
    MSHA would require that an ``audiologist'' be certified by the 
American Speech-Language-Hearing Association or licensed by a state 
board of examiners. ``Qualified technicians'' would be required to have 
been certified by the Council for Accreditation and Occupational 
Hearing Conservation (CAOHC) or another recognized organization 
offering equivalent certification.
    OSHA's noise standard requires that--

    Audiometric tests shall be performed by a licensed or certified 
audiologist, otolaryngologist, or other physician, or by a 
technician who is certified by the Council of Accreditation for 
Occupational Hearing Conservation, or who has satisfactorily 
demonstrated competence in administering audiometric examinations, 
obtaining valid audiograms, and properly using, maintaining and 
checking calibration and proper functioning of the audiometers being 
used. A technician who operated microprocessor audiometers does not 
need to be certified. A technician who performs audiometric tests 
must be responsible to an audiologist, otolaryngologist or 
physician.

    MSHA received comments that specifically addressed the 
qualifications of persons conducting audiometric tests. Some commenters 
were concerned that physicians may not have the specific knowledge 
necessary to conduct audiometric testing. One of these commenters 
stated that:

    * * * many physicians are not well versed in problems of 
audition, especially occupational noise induced hearing loss [NIHL]. 
If physicians are to be included in the list of acceptable 
supervisors, they should be limited to ``qualified occupational 
physicians,'' or perhaps ``qualified occupational physicians with 
audiological experience.''

    Other commenters recognized that technicians need specific 
training, but disagreed as to whether formal certification was 
necessary. Many commenters specifically stated that MSHA should require 
CAOHC certification as the minimum acceptable criteria for training of 
audiometric technicians.
    Many commenters specifically recommended or implied that MSHA treat 
technicians who operate microprocessor audiometers the same as 
technicians who operate other types of audiometers. One stated that:

    The use of a microprocessor audiometer does not guarantee a 
valid, reliable audiogram, nor does it obviate the need for the 
technician to be familiar with the important interpersonal and 
procedural details of administering an audiogram and providing 
feedback to the employees.

    Other commenters, however, stated that persons who operate 
microprocessors do not need to be certified, but it was unclear whether 
they thought that training and demonstration of competency would be 
necessary for such technicians. Finally one commenter wanted ``maximum 
flexibility in audiometric testing.''
    One commenter on this issue stated that:

    * * * We do not believe that there are other qualified medical 
personnel [other than an audiologist or physician] who understand 
the principles of interpreting an audiogram appropriately.

    The U.S. Army (1991), Air Force (1991), and Navy (1994) regulations 
require that a physician, audiologist or technician conduct the 
audiometric tests. The audiometric technician must be CAOHC certified 
or certified through military medical training and be under the 
supervision of a physician or audiologist.
    MSHA believes that it is unnecessary to specify that physicians be 
``licensed'' or ``qualified.'' All states require physicians to be 
licensed. MSHA is concerned, however, that licensing does not imply 
qualification to conduct audiometric testing, evaluate audiograms, and 
supervise technicians in these areas. The Agency expects physicians to 
exercise professional judgement when evaluating their own 
qualifications to conduct audiometric testing. In addition, the medical 
profession enforces a high degree of accountability and ethical 
standards. Nevertheless, further comment is requested on this issue.
    MSHA believes that certification or licensing of audiologists is 
essential to an effective HCP. Properly trained and certified 
audiologists would be qualified to conduct audiometric testing, 
evaluate audiograms, and supervise technicians. Unlike physicians, MSHA 
believes that certification or licensing presupposes that the 
audiologist would be qualified to conduct audiometric testing.
    With respect to qualified technicians, MSHA considered the comments 
on this topic filed in response to the ANPRM and concluded that 
qualified technicians need to be certified by CAOHC or by an 
organization offering equivalent training. CAOHC or equivalent 
certification would assure that the technicians are qualified. While 
MSHA recognizes that the OSHA standard allows physicians discretion to 
judge the qualifications of technicians, MSHA believes requiring 
certification is not restrictive and best ensures quality control. MSHA 
would also require CAOHC or equivalent certification for technicians 
who operate microprocessor audiometers. The Agency concludes that 
requiring CAOHC or equivalent certification would not be overly 
burdensome on the mining industry.
    NIOSH commented on OSHA's proposed rule, and again on MSHA's ANPRM, 
that there may not be enough CAOHC courses offered in a given year, or 
in a wide enough geographical area, to require that all technicians be 
CAOHC certified. OSHA's preamble (46 FR 4128) in 1981 indicated that, 
at that time, there were about 6,700 CAOHC certified technicians and 
700 course directors. Since 1981, however, the number of CAOHC course 
directors has decreased to about 400, but the number of certified 
technicians has increased to about 14,000. Although this number of 
certified technicians may be sufficient to conduct the required 
audiograms in the mining industry, MSHA believes that promulgation of 
this rule will result in even more individuals seeking certification. 
In addition to CAOHC certification for audiometric technicians, MSHA 
would also accept training by any other recognized organization 
offering equivalent certification. MSHA requests information on any 
other nationally recognized program for the certification of persons to 
conduct audiometric tests.
    MSHA also considered the ``qualifications of personnel'' 
requirements from U.S. Armed Forces codes and international standards. 
The consensus was that the technician needed to be trained in 
conducting audiometric testing.
    Although the proposal would not require that the audiologist or 
physician be present when the technician conducts the audiometric test, 
MSHA would require that they directly supervise the technician to 
ensure strict adherence to testing procedures and measurement 
parameters.
Baseline Audiogram
    Section 62.140(b) of MSHA's proposal would require that, within six 
months of a miner's enrollment in an HCP, the miner shall be offered a 
valid baseline audiogram of the miner's hearing acuity against which 
subsequent annual audiograms can be compared. This would include miners 
with temporary layoffs, such as those miners employed at seasonal 
operations. However, the proposal would allow up to 12 months

[[Page 66433]]

to obtain a baseline audiogram when a mobile test van is used.
    Under existing standards for coal mines, MSHA does not specifically 
address a time frame for offering a baseline audiogram for those miners 
under a hearing conservation plan. MSHA has no requirements for 
baseline audiograms in its current metal and nonmetal noise regulation. 
This proposal is consistent with OSHA's noise regulation.
    The proposal would allow mine operators to use existing audiograms 
as the baseline, provided that they meet the testing requirements of 
this part. OSHA also accepts existing audiograms as a baseline because, 
in most cases, accepting old baseline audiograms is more protective for 
the employee. OSHA reasoned that:

    * * * old baselines will allow the true extent of the hearing 
loss over the years to be evaluated. Obtaining a new baseline 
audiogram after many years of noise exposure might be less 
protective since the new audiogram might show higher thresholds and 
the true extent of future losses would appear smaller than when 
compared with the original baseline.

    All commenters, addressing the issue of audiograms recognized the 
need to establish a baseline. The commenters varied, however, on the 
time needed to establish this baseline, i.e., from 30 days up to one 
year from the first exposure to noise. One stated that ``* * * the 
first annual or periodic audiogram should be allowed to be considered 
as the baseline or pre-employment audiogram.'' Most of the commenters, 
who specified a time frame for completing the baseline audiogram, 
agreed with OSHA's position of allowing up to six months. Only one 
comment was received, on the 1-year time allowed, for audiometric 
testing with mobile test vans. This commenter was concerned that miners 
might be exposed to noise, in the interim period, until the test van 
was available and recommended ``that the employees utilize hearing 
protection from the time they are enrolled in an HCP.''
    NIOSH (1995) recommended that the baseline audiogram be conducted 
within 30 days of enrollment in an HCP, even if a mobile test van is 
used. NIOSH believes it is unacceptable to wait up to six months for a 
baseline audiogram, because exposure to high sound levels for a 
relatively short period of time can adversely affect the hearing acuity 
of susceptible individuals.
    MSHA has also taken into consideration requirements of the U.S. 
Armed Forces and the international community with respect to baseline 
audiograms. Many in the international community and the U.S. armed 
services agree that the baseline audiogram is of primary importance.
    MSHA has determined that the baseline audiogram is essential, 
because it is the reference against which subsequent audiograms are to 
be compared. The comparison will be used to determine the extent of 
hearing loss. If the baseline audiometric test is not conducted 
properly, it will not reflect the miner's true hearing thresholds and 
any changes between baseline and subsequent tests may be masked. 
Further, existing audiograms may be used as the baseline, if they meet 
the testing requirements of this part. The use of pre-existing 
audiograms would be more protective for the affected miner and less 
burdensome on the mine operator.
    Because of the baseline audiogram's importance, it is critical to 
obtain one before exposure to hazardous noise. If this is not possible, 
then the baseline is to be obtained as soon as is reasonably possible. 
Due to remote locations and intermittent operations of many mines, MSHA 
determined that allowing six months (or 12 months if a mobile test van 
is used) for obtaining the baseline audiogram was reasonable. The 12 
month period would allow mine operators to schedule many baseline and 
annual audiograms simultaneously, and thus, substantially reduce the 
cost when mobile test vans are used.
    It should be noted that the provisions of Sec. 62.120 of MSHA's 
proposal would require mine operators to ensure that all miners 
enrolled in a hearing conservation program be provided hearing 
protectors until they receive a baseline audiogram; and require the 
operator to ensure the protection is used if the need to wait for a 
mobile test van delays the initial audiogram past 6 months.
    MSHA solicits additional comments on the appropriate time frame for 
obtaining audiograms, especially in remote mining areas.
14-hour Quiet Period
    Section 62.140(b)(2) of the proposal would require that the mine 
operator ensure that the affected miner is not exposed to workplace 
noise for at least a 14-hour period immediately prior to receiving the 
baseline audiogram.
    MSHA has no existing requirement in this area. The proposal is 
similar to OSHA's noise standard except that, as discussed below, OSHA 
permits the use of hearing protectors in lieu of removal from workplace 
noise.
    The 14-hour quiet period is intended to provide a miner's hearing 
with sufficient rest to allow recovery from any temporary threshold 
shift (TTS) caused by pre-test noise exposure. If the baseline 
audiogram is skewed by TTS, subsequent comparisons to annual audiograms 
would not provide accurate indications of the extent of damage incurred 
during the time span between the baseline and subsequent tests.
    There were numerous comments concerning the time frame for a quiet 
period. Of these, most suggested that the 14 hours mandated in OSHA's 
noise standard was sufficient to minimize any TTS. Others recommended 
different time frames for the quiet period. One stated that ``* * * 
there are sufficient human data in the literature to establish that a 
14-hour quiet period is too short.'' Several commented that:

    A suitable quiet period of 24 hours prior to the performance of 
audiometric testing would be preferred. However, a 16-hour quiet 
period would often meet the needs of most operations, being the 
amount of time normally between the end of one days work and 
starting time for the next.

One thought that eight hours was enough. Another commented that a quiet 
period should be allowed but not required for the initial test. 
Further, this commenter stated that 24 hours should be required for 
confirmation testing.
    Fodor and Oleinick (1986) in their paper on workers' compensation 
reported that one researcher found full recovery from ``physiological 
fatigue'' in 16 hours, with recovery from ``pathological fatigue'' 
taking longer. This researcher reported that the initial recovery seems 
to be a logarithmic function of time and the longer recovery period is 
a linear function. Most researchers, however, report complete recovery 
from TTS taking no longer than 16 hours provided the TTS did not exceed 
40 dB. On the other hand, some states require that a worker be away 
from noise exposure for six months before evaluating hearing loss for 
workers' compensation purposes.
    MSHA concludes, after reviewing the scientific literature and the 
standards of various jurisdictions, that the length of time required to 
obtain full recovery from TTS depends upon the magnitude of the sound 
pressure level, the length of exposure, the frequencies affected, the 
person's age, and the person's susceptibility to hearing damage. 
Because the mine operator has no control over the non-occupational 
noise exposure of a miner, MSHA decided against limiting non-
occupational noise to a specified sound level during the quiet period; 
however, as noted below, MSHA is requiring that the mine operator 
notify employees of the need to avoid high levels of noise during the 
14-hour period preceding the test, which it

[[Page 66434]]

hopes will limit non-occupational noise exposure. With the exception of 
the EEC (15 minute quiet period), the consensus of the international 
community and the U.S. armed services is that there should be a quiet 
period of at least 14 hours. MSHA decided that a 14-hour quiet period 
would be the most appropriate alternative and is consistent with OSHA's 
requirements, comments to the ANPRM, and its review of available 
literature. A quiet period longer than 14 hours could place an undue 
burden on mine operators as the miner may have to stay away from work 
to comply with the quiet period if the miner works a slightly extended 
shift; many work shifts exceed 8 hours especially when a lunch period 
is taken into account.
Use of Hearing Protectors for 14-hour Quiet Periods
    Section 62.140(b)(2) of the proposed standard would also prohibit 
the use of hearing protectors as a substitute for the 14-hour quiet 
period. As noted previously, OSHA currently does allow hearing 
protectors to be used during the required 14-hour quiet period.
    When it first promulgated its Hearing Conservation Amendment in 
1981, OSHA did not permit the substitution of hearing protectors for 
the 14-hour quiet period. This decision generated much discussion among 
commenters believing that it was unnecessarily restrictive. Even 
professional audiologists strongly disagreed on this issue. One 
commenter suggested that if the hearing protector reduced the level of 
sound energy reaching the ear to 80 dBA or less, this would effectively 
reduce the amount of baseline contamination to less than the usual 
amount of audiometric measurement error. Commenters also cited problems 
such as additional overtime wages, disruptions of work schedules, and 
non-occupational noise exposure.
    In 1983, OSHA revised its Hearing Conservation Amendment to allow 
the use of hearing protectors as an alternative for the 14-hour quiet 
period prior to the baseline audiogram. OSHA concurred with the large 
number of commenters who testified that the use of hearing protectors 
may provide sufficient attenuation to prevent noise-induced TTS from 
contaminating baseline audiograms.
    MSHA received many comments addressing this issue. Several of these 
stated that hearing protectors should not be substituted for the quiet 
period. Their general consensus can be summarized by one commenter who 
stated that:

    * * * the use of HPDs cannot be relied upon to reduce the noise 
in all cases to a level suitable to be considered quiet for the 
purpose of establishing baseline audiograms, especially if 
individual variations in susceptibility to noise induced hearing 
loss are considered.

Other commenters believed that the use of hearing protectors should be 
allowed because they prevent TTS. One such commenter wanted a 
qualification stating that:

    * * * in many instances it may simply not be practical or 
possible to test everyone for their baselines as they come to the 
workshift, and thus reliance on HPDs for the 14-hr. noise-free 
period is required. Thus MSHA should allow use of HPDs in lieu of 
the 14 hrs., but with the following stipulation:
    * * * no more than five days prior to the test, 1) the employees 
whose hearing is to be evaluated receive refresher training in the 
use of their protectors, and 2) the condition of the hearing 
protector(s) the employee is to wear is checked and found 
satisfactory. Any employee whose TWA exceeds 100 dBA shall be 
required to wear an earplug together with an earmuff * * * 

    Some researchers, Shaw (1985) and Suter (1983), contend that sound 
levels must be below 72 dBA to be considered ``effective quiet.'' 
Schwetz et al. (1980) found that a sound level below 85 dBA is needed 
for recovery of TTS. Individuals with TTS recovered their normal 
hearing quicker when exposed to 75 dBA sound level rather than 85 dBA. 
The NIOSH Criteria Document (1972) recommends a sound pressure level of 
65 dB as ``effective quiet'' based on work by Schmidek et al (1972). 
Hodge and Price (1978) concluded that the level would have to fall 
below 60 dBA to be effective quiet and not contribute to the 
development of a TTS.
    MSHA's proposal differs from OSHA's standard, in that it would not 
allow hearing protectors to be substituted for the 14-hour quiet period 
prior to the baseline audiogram. Although MSHA recognizes that its 
decision may pose some scheduling problems for mine operators, it 
should be emphasized that the quiet period is required only for the 
baseline audiogram. Mine operators, however, may choose to employ it 
for the annual audiograms.
    MSHA has determined that the problems associated with the use of 
individual hearing protectors are too great to guarantee an accurate 
baseline measurement. Data indicate that in order to provide effective 
quiet, the sound levels encountered during the quiet period would need 
to be below 80 dBA. MSHA is particularly concerned with the ability of 
hearing protectors to attenuate noise to such low levels in order to 
prevent contamination of the baseline. Even at 80 dBA, some researchers 
concluded that this level may be inadequate for the most susceptible 
individuals. Moreover, the typical sound levels in mining are higher 
than those experienced in general industry; therefore, hearing 
protectors would need to attenuate the noise to a greater degree. 
Although MSHA contends that hearing protectors can provide some 
protection to miners whose exposures do not exceed the PEL, MSHA has 
concluded that engineering and administrative controls provide much 
more effective protection. MSHA's concerns with the ability of hearing 
protectors to provide adequate attenuation are addressed in connection 
with the requirements of proposed Sec. 62.120(b), under the heading of 
Hearing protector effectiveness.
Notification to Avoid High Sound Levels
     Section 62.140(b)(3) of the proposal would require mine operators 
to notify miners to avoid high levels of non-occupational noise during 
the 14-hour period before taking the baseline audiogram. This 
requirement is the same as OSHA's noise standard.
    In the 1983 preamble to its Hearing Conservation Amendment (48 FR 
9757), OSHA emphasizes that, even if workers received this information 
in training classes, such notification would aid memory and, thus, 
provide additional support to the goal of obtaining a valid baseline 
audiogram. OSHA concludes its discussion of this issue as follows:

    Although employers are not responsible for employee noise 
exposures sustained away from the workplace, the likelihood of non-
occupational noise exposure contaminating the baseline audiogram can 
be substantially reduced by counseling workers of the need to avoid 
such exposures in the period before their baseline test. Therefore, 
this requirement is necessary and appropriate for the implementation 
of a successful hearing conservation program.

    Only a few commenters offered an opinion on this specific issue in 
response to MSHA's ANPRM. These commenters agreed that workers need to 
be advised to avoid non-occupational noise exposure prior to taking the 
baseline audiogram.
    MSHA believes that it is appropriate for operators to notify miners 
of the importance of avoiding high noise areas in order to obtain valid 
baseline audiograms. The proposed requirement is consistent with OSHA's 
noise standard and the limited commenter responses.
Annual Audiogram
    Section 62.140(c) of MSHA's proposal requires that, after 
establishing a baseline, the miner to be offered a new

[[Page 66435]]

audiogram once every 12 months as long as the miner remains in the HCP.
    Existing MSHA standards require coal mine operators to submit a 
hearing conservation plan, which includes conducting periodic 
audiograms, for each miner exposed to noise in excess of the PEL. 
Because the use of hearing protectors is considered to provide 
compliance with the PEL in this industry, few receive audiograms. 
Moreover, there are no standards requiring audiograms for metal and 
nonmetal workers.
    OSHA requires, after the baseline audiogram has been obtained, an 
annual audiogram for each employee exposed at or above its action level 
to identify changes in hearing acuity, so that the use of hearing 
protectors can be prescribed or other follow-up measures initiated 
before hearing loss progresses. The preamble to OSHA's hearing 
conservation amendment (46 FR 4143) states:

    OSHA has chosen to retain the annual audiometric test 
requirement because of the potential seriousness of the hearing 
damage that can occur within a 2-year period. For employees exposed 
to high levels of noise, a 2-year period between audiograms might 
allow too much hearing loss to occur before identifying the loss and 
taking remedial steps.

    In response to its ANPRM, MSHA received numerous comments that 
specifically addressed periodic audiograms. Many of these supported 
annual testing and a few recommended a different time period. These 
latter commenters suggested the following alternative time periods: 
once or twice a year, depending on the intensity of the exposure; every 
other year; and based upon need.
    MSHA concludes that the determination of an STS in the one-year 
period between required audiograms is meaningful for detecting the type 
of problems for which HCP enrollment is the purpose. Detection of an 
STS triggers several important actions under the proposal. Retraining 
of the miner would be required. If the miner is enrolled in the HCP as 
a result of noise exposure above the action level, but the miner's 
noise exposure is below the PEL, detection of an STS would require the 
provision of a hearing protector--which a miner at that exposure level 
would otherwise not be required to utilize. If the miner was already 
using a hearing protector, it would have to be replaced. Detection of 
an STS would also require reevaluation of the engineering and 
administrative controls being used. Waiting two years or more between 
periodic audiograms could allow excessive hearing damage to miners. 
MSHA also recognizes that some miners may be more susceptible to 
hearing damage from noise exposure, and a few may be exposed to high 
sound levels, such that annual audiometric testing may not be frequent 
enough to prevent an STS.
    In light of the comments to MSHA's ANPRM, the Agency's review of 
the literature and pertinent governmental regulations, and OSHA's 
existing requirements, MSHA has tentatively concluded that annual 
audiometric testing is both necessary and appropriate. Annual 
audiometric testing is an integral part of a comprehensive HCP.
Supplemental Baseline
    Section 62.140(d) of MSHA's proposal would require the mine 
operator to establish a ``supplemental audiogram'' when: (1) the STS 
revealed by the annual audiogram is persistent, or (2) the hearing 
threshold shown in the annual audiogram indicates significant 
improvement over the baseline audiogram.
    These proposed requirements are similar to those in OSHA's noise 
standard except for the terminology.
    In response to its ANPRM, MSHA received numerous comments on 
circumstances in which it was not appropriate to use the original 
baseline audiogram. Many commenters were in favor of revising the 
baseline if an STS was persistent. One stressed the need for clear 
guidelines for baseline revision to avoid the use of a variety of 
creative methods which could result in different STS totals. Other 
commenters were in favor of revising the baseline if the annual 
audiogram showed an improvement in hearing. Another recommended 
revising the baseline only if the improvement was consistent for at 
least two or three consecutive tests. A final commenter wanted the 
baseline revised only if there was a testing error.
    MSHA believes, after reviewing these comments and standards of the 
U.S. Armed Forces, that revising the baseline after an STS has been 
identified would prevent this same STS from being identified 
repeatedly. The annual audiogram on which the STS is identified would 
then become the ``supplemental baseline audiogram.'' This supplemental 
baseline would be used for comparison with future annual audiograms to 
identify a second STS. The ``baseline audiogram'' would continue to be 
used to quantify the total hearing loss in determining whether the loss 
constitutes a ``reportable hearing loss''. To avoid confusion in the 
mining industry, MSHA is proposing the term ``supplemental baseline'' 
rather than the term ``revised baseline'' used under OSHA. Since all 
audiograms are to be retained as part of the audiometric test record 
(see Sec. 62.150(c)), supplementation of the baseline audiogram would 
not permit the destruction of the original baseline audiogram.
    MSHA would also require supplementation of the baseline if the 
annual audiogram shows significant improvement in hearing level because 
this would more closely resemble the miner's actual hearing acuity 
prior to being exposed to occupational noise. In this case, 
supplementation of the baseline would be more protective because it 
would allow more accurate evaluation of the true extent of future 
hearing loss. Therefore, when a baseline is revised due to an 
improvement of hearing acuity, this supplemental baseline would be 
considered as the original baseline for determining when an STS occurs 
and for quantifying the total hearing loss for reportablility under 
part 50. The latter is reflected in the definition of reportable 
hearing loss.

Section 62.150  Audiometric Test Procedures

    MSHA proposes not to include specific procedural requirements for 
conducting audiometric tests, calibrating audiometers, and qualifying 
audiometric test rooms. Instead, MSHA proposes a performance-oriented 
requirement that audiometric testing be conducted in accordance with 
scientifically validated procedures. MSHA would specify the test 
frequencies, but would allow the physician or the audiologist to use 
professional judgment in choosing the appropriate testing procedure(s) 
and require certification of the scientific validity of the procedures.
    While this approach may require somewhat more in the way of 
paperwork requirements, MSHA believes this is far preferable to the 
alternative of a detailed specification standard, which could stifle 
technology and impede improvements in methodology.
    The proposal would also specify what records must be maintained, 
and for how long, at the mine site. The proposed items included in the 
audiometric test record--name, job classification, audiograms and 
certifications as to the procedures used to take them, any exposure 
determinations, and the results of any follow-up examinations--would 
provide information essential for evaluating a miner's audiogram, among 
other purposes.

[[Page 66436]]

    The records are to be retained for at least six months beyond the 
duration of the miner's employment. The six month retention period at 
the mine site would assure that the audiometric test records of miners 
who have short periods of unemployment are not destroyed and are 
available for use by the mine operator to conduct further evaluations 
upon the miner's return. In practice, MSHA believes that many mine 
operators will keep miner's audiograms long after the miner's 
employment ceases, for use if the miner should file a subsequent 
workers' compensation claim for hearing loss.
    Currently MSHA's metal and nonmetal noise standards do not contain 
audiometric testing provisions. While Coal's noise standard requires 
audiometric testing, it does not specify how it is to be conducted. 
MSHA's proposal differs from OSHA's noise standard which contains 
detailed procedures in 29 CFR Sec. 1910.95(h) and the associated 
Appendices C, D, and E.
    Several commenters generally supported MSHA's adoption of 
audiometric testing requirements that are the same as OSHA's. A number 
of commenters made specific recommendations regarding various aspects 
of conducting audiograms including audiometric test instruments, 
calibration procedures, and audiometric test rooms. Since MSHA has 
decided not to specify audiometric test requirements in the proposed 
rule, a discussion of the comments on specific procedures is not 
included (except in the section which follows, Test procedures).
    ANSI has several standards which impact the audiometric test 
procedure. ANSI S3.21-1978 ``Methods for Manual Pure-Tone Threshold 
Audiometry'' provides detailed procedures for conducting audiometric 
tests. ANSI S3.1-1991 ``Criteria for Maximum Ambient Noise Levels for 
Audiometric Test Rooms'' provides a criteria for the maximum background 
sound pressure levels neccessary in order to obtain a valid audiogram. 
ANSI S3.6-1996 ``Specifications for Audiommeters'' provides design 
criteria for various classes of audiometers.
    After reviewing comments, the scientific literature and several 
governmental standards, MSHA chose not to include detailed, highly 
technical procedures and criteria for conducting audiometric testing in 
the proposal. Instead MSHA chose a performance-oriented approach by 
proposing to require that audiometric testing procedures be governed by 
scientifically validated methods. Because the person responsible for 
conducting the tests is a physician, audiologist, or qualified 
technician, he/she should be familiar with scientifically validated 
procedures. MSHA would allow the physician or the audiologist to use 
professional judgement in choosing the appropriate testing 
procedure(s).
    Moreover, audiometer manufacturers provide recommendations on 
audiometer use and calibration (both laboratory and field). Because the 
manufacturers are aware of the intricacies of their instruments, they 
would be the most qualified to issue recommendations on the use and 
calibration of their audiometers. By following manufacturer's 
recommendations accurate audiometric testing is assured without MSHA 
mandating detailed calibration specifications.
    By not specifying a single test procedure, MSHA would permit the 
use of any scientifically validated procedure. If a new, possibly more 
accurate procedure would be validated, the medical professional could 
readily adopt its use. If, however, current procedures were adopted in 
the rule, an amendment would be needed to permit the use of any new 
procedure.
    Even though MSHA found no single comprehensive criteria for 
audiometric testing, save OSHA's, there are criteria which deal with 
various aspects of testing. For example, ANSI has standards on 
background sound pressure levels for audiometric testing, methods for 
pure tone audiometry, and for specifications for audiometers. MSHA 
expects that most audiograms would be conducted using OSHA's 
requirements, since many physicians and audiologists are familiar with 
those regulations. Further, many texts and CAOHC training courses 
discuss OSHA's audiometric testing procedures and criteria. Although 
MSHA has not proposed detailed specifications in its standard, the 
Agency contemplates publication of nonmandatory guidelines describing 
what it believes to be the latest scientific procedures for conducting 
audiometric tests.
    MSHA, realizing that performance-oriented standards for audiometric 
testing may be controversial, solicits comments on this approach, and 
continues to solicit comments on the audiometric test procedures, 
permissible background sound pressure levels, and calibration 
requirements for audiometers.
Test Frequencies
    The proposal would require that audiometric tests be pure tone, air 
conduction, hearing threshold examinations, with test frequencies at 
500, 1000, 2000, 3000, 4000, and 6000 Hz. The proposal also specifies 
that these examinations be taken separately for each ear at the given 
test frequencies. In response to MSHA's ANPRM, no commenters 
specifically addressed audiometric test frequencies. Several, however, 
generally supported MSHA's adoption of audiometric testing requirements 
that are the same as OSHA's. MSHA's proposal would be consistent with 
OSHA's requirements with respect to testing frequencies, as well as 
consistent with the NIOSH criteria document (1972).
    Although none of the commenters directly addressed audiometric test 
procedures, several stated that MSHA should adopt or follow the OSHA 
Hearing Conservation Amendment.
    As noted in part II of this preamble, noise-induced hearing loss is 
a permanent sensorineural condition that cannot be improved medically. 
It is characterized by a declining sensitivity to high frequency 
sounds. This loss usually appears first and is most severe at the 4000 
Hz frequency. The ``4000 Hz notch'' in the audiogram is typical of 
NIHL. Continued exposure causes the loss to include other audiometric 
test frequencies, with 500 Hz being the least affected. While 500, 
1000, and 6000 Hz are not included in the definition of STS, MSHA, like 
OSHA, believes that these test frequencies contribute to a more 
complete audiometric profile and are helpful in assessing the validity 
of the audiogram as a whole. Furthermore, the inclusion of 500 and 1000 
Hz makes it easier for an audiologist or physician to differentiate 
conductive hearing loss from NIHL, and the inclusion of 6000 Hz would 
better differentiate between presbycusis and NIHL.
Certification
    Section 62.150(b) of MSHA's proposal would require that mine 
operators obtain a certification, from whomever conducts audiometric 
tests under this part, that such tests were conducted according to a 
scientifically validated procedure.
    OSHA's current noise standard does not require such certification. 
OSHA has specific audiological test procedures, allowable background 
sound pressure levels in audiometric test rooms, and audiometer 
calibration requirements. MSHA's metal and nonmetal noise standards do 
not contain audiometric testing provisions. While Coal's noise standard 
requires audiometric testing, it does not specify how it is to be 
conducted.
    MSHA did not address this issue of certification in its ANPRM and, 
therefore, no comments were received.

[[Page 66437]]

    MSHA's proposal would relieve the mine operator from specifying the 
audiological test procedure and criteria. The mine operator would rely 
on the professional judgement of the physician or audiologist to select 
the appropriate tests and criteria. Certification would not be accepted 
from a qualified technician; pursuant to the proposed provisions in 
Sec. 62.140, qualified technicians are to perform their work under the 
supervision of a physician or audiologist. MSHA believes that it is 
necessary for the physician or audiologist to certify that the 
audiological tests were conducted in accordance with a scientifically 
validated procedure. In most cases, the mine operator does not have 
sufficient medical knowledge to determine if the tests were properly 
conducted and must rely on the judgement of a physician or audiologist. 
The certification will stand as evidence that the audiological tests 
were conducted in accordance with the requirements for a scientifically 
validated procedure.
Audiometric Test Recordkeeping and Retention
    Section 62.150(c) of MSHA's proposal would require that mine 
operators maintain a record of each required audiometric test. This 
record would contain--
    (1) the name and job classification of the miner tested
    (2) a copy of the miner's audiogram(s) (original baseline, annual, 
and supplemental baseline);
    (3) certification(s) that the tests were conducted using 
scientifically validated procedures;
    (4) any exposure determination for the miner; and
    (5) the results of any follow-up examination(s).
    This information would not have to be written on the actual 
audiogram as long as it was kept with the audiogram. The audiometric 
test records would be required to be maintained at the mine site for 
the duration of the affected miner's employment plus at least six 
months.
    Although not defined in this proposal, by the term ``duration of 
employment'' MSHA means the period of time between the date of a 
miner's initial hiring and the date on which the miner is released, 
quits, retires, or dies. There must be a lapse of at least six months 
beyond formal termination of employment before a mine operator could 
destroy the audiometric test records. Moreover, it is MSHA's intent 
that a layoff, strike, lockout, furlough, period of leave (both paid 
and unpaid), or other temporary break in service would not be 
considered as a formal termination of employment, even if it exceeds 
six months.
    MSHA's existing standards have no requirements in this area. OSHA's 
noise standard requires that employers maintain a record of the 
audiometric test results and maintain these records for the duration of 
employment.
    Since the publication of the noise standard, OSHA promulgated 29 
CFR 1910.20 Access to employee medical records. This standard applies 
to all medical records required to be kept pursuant to OSHA standards--
noise records are treated in the same way as carcinogen records. Under 
1910.20, OSHA requires that medical records for each employee be 
maintained for at least the duration of employment plus (30) years, 
with the exception of employees who have worked for less than (1) year 
for the employer. The medical records for these employees need not be 
retained beyond the term of employment if they are provided to the 
employee upon termination. Further this standard requires that exposure 
records be maintained for at least 30 years.
    Additionally, OSHA's noise standard requires that the audiometric 
test record include--
    (1) name and job classification of the employees;
    (2) date of the audiogram;
    (3) examiner's name;
    (4) date of the last acoustic or exhaustive calibration of the 
audiometer; and
    (5) employee's most recent noise exposure assessment.
    Additionally, employers are required to maintain an accurate record 
of background sound pressure levels in audiometric test rooms. OSHA's 
noise standard has no requirement to maintain these records at the 
employer's work site.
    MSHA received a number of comments specifically addressing time 
frames for maintaining audiometric test records. One commenter 
recommended that they be maintained for 30 years. Two commenters 
recommended that such records be retained for the duration of the 
miner's employment plus 30 years. Most of the commenters on this issue 
recommended that MSHA require that audiometric test results be kept for 
the duration of employment.
    MSHA also reviewed the audiometric test recordkeeping and retention 
requirements from the U.S. Armed Forces and various other countries. 
Generally, the audiometric test record is to be maintained for at least 
the duration of employment.
    MSHA considered allowing mine operators to keep the audiometric 
test record at a location other than the mine site. The Agency 
concluded, however, that this alternative was impractical because it 
could delay MSHA's access to such records. Furthermore, it would be 
burdensome for mine operators to copy and mail the records or send a 
fax of these records to the Agency.
    MSHA believes that this record should be retained for at least six 
months beyond the duration of the miner's employment. The risk of harm 
stops with the cessation of employment; keeping the records an 
additional 6 months would assure that a miner's audiometric test 
records are not destroyed and are available for use by the mine 
operator to conduct further evaluations should a miner return within 
that time period. In practice, MSHA believes that many mine operators 
will keep miner's audiograms long after the miner's employment ceases, 
for use if the miner should file a subsequent workers' compensation 
claim for hearing loss. In some states, the worker has many years 
following employment to file such a claim.
    The proposed items included in the audiometric test record would 
provide essential information to MSHA and to the health professional 
for evaluating a miner's audiogram. The information is also necessary 
for identifying the audiograms, evaluating whether the audiometric 
tests have been conducted properly, and for determining whether the 
results are valid. Further, the information is critical for the 
evaluator in determining whether an identified hearing loss was not 
work related or aggravated by occupational noise exposure.

Section 62.160  Evaluation of Audiograms

    MSHA's proposal would require that the mine operator inform the 
person evaluating the audiogram of the requirements of this part and 
provide them with copies of the miner's audiometric test records. The 
mine operator would be responsible for having a physician, audiologist, 
or qualified technician determine if an audiogram is valid and if a 
standard threshold shift (STS) or reportable hearing loss has 
occurred--in which case certain actions are required pursuant to 
Sec. 62.180 and Sec. 62.190. Time frames and privacy protection are 
part of the proposal, as is a requirement for a prompt retest if an 
audiogram is invalid.
    STS is defined in this proposal, as in OSHA's standard, as a change 
in a worker's hearing acuity for the worse,

[[Page 66438]]

relative to that worker's baseline audiogram, of an average of 10 dB or 
more at 2000, 3000, and 4000 Hz in either ear. If the STS is determined 
to be permanent, a supplemental baseline is established pursuant to 
Sec. 62.140 and this becomes the baseline for determining any future 
STS. This definition is sufficiently restrictive to locate meaningful 
shifts in hearing, yet not so stringent as to create unnecessary 
follow-up procedures; the averaging of hearing levels at adjacent 
frequencies will reduce the effect of testing errors at single 
frequencies.
    The proposal would permit but not require mine operators to adjust 
audiometric test results by applying a correction for presbycusis 
before determining whether an STS or reportable hearing loss has 
occurred, and it includes tables for this purpose. Presbycusis is the 
progressive loss of hearing acuity associated with the aging process. 
The proposed adjustment for presbycusis is optional; however, if a mine 
operator uses this approach, it must be applied uniformly to both the 
baseline and annual audiograms in accordance with the procedures and 
values listed in the proposed standard. Although this is the position 
taken in the proposal, MSHA notes that the latest NIOSH advice on this 
topic has advised against the use of presbycusis correction factors. 
Moreover, the Agency is concerned about locking-in specific presbycusis 
adjustment tables. MSHA, therefore, requests additional comments on 
whether to use presbycusis corrections for audiograms and, if so, how 
to provide for such adjustment in a regulatory context.
    MSHA's existing noise standards do not address the evaluation of 
audiograms. MSHA's proposed requirements would be similar to those in 
OSHA's noise standard; the few differences are noted below.
Information Provided to Reviewer
    Section 62.160(a)(1) of MSHA's proposal would require that the mine 
operator inform the person evaluating the audiogram of the requirements 
of this part and provide the evaluator with copies of the miner's 
audiometric test records. OSHA requires employers to provide the 
persons evaluating audiograms with a copy of the requirements of its 
standard, copies of the employee's baseline and most recent audiometric 
test records, background sound pressure levels in the audiometric test 
room, and a record of audiometer calibration.
    In its ANPRM, MSHA did not address what information the mine 
operator should provide to the person evaluating audiograms. The 
commenters, therefore, did not address this issue specifically. In 
discussing related topics, some commenters recommended that MSHA adopt 
OSHA's requirements on this issue.
    Recently, research has implicated exposure to chemicals as 
aggravating hearing loss, Fetcher (1995), Morata (1989, 1993, 1995). 
MSHA requests comments as to how to address various aspects of this 
possible relationship. For example, could exposure to chemicals cause 
an invalid audiogram? What information should reviewers have about 
chemical exposure? Any research results on this topic would be welcome.
    MSHA believes that providing certain information is necessary for 
physicians and audiologists to evaluate the accuracy and validity of 
miners' audiograms. For example, the evaluator would need to know the 
procedure for determining an STS, the criteria for retest or medical 
follow-up, presbycusis correction procedures, and recordkeeping 
requirements.
    Review of audiogram. Under Sec. 62.160(a)(2) of this proposal, the 
mine operator would be responsible for having a physician, audiologist, 
or qualified technician determine if an audiogram is valid and if an 
STS or reportable hearing loss has occurred. MSHA's proposal is 
consistent with the present OSHA noise standard.
    Of the many commenters on this specific issue, most believed that 
professional review was necessary. One of these said that ``MSHA should 
require an audiologist or physician to evaluate audiograms that show 
standard threshold shifts [STS] or other unusual changes''.
    A few commenters felt that professional review was unnecessary. 
These commenters indicated that the person conducting the audiogram 
could inform the employee of the results, and explain the significance 
of these results, so that the employee could make any decisions 
regarding further testing or evaluation.
    The U.S. Armed Services and the international community vary on the 
medical expertise required to review audiograms.
    MSHA believes that audiograms need to be reviewed for validity; as 
noted below, if audiograms are not valid, the proposal would require a 
retest. Examples of questionable audiograms are audiograms that show: 
large unilateral differences in hearing thresholds between the two 
ears; unusual frequency patterns that are not typical of NIHL; 
thresholds that are not repeatable; or an unusually large hearing loss 
over a yearly period. MSHA maintains that the review of audiograms is 
an integral part of an audiometric testing program.
Qualifications for Audiogram Reviewers
    Under Sec. 62.160(a)(2) of this proposal, a mine operator would be 
required to have a physician, audiologist or a qualified technician who 
would be under the supervision of a physician or audiologist evaluate 
audiograms to determine their validity and whether an STS or reportable 
hearing loss has occurred. The qualifications of these individuals to 
conduct this evaluation are discussed under Sec. 62.140 Qualifications 
of personnel along with the comments received on this issue.
Standard Threshold Shift (STS)
    This proposal would require the evaluator to determine whether a 
miner has incurred an STS in his/her hearing. STS is defined in this 
proposal as a change in a worker's hearing threshold relative to that 
worker's baseline audiogram of an average of 10 dB or more at 2000, 
3000, and 4000 Hz in either ear. This requires that hearing loss be 
calculated by subtracting the current hearing levels from those on the 
baseline audiogram at 2000, 3000, and 4000 Hz; when the hearing losses 
at each frequency are averaged (added up and divided by three); if the 
average loss in either ear has reached 10 dB, it constitutes an STS. If 
the STS is determined to be permanent, a supplemental baseline is 
established pursuant to Sec. 62.140 and this becomes the baseline for 
determining any future STS. The definitions of ``baseline audiogram'', 
``supplemental baseline audiogram'', and ``standard threshold shift'' 
are discussed in detail in connection with proposed Sec. 62.110.
    OSHA defines an STS in essentially the same way, requiring that 
employees' annual audiograms be compared to their baseline audiogram to 
determine if the annual audiogram is valid and if an STS has developed.
    Of the numerous comments addressing the issue of STS in response to 
MSHA's ANPRM, many endorsed OSHA's definition of STS. One commenter 
stated that:

    The Standard Threshold Shift (STS) concept is the basic 
foundation of a hearing conservation program and is the best 
indicator of early noise-induced hearing loss [NIHL]. It enables 
those conducting the audiometric examinations to have the needed 
``red flag'' to indicate when additional testing or evaluation is 
needed. It also enables the effectiveness of the employer's hearing 
conservation program to be evaluated and monitored. The criteria 
must be sensitive enough to identify meaningful changes in hearing 
but must not be so sensitive as to

[[Page 66439]]

pick up spurious shifts or ``false-positives.'' * * * Identifying a 
standard threshold shift therefore means that the shift value must 
be outside the range of audiometric error ( 5 dB) and 
serious enough to warrant prompt attention.* * * The averaging of 
shifts over adjacent frequencies minimizes normal test error, and 
random errors will tend to cancel each other out. * * *
    In considering the frequencies to be used, it is noted that 4000 
Hz is generally considered to be affected by noise the earliest and 
most severely. The 2000 and 3000 Hz frequencies are very important 
in understanding speech and should also be included in the 
definition of STS.
    For the above-mentioned reasons, as well as simplifying the 
process in facilities which have operations under both MSHA and OSHA 
jurisdiction, we recommend MSHA adopt an average shift of 10 dB or 
more at 2000, 3000, and 4000 Hz, relative to the baseline audiogram. 
* * *

    Of those commenters who did not endorse OSHA's STS criteria, one 
stated that OSHA's STS definition was ``* * * not stringent enough and 
the worker hearing loss has progressed too far with this shift to be a 
reliable preventive measure.'' Another stated--

    * * * the suggested criteria [OSHA's STS definition] provides no 
benefit but additional testing, specialist costs, reporting, 
administrative costs, and potential MSHA punitive fines. * * *
    The STS concept is misguided. A significant percentage * * * of 
people will have changes take place in their hearing which would 
qualify as an STS without any exposure to occupational noise.

    Royster (1992) proposes a definition of STS that is different from 
OSHA's. In her definition, 15 dB of hearing loss (relative to the 
baseline) must occur at any audiometric test frequency from 500 to 6000 
Hz on two sequential audiograms, before the STS is established. The 15 
dB of hearing loss which occurs on two sequential audiograms identifies 
the largest number of true positives (permanent threshold shifts) and 
the least number of false positives (temporary threshold shifts 
mistakenly identified as permanent threshold shifts).
    NIOSH (1995) recommends that the criteria for an STS be a 15 dB 
decrease in hearing acuity at any one of the audiometric test 
frequencies from 500 to 6000 Hz on two sequential audiograms. The shift 
in hearing acuity must be in the same ear. The second audiogram would 
be administered as soon as reasonable. NIOSH believes this criteria is 
sufficiently stringent to detect beginning hearing loss, yet won't 
include workers whose hearing acuity is simply showing normal 
variability. If the 15 dB change is found, an immediate retest should 
be conducted and followed by a confirmation test within 30 days. The 
confirmation test should be preceded by 14 hours of quiet.
    This draft criteria for STS differs from the criteria recommended 
by NIOSH in their 1972 criteria document. NIOSH's previous criteria 
defined STS as a change of 10 dB or more at 500, 1000, 2000 or 3000 Hz; 
or 15 dB or more at 4000 or 6000 Hz.
    There are some instances where large shifts in hearing level occur 
at higher test frequencies (4000 and 6000 Hz) with little or no change 
in hearing level at the middle frequencies. While large shifts are 
uncommon, they may occur in noise-sensitive individuals, especially in 
the early stages of NIHL. Correctly identifying significant threshold 
shifts is particularly important for workers who have already begun to 
lose their hearing. The proposed definition of STS would identify 
individuals suffering shifts as large as 30 dB at 4000 Hz with no 
shifts at the lower frequencies (30 plus 0 plus 0 divided by 3 equals 
10, an STS). This permits the early identification of individuals at 
risk, so that corrective measures could be taken.
    MSHA's proposed definition of STS is sufficiently restrictive to 
locate meaningful shifts in hearing, yet not so stringent as to create 
unnecessary follow-up procedures. The averaging of hearing levels at 
adjacent frequencies will reduce the effect of testing errors at single 
frequencies. The occurrence of an STS is serious enough to warrant 
prompt attention because it may be a precursor to material impairment 
of hearing. It is important to note that MSHA does not equate STS with 
material impairment caused by NIHL.
    MSHA believes, after considering the relevant factors and reviewing 
current U.S. military and international standards, that the proposed 
definition of STS is the most appropriate and consistent with the 
purposes of its hearing conservation standard. The proposed definition 
of STS--
    (1) is adequately supported in OSHA's record for its Hearing 
Conservation Amendment;
    (2) is the criteria recommended or accepted by most commenters to 
MSHA's ANPRM;
    (3) results in a high degree of accuracy in identifying workers for 
follow-up;
    (4) concentrates on those frequencies that are the earliest or the 
most severely affected by noise; and
    (5) is a recognized and relatively simple approach.
    Because NIOSH revised its recommendation for the criteria of an 
STS, MSHA requests comments on NIOSH's new criteria. Furthermore, any 
data on the advisability of using either the MSHA proposed criteria of 
STS or NIOSH's criteria of STS would be welcomed.
Reportable Hearing Loss
    The proposal would require the evaluator to determine if there has 
been a ``reportable hearing loss''. See the discussion of ``Reporting 
noise-induced hearing loss (NIHL)'' under Sec. 62.190 Notification of 
results.
Instruction to Medical Professional
    Section 62.160(a)(3) of the proposal would require the mine 
operator to instruct the physician or audiologist not to reveal to the 
mine operator any specific findings or diagnoses unrelated to the 
miner's exposure to noise or the wearing of hearing protectors without 
the written consent of the miner. Currently, neither MSHA nor OSHA have 
such a provision in their noise standards; OSHA does have such 
provisions in air quality standards like benzene and lead.
    The topic of instructions to medical professionals was not raised 
in the ANPRM. Therefore, no comments on this issue were received.
    MSHA believes that this requirement is necessary to safeguard the 
privacy of individuals. The mine operator does not need to be informed 
of medical conditions unrelated to occupational noise exposure. MSHA's 
rationale is that if the mine operator had confidential medical 
information, the mine operator could use it to justify an adverse 
action against the miner.
30-Day Requirement
    According to Sec. 62.160(a)(4) of MSHA's proposal, the mine 
operator would have 30 days to obtain the audiometric results and the 
interpretation of the results from the person evaluating the audiogram. 
OSHA does not specify a time period for evaluating audiograms.
    MSHA's ANPRM did not address the issue of time frame for evaluating 
audiograms. A few commenters, however, expressed concern with the 
length of time that some service providers take to report results to 
the employer. One stated that:

    Service providers have taken undue advantage of a perceived 
`grace period' in the OSHA Hearing Conservation Amendment to inform 
employees of a shift in hearing. * * * the lag time may total six to 
eight weeks. This is a disservice to the employee, and is certainly 
preventable.
    Notification of STS, including the optional retest of STS-
affected employees, should be completed within a 30-day period 
following testing. OSHA's time limit of 21 days following 
notification to the employer creates a loophole which makes the 
employee wait all too long for feedback regarding STS.


[[Page 66440]]


    The other commenter stated that:

    In reality, from the time the hearing test is sent to an 
audiologist or physician to review, it is reviewed, recommendations 
made, it is returned to the plant personnel and the plant has 21 
days to notify the employee, the total process often stretches into 
a 45-60 day time frame.

    MSHA believes that a 30-day limit to evaluate audiograms is 
reasonable and necessary to prevent undue delays in the evaluation of 
the audiogram and notification to the miner of the results. Under 
proposed Sec. 62.190, a miner would have to be notified within 10 
working days of audiogram results obtained by the mine operator, as 
discussed in connection with that section; accordingly, the net result 
of these provisions is a maximum delay of approximately 44 days from 
the date of audiometric testing to the notification of the miner. If a 
retest was conducted, which, as discussed below must be done within 30 
days of receiving a determination that the original test was invalid, 
this delay in notification could be as long as 104 days. If the miner's 
employment ceases during this delay period, the mine operator would be 
required to provide the miner with a copy of the audiometric test 
records as required by Sec. 62.200(c), including the results of all 
testing, as soon as the record is complete. MSHA welcomes comments on 
this issue.
Audiometric Retest
    Section 62.160(b)(1) of the proposal would require a mine operator 
to conduct a retest, if the audiogram was judged to be invalid, within 
30 calendar days of receiving this information--provided, however, that 
the 30-day time frame is stayed until any medical pathology resulting 
in the invalid audiogram has improved to the point that a valid 
audiogram may be obtained. In addition, Sec. 62.160(b)(2) of the 
proposal would allow a mine operator to obtain one retest within 30 
days after an STS or reportable hearing loss is found, and to 
substitute the retest audiogram for the annual audiogram. The latter 
retest is not mandatory.
    OSHA also permits a retest within 30 days to confirm an STS, but 
does not specifically require a retest if the audiogram is judged to be 
invalid.
    Many commenters supported OSHA's retest provision as written, while 
others supported it with qualifications. One commenter believed that a 
60-day period was appropriate. Another believed that a 30-day 
limitation to both retest and notify was appropriate because:

    Service providers have taken undue advantage of a perceived 
grace period in the OSHA Hearing Conservation Amendment to inform 
employees of a shift in hearing. By the time audiometric tests are 
administered, entered into a computer, returned to an employer, and 
then finally returned to the employee, the lag time may total six to 
eight weeks. This is a disservice to the employee, and is certainly 
preventable.

    Other commenters stated different views. One commenter stated that:

    * * * most programs involve the use of testing vans that cannot 
easily make a return trip in 30 days because of scheduling limits. 
It would also be extremely expensive to make a return trip to 
confirm a single STS. If an employee is found to have a significant 
hearing loss, he should be required to wear hearing protectors in 
all noise environments of 85 dBA or greater. If the next scheduled 
audiogram also shows the hearing loss, then the loss should be 
considered confirmed.

    Another commenter stated that:

    * * * an employee with a change in hearing could be immediately 
counseled, refitted [i.e., hearing protectors], educated, notified 
and return to his job. This would be more cost-effective than 
bringing him back prior to the shift to get a hearing test showing 
there is no STS.

    MSHA believes, after considering comments and reviewing U.S. armed 
forces and international standards, that the retest provisions are 
necessary to assure that valid audiograms are provided in a timely 
fashion. The retest should be conducted within a reasonable time, and 
30 days is believed to be adequate, with the caveat that this time 
frame does not begin to run until any medical pathology causing a 
validity problem has improved to the point that a valid audiogram can 
be obtained. MSHA recognizes that in such cases it will not be possible 
to wait for a mobile van; but MSHA believes that in the limited number 
of cases where a retest is required, it is appropriate and necessary to 
send the miner to the nearest available facility for such a test.
    The provision to obtain an optional retest if an STS is detected is 
desirable. This would permit the mine operator to substantiate that an 
STS had occurred, thus confirming permanent hearing loss. By detecting 
only permanent hearing loss, the mine operator would have better 
information on which to base administrative, technical, and financial 
decisions relative to retraining the miner, permitting the miner to 
select a different or additional hearing protector, and reviewing the 
effectiveness of the noise controls.
Use of Age Correction (Presbycusis Factors)
    Section 62.160(c) of the proposal would permit mine operators to 
adjust audiometric test results by applying a correction for 
presbycusis before determining whether an STS or reportable hearing 
loss has occurred. Presbycusis is the progressive loss of hearing 
acuity associated with the aging process. This adjustment for 
presbycusis is optional; however, if it is used, it must be applied 
uniformly to both the baseline and annual audiograms in accordance with 
the procedures and values listed in Sec. 62.160(c) (1) through (4).
    OSHA's noise standard also permits the use of presbycusis 
correction factors. MSHA's proposal would be essentially the same as 
OSHA's Appendix F: Calculations and Application of Age Corrections to 
Audiograms. Both MSHA's proposal and OSHA's Appendix F adopt the 
procedures and age correction tables used by NIOSH in its criteria 
document (1972).
    Commenters to OSHA's Hearing Conservation Amendment (48 FR 9763) 
suggested that the use of such presbycusis factors also would account 
for those cases of NIHL that arise from causes other than occupational 
noise exposure. In the preamble to its Hearing Conservation Amendment 
(48 FR 9763), OSHA states that:

* * * these correction factors will aid in distinguishing between 
occupationally induced and age-induced hearing loss. This is 
particularly important because the pattern of hearing loss due to 
aging closely resembles that of noise-induced hearing loss [NIHL]. * 
* * Therefore, although * * * the use of a correction factor may 
complicate calculation procedures and cause some errors, * * * 
professional supervision of the hearing conservation program will 
ensure that audiometric technicians understand how to use the age 
correction chart * * *

    Most commenters who addressed this issue in MSHA's ANPRM, contend 
that the use of presbycusis correction factors is appropriate. Many of 
these commenters supported MSHA's use of the same criteria as in OSHA's 
Appendix F. Other commenters recommended age corrections different than 
those used by OSHA. One commenter suggested that MSHA use the ISO 
1999.2 (1989) standard. Another one suggested that, because the NIOSH 
criteria is almost 20 years old, ``The criteria used should be the most 
recent and [accepted] data.''
    Several commenters believed that applying presbycusis factors would 
reduce unnecessary recordkeeping and follow-up procedures. One stated 
that:

    Many audiometric computer programs used for processing data have 
this correction calculation built in the software. To change to some 
other criteria or to remove this factor will result in the 
modification of numerous systems and a need to switch back and 
forth,

[[Page 66441]]

depending on whether the operator is OSHA or MSHA regulated.

Another of these suggested that MSHA require the use of such correction 
factors, rather than allow their use to be optional, because such 
optional use could result in discrepancies in results among audiometric 
testing services.
    A few commenters suggested that it would be better not to adjust 
audiometric test results for presbycusis. They maintained that the 
place to claim credit for presbycusis is in determining workers' 
compensation and not in the institution of an HCP. These commenters 
believed that not everyone who ages loses their hearing to the same 
degree, and that the use of presbycusis corrections might mask changes 
for older adults who have previously had good hearing.
    Finally, one commenter recommended that MSHA seek medical advice 
from national sources to determine what the medical community 
recognizes as changes occurring from aging.
    In contrast to NIOSH's presentation of one set of presbycusis data, 
the ISO Document ISO 1999:1990(E) (1990) gives a dual set of values for 
the non-industrial noise exposed population. These data are offered in 
two tables. One table represents a highly screened, otologically normal 
population, i.e., persons in a normal state of health, free from all 
signs and symptoms of ear disease and obstructing wax in the ear 
canals, and having no history of undue exposure to noise. The second 
table represents an unscreened population from an industrialized 
country. The ISO states that the choice of using the screened or 
unscreened data base depends on what question is to be answered. It 
states:

    For example, if the amount of compensation that could be due to 
a population of noise-exposed workers is to be estimated, and 
otological irregularities and non-occupational noise exposure are 
not considered in compensation cases, unscreened populations will 
form the more appropriate data bases.

The ISO further states, however, that its standard ``* * * is based on 
statistical data and therefore shall not be used to predict or assess 
the hearing impairment or hearing handicap of individual persons.'' The 
ISO data would be more difficult to use than NIOSH data because its 
interpretation would require a higher level of statistical and 
mathematical expertise.
    NIOSH (1995) now recommends that audiograms not be corrected for 
presbycusis. NIOSH believes that it is inappropriate to apply 
presbycusis correction factors from a population to an individual. 
Furthermore, there are no data to confirm that a 50 year old in 1995 
will incur the same hearing loss due to aging that a 50 year old did in 
1970. If the worker's audiogram is to be corrected for presbycusis, 
then the hearing loss of a non-occupational noise exposed group with 
the same demographic characteristics as the worker should be used. 
However, these kinds of data are not complete nor are they readily 
available.
    The following is an example of the use of presbycusis correction 
factors as proposed in MSHA's noise standard--
    (a) Determine from Tables 62-3 or 62-4 the age correction values 
for the miner by--
    (1) Finding the age at which the baseline audiogram (or 
supplementary baseline audiogram if appropriate) was taken and 
recording the corresponding values of age correction at 2000 Hz through 
4000 Hz; and
    (2) Finding the age at which the most recent audiogram was taken 
and recording the corresponding values of age correction at 2000 Hz 
through 4000 Hz.
    (b) Subtract the value found in step (1) from the value found in 
step (2). The differences calculated represent that portion of the 
change in hearing that may be due to aging.
    (c) Subtract the value found in step (b) from the hearing threshold 
level found in the annual audiogram to obtain the adjusted annual 
audiogram hearing threshold level.
    (d) Subtract the hearing threshold in the baseline audiogram (or 
supplemental baseline audiogram as appropriate) from the adjusted 
annual audiogram hearing threshold level to obtain the age-corrected 
threshold shift.
     Example: A miner is a 32-year-old male. The audiometric history in 
decibels is shown below for his right ear. A threshold shift of 10 dB 
at 2000 and 3000 Hz and 20 dB at 4000 Hz exists between the audiograms 
taken at ages 27 and 32. A retest audiogram has confirmed this shift.

------------------------------------------------------------------------
                                                     Audiometric test   
                                                      frequency (Hz)    
                   Miner's age                   -----------------------
                                                   2000    3000    4000 
------------------------------------------------------------------------
 26.............................................       5       5      10
*27.............................................       0       0       5
 28.............................................       0       0      10
 29.............................................       0       5      15
 30.............................................       5      10      20
 31.............................................      10      20      15
+32.............................................      10      10     25 
------------------------------------------------------------------------
An asterisk (*) has been used to identify the supplemental baseline     
  audiogram and a plus (+) the most recent audiogram. The annual        
  audiogram taken at age 27 becomes a supplemental baseline audiogram   
  (and is used in calculating hearing loss) because it shows a          
  significant improvement over the baseline audiogram taken at age 26.  

    Steps (a) and (b). Find the age correction values (in dB) at age 27 
and age 32 in Table 62-3. The difference, shown below, represents the 
amount of hearing loss that may be attributed to aging in the time 
period between the baseline audiogram and the most recent audiogram.

------------------------------------------------------------------------
                                                      Frequency (Hz)    
                                                 -----------------------
                                                   2000    3000    4000 
------------------------------------------------------------------------
Age 32..........................................       5       7      10
Age 27..........................................       4       6       7
Difference......................................       1       1       3
------------------------------------------------------------------------

    Step (c). Subtract the difference determined in step (b) from the 
hearing levels in the most recent audiogram. In this example, the 
adjusted hearing threshold levels are as follows:

------------------------------------------------------------------------
                                                      Frequency (Hz)    
                                                 -----------------------
                                                   2000    3000    4000 
------------------------------------------------------------------------
Age 32..........................................      10      10      25
Correction......................................       1       1       3
Adjusted........................................       9       9      22
------------------------------------------------------------------------

    Step (d). Subtract the hearing threshold level in the baseline 
audiogram from the adjusted annual audiogram hearing threshold to 
obtain the age-corrected threshold shift.

------------------------------------------------------------------------
                                                      Frequency (Hz)    
                                                 -----------------------
                                                   2000    3000    4000 
------------------------------------------------------------------------
Adjusted........................................       9       9      22
Baseline........................................       0       0       5
Shift...........................................       9       9      17
------------------------------------------------------------------------

    The average threshold shift at 2000, 3000, and 4000 Hz without age 
correction is (10+10+20)/3=13.3 dB. The average age-corrected threshold 
shift at 2000, 3000, and 4000 Hz is (9+9+17)/3=11.7 dB. This shift is 
an STS because it exceeds 10 dB, but it is not, as yet, a reportable 
hearing loss (25 dB). Intervention at this point should prevent further 
loss and subsequent impairment.
    MSHA agrees that not all individuals are affected by presbycusis to 
the same degree. Additionally, studies have

[[Page 66442]]

shown that individuals in environments free from noise exposure display 
little evidence of presbycusis. MSHA is concerned that the use of 
presbycusis corrections may allow some miners to incur excess work-
related hearing loss. For example, some miners may not have off-the-job 
noise exposure and may not have a decrement in their hearing due to 
aging at the levels specified in the presbycusis correction table. 
Nevertheless, MSHA maintains that at this time, allowing the adjustment 
of audiometric test results for presbycusis is both reasonable and 
appropriate. In industrial audiometry, this correction is often used to 
determine occupational NIHL by adjusting the measured hearing level to 
compensate for the normal loss of hearing due to aging. This is 
particularly important because the pattern of hearing loss due to aging 
resembles that of NIHL. The use of age corrections will help the mine 
operator judge how well the HCP is working. Such adjustments are 
consistent with current scientific practice, OSHA's standard, and the 
recommendations of the majority of the commenters to MSHA's ANPRM.
    MSHA selected the NIOSH presbycusis data so that all mine operators 
who correct audiograms for aging will be using the same data. Though 
there may be slight variations at individual frequencies, the NIOSH 
presbycusis values are similar to those of other well known presbycusis 
data bases, such as the U.S. Public Health Service data, those used by 
Robinson and Burns, and those of Passchier-Vermeer. The NIOSH data are 
for a highly screened population which excluded individuals with any 
significant noise exposure on-the-job, off-the-job, or during military 
service. Using a single set of presbycusis values will standardize the 
process of determining STS nationwide. If MSHA allowed mine operators 
to select their own presbycusis values, there could be major 
nonuniformity in determining STS's and reportable hearing losses. 
Nevertheless, the Agency is concerned about locking-in particular 
presbycusis adjustment tables, and requests additional comments on how 
to provide for a presbycusis adjustment in a regulatory context.
    In conclusion, MSHA believes that, at this time, scientific data 
and the consensus of commenters support allowing the use of the 
presbycusis correction factors presented in Tables 62-3 and 62-4. 
Although this is the position taken in the proposal, MSHA notes that 
the latest NIOSH advice on this topic has advised against the use of 
presbycusis correction factors. MSHA, therefore, requests additional 
comments on whether to use presbycusis corrections for audiograms.

Section 62.170  Follow-up Evaluation When Audiogram Invalid

    This section of the proposal provides that when a valid audiogram 
cannot be obtained due to a suspected medical pathology of the ear, and 
the physician or audiologist evaluating the audiogram believes that the 
problem was caused or aggravated by the miner's exposure to noise or 
the wearing of hearing protectors, a miner must be referred for a 
clinical audiological or otological evaluation as appropriate at mine 
operator expense.
    This section also provides that if the physician or audiologist 
concludes that the suspected medical pathology of the ear which 
prevents obtaining a valid audiogram is unrelated to the miner's 
exposure to noise or the wearing of hearing protectors, the miner be 
advised of the need for an otological evaluation; but in such cases, no 
financial obligation would be imposed on mine operators.
    Finally, this section would require the mine operator to instruct 
the physician or audiologist not to reveal to the mine operator any 
specific findings or diagnoses unrelated to the miner's exposure to 
noise or the wearing of hearing protectors without the written consent 
of the miner.
    OSHA's noise standard has similar follow-up requirements, except 
for the nondisclosure provision. MSHA's current noise standards have no 
follow-up evaluation provisions.
    In response to MSHA's ANPRM, many commenters supported OSHA's or 
similar requirements for referring employees to a physician for a 
medical follow-up. A few commenters, however, stated that ``MSHA need 
not include criteria for directing miners for further medical follow-up 
nor require a physician, audiologist, or other qualified medical 
personnel to evaluate the audiograms.''
    Another commenter stated the following regarding who should pay for 
these follow-up evaluations:

    * * * I have a standard recommendation when working with 
companies that they pay for all initial medical evaluations in order 
to determine disposition. I think it is as important to them to have 
documentation that an employee has a medical problem just as [when] 
he has an occupational one.

    The decision as to which type of evaluation, clinical audiological 
evaluation or otological, is appropriate will depend upon the 
circumstances. Standards from the international community and the U.S. 
Armed Forces vary to some degree regarding certain elements, such as 
the extent of follow-up examinations. A clinical audiological 
evaluation is generally more comprehensive, intensive, and accurate 
than the routine audiometric testing conducted for HCP purposes. For 
example, such testing may be warranted if an unusually large threshold 
shift occurs in one year given relatively low noise exposures. An 
otological evaluation, on the other hand, is a medical procedure 
conducted by a physician specialist (e.g., otolaryngologist) to 
identify a medical pathology of the ear. Audiometric testing can imply 
the existence of such a medical pathology. For example, a hearing loss 
in only one ear can indicate the existence of an acoustic neuroma (type 
of tumor) at an early stage. Such discovery could be potentially life 
saving. Another more common reason for an otological examination would 
be for the removal of impacted ear wax (cerumen) which reduces hearing 
acuity and can be aggravated by the use of insert-type hearing 
protectors.
    Making the determinations under this section would not require a 
diagnosis by a physician specialist confirming a medical pathology. The 
proposal is intended to allow the audiologist or physician authorized 
to review the audiograms to make a determination as to whether a 
follow-up examination is appropriate--and who pays for it. Accordingly, 
the word ``suspected'' precedes the words ``medical pathology'' in this 
section.
    If the person evaluating the audiogram believes that the suspected 
medical pathology is related to occupational noise exposure or to the 
wearing of hearing protectors, the proposal would require the mine 
operator to pay for the miner's follow-up medical evaluations. MSHA 
believes that the mine operator has the primary responsibility for 
work-related medical problems. On the other hand, if the person 
evaluating the audiogram determines that the suspected medical 
pathology is not related to the wearing of hearing protectors, then the 
proposal would require the mine operator to instruct the medical 
professional to inform the miner of the need for medical follow-up, but 
would not require the mine operator to pay for it or to be informed of 
the findings. In such cases, therefore, the follow-up otological 
examination would be at the miner's expense. Although MSHA agrees that 
taking action to keep miners healthy would be beneficial to the mine 
operator, the Agency contends that it would be inappropriate to require 
mine

[[Page 66443]]

operators to pay for non-work-related medical problems.
    MSHA also does not believe that it would be appropriate for mine 
operators to be informed of medical findings that are unrelated to the 
miner's occupational noise exposure or to the wearing of hearing 
protectors. If a mine operator would want this information, the 
proposal would permit the release of this information only upon the 
written consent of the miner. MSHA has included this provision out of 
concern for the privacy rights of the miner. A related provision is 
considered in somewhat more detail in the discussion of proposed 
Sec. 62.160.

Section 62.180  Follow-Up Corrective Measures When STS Detected

    MSHA's proposal would require that, unless a physician or 
audiologist determines that an STS is neither work-related nor 
aggravated by occupational noise exposure, mine operators would have 30 
calendar days after the finding of an STS to--
    (1) Retrain the miner in accordance with Sec. 62.130;
    (2) Provide the miner with the opportunity to select a hearing 
protector, or a different hearing protector if the miner has previously 
selected one, from the selection offered under Sec. 62.125; and
    (3) Review the effectiveness of any engineering and administrative 
controls to identify and correct any deficiencies. In addition, 
pursuant to proposed Sec. 62.120(b), an operator would be required to 
ensure that a miner who has incurred an STS wears provided hearing 
protection.
    A hearing loss of 10 dB from a miner's prior hearing level is of 
enough significance to warrant intervention by a mine operator, unless 
it is determined the loss is not work-related. If the controls in place 
are effective--including the training--this loss should not be 
occurring. It should be noted that the retraining required is to take 
place within 30 days after the finding of the STS, and thus it is 
unlikely mine operators can satisfy this requirement through their part 
48 training programs.
    MSHA's proposal does not include a provision for transferring a 
miner who incurs repeated STS's or a reportable hearing loss. A miner 
transfer program would be complex to administer, and would probably not 
be feasible in the metal and nonmetal sector. This sector consists 
largely of smaller mines which may be unable to rotate workers to other 
assignments on a long-term basis.
    Most commenters on this issue suggested that MSHA adopt OSHA's 
requirements. One of these commenters, however, disagreed with OSHA's 
allowance for discontinued use of hearing protectors when an STS was 
found to be temporary. The remaining two commenters recommended that 
the mine operator only be required to retrain the miner in the use and 
fit of the hearing protector.
    OSHA's noise standard requires that the work-relatedness of an STS 
be determined only by a physician. Employees, who have a work-related 
STS and are not using hearing protectors, must be fitted with hearing 
protectors, be trained in their use and care, and be required to use 
them. Employees who have an STS and are using hearing protectors must 
be refitted, be retrained, and be provided with hearing protectors 
offering greater attenuation when necessary. OSHA does not stipulate a 
time frame for conducting follow-up procedures.
    MSHA believes that audiologists have sufficient training and 
medical expertise to determine the work-relatedness of an STS, and that 
it would be needlessly restrictive to limit this determination to a 
physician as in OSHA's standard.
    MSHA, however, like OSHA would not permit technicians to make this 
determination. MSHA believes that while qualified to conduct and 
evaluate audiograms under the supervision of a physician or 
audiologist, technicians do not have the necessary training nor medical 
expertise to determine if an STS is work related. MSHA has determined 
that it is necessary to have a physician or audiologist determine the 
possible work relatedness of any STS. For example, the physician may 
determine that a miner's STS resulted from: a bad cold or sinus 
condition; taking certain medication, such as heavy doses of aspirin; 
or an acoustic neuroma (type of tumor). Careful diagnosis may, on the 
other hand, reveal that the STS is work related and caused by improper 
fit of the hearing protector.
    MSHA, after reviewing comments and related regulations, believes 
that the proposed corrective measures are adequate and necessary to 
prevent further deterioration of the miner's hearing acuity after an 
STS has been determined. MSHA believes that the 30 day requirement for 
retraining, selection of a hearing protector or different hearing 
protector, and evaluation of noise controls is reasonable.
Retraining
    If a miner has an STS, Sec. 62.180(a) of this proposal would 
require that the miner be retrained in accordance with Sec. 62.130, and 
a record kept of such training.
    The specific training elements contained in Sec. 62.130 are 
discussed in the provisions of this preamble describing those 
respective sections, including the required certification thereof. Such 
retraining could be conducted in conjunction with the annual refresher 
training, under 30 CFR part 48, but only if the latter is so approved 
and scheduled to be completed within 30 days of the finding of an STS. 
If the annual refresher training is not conducted within 30 days, the 
retraining for miners with an STS would have to be conducted 
separately. It would not be permissible to wait until the next annual 
refresher training.
Provide Opportunity To Select a Hearing Protector or Different Hearing 
Protector
    In the mining industry, miners are typically exposed to high sound 
levels and some of the miners may be more susceptible to hearing loss 
from the noise exposures than others. Consequently, if a miner is 
diagnosed with an STS, then he or she must be given the opportunity to 
select a hearing protector or different hearing protector.
    Section 62.180(b) of this proposal directs the mine operator to 
afford the miner the opportunity to select adequate hearing protection 
from those offered by the mine operator under Sec. 62.125. While that 
section of the proposal only requires the mine operator to offer one 
type of ear plug and one type of ear muff, MSHA presumes that most mine 
operators will offer a range of each. Pursuant to Sec. 62.120(b), the 
operator is required to ensure that a miner with an STS wears the 
hearing protector.
    The choice of hearing protectors from this selection will be based 
on the miner's personal preference. The benefits of allowing the miner 
to select his/her hearing protector are discussed under Sec. 62.125 
Selection of hearing protector. MSHA believes that even though a miner 
may select a protector with a noise reduction rating lower than that 
which might be selected by a mine operator in such cases, factors such 
as comfort are more critical in ensuring that the miner will fully 
utilize this critical piece of personal protective equipment. Moreover, 
as discussed in the section on Hearing protector effectiveness, MSHA 
has concluded that there is no standardized objective method to 
determine whether an additional or different hearing protector would 
provide the miner with greater protection. MSHA requests further 
comment on this issue.

[[Page 66444]]

Review Effectiveness of Controls
    Upon the finding of an STS, MSHA would require, under 
Sec. 62.180(c) of the proposal, the mine operator to review the 
effectiveness of any engineering and administrative controls. The mine 
operator would need to correct any deficiencies. The implementation and 
maintenance of either engineering or administrative controls or a 
combination of such controls above the PEL is the primary method for 
reducing a miner's noise exposure and, thus, reducing the risk of 
hearing loss. OSHA's current noise regulation does not require a review 
of the effectiveness of engineering and administrative controls when an 
STS is found.
    The inadequacy of engineering or administrative controls or a 
combination of such controls may well be the contributing factor in the 
development of a miner's STS. Thus, the proposal would require the mine 
operator to review the effectiveness of controls and update or modify 
them, as necessary and feasible, to reduce the miner's noise exposure.
Miner Transfer
    The Federal Mine Safety and Health Act of 1977 (30 U.S.C. 811) 
requires health standards to include, as appropriate, provisions for 
removing a miner from hazardous exposure where that miner may suffer 
material impairment of health or functional capacity. MSHA has decided 
not to include such a provision in its proposal.
    MSHA's current noise standards do not contain such a transfer 
provision. Nor does the OSHA noise standard have such a requirement.
    In its ANPRM, MSHA requested comments regarding the need for a 
transfer provision in the proposed rule for a miner with a diagnosed 
occupational hearing loss. In response, many commenters stated that a 
miner transfer provision is not appropriate. Some of the concerns 
expressed by the commenters included: the negotiation of disability 
accommodation sections in labor contracts; problems with rate retention 
and seniority provisions in existing contracts; the contribution of 
non-occupational noise exposure to the hearing loss; uncertainty as to 
the etiology of the hearing loss; and the impracticality in small 
operations. However, several commenters disagreed, indicating that the 
transfer of a miner is appropriate when other efforts to halt the 
progression of the hearing loss have failed. They added that the safety 
of a miner with a hearing loss would be jeopardized, due to the 
inability to hear warning signals and/or understand verbal instructions 
in the noisy environment (a hazard to other miners as well).
    Several of the U.S. Armed Forces, and some other countries, allow 
for removal or transfer of employees from noisy areas.
    Although MSHA would encourage mine operators to transfer miners who 
have incurred a hearing impairment, MSHA believes that a miner transfer 
provision would not be feasible, at the vast majority of small mining 
operations, because of limited personnel and non-noise exposed 
occupations. At larger mines transfer may be feasible; however, MSHA 
believes that the obligation to utilize all feasible administrative (as 
well as engineering controls) would reduce miner exposure time to 
harmful noise in much the same way as a transfer provision but without 
unwarranted complexity.

Section 62.190  Notification of Results; Reporting Requirements

    This section of the proposal would require that miners be notified 
of audiometric test findings, and that the Agency be notified of any 
instances of ``reportable hearing loss.''
    The proposal would require the mine operator, within 10 working 
days of receiving the results of an audiogram, or the results of a 
follow-up evaluation pursuant to Sec. 62.170(a)--those follow-ups on 
which the mine operator would receive results--to notify the miner in 
writing of the results and interpretations, including any finding that 
an STS or reportable hearing loss has occured. The notification would 
include an explanation of the need and reasons for any further testing 
or evaluation that may be required.
    MSHA believes that informing miners of the results of their 
audiometric tests in a timely manner is critical to the success of an 
HCP. Immediate feedback upon completion of the testing provides the 
greatest benefit.
    The proposal would require mine operators to inform MSHA of any 
reportable hearing loss, unless the physician or audiologist has 
determined the loss is neither work-related nor aggravated by 
occupational noise exposure. This essentially restates for noise the 
requirements of 30 CFR part 50, but with an explicit definition of 
reportable hearing loss for the first time. Having a uniform definition 
will ease reporting burdens on mine operators while promoting the 
development of an improved data base on hearing loss in the mining 
community.
    The proposal would define a reportable hearing loss as a change in 
hearing acuity for the worse relative to the miner's baseline audiogram 
of an average of 25 dB or more at 2000, 3000, and 4000 Hz in either 
ear. Should an annual audiogram actually indicate an improvement in 
hearing at any time, this audiogram would, pursuant to Sec. 62.140, 
become the baseline for purposes of determining whether a reportable 
hearing loss has occurred. As noted herein, MSHA is seeking comment on 
whether part 50 should collect information on harm on less dramatic 
shifts in hearing acuity, and how reporting should be accomplished in 
cases in which an operator lacks audiometric data.
Notification of the Miner
    Section 62.190(a) of MSHA's proposal would require that within 10 
working days of receiving the results of an audiogram or follow-up 
evaluation, the mine operator shall notify the miner in writing of--
    (1) the results and interpretation of an audiometric test, 
including any finding of an STS or a reportable hearing loss; and
    (2) if applicable, the need and reasons for any further testing or 
evaluation.
    MSHA has no current requirements in this area. The proposed time 
frame is consistent with the time frame for notification to the Agency, 
under part 50, of cases of reportable hearing loss. MSHA's proposal 
would differ from OSHA's standard in this regard and in several other 
respects: the miner would be informed of the need and reason for 
further medical evaluations, and the miner would be informed of the 
finding of a reportable hearing loss. Moreover, OSHA's requirement does 
not specify how long, following the annual audiogram, an employer can 
take to make this determination.
    All commenters on this issue favored notifying the employee of the 
results of audiometric testing and follow-up examinations. They 
differed, however, as to the time to be allotted for such notification 
and the requirements of such notification.
    Many commenters endorsed OSHA's requirements. One commenter agreed 
that written notification be provided within 21 days, the same as OSHA, 
but recommended that such notice be provided for all audiometric test 
results. This commenter stated:

    It is our policy to notify all employees of the results of their 
audiometric tests in writing. An appropriate time frame would be 21 
days from the time the employee's facility is made aware of the 
results. If the time frame for notification is 21 days from the time 
of the actual test, many problems may arise. If a mobile testing 
service is utilized, the results may not be sent in for analysis for 
at least

[[Page 66445]]

a week. Our audiological staff reviews all of our audiograms in-
house rather than relying on outside services for analysis. Some of 
our testing services microfilm the tests or analyze them separately 
which means that a delay of a few weeks may occur. The purpose 
should be that the employee receive results in a timely enough 
fashion so that they are meaningful.

    One commenter recommended that written notification be provided to 
the miner within 30 days of determining a confirmed STS. Another 
commenter recommended that miners be notified of an STS, including any 
optional retest, within 30 days of the testing. This commenter stated 
that:

    Service providers have taken undue advantage of a perceived 
grace period in the OSHA Hearing Conservation Amendment to inform 
employees of a shift in hearing. By the time audiometric tests are 
administered, entered into a computer, returned to an employer, and 
then finally returned to the employee, the lag time may total six to 
eight weeks. This is a disservice to the employee, and is certainly 
preventable.
    Notification of STS, including the optional retest of STS-
affected employees, should be completed within a 30-day period 
following testing. OSHA's time limit of 21 days following 
notification to the employer creates a loophole which makes the 
employee wait all too long for feedback regarding STS.

Other commenters recommended notifying miners of the results of their 
audiometric tests, but did not specify a time frame.
    The U.S. Armed Forces regulations, and standards of some members of 
the international community, vary on the time frame for notification.
    The time frame in MSHA's proposal is shorter than the time frame 
for notification in OSHA's standard, but is consistent with MSHA's 
requirement that the Agency be notified of reportable hearing losses 
within 10 working days. MSHA's proposal would also differ from OSHA's 
standard in that the miner would be informed of the need and reason for 
further medical evaluations; and the miner would be informed of the 
finding of a reportable hearing loss. In addition, pursuant to 
Sec. 62.170(b), MSHA's proposal would require the mine operator to 
instruct the physician to notify the miner of the need for an 
otological examination based upon a medical pathology of the ear that 
is unrelated to the affected miner's noise exposure or the wearing of 
hearing protectors. MSHA believes that miners have a right to know the 
results of any medical tests conducted on them.
    MSHA believes that it is appropriate to require written 
notification. Under proposed Sec. 62.200, the miner would in any event 
have access to all required records under this part upon written 
request. Providing the notices in writing would ensure there are no 
misunderstandings on the part of miners as to the severity of the 
problem.
    MSHA believes that informing miners of the results of their 
audiometric tests in a timely manner is critical to the success of an 
HCP. Immediate feedback upon completion of the testing provides the 
greatest benefit. Generally, the employee shows the most interest and 
concern regarding the effects of noise on his/her hearing immediately 
following testing. Providing the results several weeks or months later 
may have less of an impact. In many cases, however, it may not be 
feasible or practical to inform miners immediately of the results of 
their audiometric tests. The proposal, consequently, would allow mine 
operators up to 10 working days to inform the miner (the same time 
period as provided under part 50 for notification of MSHA of cases of 
reportable hearing loss). Because the proposal would allow up to 30 
calendar days to evaluate audiograms, it could be as long as 44 days 
following testing before the miner is informed of the results. In the 
case of an audiometric retest, it could be as long as 104 days before 
the miner is informed of the results of the retest. MSHA believes that 
it is necessary to specify a maximum time frame for informing miners of 
the audiometric test results in order to prevent undue delays.
Reporting Noise-Induced Hearing Loss (NIHL)
    Section 62.190(b) of this proposal would require the mine operator 
to report hearing loss under 30 CFR part 50, if the results of an 
audiogram or follow-up evaluation indicate that a miner has incurred a 
``reportable hearing loss.'' This section is designed to refine, in 
light of this proposal, MSHA's existing reporting requirements for 
injuries and illnesses in 30 CFR part 50, so as to ease reporting 
burdens on employers while promoting the development of an improved 
data base on hearing loss in the mining community.
    The current reporting requirements provide that mine operators 
report a hearing loss whenever a physician determines that it is work 
related, or whenever an award of compensation is made. NIHL is 
specifically listed among the examples of occupational illnesses to be 
reported when it is work related. The proposal would establish the 
reporting definition for this purpose: but the report would only be 
required under part 50 if the hearing loss is suspected to be work 
related.
    OSHA does not have reporting requirements: i.e., a level which 
triggers notification to the agency so that it can intervene. It does, 
however, have recording requirements for noise, so that information is 
gathered about NIHL and is available to employers, employees, and 
agency personnel. In June 1991, OSHA issued its current policy (1991) 
for reporting NIHL (on the OSHA Form 200). This policy requires 
employers to record a work-related shift in hearing of 25 dB or more in 
either ear from the original baseline audiogram averaged over 2000, 
3000, and 4000 Hz. The recording criteria use identical evaluation 
frequencies as required for determining an STS. The policy allows a 
correction for presbycusis when determining reportability. In January 
1996, OSHA published a proposal to revise agency recordkeeping 
standards. Under the proposal's mandatory Appendix B, the recording 
requirement would drop to a work-related shift in hearing of 15 dB or 
more in either ear. OSHA notes it is proposing this change to ensure 
the recording of any STS (a 10 dB shift under OSHA's standard), with 
some allowance made for instrumentation variance.
    In its ANPRM, MSHA discussed the problems that the Agency is 
experiencing with its existing reporting requirements. Of the 
commenters addressing this issue, many recommended that MSHA require 
reporting of a 10-dB average loss in either ear at 2000, 3000, and 4000 
Hz (the OSHA STS criteria). One commenter favored reporting any job-
related loss and another stated that the criteria of reporting an STS 
was too high because ``* * * the worker['s] hearing loss has progressed 
too far with this shift to be a reliable preventative measure.'' Other 
commenters stated that the STS criteria represent a slight change in 
hearing and is not meaningful for reporting purposes. Two commenters 
recommended that the criteria for reporting be that used for defining 
impairment (the AAO-HNS 1979 criteria).
    Some hearing conservation associations have opposed OSHA's current 
policy, arguing that employers should record the NIHL when the employee 
incurs an STS. Driscoll and Morrill (1987) presented the position of 
the American Industrial Hygiene Association (AIHA) in a paper entitled 
``A Position Paper on a Recommended Criterion for Recording 
Occupational Hearing Loss on OSHA Form 200''. AIHA concluded that ``a 
confirmed STS which results from workplace noise exposure is considered 
an appropriate

[[Page 66446]]

measure for surveillance or recordkeeping purposes.''
    The National Hearing Conservation Association (NHCA) in a letter 
from their President, Susan Cooper Megerson (1994), to Joseph Dear, 
Assistant Secretary of Labor for Occupational Safety and Health, urged 
OSHA to require the recording of an occupational hearing loss when an 
STS was confirmed. NHCA contends that recording hearing loss after it 
reaches an average of 25 dB or more at 2000, 3000, and 4000 Hz is 
``dangerously underprotective and not technically well founded.''
    Suter (1994) in a letter to Sue Andrei of OSHA's Policy Directorate 
urged OSHA to adopt a policy of recording persistent occupational 
hearing loss at an STS instead of at an average of 25 dB or more at 
2000, 3000, and 4000 Hz.
    MSHA's proposal would define a ``reportable hearing loss'' as a 
change in hearing threshold relative to the miner's original baseline 
audiogram of an average of 25 dB or more in either ear at 2000, 3000, 
and 4000 Hz. If a physician determines that the hearing loss is neither 
work-related nor aggravated by occupational noise exposure, then it 
would not be considered a reportable illness under part 50. As 
discussed in connection with proposed Sec. 62.140, if an audiological 
exam showed a significant improvement in hearing acuity, the original 
baseline would be supplemented to reflect this: a correction which 
would then affect the reportability of hearing loss. Furthermore, as 
noted in the discussion of proposed Sec. 62.160, the proposal would 
allow the correction of audiograms for presbycusis when determining the 
reportability of shifts in hearing threshold levels.
    In selecting its reporting criteria, MSHA took into account that a 
loss of this magnitude is one that diminishes quality of life and the 
ability to understand speech in noisy environments. MSHA's reporting 
criteria, although not impairment per se, represent a substantial loss 
which would provide a reliable indication of the effectiveness of 
MSHA's rule and enforcement programs. Moreover, the calculation would 
be the same as that used to determine an STS and, thus, not an extra 
burden. The use of other criteria, such as the AAO-HNS 1979 criteria 
for impairment, would require an additional set of calculations at 
different frequencies.
    MSHA is concerned, however, that reporting only losses of 25 dB may 
not provide MSHA a full picture of hearing loss in the mining industry. 
A loss of 25 dB is used by many states as a basis for making disability 
awards. Some have recommended that any STS (10 dB loss) should be 
captured in a hearing loss data base. OSHA, which currently requires 
any 25 dB loss to be captured in an employer's log, has proposed to 
capture any 15 dB loss. MSHA accordingly solicits comment on this 
point.
    An important goal of the proposal is to clarify the level of 
hearing loss which is reportable. MSHA believes that its current 
reporting requirements are vague; consequently, cases of NIHL are 
inconsistently reported or not reported. Some mine operators have 
reported even a small loss, while others only reported when a miner 
received an award of compensation. In other cases, mine operators have 
not reported when an award of compensation was granted because the 
miners had retired. Inconsistent reporting also results because worker 
compensation regulations vary from state to state, i.e., the same 
hearing loss would be compensable and thus reportable in some states 
and not in others. For these reasons, current hearing loss data 
reported to MSHA under part 50 cannot be used to accurately 
characterize either the prevalence or the degree of hearing loss in the 
mining industry.
    Reporting at a specified level, as required by the proposal, would 
eliminate reliance on workers' compensation awards as a criteria for 
defining NIHL to be reported. Nevertheless, part 50 would still require 
that awards of compensation be reported in those cases when the loss 
had not been previously reported. Two general examples of such cases 
are (1) if the miner had incurred the loss before the current mine 
operator conducted the baseline or pre-employment audiogram and 
subsequent testing did not measure a reportable loss, and (2) if the 
miner had not been in an HCP or had not received an audiometric test 
while employed by the operator.
    In this regard, MSHA would like comment on how to define 
``reportable'' hearing loss for those operators who do not have 
audiometric test data. Not all mine operators will be required to 
obtain audiometric test data under the proposed rule; thus, such 
operators may not be able to use a definition of reportable hearing 
loss defined in this manner. MSHA also requests specific suggestions on 
how to capture data on work-related NIHL: (1) that is not discovered 
until after the miner's employment is terminated; and (2) that the 
miner had accumulated from work with several employers.
    MSHA does not expect mine operators to report the same reportable 
hearing loss each year that a miner works at the mine. The next 
reportable hearing loss would not be reported until the miner incurs 
another 25 dB shift (50 dB shift from the original baseline). MSHA does 
intend for each ear to be treated independently in terms of a 
reportable event, unless the reportable loss occurs in both ears during 
a particular year. (For example, 28.7 dB, left ear, 25.9 dB, right ear, 
not corrected for presbycusis.) Although not specifically required in 
its proposal, MSHA anticipates that mine operators would indicate when 
reporting to MSHA--
    (1) the actual average hearing loss;
    (2) in which ear(s) the loss occurred; and
    (3) whether the audiograms were corrected for presbycusis. (For 
example, 28.7 dB, left ear, corrected for presbycusis.)

Section 62.200  Access to Records

    Authorized representatives of the Secretaries of Labor and Health 
and Human Services would have immediate access to all records required 
under this part.
    Moreover under the proposal, a miner or former miner, or his/her 
designated representative with written consent, would have access to 
all the records that the mine operator is required to maintain under 
this part for that individual miner or former miner. Also, the miners' 
representative is in all cases to have access, for miners they 
represent, to noise training records and notices required under 
Sec. 62.120(f) to be given to miners exposed to noise above various 
levels.
    The mine operator would have 15 days from receipt of a written 
request to provide such access. The proposal would define ``access'' as 
the right to examine and copy records. The first copy of any record 
requested by a person is to be provided without cost to that person, 
and any additional copies requested by that person are to be provided 
at reasonable cost.
    Upon termination of employment, mine operators would be required to 
provide a miner without cost an actual copy of all his/her own records 
(those required under this part).
    MSHA has no uniform records access provision that address these 
issues--though the Agency and NIOSH do have statutory rights to access. 
The provisions proposed here are similar to those in other health 
standards proposed in recent years by the Agency.
    Section 103(c) of the Mine Act states that:


[[Page 66447]]


    The Secretary, in cooperation with the Secretary of Health, 
Education, and Welfare, [now Health and Human Services] shall issue 
regulations requiring operators to maintain accurate records of 
employee exposures to potentially toxic materials or harmful 
physical agents which are required to be monitored or measured under 
any applicable mandatory health or safety standard promulgated under 
this Act. Such regulations shall provide miners or their 
representatives with an opportunity to observe such monitoring or 
measuring, and to have access to the records thereof. Such 
regulations shall also make appropriate provisions for each miner or 
former miner to have access to such records as will indicate his own 
exposure to toxic materials or harmful physical agents.

    OSHA's requirements for access to records incorporate its standards 
for ``Access to Employee Exposure and Medical Records'' [29 CFR 
Sec. 1910.20(a)-(e) and (g)-(i)]. OSHA's requirements and MSHA's 
proposal are essentially the same.
    All of the commenters addressing this issue favored providing 
affected miners with reasonable access to required records. Most of 
these commenters also recommended that the request for access to 
records be in writing.
    The Agency agrees, after reviewing comments and related 
regulations, that access to noise records by both employees and the 
government is essential, and does not believe the costs of providing 
such access will be significant. As noted by OSHA, in its preamble to 
its proposed Hearing Conservation Amendment (46 FR 4161)--

    Such access will serve to educate employees as to the state of 
their hearing and the effectiveness of the program, and will 
encourage their conscientious participation in it. The information 
in the records will be invaluable to the Assistant Secretary in the 
enforcement of the amendment and will be useful in research into the 
effects of occupational noise exposure. The Director of NIOSH will 
also be primarily interested in the records for research purposes.

    MSHA also agrees that requests from miners, miner's designated 
representatives, and miner's representatives be in writing. This 
requirement would benefit both the miners and mine operators by 
protecting them in matters of dispute regarding the date on which the 
request was submitted. MSHA's access to records requirements would not 
preclude the mine operators from requiring the requester to sign a 
receipt after receiving the records. In addition, the definition of 
miner's ``designated representative'' specifies that such person have 
written authorization to request records for each miner or former miner 
represented. Because requested records may contain personal, private 
information, MSHA intends that the miner's designated representative 
would present such authorization to the mine operator when requesting 
records on behalf of a miner or former miner.
    According to the proposal the mine operator would have 15 days to 
provide the miner, former miner, or miner's designated representative 
access to the requested records. MSHA believes that it is reasonable to 
require the mine operator to provide access because the proposal would 
require the records to be maintained at the mine site.
    The mine operator has some choice as to how to provide records 
requested by an employee or representative. The mine operator could 
provide a copy, make available mechanical copying facilities, or loan 
the record to the requester for a reasonable time to enable a copy to 
be made. The proposal provides that if a copy is requested, however, it 
shall be provided, and the first copy shall be at no cost. If a copy of 
the record had been provided previously without cost, the proposal 
would allow the mine operator to charge reasonable, non-discriminatory 
administrative costs for providing an additional copy of the record. 
The mine operator, however, could not charge for the first copy of new 
information which subsequently had been added to the record.
    MSHA believes that its proposed requirements for access to records 
are both reasonable and necessary to meet its mandate under the Mine 
Act. MSHA would welcome comments on what actions are required, if any, 
to facilitate the maintenance of records in electronic form by those 
mine operators who desire to do so, while ensuring access in accordance 
with these proposed requirements.

Section 62.210  Transfer of Records

    The proposed standard would require mine operators to transfer all 
records (or a copy thereof) required by this part to any successor mine 
operator. The successor mine operator would be required to receive 
these records and maintain them for the period required. Additionally, 
the successor mine operator would be required to use the baseline 
audiogram obtained from the original mine operator (or supplemental 
baseline audiogram as appropriate) for determining an STS and 
reportable hearing loss.
    MSHA's existing noise standards do not address the transfer of 
records, nor does MSHA have general standards on this point. The 
provisions proposed here are similar to those in other health standards 
proposed in recent years by the Agency. OSHA's standard requires 
transfer of records and, in addition, incorporates by reference 
transfer provisions found in its ``Access to Employee Exposure and 
Medical Records'' standards (29 CFR 1910.20 (h)). MSHA's proposal 
regarding the transfer of records is essentially the same as in OSHA's 
regulations.
    MSHA's ANPRM did not address the transfer of records and no 
comments were received on this subject. MSHA considered OSHA's 
requirements and believes that they are both reasonable and necessary 
to ensure that records are maintained for the required periods of time 
when a mine operator ceases to do business.
    Requiring successor mine operators to use the prior baseline 
audiogram will provide the miners with a greater degree of protection 
by assuring that an STS or reportable hearing loss is based on the 
original or supplemental baseline taken under the original mine 
operator, instead of based on a new baseline. Generally if a new 
baseline would be established by a successor mine operator, the miner 
would need to lose additional hearing acuity before the corrective 
action triggered by the occurrence of an STS is implemented or a 
hearing loss is required to be reported.

IV. Feasibility

    MSHA has tentatively concluded that it is feasible for the mining 
industry to take the actions specified in the proposed rule. MSHA has 
also tentatively concluded that at this time, it may not be feasible 
for the mining industry to comply with two changes that would otherwise 
be warranted to further reduce the risk of impairment from occupational 
NIHL--reducing the PEL to a TWA8 of 85 dBA, and reducing the 
exchange rate from 5-dB to 3-dB.
    As background, this part begins with a review of the pertinent 
legal requirements for setting health standards under the Mine Act and 
an economic profile of the mining industry.

Pertinent Legal Requirements

    Section 101(a)(6)(A) of the Mine Act requires the Secretary to set 
standards which most adequately assure, on the basis of the best 
available evidence, that no miner will suffer material impairment of 
health over his/ her working lifetime. In addition, the Mine Act 
requires that the Secretary, when promulgating mandatory standards 
pertaining to toxic materials or harmful physical agents, consider 
other factors, such as the latest scientific data in the field, the 
feasibility of the standard and experience gained under the Act and 
other health and safety laws. Thus, the

[[Page 66448]]

Mine Act requires that the Secretary, in promulgating a standard, 
attain the highest degree of health and safety protection for the 
miner, based on the ``best available evidence,'' with feasibility a 
consideration.
    Feasibility in this context refers to both economic and 
technological feasibility. It also refers to what is feasible for an 
entire industry, not an individual mine operator; although for this 
purpose, MSHA has considered independently the situations of the coal 
mining sector and the metal and nonmetal mining sector.
    In relation to feasibility, the legislative history of the Mine Act 
states that:

    * * * This section further provides that ``other 
considerations'' in the setting of health standards are ``the latest 
available scientific data in the field, the feasibility of the 
standards, and experience gained under this and other health and 
safety laws.'' While feasibility of the standard may be taken into 
consideration with respect to engineering controls, this factor 
should have a substantially less significant role. Thus, the 
Secretary may appropriately consider the state of the engineering 
art in industry at the time the standard is promulgated. However, as 
the circuit court of appeals have recognized, occupational safety 
and health statutes should be viewed as ``technology-forcing'' 
legislation, and a proposed health standard should not be rejected 
as infeasible when the necessary technology looms in today's 
horizon. (AFL-CIO v. Brennan, 530 F.2d 109); (CA 3 1975) Society of 
Plastics Industry v. OSHA, 509 F.2d 1301 (CA 2), cert. denied, 427 
U.S. 992 (1975).
    Similarly, information on the economic impact of a health 
standard which is provided to the Secretary of Labor at a hearing or 
during the public comment period, may be given weight by the 
Secretary. In adopting the language of [this section], the Committee 
wishes to emphasize that it rejects the view that cost benefit 
ratios alone may be the basis for depriving miners of the health 
protection which the law was intended to insure. S. Rep. No. 95-181, 
95th Cong., 1st Sess. 21 (1977).

    Thus, standards may be economically feasible even though industry 
considers them economically burdensome.
    Though the Mine Act and its legislative history are not specific in 
defining feasibility, the courts have clarified the meaning of 
feasibility. The Supreme Court, in American Textile Manufacturers' 
Institute v. Donovan (OSHA Cotton Dust), 452 U.S. 490, 508-509 (1981), 
defined the word ``feasible'' as ``capable of being done, executed, or 
effected.'' The Court stated that a standard would not be considered 
economically feasible if an entire industry's competitive structure was 
threatened. According to the Court, the appropriate inquiry into a 
standard's economic feasibility is whether the standard is capable of 
being achieved.
    Courts do not expect hard and precise predictions from agencies 
regarding feasibility. Under the ``arbitrary and capricious standard,'' 
used in judicial review of agency rulemaking under the Administrative 
Procedures Act, an agency need only base its predictions on reasonable 
inferences drawn from the existing facts. An agency is required to 
produce a reasonable assessment of the likely range of costs that a new 
standard will have on an industry. The agency must show that a 
reasonable probability exists that the typical firm in an industry will 
be able to develop and install controls that will meet the standard. 
United Steelworkers of America v. Marshall, 647 F.2d 1189 (D.C. Cir. 
1980).
    In developing a new health standard, an agency must also show that 
modern technology has at least conceived some industrial strategies or 
devices that are likely to be capable of meeting the standard, and 
which industry is generally capable of adopting. United Steelworkers of 
America v. Marshall, supra at 1272. If only the most technologically 
advanced companies in an industry are capable of meeting the standard, 
then that would be sufficient demonstration of feasibility (this would 
be true even if only some of the operations met the standard for some 
of the time). American Iron and Steel Institute v. OSHA, 577 F. 2d 825 
(3d Cir. 1978) at 832-835, see also Industrial Union Dep't., AFL-CIO v. 
Hodgson, 499 F. 2d 467 (D.C. Cir. 1974).
    In evaluating the feasibility of particular requirements under 
these legal tests, MSHA took into account how it anticipates 
interpreting those requirements. For example, in the case of the 
requirement that mine operators use all feasible engineering and 
administrative controls, the Agency considered legal guidance from the 
Federal Mine Safety and Health Review Commission as to what MSHA must 
consider, for enforcement purposes, as a feasible noise control at a 
particular mine. This guidance is discussed in the ``Questions and 
Answers'' in part I (see Question 12). MSHA also used its expert 
knowledge of particular equipment or methods of noise control available 
in the industry, and considered exposure data indicating the extent to 
which the industry would be out of compliance should a particular 
proposal be adopted.

Industry Profile

    Determining the feasibility of controls for the mining sector 
requires consideration of the composition and economics of that sector. 
The following information is reprinted from MSHA's preliminary 
Regulatory Impact Analysis (RIA), and was considered by the Agency in 
reaching preliminary conclusions.

Overall Structure of the Mining Industry

    MSHA divides the mining industry into two major segments based on 
commodity, the coal mining industry and the metal and nonmetal mining 
industry. These major industry segments are further divided based on 
type of operation (underground mines, surface mines, and independent 
mills, plants, shops, and yards). MSHA maintains its own data on mine 
type, size, and employment. MSHA also collects data on the number of 
contractors and contractor employees by major industry segment.
    MSHA categorizes mines as to size based on employment. For the 
purpose of analyzing this proposed rule, MSHA defines small mines to be 
those having fewer than 20 employees and large mines to be those having 
at least 20 employees. Table IV-1 presents the number of small and 
large mines and the corresponding number of miners, excluding 
contractors, by major industry segment and mine type. Although MSHA 
does not maintain a data base of the numbers of miners by job title, 
Table IV-2 presents an estimate of the numbers of miners by job title 
groups based in part on research conducted by the U.S. Department of 
the Interior, Bureau of Mines. The Agency does not maintain a data base 
which would allow determination of the types of services provided by 
independent contractors or the job titles of contractor employees. 
Table IV-3, however, presents MSHA data on the numbers of independent 
contractors and the corresponding numbers of employees by major 
industry segment and the size of the operation based on employment.

[[Page 66449]]



Table IV-1.--Distribution of Operations and Employment (Excluding Contractors) by Mine Type, Commodity, and Size
----------------------------------------------------------------------------------------------------------------
                                         Small (<20 EES)           Large (>20 EES)                Total         
                                   -----------------------------------------------------------------------------
             Mine type               Number of    Number of    Number of    Number of    Number of    Number of 
                                       mines        miners       Mines        Miners       Mines        Miners  
----------------------------------------------------------------------------------------------------------------
Coal:                                                                                                           
    Underground...................          466        4,630          606       49,370        1,072       54,000
    Surface.......................          875        5,337          396       30,173        1,271       35,510
    Shp/Yrd/Mll/Plnt..............          421        2,701          132        5,169          553        7,870
    Office workers................  ...........          752  ...........        5,030  ...........        5,782
                                   -----------------------------------------------------------------------------
    Coal Subtotal.................        1,762       13,420        1,134       89,742        2,896      103,162
                                   =============================================================================
Metal/nonmetal (M/NM):                                                                                          
    Underground...................          141        1,191          134       16,736          275       17,927
    Surface.......................        8,838       49,214        1,192       79,230       10,030      128,444
    Shp/Yrd/Mll/Plnt..............          288        2,146          223       18,889          511       21,035
    Office workers................  ...........        8,530  ...........       18,644  ...........       27,174
                                   -----------------------------------------------------------------------------
    M/NM Subtotal.................        9,267       61,081        1,549      133,499       10,816      194,580
                                   =============================================================================
            Total all mines.......       11,029       74,501        2,683      223,241       13,712      297,742
----------------------------------------------------------------------------------------------------------------
Source: U.S. Department of Labor, Mine Safety and Health Administration, Office of Standards, Regulations, and  
  Variances, based on preliminary 1995 MIS data (quarter 1-quarter 4, 1995). MSHA estimates assume that operator
  office workers are distributed the same as non-office workers.                                                


 Table IV-2.--Mining Workforce Estimates by Job Title Groups (Including Office Workers and Excluding Contractor 
                                                   Employees)                                                   
----------------------------------------------------------------------------------------------------------------
                                           Coal mining               M/NM mining                  Total         
         Job title groups          -----------------------------------------------------------------------------
                                      Percent       Miners      Percent       Miners      Percent       Miners  
----------------------------------------------------------------------------------------------------------------
Backhoe-crane-dragline-shovel                                                                                   
 operator.........................          1.9        2,004          2.5        4,938          2.3        6,942
Beltman-belt cleaner (coal)-belt                                                                                
 repairman........................          3.4        3,473          0.4          800          1.4        4,273
Blaster...........................          0.8          810          0.3          605          0.5        1,415
Continuous miner & related machine                                                                              
 operator.........................          4.2        4,282        (\1\)        (\1\)          1.4        4,282
Deckhand-barge & dredge operator..          0.2          156          0.6        1,103          0.4        1,259
Dozer-heavy & mobile equipment                                                                                  
 operator.........................          6.8        7,038          2.7        5,289          4.1       12,326
Driller-auger operator (coal)-rock                                                                              
 bolter (m/nm)....................          1.9        1,910          1.9        3,700          1.9        5,611
Electrician-wireman (coal)-lampman          4.0        4,127          1.9        3,780          2.7        7,908
Front-end loader-forklift (m/nm)                                                                                
 operator.........................          2.8        2,876          7.2       13,943          5.7       16,820
Grader-scraper operator...........          1.6        1,636          0.7        1,323          1.0        2,959
Laborer-miner-utility man.........         15.0       15,477         10.3       20,021         11.9       35,498
Longwall operator.................          0.7          689        (\1\)        (\1\)          0.2          689
Manager-foreman-supervisor........         11.1       11,423         10.1       19,685         10.5       31,108
Mechanic-welder-oiler-machinist...         15.0       15,457         14.7       28,546         14.8       44,003
Mine technical support............          4.4        4,521          6.7       13,039          5.9       17,561
Office workers....................          5.6        5,782         14.0       27,174         11.1       32,956
Plant operator-warehouseman.......          3.8        3,921         14.0       27,315         10.5       31,236
Roof bolter-rock driller (coal)...          5.3        5,459            0            0          1.8        5,459
Scoop tractor operator-motorman                                                                                 
 (coal)...........................          3.4        3,510            0            0          1.2        3,510
Shuttle car-tram (m/nm) operator..          3.6        3,756          0.8        1,607          1.8        5,363
Stone cutter-finisher.............            0            0          0.5          879          0.3          879
Truck driver......................          4.7        4,854         10.7       20,832          8.6       25,686
                                   -----------------------------------------------------------------------------
      Total.......................          100      103,162          100      194,580          100     297,742 
----------------------------------------------------------------------------------------------------------------
\1\ Continuous miner and longwall operators at metal/nonmetal mines are included in the job group ``laborer-    
  miner-utility man.''                                                                                          
Extrapolated from U.S. Bureau of Mines, Characterization of the 1986 Coal Mining Workforce (IC 9192) and        
  Characterization of the 1986 Metal and Nonmetal Mining Workforce (IC 9193), 1988.                             


  Table IV-3.-- Distribution of Contractors (Contr) and Contractor Employees (Miners) by Major Industry Segment 
                                              and Size of Operation                                             
----------------------------------------------------------------------------------------------------------------
                                           Small (<20)          Large (20)             Total         
                                   -----------------------------------------------------------------------------
            Contractors              Number of    Number of    Number of    Number of    Number of    Number of 
                                       contr.       miners       contr.       miners       contr.       miners  
----------------------------------------------------------------------------------------------------------------
Coal:                                                                                                           
    Other than office.............        3,580       14,310          291       12,863        3,871       27,173

[[Page 66450]]

                                                                                                                
    Office workers................  ...........        1,291  ...........        1,160  ...........        2,451
                                   -----------------------------------------------------------------------------
      Coal Subtotal...............        3,580       15,601          291       14,023        3,871       29,624
                                   =============================================================================
Metal/nonmetal (M/NM):                                                                                          
    Other than office.............        2,656       12,921          352       20,975        3,008       33,896
    Office workers................  ...........          734  ...........        1,191  ...........        1,925
    M/NM Subtotal.................        2,656       13,655          352       22,166        3,008       35,821
                                   -----------------------------------------------------------------------------
      Total.......................        6,236       29,256          643       36,189        6,879      65,445 
----------------------------------------------------------------------------------------------------------------
Source: U.S. Department of Labor, Mine Safety and Health Administration, Office of Standards, Regulations, and  
  Variances, based on preliminary 1995 MIS data (quarter 1-quarter 4, 1995). MSHA estimates assume that         
  contractor office workers are distributed the same as non-office workers.                                     

Economic Characteristics

    The U.S. mining industry's 1995 production is worth in excess of 
$58 billion in raw mineral resources. Coal mining contributed about $20 
billion to the Gross Domestic Product in 1995 and metal and nonmetal 
mining contributed about $38 billion. Another $17 billion is reclaimed 
annually from recycled metal and mineral materials such as scrap iron, 
aluminum, and glass.
    The Agency obtained financial information on the various mineral 
commodities primarily from the U.S. Department of the Interior, Bureau 
of Mines, and the U.S. Department of Energy, Energy Information 
Administration.

Structure of the Coal Mining Industry

    MSHA separates the U.S. coal mining industry into two major 
commodity groups, bituminous and anthracite. The bituminous group 
includes the mining of subbituminous coal and lignite. Bituminous 
operations represent over 93% of the coal mining operations, employ 
over 98% of the coal miners, and account for over 99% of the coal 
production. About 60% of the bituminous operations are large; whereas 
about 90% of the anthracite operations are small.
    Underground bituminous mines are more mechanized than anthracite 
mines in that most, if not all, underground anthracite mines still 
hand-load. Over 70% of the underground bituminous mines use continuous 
mining and longwall mining methods. The remaining use drills, cutters, 
and scoops. Although underground coal mines generally use electrical 
equipment, a growing number of underground coal mines use diesel 
haulage equipment.
    Surface mining methods include drilling, blasting, and hauling and 
are similar for all commodity types. Most surface mines use front-end 
loaders, bulldozers, shovels, or trucks for coal haulage. A few still 
use rail haulage. Although some coal may be crushed to facilitate 
cleaning or mixing, coal processing usually involves cleaning, sizing, 
and grading.
    Preliminary data for 1995 indicate that there are about 2900 active 
coal mines of which 1760 are small mines (about 61% of the total) and 
1130 are large mines (about 39% of the total).
    These data indicate employment at coal mines to be about 103,200 of 
which about 13,400 (13% of the total) worked at small mines and 89,700 
(87% of the total) worked at large mines. MSHA estimates that the 
average employment is 8 miners at small coal mines and 79 miners at 
large coal mines.

Structure of the Metal/Nonmetal Mining Industry

    The metal and nonmetal mining industry consists of about 70 
different commodities including metals, industrial minerals, stone, and 
sand and gravel. Preliminary data for 1995 indicate that there are 
about 10,820 active metal and nonmetal mines of which 9270 are small 
mines (about 86% of the total) and 1550 are large mines (about 14% of 
the total).
    These data indicate employment at metal and nonmetal mines to be 
about 194,600 of which about 61,100 (31% of the total) worked at small 
mines and 133,500 (69% of the total) worked at large mines. MSHA 
estimates that the average employment is 7 miners at small metal and 
nonmetal mines and 86 miners at large metal and nonmetal mines. Table 
II-4 presents the number of metal and nonmetal mines and miners by 
major commodity category, mine size, and employment. In addition, MSHA 
estimates that about 350 mines are owned by state, county, or city 
governments.

                    Table IV-4.--Estimated Distribution of Metal/Nonmetal Mines and Miners 1                    
----------------------------------------------------------------------------------------------------------------
                                         Small (<20 EES)           Large (>20 EES)                Total         
                                   -----------------------------------------------------------------------------
             Commodity               Number of    Number of    Number of    Number of    Number of    Number of 
                                       Mines        Miners       Mines        Miners       Mines        Miners  
----------------------------------------------------------------------------------------------------------------
Metal.............................          176        1,199          193       46,296          369       47,495
Nonmetal..........................          546        3,496          231       25,436          777       28,932
Stone.............................        2,640       23,003          894       53,157        3,534       76,160
Sand and Gravel...................        5,905       33,383          231        8,610        6,136       41,993
                                   -----------------------------------------------------------------------------
      Total.......................        9,267       61,081        1,549      133,499       10,816     194,580 
----------------------------------------------------------------------------------------------------------------
1 Includes office workers. Excludes contractors.                                                                


[[Page 66451]]

Metal Mining
    Metal mining in the U.S. consists of about 25 different 
commodities. Most metal commodities include only one or two mining 
operations. Metal mining operations represent about 3% of the metal and 
nonmetal mines, employ about 24% of the metal and nonmetal miners, and 
account for about 35% of the value of metal and nonmetal minerals 
produced in the U.S. About 48% of the metal mining operations are 
small.
    Underground metal mining uses a few basic mining methods, such as 
stope, room and pillar, and block caving with primary noise sources 
being diesel haulage equipment, pneumatic drills, and mills. Larger 
underground metal mines use more hydraulic drills and track-mounted 
haulage; whereas, smaller underground metal mines use more hand-held 
pneumatic drills. Stope mining uses more hand-held equipment. Surface 
metal mines include some of the largest mines in the world. Surface 
mining methods (drill, blast, haul) use the largest equipment and are 
similar for all commodity types.
Nonmetal Mining
    For enforcement and statistical purposes, MSHA separates stone and 
sand and gravel mining from other nonmetal mining. There are about 35 
different nonmetal commodities, not including stone or sand and gravel. 
About half of the nonmetal commodities include less than 10 mining 
operations; some include only one or two mining operations. Nonmetal 
mining operations represent about 7% of the metal and nonmetal mines, 
employ about 15% of the metal and nonmetal miners, and account for 
about 34% of the value of metal and nonmetal minerals produced in the 
U.S. About 70% of the nonmetal mining operations are small.
    Nonmetal mining uses a wide variety of underground mining methods. 
For example, potash mines use continuous miners similar to coal mining; 
oil shale uses in-situ retorting; and gilsonite uses hand-held 
pneumatic chippers. Some nonmetal commodities use kilns and dryers in 
ore processing. Others use crushers and mills similar to metal mining. 
Underground nonmetal mining operations generally use more block caving, 
room and pillar, and retreat mining methods; less hand-held equipment; 
and more electrical equipment than metal mining operations. As with 
underground mining, surface mining methods vary more than for other 
commodity groups. In addition to drilling, blasting, and hauling, 
surface nonmetal mining methods include other types of mining methods, 
such as evaporation beds and dredging.
Stone Mining
    There are basically only eight different stone commodities of which 
seven are further classified as either dimension stone or crushed and 
broken stone. Stone mining operations represent about 33% of the metal 
and nonmetal mines, employ about 39% of the metal and nonmetal miners, 
and account for about 19% of the value of metal and nonmetal minerals 
produced in the U.S. About 75% of the stone mining operations are 
small.
    Stone generally is mined from quarries using only a few different 
methods and diesel haulage to transfer the ore from the quarry to the 
mill. Crushed stone mines typically drill and blast; whereas, dimension 
stone mines typically use channel burners, drills, or wire saws. 
Milling typically includes jaw crushers, vibratory crushers, and 
vibratory sizing screens.
Sand and Gravel Mining
    Based on the number of mines, sand and gravel mining represents the 
single largest commodity group in the U.S. mining industry. About 57% 
of the metal and nonmetal mines are sand and gravel operations. They 
employ about 22% of the metal and nonmetal miners and account for about 
11% of the value of metal and nonmetal minerals produced in the U.S. 
Over 95% of the sand and gravel operations are small.
    Construction sand and gravel is generally gathered from surface 
deposits using dredges or draglines and only washing and screening 
milling methods. As in other surface mining operations, sand and gravel 
uses diesel haulage equipment, such as front-end loaders, trucks, and 
bulldozers. In addition, industrial sand and silica flour operations 
mill the ore using crushers, ball mills, screens, and classifiers.

Economic Characteristics of the Coal Mining Industry

    The U.S. Department of Energy, Energy Information Administration, 
reported that the U.S. coal industry produced a record 1.03 billion 
tons of coal in 1994 with a value of about $20 billion. Of the several 
different types of coal commodities, bituminous and subbituminous coal 
account for 91% of all coal production (940 million tons). The 
remainder of U.S. coal production is lignite (86 million tons) and 
anthracite (4 million tons). Although anthracite offers superior 
burning qualities, it contributes only a small and diminishing share of 
total coal production. Less than 0.4% of U.S. coal production in 1994 
was anthracite.
    Mines east of the Mississippi account for about 53% of the current 
U.S. coal production. For the period 1949 through 1995, coal production 
east of the Mississippi River fluctuated relatively little from a low 
of 395 million tons in 1954 to 630 million tons in 1990. (It was 568 
million tons in 1994.) During this same period, however, coal 
production west of the Mississippi increased each year from a low of 20 
million tons in 1959 to a record 490 million tons in 1995. The growth 
in western coal is due in part to environmental concerns that led to 
increased demand for low-sulfur coal, which is concentrated in the 
West. In addition, surface mining, with its higher average 
productivity, is much more prevalent in the West.
    Preliminary MSHA data for 1995 indicate that small mines produced 
about 4% of the total coal mine production (about 44 million tons) and 
large mines produced about 96% of the total (983 million tons). MSHA 
calculations indicate that the average total production per miner for 
1995 was about 3,500 tons at small mines and 11,400 tons at large 
mines. The average total coal production for 1995 was about 25,000 tons 
per small mine and 867,000 tons per large mine.
    The 1994 estimate of the average value of coal at the point of 
production is about $19 per ton for bituminous coal and lignite, and 
$36 per ton for anthracite. MSHA chose to use $19 per ton as the value 
for all coal production because anthracite contributes such a small 
amount to total production that the higher value per ton of anthracite 
does not greatly impact the total value. The total value of coal 
production in 1995 was about $20 billion of which about $0.9 billion 
was produced by small mines and $19.1 billion was produced by large 
mines. On a per mine basis, the average coal production was valued at 
$0.5 million per small mine and $17 million per large mine.
    Coal is used for several purposes including the production of 
electricity. The predominant consumer of coal is the U.S. electric 
utility industry which used 829 million tons of coal in 1995 or 80% of 
the coal produced. Other coal consumers include coke plants (33 million 
tons), residential and commercial consumption (6 million tons), and 
miscellaneous other industrial uses (73 million tons). This last 
category includes the use of coal products in the manufacturing of 
other products, such as plastics, dyes, drugs, explosives, solvents, 
refrigerants, and fertilizers.

[[Page 66452]]

    The current rate of U.S. coal production exceeds U.S. consumption 
by roughly 90 million tons annually. In 1995, 89 million tons of this 
excess production was exported and the remainder was stockpiled. Japan 
(11.8 million tons), Canada (9.4 million tons), and Italy (9.1 million 
tons) were the top three importers of U.S. coal. Year-to-year 
fluctuations in exports of U.S. coal vary more than domestic 
consumption. During the 1990's, changes in exports from the previous 
year varied from a 24% increase to a 27% decrease; whereas, changes in 
domestic consumption only varied from a 4% increase to a 1% decrease.
    The U.S. coal industry enjoys a fairly constant domestic demand. 
Its demand by electric utilities continues to increase annually. MSHA 
does not expect a substantial change in coal demand by utilities in the 
near future because of the high conversion costs of changing a fuel 
source in the electric utility industry. Energy experts predict that 
coal will continue to be the dominant fuel source of choice for power 
plants built in the future. Nuclear and hydropower currently comprise, 
and are anticipated in the future to comprise, a small fraction of fuel 
sources for utilities.
    The international market for coal was marked by several notable 
events in the 1990's. The breakup of the Soviet Union (USSR), a new 
political regime in South Africa, and economic policy changes in the 
United Kingdom and Germany contributed to price and demand changes in 
coal's global marketplace; newly independent, former USSR republics 
provided competition to U.S. companies for a share of the European coal 
market; and the deep European recession of 1993-1994 caused exports of 
coal to decrease. Similarly, the cessation of the economic boycott of 
South Africa, and its new political leadership, has led to new interest 
in South African exports. South Africa ranks third after Australia and 
the U.S. in coal exports. Its coal exploration and mining have the 
nation poised to maintain its global position. The privatization of 
British power companies and the elimination of coal subsidies in 
Germany have led to an increased interest in U.S. coal. These 
international economic policy changes are predicted to create a 
substantial export opportunity for U.S. coal over the long term.
    The net effect of these aforementioned international activities 
appears to be a continued demand for U.S. coal at or near current 
level. The U.S. can expect additional competition, however, from other 
current coal producing countries (e.g., Australia, South Africa, former 
USSR republics, Poland), as well as from new suppliers in Colombia, 
Venezuela, China, and Indonesia. The U.S. coal industry has vast 
reserves of unmined coal which is predicted to sustain coal's demand 
for another half millennium if mined at the current rate.
    The economic health of the coal industry may be summarized as a 
fairly stable market which may be subject to periodic price and demand 
fluctuations. These fluctuations are largely functions of domestic 
supply disruptions and increased international competition. The 1993 
average profit as a percent of revenue for the coal mining industry was 
about 3-4% after taxes.

Economic Characteristics of the Metal and Nonmetal Mining Industry: 
Summary

    The 1995 value of all metal and nonmetal mining output is about $38 
billion. Metal mining contributes $13.2 billion to this total and 
includes metals such as aluminum, copper, gold, and iron. Nonmetal 
mining is valued at $12.9 billion and includes commodities such as 
cement, clay, and salt. Stone mining contributes about $7.2 billion and 
sand and gravel contributes about $4.3 billion to this total.
    The entire metal and nonmetal mining industry is markedly diverse 
not only in terms of the breadth of minerals, but also in terms of each 
commodity's usage. For example, metals such as iron and aluminum are 
used to produce vehicles and other heavy duty equipment, as well as 
consumer goods such as household equipment and soda pop cans. Other 
metals, such as uranium and titanium, have limited uses. Nonmetals like 
cement are used in construction while salt is used as a food additive 
and on roads in the winter. Soda ash, phosphate rock, and potash also 
have a wide variety of commercial uses. Stone and sand and gravel are 
used in numerous industries including the construction of roads and 
buildings.
    A detailed economic picture of the metal and nonmetal mining 
industry is difficult to develop because most mines are either 
privately held corporations or sole proprietorships, or subsidiaries of 
publicly owned companies. Privately held corporations and sole 
proprietorships do not make their financial data available to the 
public. Further, parent companies are not required to separate 
financial data for subsidiaries in their reports to the Securities and 
Exchange Commission. As a result, financial data are available for only 
a few metal and nonmetal companies and these data are not 
representative of the entire industry. Each commodity has a unique 
market demand structure. The following discussion focuses on market 
forces on a few specific commodities of the metal and nonmetal 
industry.
Metal Mining
    Historically, the value of metals production has exhibited 
considerable instability. In the early 1980's, excess capacity, large 
inventories, and weak demand depressed the international market for 
metals while the strong dollar placed U.S. producers at a competitive 
disadvantage with foreign producers. Reacting to this, many metal 
mining companies reduced work forces, eliminated marginal facilities, 
sold non-core businesses, and restructured. At the same time, new 
mining technologies were developed and wage increases were restrained. 
As a result, the metal mining firms now operating are more efficient 
and have lower break-even prices than those that operated in the 
1970's.
    For the purposes of this analysis, MSHA uses the Standard and 
Poor's methodology of dividing metal mining into two categories: iron 
ore and alloying metals, and copper and precious metals. Metal mine 
production is valued in excess of $13 billion. Copper, aluminum, gold, 
and iron are the highest revenue producers of the metal industry.
    Variations in the prices for iron and alloying metals, such as 
nickel, aluminum, molybdenum, vanadium, platinum, and lead, coincide 
closely with fluctuations in the market for durable goods, such as 
vehicles and heavy duty equipment. As a result, the market for these 
metals is cyclical in nature and is impacted directly by changes in 
aggregate demand and the economy in general.
    Both nickel and aluminum have experienced strong price fluctuations 
over the past few years; however, with the U.S. and world economies 
improving, demand for such alloys is improving and prices have begun to 
recover. It must be noted that primary production of aluminum will 
continue to be impacted by the push to recycle. Recycling of aluminum 
now accounts for 30% of the aluminum used and this percent is expected 
to rise in the coming years. Due to the increase in aluminum recycling, 
prices have been falling and inventories rising since the mid to late 
1980's.
    The market for copper and precious metals, such as gold and silver, 
is marked by great uncertainty and price volatility. Prices for gold 
and silver fluctuated by as much as 17 to 25%, respectively, during 
1993. The copper market recovered substantially during

[[Page 66453]]

1994, posting a 3.7% growth in demand by 1995. The gold and silver 
markets, however, continue to be marred with speculative demand spurs; 
consistent recovery and growth have been difficult to achieve due to 
uncertainty of U.S. buyers and shifts in production in South Africa and 
Russia. In 1993, Russia began to cut back its gold production which had 
generated low prices in the global market since 1990.
    Overall, the production from metal mining increased by about 5.5% 
from 1987 to 1995; 1995 estimates put capacity utilization at 84%. MSHA 
expects that the net result for the metal mining industry may be 
reduced demand but sustained prices. The 1993 average profit as a 
percent of revenue for the metal mining industry was about a 1.3% loss 
after taxes.
Nonmetal Mining, Including Stone and Sand and Gravel
    Nonmetal mine production is valued at more than $24 billion. 
Included in this figure is the production of granite, limestone, 
marble, slate, and other forms of crushed and broken or dimension 
stone. Other prosperous commodities in the nonmetal category include 
salt, clay, phosphate rock, and soda ash. Market demand for these 
products tends not to vary greatly with fluctuations in aggregate 
demand. Stone is the leading revenue generator with 1994 production 
valued at $7.2 billion. Construction sand and gravel and industrial 
sand 1995 production is valued at about $4.3 billion.
    Evaluating financial information for nonmetal mining operations is 
particularly difficult. Financial data are available only for 
relatively large mining operations and these often engage in a wide 
variety of activities of which mining is typically only a small part. 
Many large mining firms have financial interests in mines or mills of 
different commodities, thereby making it difficult to evaluate the 
financial aspects of any specific commodity. Publicly held firms are 
not required to separate financial data for their subsidiaries in their 
reports to the Securities and Exchange Commission and financial data 
are not available for most of the small mines because they are not 
publicly owned. (About 98% of the small metal and nonmetal mining 
operations are stone, sand and gravel, or other nonmetal operations.) 
This discussion of the economic characteristics of the nonmetal mining 
industry does not separately address sand and gravel, stone, and 
miscellaneous other nonmetal mining operations as was done in the 
discussion of the nonmetal mining industry's structure.
    Sand and gravel and stone products, including cement, have a 
cyclical demand structure. As a recession intensifies, demand for these 
products sharply decreases. Some stability in the market was achieved 
during 1993 and early 1994. Demand for stone, particularly cement, is 
expected to grow by as much as 4.8% and demand for sand and gravel is 
expected to grow by as much as 2.3%.
    The U.S. is the largest soda ash producer in the world with its 
1994 production valued at about $650 million. Soda ash is used in the 
production of glass, soap and detergents, paper, and food. Both salt 
and soda ash have a fairly constant demand structure due to the 
products' uses and the lack of suitable substitutes. A 1994 industry 
analysis indicates shifts in the world demand for salt. European 
demand, impelled by the economic breakdown of Central and Eastern 
Europe, has declined; however, growth in demand has increased in Asia 
and the Far East.
    Phosphate rock, which is used primarily to manufacture fertilizer, 
has an unusual market structure. U.S. production and exports of 
phosphate rock have declined in recent years and imports from Morocco 
increased by 180% from 1991 to 1992.
    The remaining nonmetal commodities which include boron fluorspar, 
oil shale, and other minerals are produced typically by a small number 
of mining operations. Despite this fact, annual production of pumice, 
perlite, vermiculite, and some others is valued at the tens of millions 
of dollars for each product.
    Overall, the production from nonmetal mining remained relatively 
stable from 1987 to 1995; 1995 estimates put capacity utilization for 
stone and earth minerals at about 97%. The net result for the nonmetal 
mining industry may be higher demand for stone and various other 
commodities and increased prices. The 1993 average profit as a percent 
of revenue was about 3-4% for nonmetal mine production, excluding stone 
and sand and gravel; about 8% for stone mining; and about 5% for sand 
and gravel.

Feasibility of Requiring the Use of Engineering and Administrative 
Controls at a TWA8 of 90 dBA

    In this proposal, MSHA has determined that the Mine Act's objective 
to protect miners from material impairment of health can be met by 
requiring mine operators to use all feasible engineering and 
administrative controls. This approach is close to that already 
required in the metal and nonmetal sector of the industry. In the coal 
sector, attenuation of hearing protectors have been considered in 
determining compliance with the PEL, and in practice this has meant 
that few mine operators have had to institute engineering or 
administrative controls.
    The approach gives mine operators flexibility to choose those 
controls or combinations of controls which would be the most effective 
in reducing exposure to noise. If the institution of administrative 
controls does not adequately protect the miners in a given work 
situation, MSHA will require the implementation of feasible engineering 
controls. Under this approach, the Agency has to determine in the 
particular situation that the proposed engineering controls are 
feasible prior to requiring their implementation. Likewise, if the 
engineering controls prove inadequate, the Agency will require the 
implementation of feasible administrative controls.
    In the metal and nonmetal industry where this approach is currently 
implemented, smaller operations predominate. As a result, 
administrative controls are seldom feasible, and engineering controls 
may not be economically feasible for some operations. Moreover, given 
the technology available in this sector, in a few cases complete 
engineering solutions may not be technologically feasible. However 
based on the information on available controls reviewed in part III, 
including methods developed by the former Bureau of Mines, MSHA 
believes there are few cases in which noise cannot be significantly 
reduced through some sort of engineering control (including miner 
isolation). The Agency has specifically solicited comments on the 
feasibility of controls for metal and nonmetal equipment and operations 
identified as generating sound levels above a TWA8 of 105 dBA; as 
noted in part III, exposures exceeding this level constitute less than 
one-quarter of one percent of all exposures, and many mine operators do 
manage to control the exposures from such equipment. And the Agency 
welcomes comments on other specific feasibility concerns. Based on its 
review, MSHA believes most metal and nonmetal mine operators will find 
feasible engineering controls that meet their requirements.
    In the coal industry, many mine operators are larger and the 
technology is different. Many coal mine operators are large enough to 
be able to use administrative controls where engineering controls are 
not economically feasible. Moreover, based

[[Page 66454]]

on the information reviewed in part III, MSHA is confident that 
engineering solutions are available that can significantly reduce noise 
in almost all situations in which coal mining noise exceeds the PEL. 
Moreover, the Agency notes that the available engineering solutions are 
constantly changing--for example, it may be easier today than it used 
to be to find retrofit cabs for older equipment. Even in problem areas 
like coal preparation plants and highwall areas there are available 
solutions. In coal preparation plants, motor enclosures, operator 
control booths, material dampening of chutes and transfer points, and 
process area enclosures can bring about significant reductions in 
exposure; for highwall areas, exhaust mufflers and compressor barriers 
can do the same. The Agency would be interested in comments on problems 
encountered in controlling noise in coal operations and on solutions 
that have proved effective.
    In concluding that such requirements are feasible in the mining 
industry, MSHA takes into account that the proposed rule would require 
a mine operator to use all feasible engineering and administrative 
controls. On the one hand this means that MSHA will require mine 
operators to consider all possible controls so as to find a combination 
that will in fact reduce noise as much as possible. MSHA's enforcement 
policy in this regard has been noted earlier in this section (and in 
the Question and Answer section in part I). On the other hand, there 
may be situations where no combination of engineering and 
administrative controls to reduce exposures to the PEL is economically 
or technologically feasible. In such cases, the proposed standard 
specifies the other actions a mine operator must take to protect 
workers to the maximum extent possible--including the use of 
engineering and administrative controls to reduce exposures to the 
maximum extent that is feasible.
    Following is further discussion of the feasibility of 
administrative controls and engineering controls, respectively.

Feasibility of Administrative Controls

    Administrative controls refers to the practice of limiting the 
exposure of individual miners to a noise source. Administrative 
controls reduce exposure through such actions as rotation of miners to 
areas having lower sound levels, rescheduling of tasks, modifying work 
activities, or limiting the amount of time that a miner is exposed to 
noise.
    The feasibility of administrative controls to solve particular 
noise problems in any mine may be limited by a number of factors: 
limitations on the number of qualified miners capable of handling a 
specific task, labor/management agreements affecting duty assignments, 
or difficulty in ensuring that miners adhere to the administrative 
controls. Further, because the effectiveness of administrative controls 
is based on adherence to these strict time periods, mine operators may 
find it difficult to verify compliance with the administrative 
procedures.
    As explained in the discussion of proposed Sec. 62.120(c), it is 
MSHA's experience that administrative controls are relatively more 
feasible for mines with many employees and relatively less feasible for 
mines with fewer employees. As demonstrated by the industry profile, 
the mines in the coal industry are generally larger mines. It is MSHA's 
experience that many coal mine operators may prefer administrative 
controls as the primary noise control. This is, in fact, the reasons 
proposed Sec. 62.120(c) was designed to preserve mine operator choice. 
The use of such controls is much less feasible in the smaller mines 
that characterize the metal and nonmetal industry.

Feasibility of Engineering Controls

    If administrative controls are not feasible, or cannot by 
themselves reduce noise to the PEL, mine operators are to use all 
feasible engineering controls. This discussion is divided into two 
parts: the technological feasibility of such controls, and the economic 
feasibility of such controls.
Technological Feasibility of Engineering Controls
    MSHA is an active and knowledgeable partner in continually refining 
and improving existing noise control technology. At the request of 
MSHA's Coal Mine Safety and Health or Metal and Nonmetal Mine Safety 
and Health, MSHA's Technical Support actively assists mine operators in 
developing noise controls. Based upon this knowledge, and MSHA's 
experience, the Agency has determined that feasible engineering 
controls exist for the majority of equipment used in mining.
    MSHA has evaluated under actual mining conditions newly developed 
noise controls for surface self-propelled equipment, underground diesel 
powered haulage equipment, jumbo drills, track drills, hand-held 
percussive drills, draglines/shovels, portable crushers, channel 
burners, and mills, and has found them to be effective in reducing 
miners' noise exposure. Some of these feasible engineering controls are 
already designed into new equipment. In many cases, effective and 
feasible controls are available through retrofitting or the proper use 
of noise barriers. A more detailed discussion regarding the 
availability of these controls is contained in part III of this 
preamble (see Engineering Noise Controls for Mining Equipment, in the 
discussion of proposed Sec. 62.120(c) in part III). Part V of this 
preamble contains a list of publications of the former USBOM evaluating 
noise controls for various types of mining equipment.
    As noted previously, there are some instances where current noise 
control technology still cannot reduce sound levels to within a 
TWA8 of 90 dBA and where quieter replacement equipment may not be 
feasible. An example of this is a pneumatic jackleg drill used in 
hardrock mining. MSHA's data on equipment producing high levels of 
noise are discussed in part III (see the discussion of a possible dose 
ceiling in proposed Sec. 62.120(e)).
Economic Feasibility of Engineering Controls
    The data from MSHA's dual-threshold survey, presented in Tables II-
11 and II-12 in part II of this preamble, indicate that even with the 
proposed new threshold level (80 dBA), almost three-quarters of the 
metal and nonmetal samples, and almost two-thirds of the coal samples, 
already are below the PEL. No additional controls would be required in 
these cases.
    The Agency has determined that the incremental costs of the 
requirements for engineering controls would be $3.5 million a year for 
ten years, of which $2.2 million is allocable to the coal sector and 
$1.3 million to the metal and nonmetal sector. (The additional costs to 
the metal and nonmetal sector reflect in part the proposed lowering of 
the threshold, which will result in the measurement of more 
overexposures than at present.)
    As described in more detail in the Agency's preliminary RIA, to 
calculate the costs for engineering controls, MSHA evaluated various 
engineering controls and their related costs.
    In determining which engineering controls the metal and nonmetal 
industry will have to use under the proposed rule, MSHA considered the 
engineering controls that are used under the current rule. MSHA 
believes that metal and nonmetal mine operators may generally have 
exhausted the least costly engineering controls to comply with the 
current rule for some job groups. Compliance with the proposed rule for 
these job groups would require

[[Page 66455]]

that the mine operator use more expensive controls--specifically, 
retrofitting equipment--or purchase new equipment. For other job 
groups, however, mine operators may have used only those controls 
necessary to comply with the PEL and the less costly controls may still 
be available. To determine the cost of engineering controls, MSHA 
looked at the average cost of such engineering controls.
    For the coal industry, HPDs have generally been substituted for 
engineering and administrative controls, so the industry has not 
exhausted the use of relatively inexpensive controls which have been 
demonstrated to be capable of bringing about significant reductions of 
sound levels. Even though the average cost of such controls would be 
less than for the metal and nonmetal industry, the change in approach 
would require controls be used much more often than at present. This is 
why the industry would experience a relatively higher expense for 
engineering controls.
    MSHA believes the requirements for engineering and administrative 
controls clearly meet the feasibility requirements of the law. Based on 
the comments received in response to its ANPRM and discussed below, 
MSHA believes some in the industry may misunderstand the nature of the 
engineering controls required. In many cases, inexpensive controls may 
effectively eliminate overexposures.

Comments on Feasibility of Engineering and Administrative Controls

    MSHA received numerous comments indicating that engineering 
controls were not feasible to reduce a miner's noise exposure to within 
the PEL for many types of mining equipment. Several commenters stated 
that engineering controls are most effective when they are designed 
into equipment versus applied by retrofitting. Other commenters stated 
that retrofit noise controls are often not as durable or effective as 
controls installed by the equipment manufacturer. One commenter 
suggested that MSHA establish approval and certification procedures for 
equipment noise emissions, similar to those established in part 18 for 
permissible equipment used in gassy mines.
    In response to the commenters who indicated that engineering 
controls were not feasible for many types of mining equipment, MSHA 
would point out that significant progress has been made in developing 
quieter mining equipment since the mid-1970's when MSHA's existing 
noise standards were promulgated. Currently, almost all pneumatic drill 
manufacturers offer exhaust mufflers where few were available in the 
early 1970's. Similarly, almost all manufacturers of mobile surface 
equipment offer environmental and/or acoustically treated cabs. Some 
manufacturers also offer acoustically treated cabs for underground 
mining equipment, such as jumbo drills and scoop trams. As noted, the 
availability of feasible engineering noise controls is discussed in 
greater detail in the section of the preamble on Engineering Noise 
Controls for Mining Equipment.
    MSHA does not agree with the commenter who suggested that MSHA 
establish approval and certification for equipment noise emissions 
similar to part 18. Such a process could be more costly and limit a 
mine operator's flexibility in implementing noise control procedures.
    The most cited disadvantage of engineering controls is cost. In 
particular, some commenters are concerned that they would be required 
to install controls that would not, by themselves, be adequate to 
attain compliance. If this occurs, the proposal would also require that 
administrative controls be used to reduce exposure to the PEL; 
moreover, if a combination of controls does not reduce exposures to the 
PEL, hearing protectors must be worn and the affected miners enrolled 
in an HCP. These commenters believe that in such cases, costs to 
install engineering controls are wasted since they still may have to 
resort to these additional controls. More significantly, mine operators 
are concerned that requiring engineering controls will usually require 
the purchase of new equipment.
    The first concern is misplaced. Controlling noise requires the 
hierarchy of requirements proposed by Sec. 62.120(c). A mine operator 
has a choice as to what mix of engineering and administrative controls 
to use as long as together they reduce noise exposures to the PEL or as 
close thereto as feasible. Hearing protectors and enrollment in a 
hearing conservation program are helpful when nothing more can feasibly 
be done to reduce noise exposure, but they are not a substitute.
    MSHA generally agrees with the commenters who stated that 
engineering controls are most effective when factory installed. The 
Agency would encourage mine operators to purchase mining machinery 
equipped with appropriate noise controls offered by the original 
equipment manufacturer rather than retrofitting noise controls. Almost 
every piece of mining equipment currently manufactured has optional 
noise control packages. Based on comments and MSHA's experience in 
noise control, the Agency has concluded that engineering controls 
designed and installed by the manufacturer for a particular unit will 
generally be more effective and durable than a retrofit control of 
similar design. Additionally, the cost of such controls may in some 
cases be substantially higher if it is purchased from the equipment 
manufacturer on a retrofit basis, rather than at the time the unit was 
originally built.
    At the same time, as discussed in part III, MSHA has determined 
that some retrofit controls may be as effective as controls offered by 
equipment manufacturers. Examples of engineering controls which are 
routinely retrofitted onto existing mining equipment include: 
environmental cabs; control booths; sound barriers and baffles; exhaust 
mufflers; and the application of acoustical materials to equipment 
firewalls and the inside walls of cabs and control booths. Moreover, 
many successful retrofit noise controls (e.g., cabs, barrier shields, 
and drill exhaust mufflers) were developed by operators using materials 
readily available. Often the miners who use the equipment offer 
valuable suggestions on improving the design and effectiveness of these 
controls. Some of the controls developed by the mine operators have 
been adopted by manufacturers for use on both existing and new 
equipment. MSHA has determined that allowing the mine operator to 
develop controls provides the mine operator with maximum flexibility in 
complying with the standard thereby eliminating the need in those cases 
to purchase manufacturer installed controls.
Infeasibility of PEL at TWA8 of 85 dBA
    MSHA seriously considered lowering the PEL to a TWA8 of 85 dBA 
because of its conclusion that there is a significant risk of material 
impairment from noise exposures at or above this level. The Agency has 
tentatively concluded, however, that it may not be feasible at this 
time for the mining industry to reduce noise to that level.
    Exposure data collected by MSHA indicate that with a PEL at a 
TWA8 of 85 dBA and an 80 dBA threshold, over two-thirds of the 
mine operators in the metal and nonmetal industry, and over three-
quarters of the mine operators in the coal industry, would need to use 
engineering and administrative controls to reduce current exposures. 
(See Tables II-11 and II-12 in part II.)
    Moreover, the engineering controls needed to reduce those exposures 
would be more expensive, because they would have to reduce the 
exposures further than with a PEL set at a TWA8 of 90 dBA. 
Accordingly, the Agency

[[Page 66456]]

does not believe it can demonstrate that a reasonable probability 
exists that the typical mine operator will currently be able to develop 
and install controls that will meet such a standard.
    It is true that the proposed standard only requires that individual 
mine operators use those controls which are feasible for that mine 
operator. The feasibility requirement under the statute, however, is 
that the Agency make a reasonable prediction, based on the ``best 
available evidence,'' as to whether an industry can generally comply 
with a standard within an allotted period of time. The Agency must show 
that a reasonable probability exists that the typical mine operator 
will be able to develop and install controls that will meet the 
standard. Accordingly, MSHA believes that if most mine operators are 
unlikely to be able to use engineering and administrative controls to 
bring noise levels to a TWA8 of 85 dBA, the standard is not 
feasible for the industry as a whole.
Infeasibility of Exchange Rate of 3-dB
    The exchange rate is a measure of how quickly the dose of noise 
doubles. Accordingly, the measure is the rate determining how much a 
miner's exposure must be limited to compensate for increasing dose. For 
example, at a 5-dB exchange rate, the exposure permitted at a sound 
level of 90 dBA is half that permitted at a sound level of 85 dBA; a 
miner gets the same noise dose in 4 hours at 90 dBA as at 8 hours at 85 
dBA.
    The Agency gave serious consideration to changing the exchange rate 
from 5-dB to 3-dB, and is specifically seeking comment on this 
important matter. There is a consensus in the recent literature that 
noise dose actually doubles more quickly than measured by the 5-dB 
rate, and in particular consensus for an exchange rate of 3-dB. 
Moreover, MSHA has concluded that the type of noise exposure in the 
mining environment tends to warrant an exchange rate that does not 
assume significant time for hearing to recover from high sound levels--
the current exchange rate incorporates such an assumption. A full 
discussion of the scientific merits of various exchange rates, and of 
the rates used by various regulatory authorities, can be found in part 
III of the Preamble (as part of the discussion of proposed 
Sec. 62.120(a), dose determination).
    Nevertheless, the Agency is proposing to retain the existing 5-dB 
exchange rate because of feasibility considerations. Changing to a 3-dB 
rate from a 5-dB rate would significantly reduce the amount of time 
that miners could be exposed to higher sound levels without exceeding 
the permissible exposure limit. For example, MSHA estimates that the 
percentage of miners whose exposure would be in violation of a PEL set 
at a TWA8 of 90 dBA would about double if a 3-dB exchange rate is 
used. (See Table III-3 in the exchange rate discussion in part III. The 
table also indicates what would happen if the PEL were set at a 
TWA8 of 85 dBA). This means mine operators would have to utilize 
controls to reduce exposures to the PEL more frequently. Moreover, more 
expensive controls would often be required, since the need to reduce 
exposures more to get them down to the PEL.
    The feasibility requirement under the statute is that the Agency 
make a reasonable prediction, based on the ``best available evidence,'' 
as to whether an industry can generally comply with a standard within 
an allotted period of time. The Agency must show that a reasonable 
probability exists that the typical mine operator will be able to 
develop and install controls that will meet the standard. The exposure 
data noted indicate it may be difficult for MSHA to make such a 
showing.
    Furthermore, if a 3-dB exchange rate is used, it is extremely 
difficult to reduce the noise exposures to below the PEL with currently 
available engineering or administrative noise controls or a combination 
thereof.
    Accordingly, MSHA has tentatively concluded that moving the 
industry to a 3-dB exchange rate may not be feasible at this time.

Conclusion

    Based on the information before it, the Agency has tentatively 
concluded that the proposed rule meets the statutory requirements for 
feasibility, and that it may not be feasible for the mining industry, 
as a whole, at this time, to require a more protective regimen.
    The Agency is particularly interested in receiving additional data 
that would be relevant in making final determinations on the points 
discussed above.

V. References

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[[Page 66457]]

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[[Page 66458]]

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and Health Administration,

[[Page 66463]]

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Stein, Robert R. and William W. Aljoe, ``Noise Test Report: Handheld 
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Stewart, Kenneth C. and Timothy Y. Yen,''Noise Dosimeter Performance,'' 
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Investigations RI 7876, pp. 1-38, 1974.
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Valoski, Michael P., ``Improving Barrier Insertion Loss,'' U.S. 
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Informational Report IR 1117, pp. 1-17, 1980.
Valoski, Michael P., ``The Magnitude of the Noise-Induced Hearing Loss 
Problem in the Mining Industries,'' U.S. Department of Labor, Mine 
Safety and Health Administration, Informational Report IR 1220, pp. 1-
18, 1994.
Valoski, Michael P. et al., ``Comparison of Noise Exposure Measurements 
Conducted with Sound Level Meters and Noise Dosimeters under Field 
Conditions,'' U.S. Department of Labor, Mine Safety and Health 
Administration, Informational Report IR 1230, pp. 1-31, 1995.
Yen, Timothy Y. and Kenneth C. Stewart, ``Noise Dosimeter Performance--
A Second Evaluation,'' U.S. Department of Interior, Bureau of Mines, 
Information Circular IC 8754, pp. 1-39, 1977.
USBOM Noise Papers Presented in Public Forums or Published in Public 
Access Publications
Aljoe, William W. et al., ``Coal Cutting Noise Control,'' Paper 
presented at Noise-Con 87, at State College, Pennsylvania, June 8-10, 
1987, pp. 181-186.
Bartholomae, Roy C. and John G. Kovac, ``USBM Develops a Low Noise 
Percussion Drill,'' Paper presented at Inter-Noise 80, Miami, Florida, 
December 8-10, 1980, pp. 317-320.
Bartholomae, R.C. et al., ``Flammability Evaluation of Noise Control 
Products for Use in Underground Coal Mines,'' Paper presented at Inter-
Noise 80, Miami, Florida, December 8-10, 1980, pp. 637-640.
Bartholomae, Roy C. and J. Alton Burks, ``U.S. Surface Coal Mine Mobile 
Equipment: Operator Noise Exposures and Noise Controls,'' Annals of the 
American Conference of Governmental Industrial Hygienists, 14:575-590, 
1986.
Bartholomae, Roy C. and Gerald W. Redmond, ``Noise-Induced Hearing 
Loss--A Review,'' Annals of the American Conference of Governmental 
Industrial Hygienists, 14:41-61, 1986.
Bartholomae, Roy C. and Robert R. Stein, ``Noise Reducing Technologies 
for Newly Designed Mining Percussion Drills,'' Paper presented at 
Noise-Con 88, West Lafayette, Indiana, June 20-22, 1988, pp. 123-128.
Bartholomae, Roy C. and Robert R. Stein, ``ANC vs Standard Hearing 
Protectors Performance--Ideal & Non-Ideal Conditions,'' Paper presented 
at Noise-Con 91, Tarrytown, New York, July 14-16, 1991, pp. 239-244.
Bartholomae, Roy C. and James P. Rider, ``Active Noise Cancellation--
Effectiveness for Auxiliary Mine Ventilation Systems,'' Paper presented 
at Noise-Con 93, Williamsburg, Virginia, May 2-5, 1993, pp. 297-302.
Bartholomae, Roy C. and J. Alton Burks, ``Impact of Anticipated Changes 
in Mine Noise Regulations on the Coal Mining Industry,'' Paper 
presented at Noise-Con 94, Ft. Lauderdale,

[[Page 66464]]

Florida, May 1-4, 1994, pp. 1017-1022.
Bartholomae, Roy C. and J. Alton Burks, ``Impact of Anticipated Changes 
in Mine Noise Regulations on Longwall Mining,'' Paper presented at 
Longwall Show 1994, pp. 246-250.
Bartholomae, Roy C., ``Small Diameter In-The-Hole Percussion Drilling 
Tool for Percussion Drill Noise Control,'' Paper presented at Noise-Con 
94, Ft. Lauderdale, Florida, May 1-4, 1994, pp. 175-180.
Bartholomae, Roy C. and J. Alton Burks, ``Occupational Noise Exposures 
in Underground Longwall Coal Mines,'' Paper presented at Inter-Noise 
95, Newport Beach, California July 10-12, 1995, pp. 833-836.
Bender, Erich K. et al., ``Noise Control of Jumbo-Mounted Percussive 
Drills,'' Noise Control Engineering Journal 15(3): 128-137, November-
December 1980.
Burks, J.A. and E.R. Spencer, ``Measurement of Normal Incidence 
Absorption Coefficient Using Sound Intensity,'' Paper presented at 
Inter-Noise 89, Newport Beach, California, December 4-6, 1989, pp. 
1077-1080.
Burks, J.A. and E.R. Spencer, ``Effect of Fluids on the Performance of 
Acoustical Materials,'' Paper presented at Noise-Con 91, Tarrytown, New 
York, July 14-16, 1991, pp. 1-6.
Burks, J.A. and Roy C. Bartholomae, ``Noise Reduction Potential of a 
Variable Speed Driven Coal Mining Conveyor,'' Paper presented at 
Proceeding of the SME Annual Meeting, Phoenix, Arizona, February 24-27, 
1992, pp. 43-50.
Burks, J.A. and Roy C. Bartholomae, ``Evaluation of Cap-Mounted and 
Over-The-Head Earmuffs,'' Paper presented at Inter-Noise 92, Toronto, 
Ontario, Canada, July 20-22, 1992, pp. 303-306.
Casali, John G. et al., ``Physical vs. Psychophysical Measurement of 
Hearing Protector Attenuation--a.k.a. MIRE vs. REAT,'' Sound and 
Vibration, pp. 20-27, July 1995.
Dixon, Nicholas R. and Roy S. Bartholomae, ``Front-End Loader Noise 
Control,'' Paper presented at Inter-Noise 82, San Francisco, 
California, May 17-19, 1982, pp. 277-280.
Dutta, Piyush K. et al., ``Measurement and Analysis of the Stress Wave 
Generated Rod Noise in Percussive Rock Drill,'' Paper presented at the 
Proceedings of the Society for Experimental Stress Analysis Meeting, 
Dearborn, Michigan, May 31-June 4, 1981, pp. 218-226.
Dutta, Piyush K. et al., ``Development of a Low Noise Coal Mine Stoper 
Drill,'' Paper presented at Noise-Con 81, Raleigh, North Carolina, June 
8-10, 1981, pp. 245-248.
Dutta, Piyush K. and Roy C. Bartholomae, ``Development of a Quiet Jumbo 
Drill: Evaluation of Design Concepts,'' Paper presented at Noise-Con 
83, Cambridge, Massachusetts, 1983, pp. 169-176.
Galaitsis, A. et al., ``Noise Reduction of Chain Conveyors,'' Paper 
presented at Inter-Noise 80, Miami, Florida, December 8-10, 1980, pp. 
169-172.
Grant, Douglas C. et al., ``Computer Model Simulates Screening Process 
under Variety of Conditions Part I Semi-empirical Approach Allows 
Researchers more Latitude,'' Pit & Quarry, pp. 59-63, November 1982.
Grant, Douglas C. et al., ``Computer Model Simulates Screening Process 
under Variety of Conditions Part II Semi-empirical Approach Allows 
Researchers more Latitude,'' Pit & Quarry, pp. 67-68, December 1982.
Hawkes, I. and J.A. Burks, ``Investigation of Noise and Vibration in 
Percussive Drill Rods,'' Int. J. Rock Mech. Sci. & Geomech. 16:363-376, 
1979.
Kohler, Jeffrey L. et al., ``A Real-Time Engineering Control for the 
Reduction of Chain-Conveyor Noise,'' Paper presented at Noise-Con 93, 
Williamsburg, Virginia, May 2-5, 1983, pp. 91-96.
Kovac, John G., et al., ``Bulldozer Noise Control,'' SAE Technical 
Paper Series, Paper presented at the International Off-Highway Meeting 
and Exposition, MECCA, Milwaukee, September 8-11, 1980, pp. 1-6.
Kovac, J.G. et al., ``Bulldozer Noise Control,'' Paper presented at 
Inter-Noise 80, Miami, Florida, December 8-10, 1980, pp. 457-460.
Redmond, Gerald W. et al., ``Comparison of Earmuff Attenuation as 
Measured by Psychophysical and Physical Methods,'' Paper presented at 
Inter-Noise 80, Miami, Florida, December 8-10, 1980, pp. 659-662.
Redmond, Gerald W. and J. Alton Burks, ``The Ambient Noise Floor in an 
Earcup of a Hearing Protector Worn by a Human Subject,'' Annals of the 
American Conference of Governmental Industrial Hygienists 14:557-563, 
1986.
Robertson, J. et al., ``Continuous Miner Noise,'' Transactions of the 
American Society of Mechanical Engineers, 103:282-292, August 1981.
Stein, Robert R. and William W. Aljoe, ``Concentric Drill Steels for 
Noise Reduction of Percussion Drilling,'' Paper presented at Inter-
Noise 86, Cambridge, USA, July 21-23, 1986, pp. 333-336.
Stein, Robert R. and William W. Aljoe, ``Developing a Relationship 
between Power Input and Sound Power Output for Percussion Drills,'' 
Paper presented at Noise-Con 87, State College, Pennsylvania, June 8-
10, 1987, pp. 177-180.
Stein, Robert R. and Roy C. Bartholomae, ``Comparison of Sound Power 
Measurement Techniques for Mining Drills: Sound Intensity vs ISO 
3741,'' Paper presented at Inter-Noise 89, Newport Beach, California, 
December 4-6, 1989, pp. 1021-1024.
Stein, Robert R. and Roy C. Bartholomae, ``An Investigation of Sound 
Intensity Techniques Applied to Impact Noise,'' Paper presented at 
Noise-Con 90, Austin, Texas, October 15-17, 1990, pp. 403-408.
Stein, Robert R. and Roy C. Bartholomae, ``Active Noise Control of Mine 
Auxiliary Ventilation Fans,'' Paper presented at Noise-Con 91, 
Tarrytown, New York, July 14-16, 1991, pp. 133-140.
Stein, Robert R. and J. Alton Burks, ``Controlling Worker Exposure to 
Noise on Longwall Faces,'' Paper presented at Proceeding of the SME 
Annual Meeting, Phoenix, Arizona, February 24-27, 1992, pp. 279-285.
Stephan, Robert W. et al., ``A Mathematical Model to Predict the 
Potential Impact of Noise Control Measure on Reducing Miner 
Overexposures,'' Annals of the American Conference of Governmental 
Industrial Hygienists, 14:631-642, 1986.
Wright, William H. and John G. Casali, ``The Effect of Passive and 
Electronic Amplitude-Sensitive Hearing Protectors on the Detection of a 
Warning Signal,'' NVLAP Report, March 1994.

List of Subjects

30 CFR Parts 56 and 57

    Metal and nonmetal, Mine safety and health, Noise.

30 CFR Part 62

    Mine safety and health, Noise.

30 CFR Parts 70 and 71

    Coal, Mine safety and health, Noise.


[[Page 66465]]


    Dated: November 26, 1996.
J. Davitt McAteer,
Assistant Secretary for Mine Safety and Health.

    It is proposed to amend Chapter I of Title 30 of the Code of 
Federal Regulations as follows:

PART 56--[AMENDED]

    1. The authority citation for part 56 continues to read as follows:

    Authority: 30 U.S.C. 811, 957, 961.

    2. Section 56.5050 and the undesignated center heading preceding it 
are removed.

PART 57--[AMENDED]

    3. The authority citation for part 57 continues to read as follows:

    Authority: 30 U.S.C. 811, 957, 961.

    4. Section 57.5050 and the undesignated center heading preceding it 
are removed.

PART 70--[AMENDED]

    5. The authority citation for part 70 continues to read as follows:

    Authority: 30 U.S.C. 811 and 961.

    6. Subpart F (Secs. 70.500-70.511) is removed.

PART 71--[AMENDED]

    7. The authority citation for part 71 continues to read as follows:

    Authority: 30 U.S.C. 811, 951, 957, 961.

    8. Subpart I (Secs. 71.800-71.805) is removed.
    9. Subchapter M is redesignated as subchapter I, subchapter N is 
redesignated as subchapter K, and Subchapter N is reserved.
    10. A new Subchapter M is added, ``Uniform Mine Health 
Regulations.''
    11. A new part 62 is added to new Subchapter M to read as follows:

PART 62--OCCUPATIONAL NOISE EXPOSURE

Sec.
62.100  Purpose and scope; effective date.
62.110  Definitions.
62.120  Limitations on noise exposure.
62.125  Hearing protectors.
62.130  Training.
62.140  Audiometric testing program.
62.150  Audiometric test procedures.
62.160  Evaluation of audiogram.
62.170  Follow-up evaluation when audiogram invalid.
62.180  Follow-up corrective measures when STS detected.
62.190  Notification of results; reporting requirements.
62.200  Access to records.
62.210  Transfer of records.

    Authority: 30 U.S.C. 811, 857, 861.


Sec. 62.100  Purpose and scope; effective date.

    The purpose of these standards is the prevention of occupational 
noise-induced hearing loss among miners. This part sets forth mandatory 
health standards for each surface and underground metal, nonmetal, and 
coal mine subject to the Federal Mine Safety and Health Act of 1977. 
The provisions of this part shall take effect (one year from the date 
of publication of the final rule).


Sec. 62.110  Definitions.

    The following definitions apply in this part:
    Access. The right to examine and copy records.
    Audiologist. A professional, specializing in the study and 
rehabilitation of hearing, who is certified by the American Speech-
Language-Hearing Association (ASHA) or licensed by a state board of 
examiners.
    Baseline audiogram. The audiogram recorded pursuant to Sec. 62.140 
against which subsequent audiograms are compared to determine the 
extent of hearing loss, except in those specific situations in which 
this part requires the use of a supplemental baseline audiogram for 
such a purpose.
    Criterion level. The sound level which if constantly applied for 8 
hours results in a dose of 100% of that permitted by the standard.
    Decibel (dB). A unit of measure of sound levels. MSHA defines 
decibel in two different ways depending upon the use.
    (1) For measuring sound pressure levels, the decibel is 20 times 
the common logarithm of the ratio of the measured sound pressure to the 
standard reference pressure of 20 micropascals (Pa), which is 
the threshold of normal hearing acuity at 1000 Hz.
    (2) For measuring hearing threshold levels, the decibel is the 
difference between audiometric zero (reference pressure equal to 0 
hearing threshold level) and the threshold of hearing of the individual 
being tested at each test frequency.
    Decibel, A-weighted (dBA). Sound levels measured using the A-
weighting network. A-weighting refers to the frequency response network 
closely corresponding to the frequency response of the human ear. This 
network attenuates sound energy in the lower and upper frequencies 
(<1000 and >5000 Hz) and slightly amplifies those frequencies between 
1000 and 5000 Hz to which the ear is more sensitive.
    Designated representative. Any individual or organization to whom a 
miner gives written authorization to exercise a right of access to 
records.
    Exchange rate. The amount of increase in sound level, in decibels, 
which would require halving of the allowable exposure time to maintain 
the same noise dose.
    Hearing conservation program (HCP). The term is used in this part 
as a generic reference to the requirements of Secs. 62.140 through 
62.190, such as audiometric testing, evaluation and follow-up 
examinations.
    Hearing protector. Any device or material, capable of being worn on 
the head or in the ear canal, sold wholly or in part on the basis of 
its ability to reduce the level of sound entering the ear, and that has 
a scientifically accepted indicator of noise reduction value.
    Hertz (Hz). Unit of measurement of frequency numerically equal to 
cycles per second. The audible range of frequencies for humans with 
normal hearing is 20 to 20000 Hz.
    Medical pathology. A condition or disease affecting the ear.
    Qualified technician. A technician who has been certified by the 
Council for Accreditation in Occupational Hearing Conservation (CAOHC) 
or by another recognized organization offering equivalent 
certification.
    Reportable hearing loss. A change in hearing acuity for the worse, 
relative to the miner's baseline audiogram or, in the case of a 
supplemental baseline audiogram established pursuant to 
Sec. 62.140(d)(2), relative to such supplemental baseline audiogram, of 
an average of 25 dB or more at 2000, 3000, and 4000 Hz in either ear.
    Sound level. The sound pressure level measured in decibels using a 
weighting network (e.g., A-weighted) and exponential time averaging 
(e.g., slow response). The A-weighting network and the slow response 
time are defined in ANSI S1.4-1983, ``American National Standard 
Specification for Sound Level Meters.''
    Standard threshold shift (STS). A change in hearing acuity for the 
worse relative to the miner's baseline audiogram, or relative to the 
most recent supplemental baseline audiogram where one has been 
established, of an average of 10 dB or more at 2000, 3000, and 4000 Hz 
in either ear.
    Supplemental baseline audiogram. An annual audiogram designated, as 
a result of the circumstances set forth in Sec. 62.140(d)(1) or those 
set forth in Sec. 62.140(d)(2), to be utilized in lieu of a miner's 
original baseline audiogram in measuring changes in hearing acuity.

[[Page 66466]]

    Time-weighted average-8 hour (TWA8). That sound level, which 
if constant over 8 hours, would result in the same noise dose as is 
measured.


Sec. 62.120  Limitations on noise exposure.

    (a) Dose determination.
    (1) A miner's noise dose (D) is computed by the formula: D = 
100(C1/T1 + C2/T2 + * * * + Cn/Tn), where 
Cn is the total time of exposure at a specified sound level, and 
Tn is the reference duration of exposure at that sound level set 
forth in Table 62-1.
    (2) Table 62-2 is to be utilized when converting noise measurements 
from dosage readings to equivalent TWA8 readings.

                     Table 62-1.--Reference Duration                    
------------------------------------------------------------------------
                                                              Reference 
             L (dBA, slow-response sound level)              Duration, T
                                                                (hour)  
------------------------------------------------------------------------
85.........................................................         16.0
86.........................................................         13.9
87.........................................................         12.1
88.........................................................         10.6
89.........................................................          9.2
90.........................................................          8.0
91.........................................................          7.0
92.........................................................          6.1
93.........................................................          5.3
94.........................................................          4.6
95.........................................................          4.0
96.........................................................          3.5
97.........................................................          3.0
98.........................................................          2.6
99.........................................................          2.3
100........................................................          2.0
101........................................................          1.7
102........................................................          1.5
103........................................................          1.3
104........................................................          1.1
105........................................................          1.0
106........................................................         0.87
107........................................................         0.76
108........................................................         0.66
109........................................................         0.57
110........................................................         0.50
111........................................................         0.44
112........................................................         0.38
113........................................................         0.33
114........................................................         0.29
115........................................................         0.25
------------------------------------------------------------------------
Note: For any value, the reference duration (T) in hours is computed by:
  T = 8/2(L-90)/5, where L is the measured A-weighted, slow-response    
  sound level.                                                          


        Table 62-2.--Conversion From ``Dose'' to Equivalent TWA8        
------------------------------------------------------------------------
               Dose (percent noise exposure)                     TWA8   
------------------------------------------------------------------------
25.........................................................         80.0
29.........................................................         81.0
33.........................................................         82.0
38.........................................................         83.0
44.........................................................         84.0
50.........................................................         85.0
57.........................................................         86.0
66.........................................................         87.0
76.........................................................         88.0
87.........................................................         89.0
100........................................................         90.0
115........................................................         91.0
132........................................................         92.0
152........................................................         93.0
174........................................................         94.0
200........................................................         95.0
230........................................................         96.0
264........................................................         97.0
303........................................................         98.0
350........................................................         99.0
400........................................................        100.0
460........................................................        101.0
530........................................................        102.0
610........................................................        103.0
700........................................................        104.0
800........................................................        105.0
920........................................................        106.0
1056.......................................................        107.0
1213.......................................................        108.0
1393.......................................................        109.0
1600.......................................................        110.0
1838.......................................................        111.0
2111.......................................................        112.0
2425.......................................................        113.0
2786.......................................................        114.0
3200.......................................................        115.0
3676.......................................................        116.0
4222.......................................................        117.0
4850.......................................................        118.0
5572.......................................................        119.0
6400.......................................................        120.0
------------------------------------------------------------------------
Interpolate between the values found in this Table, or extend the table,
  by using the formula: TWA8 = 16.61 log10 (D/100) + 90.                

    (3) A miner's noise exposure measurement shall:
    (i) Not be adjusted on account of the use of any hearing protector;
    (ii) Integrate all sound levels from 80 dBA to at least 130 dBA 
during the miner's full workshift;
    (iii) Use a 90 dBA criterion level and a 5-dB exchange rate; and
    (iv) Use an A-weighting and a slow-response instrument setting.
    (b) Action level. When a miner's noise exposure exceeds a TWA8 
of 85 dBA during any workshift, or equivalently a dose of 50%, the 
operator shall take the actions specified in paragraphs (b)(1) and (2) 
of this section and, at the request of the miner, also take the actions 
specified in paragraph (b)(3) of this section.
    (1) An operator shall provide the miner training that includes the 
instruction required by Sec. 62.130, at the time exposure exceeds the 
action level and every 12 months thereafter that exposure continues to 
exceed the action level.
    (2) An operator shall enroll the miner in a hearing conservation 
program which shall meet the requirements of Secs. 62.140 through 
62.190. Moreover, the operator shall, with respect to any miner 
enrolled in such program, provide hearing protection in accordance with 
the requirements of Sec. 62.125 until such time as a baseline audiogram 
has been obtained. If it takes more than 6 months to conduct the 
baseline audiogram, or if the miner is determined to have incurred an 
STS, the operator shall ensure that the hearing protection is provided 
to the miner and worn by the miner.
    (3) At the request of any miner, the operator shall provide hearing 
protection to the miner in accordance with the requirements of 
Sec. 62.125.
    (c) Permissible exposure level (PEL). No miner shall be exposed to 
noise exceeding a TWA8 of 90 dBA (PEL) during any workshift, or 
equivalently a dose of 100%.
    (1) If a miner's noise exposure exceeds the PEL, the operator 
shall, in addition to taking the actions required under paragraph (b) 
of this section, use all feasible engineering and administrative 
controls to reduce the miner's noise exposure to the PEL. When 
administrative controls are used to reduce a miner's exposure, the 
operator shall post these procedures on the mine bulletin board and 
provide a copy to affected miners.
    (2) If a miner's noise exposure exceeds the PEL despite the use of 
the controls required by paragraph (c)(1) of this section, the operator 
shall take the actions required by this paragraph for that miner.
    (i) The operator shall use the controls required by paragraph 
(c)(1) of this section to reduce the miner's noise exposure to as low a 
level as is feasible.
    (ii) The operator shall ensure that a miner whose exposure exceeds 
the PEL takes the hearing examinations offered through enrollment in 
the hearing conservation program.
    (iii) The operator shall provide hearing protection to a miner 
whose exposure exceeds the PEL and shall ensure the use thereof. The 
hearing protection shall be provided and used in accordance with the 
requirements of Sec. 62.125.
    (d) Dual hearing protection level. Whenever a miner's noise 
exposure exceeds a TWA8 of 105 dBA during any workshift, or 
equivalently a dose of 800%, the operator shall ensure that the miner 
is provided and uses both ear plug and ear muff type protectors 
pursuant to Sec. 62.125.
    (e) Ceiling level. At no time shall a miner be exposed to sound 
levels exceeding 115 dBA.

[[Page 66467]]

    (f) Operator exposure evaluation; employee notification.
    (1) Operators shall establish a system of monitoring which 
effectively evaluates each miner's noise exposure.
    (2) Whenever a miner's exposure is determined to exceed the action 
level, the permissible exposure level, the dual hearing protection 
level, or the ceiling level established by this section, according to 
exposure evaluations conducted either by the operator or by 
representatives of the Secretary of Labor, and the miner has not 
received notification of exposure at such level within the prior 12 
months, the operator shall, within 15 calendar days, notify the miner 
in writing of the exposure determination and the corrective action 
being taken. The operator shall maintain at the mine site a copy of any 
such miner notification, or a list on which the relevant information 
about that miner's notice is recorded, for the duration of the affected 
miner's exposure above the action level and for at least 6 months 
thereafter.


Sec. 62.125  Hearing protectors.

    When hearing protection is required pursuant to this part, an 
operator shall:
    (a) Allow the miner, after such miner has received the training 
specified by Sec. 62.130 at least once, to choose a hearing protector 
from at least one muff type and one plug type, and in the event dual-
hearing protection is required, to choose one of each type;
    (b) In those cases in which the operator is required to ensure the 
use by a miner of hearing protection, ensure that the protector is worn 
by the miner when exposed to sound levels which are required to be 
integrated into a miner's noise exposure measurement;
    (c) Ensure that the hearing protection is fitted and maintained in 
accordance with the manufacturer's instructions;
    (d) Provide the hearing protectors and necessary replacements at no 
cost to the miner; and
    (e) Allow the miner to choose a different hearing protector if 
wearing the selected protector is subsequently precluded due to medical 
pathology of the ear.


Sec. 62.130  Training.

    (a) Miner training required by this part shall include the 
following instruction:
    (1) The effects of noise on hearing;
    (2) The purpose and value of wearing hearing protectors;
    (3) The advantages and disadvantages of the hearing protectors to 
be offered;
    (4) The care, fitting, and use of the hearing protector worn by the 
miner and the various types of hearing protectors offered by the 
operator;
    (5) The general requirements of this part;
    (6) The operator's and miner's respective tasks in maintaining mine 
noise controls; and
    (7) The purpose and value of audiometric testing and a summary of 
the procedures.
    (b) The training requirement under this part shall only be met if 
the operator certifies the date and type of training given each miner. 
The type of training may be initial noise training of a miner, annual 
retraining of a miner, or special retraining required for a miner as a 
result of the detection of an STS. The certification shall be signed by 
the person conducting the training. The operator shall maintain the 
miner's most recent certification at the mine site for as long as the 
miner is exposed to noise above the level which required the training 
and for at least 6 months thereafter.


Sec. 62.140  Audiometric testing program.

    (a) Audiometric tests performed pursuant to this part shall be 
conducted by a physician, an audiologist, or a qualified technician 
under the direction or supervision of a physician or an audiologist, 
and pursuant to the procedures set forth in Sec. 62.150.
    (b) Baseline audiogram. A miner enrolled in a hearing conservation 
program shall be offered a valid baseline audiogram of the miner's 
hearing acuity against which subsequent annual audiograms can be 
compared.
    (1) The valid baseline audiogram shall be offered within 6 months 
of enrolling the miner in an HCP, except that where mobile test vans 
are used to meet the audiometric test requirements of this section, the 
valid baseline audiogram shall be offered within 12 months of enrolling 
the miner in an HCP. An existing audiogram of the miner's hearing 
acuity may be used as the baseline audiogram if it meets the 
audiometric testing requirements of this part.
    (2) The operator shall not expose the miner to workplace noise for 
at least 14 hours before conducting the baseline audiogram. Hearing 
protectors shall not be used as a substitute for this quiet period.
    (3) The operator shall notify miners of the need to avoid high 
levels of noise during the 14-hour quiet period before taking the 
baseline audiogram.
    (4) The operator shall not revise either a miner's baseline 
audiogram, or supplemental baseline audiogram where one has been 
established, due to changes in enrollment status in the HCP except for 
periods of unemployment exceeding 6 consecutive months.
    (c) Annual audiogram. After establishing the baseline audiogram, 
the operator shall offer a subsequent valid audiogram at intervals not 
exceeding 12 months for as long as the miner remains in the HCP.
    (d) Supplemental baseline audiogram. An annual audiogram shall be 
deemed to be a supplemental baseline audiogram when, in the judgment of 
the audiologist or physician:
    (1) The standard threshold shift (STS) revealed by the audiogram is 
permanent; or
    (2) The hearing threshold shown in the annual audiogram indicates 
significant improvement over the baseline audiogram.


Sec. 62.150  Audiometric test procedures.

    (a) The operator shall assure that all audiometric testing required 
under this part is conducted in accordance with scientifically 
validated procedures. Audiometric tests shall be pure tone, air 
conduction, hearing threshold examinations, with test frequencies 
including as a minimum 500, 1000, 2000, 3000, 4000, and 6000 Hz. Each 
ear shall be tested separately.
    (b) The operator shall obtain from the physician, audiologist, or 
qualified technician who conducts an audiometric test required under 
this part, a certification that the testing was conducted in accordance 
with paragraph (a) of this section.
    (c) The operator shall compile an audiometric test record for each 
miner tested. Such record shall include the following:
    (1) Name and job classification of the miner who has undergone the 
audiometric test(s);
    (2) A copy of all of the miner's audiograms required under this 
part;
    (3) Certification(s) as required under paragraph (b) of this 
section;
    (4) Any exposure determination for the miner; and
    (5) The results of any follow-up examination(s).
    (d) Audiometric test records shall be maintained at the mine site 
for the duration of the affected miner's employment plus at least 6 
months.


Sec. 62.160  Evaluation of audiogram.

    (a) The operator shall:
    (1) Inform persons evaluating audiograms of the requirements of 
this part and provide them with a copy of the miner's audiometric test 
records;
    (2) Have a physician, an audiologist, or a qualified technician who 
is under the direction or supervision of a physician or audiologist:
    (i) Determine if the audiogram is valid; and

[[Page 66468]]

    (ii) Determine if an STS or a reportable hearing loss, as defined 
in this part, has occurred;
    (3) Instruct the physician or audiologist not to reveal to the 
operator any specific findings or diagnoses unrelated to the miner's 
exposure to noise or wearing of hearing protectors without the written 
consent of the miner; and
    (4) Obtain the results, and the interpretation of the results of 
any audiogram conducted under this part within 30 calendar days of 
conducting the audiogram.
    (b)(1) The operator shall conduct an audiometric retest within 30 
calendar days of receiving a determination that a required audiogram is 
invalid and that any medical pathology has improved to the point that a 
valid audiogram may be obtained.
    (2) If the results of an annual audiogram demonstrate that the 
miner has incurred an STS or reportable hearing loss, the operator may 
conduct one retest within 30 calendar days of receiving the results of 
the audiogram and consider the results of the retest as the annual 
audiogram.
    (c) In determining whether an STS or reportable hearing loss has 
occurred, allowance may be made for the contribution of aging 
(presbycusis) to the change in hearing level by adjusting the 
audiograms used in making those determinations according to the 
following procedures:
    (1) Determine from Tables 62-3 or 62-4 the age correction values 
for the miner by:
    (i) Finding the age at which the baseline audiogram, or 
supplemental baseline audiogram as appropriate, was taken, and 
recording the corresponding values of age corrections at 2000, 3000, 
and 4000 Hz; and
    (ii) Finding the age at which the most recent audiogram was taken 
and recording the corresponding values of age corrections at 2000, 
3000, and 4000 Hz.
    (2) Subtract the value determined in paragraph (c)(1)(i) of this 
section from the value determined in paragraph (c)(1)(ii) of this 
section. The differences calculated represent that portion of the 
change in hearing that may be due to aging.
    (3) Subtract the value determined in paragraph (c)(2) of this 
section from the hearing threshold level found in the annual audiogram 
to obtain the adjusted annual audiogram hearing threshold level.
    (4) Subtract the hearing threshold in the baseline audiogram or 
supplemental baseline audiogram from the adjusted annual audiogram 
hearing threshold level determined in paragraph (c)(3) of this section 
to obtain the age-corrected threshold shift.

         Table 62-3.--Age Correction Value in Decibels for Males        
------------------------------------------------------------------------
                                                    Audiometric test    
                                                    frequencies (Hz)    
                    Years                     --------------------------
                                                 2000     3000     4000 
------------------------------------------------------------------------
20 or younger................................        3        4        5
21...........................................        3        4        5
22...........................................        3        4        5
23...........................................        3        4        6
24...........................................        3        5        6
25...........................................        3        5        7
26...........................................        4        5        7
27...........................................        4        6        7
28...........................................        4        6        8
29...........................................        4        6        8
30...........................................        4        6        9
31...........................................        4        7        9
32...........................................        5        7       10
33...........................................        5        7       10
34...........................................        5        8       11
35...........................................        5        8       11
36...........................................        5        9       12
37...........................................        6        9       12
38...........................................        6        9       13
39...........................................        6       10       14
40...........................................        6       10       14
41...........................................        6       10       14
42...........................................        7       11       16
43...........................................        7       12       16
44...........................................        7       12       17
45...........................................        7       13       18
46...........................................        8       13       19
47...........................................        8       14       19
48...........................................        8       14       20
49...........................................        9       15       21
50...........................................        9       16       22
51...........................................        9       16       23
52...........................................       10       17       24
53...........................................       10       18       25
54...........................................       10       18       26
55...........................................       11       19       27
56...........................................       11       20       28
57...........................................       11       21       29
58...........................................       12       22       31
59...........................................       12       22       32
60 or older..................................       13       23       33
------------------------------------------------------------------------


        Table 62-4.--Age Correction Value in Decibels for Females       
------------------------------------------------------------------------
                                                    Audiometric test    
                                                    frequencies (Hz)    
                    Years                     --------------------------
                                                 2000     3000     4000 
------------------------------------------------------------------------
20 or younger................................        4        3        3
21...........................................        4        4        3
22...........................................        4        4        4
23...........................................        5        4        4
24...........................................        5        4        4
25...........................................        5        4        4
26...........................................        5        5        4
27...........................................        5        5        5
28...........................................        5        5        5
29...........................................        5        5        5
30...........................................        6        5        5
31...........................................        6        6        5
32...........................................        6        6        6
33...........................................        6        6        6
34...........................................        6        6        6
35...........................................        6        7        7
36...........................................        7        7        7
37...........................................        7        7        7
38...........................................        7        7        7
39...........................................        7        8        8
40...........................................        7        8        8
41...........................................        8        8        8
42...........................................        8        9        9
43...........................................        8        9        9
44...........................................        8        9        9
45...........................................        8       10       10
46...........................................        9       10       10
47...........................................        9       10       11
48...........................................        9       11       11
49...........................................        9       11       11
50...........................................       10       11       12
51...........................................       10       12       12
52...........................................       10       12       13
53...........................................       10       13       13
54...........................................       11       13       14
55...........................................       11       14       14
56...........................................       11       14       15
57...........................................       11       15       15
58...........................................       12       15       16
59...........................................       12       16       16
60 or older..................................       12       16       17
------------------------------------------------------------------------

Sec. 62.170  Follow-up evaluation when audiogram invalid.

    (a) If a valid audiogram cannot be obtained due to a suspected 
medical pathology of the ear which the physician or audiologist 
believes was caused or aggravated by the miner's exposure to noise or 
the wearing of hearing protectors, the operator shall refer the miner 
for a clinical audiological evaluation or an otological examination, as 
appropriate, at no cost to the miner.
    (b) The operator shall instruct the physician or audiologist that 
if a valid audiogram cannot be obtained due to a suspected medical 
pathology of the ear which the physician or audiologist concludes is 
unrelated to the miner's exposure to noise or the wearing of hearing 
protectors, the physician or audiologist shall inform the miner of the 
need for an otological examination.
    (c) The operator shall instruct the physician or audiologist not to 
reveal to the operator any specific findings or diagnoses unrelated to 
the miner's exposure to noise or the wearing of hearing protectors 
without the written consent of the miner.

[[Page 66469]]

Sec. 62.180  Follow-up corrective measures when STS detected.

    Unless a physician or audiologist determines that an STS is neither 
work-related nor aggravated by occupational noise exposure, the 
operator shall within 30 calendar days of receiving evidence of an STS 
or receiving the results of a retest confirming an STS:
    (a) Retrain the miner, including the instruction required by 
Sec. 62.130;
    (b) Provide the miner with the opportunity to select a hearing 
protector, or a different hearing protector if the miner has previously 
selected a hearing protector, from among those offered by the operator 
pursuant to Sec. 62.125; and
    (c) Review the effectiveness of any engineering and administrative 
controls to identify and correct any deficiencies.


Sec. 62.190  Notification of results; reporting requirements.

    (a) Within 10 working days of receiving the results of an 
audiogram, or receiving the results of a follow-up evaluation required 
under Sec. 62.170(a), the operator shall notify the miner in writing 
of:
    (1) The results and interpretation of the audiometric test, 
including any finding of an STS or reportable hearing loss; and
    (2) If applicable, the need and reasons for any further testing or 
evaluation.
    (b) If evaluation of the audiogram shows that a miner has incurred 
a reportable hearing loss as defined in this part, the operator shall 
report such loss to MSHA as a noise-induced hearing loss in accordance 
with part 50 of this title unless a physician or audiologist has 
determined that the loss is neither work-related nor aggravated by 
occupational noise exposure.


Sec. 62.200  Access to records.

    (a) The authorized representatives of the Secretaries of Labor and 
Health and Human Services shall have access to all records required 
under this part. Upon written request, the operator shall provide, 
within 15 calendar days of the request, access to records as indicated 
below:
    (1) The miner, former miner, or, with the miner's written consent, 
the miner's designated representative shall have access to all records 
that the operator is required to maintain for that individual miner 
under this part; and
    (2) The miners' representative shall in all cases have access to 
training records compiled pursuant to section Sec. 62.130, and to 
copies of notices made pursuant to Sec. 62.120(f)(2), for the miners 
whom they represent.
    (b) Upon termination of a miner's employment, the operator shall 
provide the miner without cost with a copy of all records that the 
operator is required to maintain for that individual miner under this 
part.
    (c) If a person who has access to certain records under this 
section requests a copy of a record, the operator shall provide the 
first copy of such record requested by a person at no cost to that 
person, and any additional copies requested by that person at 
reasonable cost.


Sec. 62.210  Transfer of records.

    (a) Whenever an operator ceases to do business, that operator shall 
transfer all records required to be maintained by this part, or a copy 
thereof, to any successor operator who shall receive these records and 
maintain them for the required period.
    (b) The successor operator shall use the baseline audiogram, or 
supplemental baseline audiogram as appropriate, obtained by the 
original operator for determining the existence of an STS or reportable 
hearing loss.

[FR Doc. 96-30733 Filed 12-16-96; 8:45 am]
BILLING CODE 4510-43-P