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, 1992

Mr. Garry Stubblefield Senior
Technician Petrocon Engineering, Inc.
P.O. Box 20397
Beaumont, Texas 77720-0397

Dear Mr. Stubblefield:

This is in response to your letter of June 12, to Mr. Gilbert J. Saulter, Dallas Regional Administrator for the Occupational Safety and Health Administrator (OSHA). Your letter was forwarded to the Directorate of Compliance Programs for response. Please accept our apologies for the delay in responding.

In your letter you requested an interpretation on the Final Rule on Process Safety Management (PSM) of Highly Hazardous Chemicals published in Volume 57, Number 36 of the Federal Register on Monday, February 24, 1992. In particular, you sought clarification on whether metallurgical certifications are required for each component, including pipe sections, fittings, valves, etc., and connecting joint welds, of systems handling highly hazardous chemicals in order to be in compliance with the PSM Standard. You requested this clarification with respect to existing facilities at which there are no material specifications data on these piping systems.

A PSM directive is being developed by OSHA to provide interpretative guidance and inspection procedures to our field staff. We will send you a copy of the directive when it is completed in the near future. Please refer to that directive for answers to your questions.

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