July 19, 1989

MEMORANDUM FOR:   LINDA R. ANKU
                 REGIONAL ADMINISTRATOR

THROUGH:          LEO CAREY, DIRECTOR
                 OFFICE OF FIELD PROGRAMS

FROM:             PATRICIA K. CLARK, ACTING DIRECTOR
                 DIRECTORATE OF COMPLIANCE PROGRAMS

SUBJECT:         Policy concerning OSHA's Hearing Conservation Amendment

It appears that the policy issues are:

1. Is it acceptable to revise baselines that are discovered to be invalid due to improper testing procedures; and

2. Must employees be notified of hearing loss if none occurred once the invalid baselines are revised.

The standard allows for valid baselines to be revised when:

1. A standard threshold shift (STS) is persistent; or

2. An annual audiogram shows significant improvement.

In order for an audiogram to be valid it must, in addition to other factors, meet the audiometric test requirements of the standard (1910.95(h)). If it is later discovered and sufficiently documented that the baseline was not valid then the first valid audiogram becomes the valid baseline for the purposes of comparing future audiograms. Thus, it may be acceptable to revise baselines that are discovered to be invalid due to improper testing procedures. However, we are confused as to how the company can show by using more recent audiograms that the original baselines should have shown the employees had worse hearing.

Employers must have notified employees, however, of any STS's that occurred prior to the revision of the baseline. Notification of the occurrence of a STS must be within 21 days of the determination. Thus, there should not be underreporting of STS's. If it is later determined that the baseline is invalid and that actually no STS's occurred, then the employer should notify all affected employees of the new results. In addition, all audiometric test records, including any invalid ones, must be retained for the duration of the affected employee's employment.

I hope this information is helpful.