Revising one-ear baseline audiograms

February 10, 2006

Dr. Robert Williams

Director Audiology

TK Group Incorporated

[Recipient address omitted]

Dear Dr. Williams:

Thank you for your August 3, 2005 letter to the Occupational Safety and Health Administration (OSHA) regarding the requirements for revising baseline audiograms under the Occupational Noise standard, 29 CFR 1910.95. In particular, you are requesting further clarification of our May 8, 2003 letter to Ms. Linda Ballas. This letter constitutes OSHA's interpretation only of the requirements discussed and may not be applicable to any question not delineated within your original correspondence.

In the May 8th 2003 letter, we stated a baseline may only be revised if there is a standard threshold shift of greater than 10 dB. If a shift occurs in only one ear, then only the baseline for that ear would be permitted to be revised under the standard. In your letter you state that many professionals had previously adopted a methodology of revising the baseline for both ears, even when there was only a shift in one ear. This confusion may have been partially due to the available commercial software that was available to track hearing loss which offered that methodology as a configurable option.

Since the May 8th 2003 letter, many of the computer programs that track hearing loss have been corrected to properly record shifts that occur in only one ear. Professionals who are correcting their databases may find it useful to completely rebuild them in order to reflect accurate historical tracking of standard threshold shift events. Some computer programs may even do this automatically, when they are updated to the single ear criteria. However, OSHA will usually look at whether the employer is currently out of compliance and whether the employer is evaluating what noise sources or work procedures may be currently contributing to employee hearing loss. Therefore, the employer would not need to go back further than the previous year's audiogram and ensure all future audiograms are revised in the same manner.

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

Sincerely,

Richard E. Fairfax, Director

Directorate of Enforcement Programs