July 29, 1991

Mr. Claud Gingrich
L. A. Motley and Company
1800 K Street, N.W., Suite 1000
Washington, D.C. 20006

Dear Mr. Gingrich:

This is in response to Cabot Safety Corporation's request regarding an insert earphone for audiometric testing it manufactures that is designated ER-3A. The company is seeking a determination from the Occupational Safety and Health Administration (OSHA) that an employer using the insert earphone for conducting the audiometric testing it must make available for its employees under the requirements of the standard for occupational noise exposure, 29 CFR 1910.95, is committing a de minimis violation.

OSHA has concluded that an employer using insert earphone ER-3A is committing a de minimis violation of 29 CFR 1910.95(h)(2) if all the following procedures are observed:

(1)

The audiometer is calibrated using the reference equivalent threshold sound pressure levels and the coupler presented in Appendix G to ANSI S3.6-1989.

(2)

Employees are informed that audiometric testing with insert earphones is optional and, if they prefer, they may continue to have their hearing tested using supra-aural earphones.

(3)

Industrial audiometry using ER-3A insert earphones is not substituted for referring an employee for a clinical audiological evaluation.

(4)

The testing is done in a room where the background sound pressure levels meet OSHA's requirements.

(5)

Measurements of background sound pressure levels in the audiometric test room are done as frequently as necessary to identify how the levels differ during audiometric testing with supra-aural earphones from the levels during audiometric testing with ER-3A insert earphones.

(6)

Measurements of background sound pressure levels are recorded and the records are retained as long as they relate to any current employee's audiograms and, upon request, are provided for review to the Assistant Secretary of Labor for Occupational Safety and Health, or a designee.

(7)

The audiologist, otolaryngologist, or other physician responsible for conducting the audiological testing identifies ear canals that prevent achievement of an acceptable fit with insert earphones, or assures that any technician under his/her authority who conducts audiometric testing with insert earphones has the ability to and does identify such ear canals.

(8)

The ER-3A insert earphones are not used for audiometric testing of employees with ear canals that prevent achievement of an acceptable fit.

(9)

Technicians who conduct audiometric tests are successfully trained in the correct insertion of the earphones into the ear canals.

(10)

When the change in earphones is made, final audiometric testing with supra-aural earphones is also conducted when initial testing with ER-3A insert earphones is conducted.

(11)

The final audiogram obtained with supra-aural earphones is compared with the baseline audiogram obtained with supra-aural earphones to determine if an employee has suffered a standard threshold shift (STS) and to determine whether to adopt the final audiogram obtained with supra-aural earphones as a revised baseline.

(12)

A baseline audiogram for comparing future audiograms to be obtained with ER-3A insert earphones is compiled from the initial audiogram obtained with ER-3A insert earphones and the baseline audiogram obtained with supra-aural earphones. The baseline audiogram is compiled by using the lowest hearing level from the two audiograms for each test frequency. The audiologist, otolaryngologist, or other physician responsible for conducting the audiological testing personally compiles the audiogram.

(13)

The audiograms and calculations involved in performing procedure (11) are preserved as records and retained for the duration of the affected employee's employment and, upon request, are provided for review to the Assistant Secretary of Labor for Occupational Safety and Health, or a designee.

An example to help explain procedure (11) follows:

    Test frequency (Hertz)..............    500    1000    2000    3000    4000    6000

    Baseline audiogram obtained 
      with supra aural earphones (dB)...     25      25      20      20      20      15

    Initial audiogram obtained 
      with ER-3A insert earphones.......      0       0       5      20      20      20

    Baseline audiogram compiled 
      from the two above audiograms.....      0       0       5      20      20      15

Sincerely,

Patricia K. Clark, Director
Directorate of Compliance Programs