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U.S. Department of Labor |
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| Occupational Safety &
Health Administration |
Standard Interpretations
05/08/2003 - Baseline audiogram
revision due to persistent STS or improved thresholds; revision
must be made for each ear separately.
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| This letter constitutes OSHA's
interpretation only of the requirements discussed and
may not be applicable to any situation not delineated
within the original correspondence. |
May 8, 2003
Ms. Linda Ballas
Linda Ballas & Associates
4413 Copper Creek Lane
Toledo, OH 43615
Dear Ms. Ballas:
Thank you for your January 21 letter to the Occupational Safety
and Health Administration (OSHA) regarding the Occupational
Noise standard. In your letter, you requested a clarification
about how baseline audiograms should be revised. You also
pointed out that two of our letters of interpretation provide
contradictory guidance and are causing confusion among hearing
associates. A corrected response appears below.
The Occupational Noise Standard, 29 CFR 1910.95, requires
employers to establish and maintain an audiometric testing
program for all employees whose exposures equal or exceed an
8-hour time-weighted average (TWA) of 85 decibels on the
"A" scale (dBA). Annual audiograms are compared to the
baseline audiogram to determine if hearing loss is occurring.
If a standard threshold shift (STS), defined as an average of 10
dBA or more at 2000, 3000, and 4000 Hz, occurs in either ear,
the employer must follow certain procedures outlined in the
standard, including notifying the affected employee in writing.
Hearing loss cases that meet specific criteria must be recorded
on the OSHA 300 log according to the recordkeeping requirements
of 1904.10.
With regard to your request for a clarification as to how to
revise the baseline, OSHA allows employers to revise the
baseline by substituting the annual audiogram for the baseline
audiogram when the reviewing professional determines that an STS
is persistent. Such a revision would serve to prevent the same
STS from being identified repeatedly for an employee whose
hearing has stabilized. As a corollary, an annual audiogram may
be substituted for the baseline audiogram when thresholds have
significantly improved.
When the professional evaluating the audiogram determines that a
baseline revision is appropriate, whether due to a persistent
STS or improved thresholds, the baseline must be revised for
each ear separately. For example, although an employee's annual
audiogram shows hearing thresholds deteriorating in both ears
simultaneously, occasionally an audiogram will show that an
employee is suffering an STS in only one ear. This can sometimes
be attributed to working near a loud noise source that is close
to the affected ear. If such a shift is shown to be persistent
in the judgment of the professional evaluating the audiogram,
then the baseline audiogram may be revised due to the persistent
STS. A baseline audiogram that shows a persistent shift for only
one ear may be revised for only that ear. The baseline may not
be revised for the other unaffected ear. This procedure is
required because it provides a clear indication of how each ear
is affected by noise.
Thank you for your interest in occupational safety and health
and bringing these letters to our attention. The erroneous 1996
letter to Mr. Dean Harris will be removed from our website
shortly. We hope you find this information helpful. OSHA
requirements are set by statute, standards and regulations. Our
interpretation letters explain these requirements and how they
apply to particular circumstances, but they cannot create
additional employer obligations. This letter constitutes OSHA's
interpretation of the requirements discussed. Note that our
enforcement guidance may be affected by changes to OSHA rules.
Also, from time to time we update our guidance in response to
new information. To keep apprised of such developments, you can
consult OSHA's website at http://www.osha.gov.
If you have any further questions, please feel free to contact
the Office of Health Enforcement at (202) 693-2190.
Sincerely,
Richard E. Fairfax, Director
Directorate of Enforcement Programs
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Standard Interpretations
05/08/2003 - Baseline audiogram revision
due to persistent STS or improved thresholds; revision must be made for
each ear separately.
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STS Recommendation