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.

March 1, 1993

Richard F. Andree, CSP, PE, Ph.D.
Executive Vice President
Safety and Health Management Consultants, Inc.
161 William Street
New York, New York 10038

Dear Dr. Andree:

Thank you for your letter of June 5, 1992, addressed to the Occupational Safety and Health Administration (OSHA), regarding ethylene oxide (ETO) tank changing operations and OSHA's letter of January 29, 1992, addressed to Mr. George L. Notarianni of Logan Associates, Inc.

You expressed concern regarding OSHA's position "that an alternative to requiring respiratory protection during ETO tank changing operations may include the use of real-time continuous exposure monitoring coupled with emergency procedures."

OSHA considers the implementation of the procedures detailed in our letter to Mr. Notarianni to be a way of providing additional protection to employees who operate or work in the general area of sterilizing equipment. This method however, would not adequately protect the employees who would be changing ETO tanks in the case of a high unexpected exposure. As discussed in our correspondence to Mr. Notarinni the requirement for respiratory protection is specifically addressed in the ETO regulation. The standard 29 CFR 1910.1047 requires the use of a positive pressure full facepiece supplied air respirator or a positive pressure full facepiece self-contained breathing apparatus (SCBA) where the concentration of ETO is unknown as indicated in paragraph (g)(2), this would be generally be the case if there was an unexpected release during tank changing operations.

We hope this information is useful to you.


Roger A. Clark, Director
Directorate of Compliance Programs