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 http://www.osha.gov.

February 4, 2013

Mr. Timothy A. Wilkins
Managing Partner
Bracewell & Giuliani LLP
111 Congress Avenue
Suite 2300
Austin, Texas 78701-4061

Dear Mr. Wilkins,

Thank you for your letter to the Occupational Safety and Health Administration (OSHA). This letter constitutes OSHA's interpretation only of the requirements referenced below and may not be applicable to any question not included in your original correspondence. Your inquiry is related to the application of OSHA's standard, Process Safety of Highly Hazardous Chemicals (PSM), 29 CFR 1910.119, specifically, the exemption for hydrocarbon fuels used solely as fuels for workplace consumption.

You asked for a formal interpretation regarding OSHA's use of the word "hydrocarbon" in 29 CFR 1910.119(a)(1)(ii)(A): "Hydrocarbon fuels used solely for workplace consumption as a fuel (e.g., propane used for comfort heating, gasoline for vehicle refueling), if such fuels are not part of a process containing another highly hazardous chemical covered by this standard."

Since the promulgation of PSM, OSHA issued 13 letters of interpretation regarding 29 CFR 1910.119(a)(1)(ii)(A), also known as the fuels exemption:

  • King Letter - June 19, 1992
  • Marvin Letter - August 28, 1992
  • Trinkl Letter - September 16, 1992
  • Cole Letter - October 22, 1992
  • Zoll Letter - April 14, 1993
  • Stubblefield Letter - June 9, 1993
  • Orth Letter - August 19, 1993
  • Hudnall Letter - April 7, 1994
  • Evans Letter - September 14, 1995
  • Hudnall Letter -November 28, 1995
  • Lee Letter - November 23, 1999 (rescinded by the Foulke Letter - December 8, 2000)
  • Adams Letter - September 21, 2000
  • Foulke Letter - December 8, 2000

The 13 letters are consistent in the application of the exemption - that the material must be a fuel used solely for workplace consumption and that it cannot be used in conjunction with a covered process. However, the letters above involve a variety of chemicals used as fuels and OSHA has never offered a definition of hydrocarbon.

Hawley's Condensed Chemical Dictionary, 14th Edition, 2001, defines hydrocarbon as "an organic compound consisting exclusively of carbon and hydrogen." Employers must apply the requirements of PSM to any fuel process wherein the material used as a fuel does not meet the definition of hydrocarbon. In other words, any process that contains 10,000 pounds or more of a flammable liquid or gas fuel that is not a hydrocarbon fuel is a PSM-covered process not excepted by 29 CFR 1910.119(a)(1)(ii)(A).

To eliminate confusion, OSHA rescinds the 1992 King and the 1994 Hudnall letters because each of these involves a material that does not meet the definition of hydrocarbon (coke oven gas and methanol, respectively).

In your letter, you ask specifically about hydrogen used as a fuel for powered industrial trucks. Hydrogen does not meet the definition of hydrocarbon, as you point out in your letter. In addition, hydrogen presents very unique thermodynamic and combustion properties not envisioned in the preparation of the fuels exemption. Furthermore, the storage of hydrogen in amounts greater than the threshold quantity is not within OSHA's intent of excluding low-risk hydrocarbon fuel applications. Therefore, processes containing a threshold quantity of hydrogen used as a fuel must meet all requirements of PSM.

Thank you for your interest in occupational safety and health. OSHA sets requirements 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 http:/www.osha.gov. If you have any further questions, please feel free to contact the Office of Chemical Process Safety and Enforcement Initiatives at (202) 693-2341.

Sincerely,

Thomas Galassi, Director
Directorate of Enforcement Programs