Quiet time before workplace audiometric testing

December 21, 2007

Mr. Milan Racic

[Recipient address omitted]

Dear Mr. Racic:

Thank you for your questions to the Occupational Safety and Health Administration's (OSHA's) Directorate of Enforcement Programs (DEP), requesting an interpretation of the Occupational Noise Exposure standard, 29 CFR 1910.95. Please be aware that this response may not be applicable to any questions or scenarios not delineated within your original correspondence. Your paraphrased questions and our replies are provided below.

Question 1: What is OSHA's position regarding the required "quiet time" before audiometric testing is done? Is it two days away from work?

Reply 1: The Occupational Noise standard at 29 CFR 1910.95(g)(5)(iii) states that testing to establish a baseline must immediately be preceded by fourteen (14) hours without workplace noise. There is no requirement for fourteen (14) hours without exposure to workplace noise for annual audiograms as there is for baseline audiograms.

However, please be aware that a temporary threshold shift (TTS) could possibly contaminate an annual audiogram if an employee was exposed to noise prior to taking the audiogram. It is this audiogram which is compared to the baseline audiogram to determine whether a Standard Threshold Shift (STS) has occurred. The audiologist, otolaryngologist, or physician cannot override this STS determination simply because of possible TTS contamination. Only a retest audiogram, taken within 30 days of the annual audiogram, can be used to replace the annual audiogram and the STS determination.

Question 2: Can an employee's audiometric testing be conducted after the employee has worked a full-shift in a noisy environment, and was wearing hearing protection?

Reply 2: Yes. An employer may substitute the use of hearing protection when the fourteen hours of quiet time cannot be met. If TTS contamination is a problem, the retest audiogram should be preceded by 14 hours free from workplace noise, (but this is not required by the standard). If no retest is done, the annual audiogram and its STS determination are conclusive, and the follow-up procedures and written notification of the STS determination to the employee must be done.

Thank you for your interest in occupational safety and health. We hope you find this information helpful. OSHA requirements are set by statute, standards, and regulations. Or 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. 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 may consult OSHA's website at http://www.osha.gov.

If you have any further questions, please feel free to contact the OSHA Office of Health Enforcement at (202) 693-2190.

Sincerely,

Richard E. Fairfax, Director

Directorate of Enforcement Programs