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 https://www.osha.gov.

August 1, 1994

C. M. Carter, CIH
Mountain Technical Cente
10100 West Ute Avenue (80127)
Post Office Box 625005
Littleton, Colorado 80162-5005

Dear Mr. Carter:

This is in response to your letter of February 3, to several Regions of the Occupational Safety and Health Administration (OSHA) requesting clarification of the policy for classifying violations as repeated, as well as clarification of specific regulations. Since your letter was received by several OSHA Regional Offices, we are providing a coordinated response from the OSHA National Office.

The repeat violation policy you identified in your letter applies for any violation, not only high gravity serious violations. A copy of a memorandum dated July 11, 1991, for OSHA Regional Administrators that clarifies this point is enclosed.

With respect to unusual work shifts and occupational noise exposure, the noise standard gives the maximum time within a workday an employee may be exposed to each sound level and combination of sound levels, regardless of the length of the workday. Thus the permissible exposure limit for noise for an extended work day is the same as the limit for an 8-hour work day. Please note, however, that since there is more time for exposure to noise on extended work days, overexposure to noise can occur more readily on these days.

Concerning noise attenuation afforded by hearing protectors, OSHA does not reduce the calculated noise attenuation by 50% when determining compliance with the hearing protector attenuation requirements at 29 CFR 1910.95(j)(2) or (3). OSHA only applies the 50% reduction factor to the calculated noise attenuation when establishing whether engineering controls for noise must be implemented. The use of hearing protectors that provide twice the required noise attenuation is one of conditions that must be met before OSHA will agree that the implementation of engineering controls is not required.

We appreciate the opportunity to clarify these matters for you.


Ruth E. McCully, Director
Office of Health Compliance Assistance