OSHA Regulations (Standards - 29 CFR)
Occupational noise exposure. - 1910.95
- Standard Number: 1910.95
- Standard Title: Occupational noise exposure.
- SubPart Number: G
- SubPart Title: Occupational Health and Environmental Control
Protection against the effects of noise exposure shall be provided when
the sound levels exceed those shown in Table G-16 when measured on the A scale of a
standard sound level meter at slow response. When noise levels are determined by octave
band analysis, the equivalent A-weighted sound level may be determined as follows:
FIGURE G-9 - Equivalent A-Weighted Sound Level
Equivalent sound level contours. Octave band sound pressure levels may
be converted to the equivalent A-weighted sound level by plotting them on this graph and
noting the A-weighted sound level corresponding to the point of highest penetration into
the sound level contours. This equivalent A-weighted sound level, which may differ from
the actual A-weighted sound level of the noise, is used to determine exposure limits from
When employees are subjected to sound exceeding those listed in Table
G-16, feasible administrative or engineering controls shall be utilized. If such controls
fail to reduce sound levels within the levels of Table G-16, personal protective equipment
shall be provided and used to reduce sound levels within the levels of the table.
If the variations in noise level involve maxima at intervals of 1 second
or less, it is to be considered continuous.
TABLE G-16 - PERMISSIBLE NOISE EXPOSURES (1)
Duration per day, hours
Sound level dBA slow response
1 1/2 ..........................
1/4 or less..................
Footnote(1) When the daily noise exposure is composed of two or
more periods of noise exposure of different levels, their combined
effect should be considered, rather than the individual effect of
each. If the sum of the following fractions: C(1)/T(1) + C(2)/T(2)
C(n)/T(n) exceeds unity, then, the mixed exposure should be
considered to exceed the limit value. Cn indicates the total time of
exposure at a specified noise level, and Tn indicates the total time
of exposure permitted at that level. Exposure to impulsive or impact
noise should not exceed 140 dB peak sound pressure level.
"Hearing conservation program."
The employer shall administer a continuing, effective hearing
conservation program, as described in paragraphs (c) through (o) of this section, whenever
employee noise exposures equal or exceed an 8-hour time-weighted average sound level (TWA)
of 85 decibels measured on the A scale (slow response) or, equivalently, a dose of fifty
percent. For purposes of the hearing conservation program, employee noise exposures shall
be computed in accordance with appendix A and Table G-16a, and without regard to any
attenuation provided by the use of personal protective equipment.
For purposes of paragraphs (c) through (n) of this section, an 8-hour
time-weighted average of 85 decibels or a dose of fifty percent shall also be referred to
as the action level.
When information indicates that any employee's exposure may equal or
exceed an 8-hour time-weighted average of 85 decibels, the employer shall develop and
implement a monitoring program.
The sampling strategy shall be designed to identify employees for
inclusion in the hearing conservation program and to enable the proper selection of
Where circumstances such as high worker mobility, significant variations
in sound level, or a significant component of impulse noise make area monitoring generally
inappropriate, the employer shall use representative personal sampling to comply with the
monitoring requirements of this paragraph unless the employer can show that area sampling
produces equivalent results.
All continuous, intermittent and impulsive sound levels from 80 decibels
to 130 decibels shall be integrated into the noise measurements.
Instruments used to measure employee noise exposure shall be calibrated
to ensure measurement accuracy.
Monitoring shall be repeated whenever a change in production, process,
equipment or controls increases noise exposures to the extent that:
Additional employees may be exposed at or above the action level; or
The attenuation provided by hearing protectors being used by employees
may be rendered inadequate to meet the requirements of paragraph (j) of this section.
"Employee notification." The employer shall notify each
employee exposed at or above an 8-hour time-weighted average of 85 decibels of the results
of the monitoring.
"Observation of monitoring." The employer shall provide
affected employees or their representatives with an opportunity to observe any noise
measurements conducted pursuant to this section.
"Audiometric testing program."
The employer shall establish and maintain an audiometric testing program
as provided in this paragraph by making audiometric testing available to all employees
whose exposures equal or exceed an 8-hour time-weighted average of 85 decibels.
The program shall be provided at no cost to employees.
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 in 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 operates microprocessor
audiometers does not need to be certified. A technician who performs audiometric tests
must be responsible to an audiologist, otolaryngologist or physician.
All audiograms obtained pursuant to this section shall meet the
requirements of Appendix C: "Audiometric Measuring Instruments."
Within 6 months of an employee's first exposure at or above the action
level, the employer shall establish a valid baseline audiogram against which subsequent
audiograms can be compared.
"Mobile test van exception." Where mobile test vans are used
to meet the audiometric testing obligation, the employer shall obtain a valid baseline
audiogram within 1 year of an employee's first exposure at or above the action level.
Where baseline audiograms are obtained more than 6 months after the employee's first
exposure at or above the action level, employees shall wearing hearing protectors for any
period exceeding six months after first exposure until the baseline audiogram is obtained.
Testing to establish a baseline audiogram shall be preceded by at least
14 hours without exposure to workplace noise. Hearing protectors may be used as a
substitute for the requirement that baseline audiograms be preceded by 14 hours without
exposure to workplace noise.
The employer shall notify employees of the need to avoid high levels of
non-occupational noise exposure during the 14-hour period immediately preceding the
"Annual audiogram." At least annually after obtaining the
baseline audiogram, the employer shall obtain a new audiogram for each employee exposed at
or above an 8-hour time-weighted average of 85 decibels.
"Evaluation of audiogram."
Each employee's annual audiogram shall be compared to that employee's
baseline audiogram to determine if the audiogram is valid and if a standard threshold
shift as defined in paragraph (g)(10) of this section has occurred. This comparison may be
done by a technician.
If the annual audiogram shows that an employee has suffered a standard
threshold shift, the employer may obtain a retest within 30 days and consider the results
of the retest as the annual audiogram.
The audiologist, otolaryngologist, or physician shall review problem
audiograms and shall determine whether there is a need for further evaluation. The
employer shall provide to the person performing this evaluation the following information:
A copy of the requirements for hearing conservation as set forth in
paragraphs (c) through (n) of this section;
The baseline audiogram and most recent audiogram of the employee to be
Measurements of background sound pressure levels in the audiometric test
room as required in Appendix D: Audiometric Test Rooms.
Records of audiometer calibrations required by paragraph (h)(5) of this
If a comparison of the annual audiogram to the baseline audiogram
indicates a standard threshold shift as defined in paragraph (g)(10) of this section has
occurred, the employee shall be informed of this fact in writing, within 21 days of the
Unless a physician determines that the standard threshold shift is not
work related or aggravated by occupational noise exposure, the employer shall ensure that
the following steps are taken when a standard threshold shift occurs:
Employees not using hearing protectors shall be fitted with hearing
protectors, trained in their use and care, and required to use them.
Employees already using hearing protectors shall be refitted and
retrained in the use of hearing protectors and provided with hearing protectors offering
greater attenuation if necessary.
The employee shall be referred for a clinical audiological evaluation or
an otological examination, as appropriate, if additional testing is necessary or if the
employer suspects that a medical pathology of the ear is caused or aggravated by the
wearing of hearing protectors.
The employee is informed of the need for an otological examination if a
medical pathology of the ear that is unrelated to the use of hearing protectors is
If subsequent audiometric testing of an employee whose exposure to noise
is less than an 8-hour TWA of 90 decibels indicates that a standard threshold shift is not
persistent, the employer:
Shall inform the employee of the new audiometric interpretation; and
May discontinue the required use of hearing protectors for that
"Revised baseline." An annual audiogram may be substituted for
the baseline audiogram when, in the judgment of the audiologist, otolaryngologist or
physician who is evaluating the audiogram:
The standard threshold shift revealed by the audiogram is persistent; or
The hearing threshold shown in the annual audiogram indicates
significant improvement over the baseline audiogram.
"Standard threshold shift."
As used in this section, a standard threshold shift is a change in
hearing threshold relative to the baseline audiogram of an average of 10 dB or more at
2000, 3000, and 4000 Hz in either ear.
In determining whether a standard threshold shift has occurred,
allowance may be made for the contribution of aging (presbycusis) to the change in hearing
level by correcting the annual audiogram according to the procedure described in Appendix
F: "Calculation and Application of Age Correction to Audiograms."
"Audiometric test requirements."
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. Tests at each frequency shall be taken separately for each ear.
Audiometric tests shall be conducted with audiometers (including
microprocessor audiometers) that meet the specifications of, and are maintained and used
in accordance with, American National Standard Specification for Audiometers, S3.6-1969,
which is incorporated by reference as specified in Sec. 1910.6.
Pulsed-tone and self-recording audiometers, if used, shall meet the
requirements specified in Appendix C: "Audiometric Measuring Instruments."
Audiometric examinations shall be administered in a room meeting the
requirements listed in Appendix D: "Audiometric Test Rooms."
The functional operation of the audiometer shall be checked before each
day's use by testing a person with known, stable hearing thresholds, and by listening to
the audiometer's output to make sure that the output is free from distorted or unwanted
sounds. Deviations of 10 decibels or greater require an acoustic calibration.
Audiometer calibration shall be checked acoustically at least annually
in accordance with Appendix E: "Acoustic Calibration of Audiometers." Test
frequencies below 500 Hz and above 6000 Hz may be omitted from this check. Deviations of
15 decibels or greater require an exhaustive calibration.
An exhaustive calibration shall be performed at least every two years in
accordance with sections 4.1.2; 4.1.3.; 18.104.22.168; 4.2; 4.4.1; 4.4.2; 4.4.3; and 4.5 of the
American National Standard Specification for Audiometers, S3.6-1969. Test frequencies
below 500 Hz and above 6000 Hz may be omitted from this calibration.
Employers shall make hearing protectors available to all employees
exposed to an 8-hour time-weighted average of 85 decibels or greater at no cost to the
employees. Hearing protectors shall be replaced as necessary.
Employers shall ensure that hearing protectors are worn:
By an employee who is required by paragraph (b)(1) of this section to
wear personal protective equipment; and
By any employee who is exposed to an 8-hour time-weighted average of 85
decibels or greater, and who:
Has not yet had a baseline audiogram established pursuant to paragraph
Has experienced a standard threshold shift.
Employees shall be given the opportunity to select their hearing
protectors from a variety of suitable hearing protectors provided by the employer.
The employer shall provide training in the use and care of all hearing
protectors provided to employees.
The employer shall ensure proper initial fitting and supervise the
correct use of all hearing protectors.
"Hearing protector attenuation."
The employer shall evaluate hearing protector attenuation for the
specific noise environments in which the protector will be used. The employer shall use
one of the evaluation methods described in Appendix B: "Methods for Estimating the
Adequacy of Hearing Protection Attenuation."
Hearing protectors must attenuate employee exposure at least to an
8-hour time-weighted average of 90 decibels as required by paragraph (b) of this section.
For employees who have experienced a standard threshold shift, hearing
protectors must attenuate employee exposure to an 8-hour time-weighted average of 85
decibels or below.
The adequacy of hearing protector attenuation shall be re-evaluated
whenever employee noise exposures increase to the extent that the hearing protectors
provided may no longer provide adequate attenuation. The employer shall provide more
effective hearing protectors where necessary.
The employer shall institute a training program for all employees who
are exposed to noise at or above an 8-hour time-weighted average of 85 decibels, and shall
ensure employee participation in such program.
The training program shall be repeated annually for each employee
included in the hearing conservation program. Information provided in the training program
shall be updated to be consistent with changes in protective equipment and work processes.
The employer shall ensure that each employee is informed of the
The effects of noise on hearing;
The purpose of hearing protectors, the advantages, disadvantages, and
attenuation of various types, and instructions on selection, fitting, use, and care; and
The purpose of audiometric testing, and an explanation of the test
"Access to information and training materials."
The employer shall make available to affected employees or their
representatives copies of this standard and shall also post a copy in the workplace.
The employer shall provide to affected employees any informational
materials pertaining to the standard that are supplied to the employer by the Assistant
The employer shall provide, upon request, all materials related to the
employer's training and education program pertaining to this standard to the Assistant
Secretary and the Director.
"Exposure measurements." The employer shall maintain an
accurate record of all employee exposure measurements required by paragraph (d) of this
The employer shall retain all employee audiometric test records obtained
pursuant to paragraph (g) of this section:
This record shall include:
Name and job classification of the employee;
Date of the audiogram;
The examiner's name;
Date of the last acoustic or exhaustive calibration of the audiometer;
Employee's most recent noise exposure assessment.
The employer shall maintain accurate records of the measurements of the
background sound pressure levels in audiometric test rooms.
"Record retention." The employer shall retain records required
in this paragraph (m) for at least the following periods.
Noise exposure measurement records shall be retained for two years.
Audiometric test records shall be retained for the duration of the
affected employee's employment.
"Access to records." All records required by this section
shall be provided upon request to employees, former employees, representatives designated
by the individual employee, and the Assistant Secretary. The provisions of 29 CFR 1910.20
(a)-(e) and (g)-
apply to access to records under this section.
"Transfer of records." If the employer ceases to do business,
the employer shall transfer to the successor employer all records required to be
maintained by this section, and the successor employer shall retain them for the remainder
of the period prescribed in paragraph (m)(3) of this section.
Appendices A, B, C, D, and E to this section are incorporated as part of
this section and the contents of these appendices are mandatory.
Appendices F and G to this section are informational and are not
intended to create any additional obligations not otherwise imposed or to detract from any
"Exemptions." Paragraphs (c) through (n) of this section shall
not apply to employers engaged in oil and gas well drilling and servicing operations.
"Startup date." Baseline audiograms required by paragraph (g)
of this section shall be completed by March 1, 1984.
[39 FR 23502, June 27, 1974, as amended at 46 FR 4161, Jan. 16, 1981; 46
FR 62845, Dec. 29, 1981; 48 FR 9776, Mar. 8, 1983; 48 FR 29687, June 28, 1983; 54 FR
24333, June 7, 1989; 61 FR 5507, Feb. 13, 1996; 61 FR 9227, March 7, 1996]