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 23, 1995

Ms. Janet Fox
Occupational Health Department
Con Edison 30 Flatbush Avenue
Brooklyn, New York 11217

Dear Ms. Fox:

This is in response to your letter of April 4, 1995 requesting clarification of the Electrical Protective Equipment standard, 29 CFR 1910.137. In your letter, you specifically requested that the Occupational Safety and Health Administration (OSHA) clarify what the certification requirements are for ozone-resistant electrical protective equipment. Please accept our apology for the delay in responding.

Section 1910.137 does not require employers to certify ozone resistance testing. Under paragraph 1910.137(a)(1), ozone-resistant testing of electrical protective equipment is a manufacturing requirement. Paragraph 1910.137(b)(2)(xii) requires employers to certify that rubber insulating equipment has been tested as required by paragraphs 1910.137(b)(2)(viii), 1910.137(b)(2)(ix), and 1910.137(b)(2)(xi). These three paragraphs do not require rubber insulating equipment to be subject to ozone resistant tests.

The note following paragraph 1910.137(b)(2)(ix) states that standard electrical test methods are given in the American Society for Testing and Materials (ASTM) standards listed in the note. While an employer is free to conduct any of the tests contained in ASTM standards, paragraph 1910.137(b)(2)(ix) refers only to electrical tests.

Please note that ASTM D120, D1048, D1049, D1050, and D1051 are manufacturing specifications applying to the design and manufacture of rubber insulating equipment. While an employer may conduct electrical tests using the test methods given in the aforementioned ASTM standards to comply with paragraph 1910.137(b)(2), many of the test methods contained in the ASTM standards are intended to be used by the manufacturer rather than the purchaser (that is, the employer for subsequent use by employees) of rubber insulating equipment. Employers are encouraged to follow ASTM F478, F479, and F496, which are also listed in the note following paragraph 1910.137(b)(2)(ix), for the in-service use, care, and testing of rubber insulating equipment. This second set of ASTM standards is meant for use by purchasers and users to ensure that rubber insulating equipment remains safe for its intended use. In fact, paragraph 1910.137(b)(2) is based on the requirements from these ASTM standards.

We appreciate your interest in employee safety and health. If we may be of further assistance, please contact the [Office of General Industry Enforcement at (202) 693-1850].


John B. Miles, Jr., Director
Directorate of Compliance Programs

[Corrected 3/25/2009]