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.

November 23, 1999

Mr. Steven Lee
Environmental Engineer
Libbey Glass, Inc.
4302 Jewella Avenue
Shreveport, LA 71109

Dear Mr. Lee:

Thank you for your November 4, 1998 letter to the Occupational Safety and Health Administration's (OSHA's) Directorate of Compliance Programs (DCP). You have questions regarding your table glassware manufacturing process as it relates to OSHA's Process Safety Management of Highly Hazardous Chemicals; Explosives and Blasting Agents (PSM) standard (29 CFR §1910.119). We apologize for the delay in our response.

Question: We manufacture table glassware, SIC Code 3229. As part of the process, molten glass is delivered to each mold as the table is indexed in a rotating motion. A plunger is then used to press the glassware into a desired shape. To provide lubrication between the glass and steel a fuel mixture consisting of Methyl Acetylene, Propadiene and Propylene is ignited and injected into the mold. The products of combustion which are high in carbon content, coat the mold allowing easy release of the freshly formed glassware. Does our fuel stored on site in a quantity greater than 10,000 pounds and used for our manufacturing process described above meet the exemption 1910.119(a)(1)(ii)(A)? Our manufacturing process does not contain another highly hazardous chemical (HHC) covered by the PSM standard.

Response: The process you described is a PSM-covered process and the hydrocarbon fuels exception you specified (29 CFR §1910.119(a)(1)(ii)(A)) does not apply to your process. We offer the following to explain our response.

The process you described above is a covered PSM process for the following reasons:







  1. A highly hazardous chemical (HHC)- flammable gas exists in the process (per U.S. Dept. of Transportation's 49 CFR §172.101- Hazardous Materials Table: Methyl Acetylene, Propadiene and Propylene are listed as flammable gases);
  2. The quantity of flammable gas is greater than the threshold quantity (TQ) for flammable gas (TQ greater than or equal to 10,000 pounds); and
  3. By design, the combustion products of the flammable gas are used in the manufacturing process to coat molds.

The hydrocarbon fuels exception is not applicable in this case because the flammable gas is not "used solely for workplace consumption as a fuel." The use of the combustion products of the flammable gas to coat the molds goes beyond the use of the gas solely as a workplace fuel. Examples of workplace consumption of fuel includes propane used for comfort heating and gasoline used for vehicle refueling.

Thank you for your interest in occupational safety and health. We hope you find this information helpful. Please be aware that OSHA's enforcement guidance is subject to periodic review and clarification, amplification, or correction. Such guidance could also be affected by subsequent rulemaking. In the future, should you wish to verify that the guidance provided herein remains current, you may consult OSHA's web-site at http://www.osha.gov. If you have any further questions, please feel free to contact the Office of General Industry Compliance Assistance at (202) 693-1850.


Richard E. Fairfax, Director
Directorate of Compliance Programs