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 9, 1993

Mr. Gene F. Tappan
Regulatory Affairs Manager
Reskitt & Coleman Inc.
1655 Valley Road
Post Office Box 143
Wayne, New Jersey 07474-0943

Dear Mr. Tappan:

The purpose of this letter is to correct a misinterpretation of the Process Safety Management (PSM) of Highly Hazardous Chemicals Standard 29 CFR 1910.119 in our December 24, 1992 letter to you. Please disregard and discard the earlier letter of interpretation. The question you asked and our reply with the corrected interpretation follow.

Question: Does the PSM standard apply to the following operation at one of our facilities? Hydrogen peroxide is delivered by our vendor from a tank truck. The truck contains a 70% hydrogen peroxide water solution. The driver connects his truck to our pipe manifold and pumps a specified amount of the 70% hydrogen peroxide into our receiving tank. Prior to the delivery, we fill the tank with sufficient water to dilute the incoming peroxide to 35%. The delivery process takes up to 60 minutes and is observed closely by the driver. When the ordered quantity has been delivered, the driver stops the pump and disconnects the hose. Our personnel take no part in the unloading operation.

Reply: Both OSHA's PSM Standard and Department of Transportation (DOT) regulations apply in the situation you describe. Please refer to the following interpretation to determine when the PSM standard would cover the work site process you describe, and when DOT regulation would be paramount.

When visiting a work site at which there is a covered process, cargo tank motor vehicles (CTMV's) are covered by the PSM standard. These CTMV's would be covered by OSHA standards to the extent they are not covered otherwise by the Hazardous Material Regulations of the Department of Transportation (DOT) (See 49 CFR Subchapter C and particularly, Part 177 - Carriage by Public Highway). These DOT regulations cover the cargo tank design, construction, maintenance (including repairs) and operations of CTMV's. Operations regulated by DOT include loading and unloading, connected cargo transfer hoses whether provided from the CTMV or not, attendance by a qualified person during loading and unloading and associated training.

When the Department of Transportation (DOT) has jurisdiction of the unloading of a CTMV, an attendant who is a qualified person must be present, in compliance with the Hazardous Material Regulations, 49 CFR Subchapter C. Furthermore, DOT's jurisdiction ends and OSHA's jurisdiction begins at the connection between the hose from the CTMV and the process when unloading hazardous material as described above.

When a CTMV containing 7500 pound (3401.2kg) or a greater amount of hydrogen peroxide, 52% by weight or greater, is connected to a work site process which has the capacity to contain these threshold or greater 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 compliance with the PSM standard, he or she must have an effective dilution program (and be prepared to demonstrate to OSHA) that such a program precludes an otherwise covered concentration amount of hydrogen peroxide from being in the process at any particular time.

Please note that the amount of 52% by weight or greater concentration 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 of hydrogen peroxide would not be covered by the PSM Standard.

Thank you for your interest in occupational safety and health. If we may be of further assistance please contact us.


Roger A. Clark, Director
Directorate of Compliance Programs