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.

August 13, 1981

Mr. David W. Morris
Division Manager, Human Resources
Chloride Automotive Batteries
3507 50th Street South
P.O. Box 1124
Tampa, Florida 33601

Dear Mr. Morris:

Your letter to Mr. Loren B. Canada, Sr., of our Macon, Georgia, Area Office has been forwarded to OSHA's National Office for a response because an issue of nationwide significance is involved.

You request in your letter that OSHA regard powered, air-purifying helmets as a form of engineering control. We do not feel that the Agency can adopt this position.

Powered, air-purifying helmets are a form of protection worn by employees against hazardous airborne substances. Clearly, forms of protection that must be worn are personal protective equipment. In order for a device or method to qualify as an engineering control for an airborne substance, it must reduce the amount of the airborne substance in the surroundings in which individuals move about. For that matter, the ultimate objective of an engineering control is to improve the environment to the point that personal protective equipment need not be worn. Thus, powered, air-purifying helmets must be considered personal protective equipment, and not engineering controls.

We appreciate the opportunity to comment on your concern. If we can serve you again, we shall be glad to do so.


Bruce Hillenbrand
Acting Director
Federal Compliance and State Programs