February 13, 2004

Dr. Louis Hosek, Ph.D.
Manager - Industrial Hygiene
American Electric Power
P.O. Box 660164
Dallas, TX 75266-0164

Dear Dr. Hosek:

Thank you for your September 25, 2003 letter to the Occupational Safety and Health Administration (OSHA) requesting clarification of OSHA's occupational noise standard, 29 CFR 1910.95. Please be aware that this response may not be applicable to any question or scenario not delineated within your original correspondence. Your questions and our responses are provided below.

Question 1: How many days per year would an employee have to be exposed to an environment with noise levels in excess of the 85 decibel (dB) time weighted average (TWA) before he/she is required to be covered by the company's hearing conservation program (HCP) (i.e., one day, ten days, thirty days)?

Response: One day. The occupational noise exposure standard requires that all employees exposed to noise levels at or above 85 dB on an 8-hour (TWA) must be included in a HCP. This includes employees who may have only occasional exposures at this level. Thus, for example, the HCP provisions would apply with respect to an engineer or other such employees who visit a facility several times a year and are exposed to TWA noise levels at or above 85 dB, even though they may not experience any other such exposures during the year.

When enforcing the standard, OSHA reviews employer records and may perform personal monitoring to determine if all employees with exposures equaling or exceeding the TWA of 85 dB have been included in the HCP.

Question 2: Once in the program, how long does an employee have to go without being exposed to 85 dB to be removed from the program?

Response: Employees who have not been exposed to noise levels equal to or exceeding 85 dB (as an 8-hour TWA) for an entire year following their last annual audiogram may be removed from the program.

Question 3: If an employee has been in an HCP, experienced a standard threshold shift (STS) and then, at a later time, changed jobs to an area where they are no longer in the program, are there any continuing obligations under the program with regard to this employee?

Response: In such a situation, employers would be required to comply with the provisions detailed in 1910.95(m). This paragraph requires the employer to retain noise exposure measurements relating to the employee for two years and to retain audiometric test records for the duration of the affected employee's employment.

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. 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 Programs at (202) 693-2190.

Sincerely,


Richard E. Fairfax, Director
Directorate of Enforcement Programs