Commercial-grade chemicals under process safety management

NOTICE: This is an OSHA Archive Document, and may no longer represent OSHA Policy. It is presented here as historical content, for research and review purposes only.

June 22, 1993

Mr. F. L. Lambert
Environmental and Technical Division
Westvaco-Chemical Division
[Recipient address omitted]
Dear Mr. Lambert:

This is in response to your April 30 letter requesting clarification of the Process Safety Management (PSM) of Highly Hazardous Chemicals (HHC's) standard, 29 CFR 1910.119. In your letter you specifically requested confirmation that, if HHC's which are listed without specified concentration limits in Appendix A of the PSM standard are at commercial grades less than 99 percent purity, the PSM standard is not applicable.

The substances listed in Appendix A without specified concentration limits are intended to be covered by the PSM Standard at commercial grade percentages of purity because the commercial grade of most of the HHC's is approximately 99 percent purity. Many of the HHC's, if not actually at 99% purity, are only one to two percent less than 99 percent pure. For example, the commercial grades of acrolein and allyl chloride are 97 percent purity. Some of these HHC's are considerably less than 99 percent pure. For example, the commercial grade of hydrogen fluoride is 70 percent (30% is pyridine).

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

Sincerely,
Roger A. Clark, Director
Directorate of Compliance Programs

[Requester letter reproduced on OSHA page; omitted here.]