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Persistent hearing threshold shift and baseline audiograms

Summary An audiologist asked what OSHA meant by a persistent standard threshold shift in hearing tests. OSHA said it meant a shift confirmed by a later audiogram. The rule permitted, but did not require, a supervising audiologist to use the annual test as a new baseline when they judged the shift persistent.
Document
Federal opinion letter
Agency
Occupational Safety and Health Administration (OSHA)
Document number
1986-06-04-0
Date issued
June 4, 1986
Status
Active
Status last verified October 10, 2026
Topics
Workplace Safety OSHA 1910 Hearing Conservation Audiograms
Source
View the official document

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About this page: The full text below is the official document from Occupational Safety and Health Administration (OSHA). Ezel adds the plain-English summary and tracks the document's status. The official source linked on this page is authoritative for any reliance.

June 4, 1986

Ms. Mari Franqui
CCC-A, Audiologist
ADVANTAGE Health Systems, Inc.
[Recipient address omitted]
Dear Ms. Franqui:

This is in response to your letter of March 31 concerning persistent standard threshold shift (STS).

"Persistent STS" is a term the Occupational Safety and Health Administration (OSHA) uses to mean an STS that is subsequently confirmed by another audiogram.

If you are supervising the audiometric testing program, then, in accordance with 29 CFR 1910.95(g)(9)(i), you as an audiologist may substitute an annual audiogram for the baseline audiogram when in your judgment the annual audiogram reveals that an STS is persistent. It is not mandatory that you make the substitution, but whenever you conclude that it is appropriate, the above cited provision permits that the substitution be made.

Thank you for contacting us. If we may assist you again in the future, we shall be glad to do so.

Sincerely,
John B. Miles, Jr., Director
Directorate of Field Operations

[Requester letter reproduced on OSHA page; omitted here.]

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