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.

October 11, 2022

Dr. James A. Norris
Edare, LLC
48 Lafayette Street
Lebanon, New Hampshire 03766

Dear Dr. Norris:

Thank you for your letter to the Occupational Safety and Health Administration's (OSHA's) Directorate of Enforcement Programs. You requested a confirmation on whether the American National Standards Institute (ANSI) standard S3.1-1999 (R2018) is acceptable to use to obtain measurements addressed in the OSHA Occupational Noise Exposure standard (noise standard), 29 CFR § 1910.95, Appendix D. This letter constitutes OSHA's interpretation only of the requirements discussed and may not be applicable to any questions not delineated within your original correspondence. Your specific question is paraphrased below, followed by OSHA's response

Background:

Your letter stated that OSHA's Noise standard, Appendix D (mandatory), Audiometric Test Rooms, includes Table D-1, Maximum Allowable Octave-Band Sound Pressure Levels (MAOSPL) which specifies Maximum Permissible Ambient Noise Levels (MPANL) for Audiometric Test Rooms, were based on an ANSI standard from 1960 (S3.1-1960). You also state in your letter that ANSI had made several revisions (1977, 1991, and 1999) to ANSI S3.1-1960 standard as research has improved the understanding of how ambient noise impacts audiograms, with the most recent revision in 2018.

Your letter also referenced OSHA's June 9, 2017, letter to Mr. A Gregg Moore which states that the ANSI S3.1-1999 MPANL's are allowed to be used for audiometric testing with insert earphones. However, in a conversation between our offices it was relayed that the Moore letter was specific to “insert earphones” and you wanted clarification that the updated ANSI standard S3.1-1999 (R2018) would be accepted for other types of earphones including circular earphones.

Question: Will OSHA allow the use of the ANSI S3.1-1999 (R2018) Maximum Permissible Ambient Noise Levels (MPANLs) in lieu of the MPANLs in the occupational noise exposure standard, 29 CFR 1910.95 Appendix D, Table D-1?

Response: Yes, OSHA will allow the use of ANSI MPANLs in lieu of the MPANLs in the occupational noise exposure standard when insert earphones or other types of earphones (e.g., circular) are used.

Thank you for your interest in occupational safety and health. I hope you find this information helpful. OSHA's requirements are set by statute, standards, and regulations. Letters of interpretation do not create new or additional requirements but rather explain these requirements and how they apply to particular circumstances. This letter constitutes OSHA's interpretation of the requirements discussed. From time to time, letters are affected when the agency updates a standard, a legal decision impacts a standard, or changes in technology affect the interpretation. To assure that you are using the correct information and guidance, please consult OSHA's website at www.osha.gov.

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

Sincerely,

Kimberly A. Stille, Director
Directorate of Enforcement Programs