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, 1992

Mr. Frank R. Samartinov
Process Safety Engineer
Hoechst Celanese
P.O. Box 4,
Highway 70 West
Salisbury, North Carolina 28144

Dear Mr. Samartino:

This is in response to your May 11 letter, requesting written confirmation that the Final Rule on Process Safety Management (PSM) of Highly Hazardous Chemicals published in Volume 57, Number 35 of the Federal Register on Monday, February 24, 1992 does not apply to muriatic (32% HCL) acid.

The chemical names: hydrogen chloride (HCL) and anhydrous hydrochloric acid are included in the highly hazardous chemicals listing in Appendix A of the PSM standard. Anhydrous (without water) hydrochloric acid is hydrogen chloride. Both hydrogen chloride and anhydrous hydrochloric acid are identified by the same Chemical Abstract Service (CAS) Number 7647-01-0, as denoted in Appendix A. Hydrochloric acid (muriatic acid), that is, a solution of hydrogen chloride gas in water, is not listed in Appendix A and therefore, is not considered to be a highly hazardous chemical subject to the PSM standard.

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


Patricia K. Clark, Director
Directorate of Compliance Programs