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.

April 14, 1978

Mr. Thomas G. Gillum
1215 North Edward Street
Decatur, Illinois 62522

Dear Mr. Gillum:

This is in response to your letter regarding the use of compressed air for cleaning purposes with a pressure greater than 30 P.S.I. and the use of air guns with long pipes.

Enclosed is a copy of the Occupational Safety and Health Administration Program Directive 100-1, dated February 14, 1972. In short, the use of compressed air for cleaning purposes at pressures greater than 30 P.S.I. is permissible, if the outlet or source is fitted with a relief device that drops the pressure to less than 30 P.S.I. if the flow is dead ended. Air guns used with long pipes are acceptable, if they meet the requirements of 29 CFR 1910.242(b).

The Occupational Safety and Health Act of 1970 contains no provisions allowing approval or endorsement of equipment. Alteration or misapplication of an otherwise safe piece of equipment could easily create a hazardous condition beyond the control of the manufacturer. Statements alleging products have OSHA approval or certification are erroneous. Those that come to OSHA's attention are forwarded to the Office of the Solicitor for appropriate action.

For your information, enclosed is a copy of the Grain Elevator Industry Hazard Alert booklet that we sent to the industry.

We appreciate receiving your informative letter and your continuing interest in occupational safety and health. If I may be of any further assistance, please feel free to contact [the Office of General Industry Compliance Assistance at (202) 693-1850].


Bruce Hillenbrand
Acting Director,
Federal Compliance and State Programs