Positive and negative user seal checks for respirators

April 10, 2007

Mr. Dan Westrum

Wenck Associates, Inc.

[Recipient address omitted]

Dear Mr. Westrum;

Thank you for your February 22, 2007 letter to the Occupational Safety and Health Administration's (OSHA's) Directorate of Enforcement Programs (DEP) regarding the use of respiratory protection. Your letter specifically requests clarification on the performance of user seal checks and whether both or either of the positive and negative seal checks described in Appendix B-1 are required when donning a respirator. 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.

The Respiratory Protection standard, 29 CFR 1910.134, requires employers to ensure their employees perform a user seal check each time they don a tight-fitting respirator using either the "user seal check" procedures in Appendix B-1 or equally effective procedures recommended by the respirator manufacturer. When following Appendix B, both the positive and negative seal checks are required to be performed, if possible. Variations in the construction of respirators may make the performance of either the positive or the negative seal check impossible to perform. In this case, the employer must follow the manufacturer's recommendations. The "equally effective" phrase is intended to ensure that the recommended procedures have been demonstrated to be effective in identifying respirators that do not seal properly when donned or adjusted. This may at times involve performing only the positive or negative seal check. If no method exists to check whether a respirator re-seals during multiple re-donnings under actual workplace conditions, it is not acceptable for use, and a different respirator must be selected. OSHA does not permit the use of tight-fitting respirators that cannot be seal-checked.

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 http://www.osha.gov.

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

Sincerely,

Richard E. Fairfax, Director

Directorate of Enforcement Programs