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 3, 1976

Mr. Roy T. Dodge
Chief of Design
and Construction
Washington Metropolitan
Area Transit Authority
600 Fifth Street, N.W.
Washington, D.C. 20001

Dear Mr. Dodge:

This is in response to your letter of May 13, 1976 (copy enclosed), regarding the conclusion reached at our meeting of May 6, 1976, on the handling, storing, and using of Methlacetylene- Propadiene, Stabilized (MPS) gas in below ground-level construction work.

This office concurs with your understanding of the conclusions reached on the handling, storing, and use of MPS gas. In addition, the following comments are offered:

1. The total number of MPS gas cylinders below ground on any given day shall be limited to that day's intended use.

2. MPS fuel gas may be used under controlled conditions in gas welding and cutting in areas that may be defined as confined spaces, as long as the cylinders remain outside of the confined spaces.

3. The above understanding is based on our interpretation of existing OSHA and national consensus standards.

If I may be of any further assistance, please feel free to contact me.


Donald A. Shay, Director
Office of Compliance Programming