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 15, 1995

Mr. George W. Goodman
Cummins, Goodman, Fish & Peterson, P.C.
P.O. Box 17
434 N. Evans Street
McMinnville, Oregon 97128

Dear Mr. Goodman:

Thank you for your letter of May 16, addressed to Deputy Assistant Secretary, James W. Stanley, regarding your client's chlorine storage facility plan and the applicability of the Process Safety Management (PSM) of Highly Hazardous Chemicals Standard, 29 CFR 1910.119. Your letter was forwarded to our office for response.

The review of the information provided in you letter indicated that the construction of the chlorine storage facility in question would be subject to the provisions of the PSM Standard, 29 CFR 1910.119.

A "process," as defined in 1910.119(b), "means any activity involving a highly hazardous chemical including any use, storage, manufacturing, handling, or the on-site movement of such chemicals, or combination of these activities. For purposes of this definition, any group of vessels which are interconnected and separate vessels which are located such that a highly hazardous chemical could be involved in a potential release shall be considered a single process."

From your description and the drawings submitted to us, it is obvious the facility's vessels are interconnected, even though the chlorine is being pumped from one vessel at a time. Further, the total quantity of stored chlorine on site is estimated to be 14,400 lbs. (12 tanks x 1200 lbs.) which exceeds the threshold quantity.

You have indicated that the lack of a "reasonably foreseeable probability" of chlorine release to cause a total release in excess of the threshold quantity would render the PSM standard inapplicable. The description and the drawings that you have forwarded to our office do not support this indication. The plan incorporated in the design of the facility acknowledges that release of chlorine from the containers is possible, as it was stated in your letter, "the containers are elevated sufficiently to prevent them from standing in water or any liquid chlorine that may be released." Further, the threshold quantity is the cut off point for the applicability of the PSM Standard, and is not the quantity for the total amount released in case of mishaps.

Due to the above reasons the subject facility would be subject to the provisions of the PSM Standard.

We appreciate your interest in occupational safety and health. If you need further assistance, please contact Alcmene Haloftis of my staff at 202-219-8031.


John B, Miles, Jr., Director
Directorate of Compliance Programs