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.

September 8, 1993

Mr. Lawrence W. Bierlein
Shaw, Pittman, Pott & Trowbridge
2300 N. Street, N.W.
Washington, D.C. 20037-1128

Dear Mr. Bierlein:

This is in further response to your March 24, letter to Mr. Rolland Stroup of my staff requesting clarification on the applicability of the Process Safety Management (PSM) of Highly Hazardous Chemicals Standard, 29 CFR 1910.119 to delivery of hydrogen peroxide, 52% by weight or greater delivered by cargo tank motor vehicles (CTMV'S) which carry 7500 pound (3401.2kg) or greater amounts.

In your letter, you indicated that the CTMV driver, with no involvement of work site employees, dilutes the hydrogen peroxide downstream of the delivery hose, by water mixing from work site interconnected piping or by prefilling the storage tank with water from work site interconnected piping prior to delivery of the hydrogen peroxide. In either case, you indicated that there is less than a threshold quantity, that is, 7500 pounds (3401.2kg) of the subject hydrogen peroxide, in the process at any particular point in time.

Please note that the amount of hydrogen peroxide in the CTMV is not included for the purpose of determining whether there is a threshold quantity or greater amount in a work site process. As such, CTMV delivery to a process which has a capacity less than 7500 pounds would not be covered by the PSM standard.

We agree with your conclusion that the Department of Transportation (DOT) has jurisdiction over CTMV unloading which must be attended by a qualified person who may be the CTMV driver in compliance with the Hazardous Material Regulations, 49 CFR Subchapter C. Further we agree that DOT's jurisdiction ends and OSHA's jurisdiction begins at the connection between the hose from the CTMV and the process when unloading hazardous materials as described above.

Any use of the facility or operation of a process by the CTMV driver to dilute the subject hydrogen peroxide is deemed to be under OSHA's jurisdiction. When a CTMV containing threshold or greater amounts of hydrogen peroxide, is connected to a work site process which has the capacity to contain these amounts, the process may be subject to the PSM standard. The work site employer will be held responsible by OSHA for this determination.

If the work site employer intends to operate the aforementioned process to avoid being subject to the PSM standard, he or she must have an effective dilution program (and be prepared to demonstrate this to OSHA) that precludes an otherwise covered concentration and amount of hydrogen peroxide from being in the process at any particular time. This dilution program must address contractor employees, for example, the CTMV driver, when involved.

Thank you for your interest in Occupational Safety and Health. If we can be of further assistance, please contract us.


Roger A. Clark, Director
Directorate of Compliance Programs