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.

June 24, 1994

Mr. Gavin Burdge
Industrial Hygienist
Laidlaw Environmental Services
407 Burton Road
Lexington, SC 29072

Dear Mr. Burdge:

This is in response to your May 19 letter to Roger Clark, former Director of Compliance Programs. In your letter, you requested an interpretation of the Process Safety Management Standard (PSM) of Highly Hazardous Chemicals (HHCs) standard, 29 CFR 1910.119.

As indicated in your conversation with Ms. Alcmene Haloftis of my staff, extensive additional documentary information would be required to answer your question:

1. Describe the purpose of the process;

2. Describe the process in detail, including major components and activities (see the 1910.119(b) definition of process); for example, what is interconnected by piping?

3. Identify HHCs including flammable liquids and toxic or reactive substances covered by the PSM standard;

4. Describe methods and conditions of storage. For example, are flammable liquids stored in atmospheric tanks (see 1910.119(b) definition)? and

5. Describe other worksite processes containing HHCs, and their location relative to the process above.

It is likely that additional questions would arise when this basic information is provided. Therefore, I suggest that you contact the South Carolina Department of Labor, which administers the OSHA program in South Carolina:


South Carolina Department of Labor
3600 Forest Drive
P.O. Box 11329
Columbia, SC 29211-1329


(803) 734-9594

They will be able to respond more completely, since they may already be familiar with your facilities in the State. They are situated locally, and may more easily meet with you to discuss your inquiry. Also, in the event of enforcement action in South Carolina, the South Carolina Department of Labor, not Federal OSHA, will be involved.

If the State cannot provide the additional information required, I suggest that you contact the OSHA Regional Office:


R. Davis Layne, Regional Administrator
US Department of Labor - OSHA
1375 Peachtree Street, N.E., Suite 587
Atlanta Georgia, 30367


(404) 347-3573

I hope this information is useful to you. If we may be of further assistance, please let me know.

Thank you for your interest in occupational safety and health.


Raymond E. Donnelly, Director
Office of General Industry Compliance Assistance