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 26, 1991

Mr. Micheal S. Welsh
Vice President
Technical Services
Envirosafe Management Services, Inc.
P.O. Box 833
Valley Forge, Pennsylvania 19482-0833

Dear Mr. Welsh:

This is in response to your July 12 letter requesting a determination on whether or not your storage and handling of combustible liquids ontaining PCBs constitutes a de minimis violation, based on compliance with requirements of agencies other than the Occupational Safety and Health Administration (OSHA).

In accordance with the Environmental Protection Agency (EPA) regulation 40 CFR 761.65(b)(1)(i), the storage facility for disposal of PCBs is required to have an adequate roof and walls, that is, a building, to prevent rainwater from reaching the stored PCBs and associated PCB items. Also, by 40 CFR 761.65(c)(7)(i), storage containers for liquid PCBs are required to be designed, constructed and operated in compliance with OSHA standards, 29 CFR 1910.106, flammable and combustible liquids. In accordance with 40 CFR 761.65(b)(1)(i), the filling and emptying connections of combustible liquid storage tanks are required to be made and broken in the building.

On the other hand, 29 CFR 1910.106(b)(2)(viii)(f) requires that flammable and combustible liquid storage tank filling and emptying connections which are made and broken shall be located outside of buildings at a location free from any source of ignition and not less than 5 feet away from any building. The petroleum based oils used in PCB units being processed usually are Class IIIB liquids which have flash points at or above 200 degrees F (91.67 degrees C) and are not subject to 29 CFR 1910.106 standards. The diesel oil which is used to flush the PCB units and then is discarded to the storage tanks containing combustible liquids contaminated with PCBs, is a Class IIIA liquid which has a flash point at or above 140 degrees F (60 degrees C) and below 200 degrees F (91.67 degrees C) and is therefore subject to 29 CFR 1910.106 standards.

Since EPA incorporated the 29 CFR 1910.106 standards in order to preclude workplace fire and explosion hazards which are not addresses otherwise by EPA regulations, OSHA's de minimis policy does not apply; however, a variance with respect to 29 CFR 1910.106 may be appropriate. Should you choose to pursue a variance, please refer to the enclosed copy of 29 CFR 1905.

Section 1905.11 delineates the criteria necessary to obtain a permanent variance. You must demonstrate through information on engineering design and controls and associated work practices that combustible vapors will not accumulate in the building during PCB processing operations and that the workplace is free of ignition sources. Your application should be forwarded to the Occupational Safety and Health Administration, Office of Variance Determination, Room N-3651, 200 Constitution Avenue, N.W., Washington, D.C. 20210.

We appreciate your interest in employee safety and health. If we can be of further assistance, please do not hesitate to contact us.


Patricia K. Clark, Director
Directorate of Compliance Programs