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OSHA and PHMSA jurisdiction at underground gas storage sites

Summary A consultant asked whether PHMSA pipeline rules displaced OSHA at geological gas or hazardous-liquid storage facilities. OSHA said displacement requires a case-specific regulation covering the particular working condition; PHMSA had not generally regulated work in underground formations. Some aboveground pipeline-repair conditions could be displaced, while other workplace hazards, including PSM issues, could remain under OSHA.
Document
Federal opinion letter
Agency
Occupational Safety and Health Administration (OSHA)
Document number
2008-10-07
Date issued
October 7, 2008
Status
Unknown
This jurisdiction discussion reflects 2008 PHMSA regulations and facts; current application has not been confirmed. OSHA states that a referenced 1992 interpretation is no longer operative.
Status last verified October 8, 2026

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The current status of this document is unclear
This jurisdiction discussion reflects 2008 PHMSA regulations and facts; current application has not been confirmed. OSHA states that a referenced 1992 interpretation is no longer operative. It may no longer reflect the agency's current position. Treat this page as historical context, not current guidance, and verify current law before relying on anything here.
About this page: The full text below is the official document from Occupational Safety and Health Administration (OSHA). Ezel adds the plain-English summary and tracks the document's status. The official source linked on this page is authoritative for any reliance.

October 7, 2008

Ms. Joanne B. Linhard

Consultant

[Recipient address omitted]

Dear Ms. Linhard:

Thank you for your December 15, 2006 letter to the Occupational Safety and Health Administration's (OSHA's) Directorate of Enforcement Programs (DEP) requesting information on the extent of OSHA's jurisdiction over worksites involving geological and underground storage facilities for gas and hazardous liquids. This is a follow-up to our interim letter, dated March 24, 2006, that we provided to you on this matter and is based on information you provided in your letter to me. Please be aware that this response is not applicable to any question or situation not delineated within your original correspondence. We apologize for the delay in our response.

Background

The Occupational Safety and Health Act of 1970, 29 USC 651 et. seq., provides OSHA with the authority to issue and enforce standards and regulations for workplace safety and health. Pursuant to this authority, OSHA established its occupational safety and health standards (29 CFR Parts 1900-1999) which are designed for the purpose of protecting workers in the workplace.

The Federal pipeline safety laws (49 USC Chapter 601) provide the Department of Transportation's Pipeline and Hazardous Materials Safety Administration (PHMSA) with the authority to issue and enforce standards to protect the public, property, and the environment from potential risks associated with pipeline transportation. Pursuant to this authority, PHMSA established its pipeline safety regulations (49 CFR Parts 190-199) which are designed for the purpose of protecting the public, property, and the environment.

Section 4(b)(1) of the OSH Act (29 USC §653(b)(1)), states that:

Nothing in this Act shall apply to working conditions of employees with respect to which other Federal agencies . . . exercise statutory authority to prescribe or enforce standards or regulations affecting occupational safety or health. This provision of the OSH Act prohibits OSHA from regulating working conditions when another Federal agency has statutory authority to prescribe or enforce standards or regulations covering occupational safety and exercises such authority.

Applying Section 4(b)(1), the U.S. Supreme Court has ruled that the issuance of safety regulations that apply to a given industry by another Federal agency does not automatically displace OSHA from using its statutory authority to protect workers in that industry (Chao v. Mallard Bay Drilling, Inc., 524 U.S. 235 (2002)). In order to determine whether another agency has exercised its authority by issuing an applicable regulation, a case-by-case analysis is generally required to determine whether that agency has issued a specific regulation that directly applies to a particular scenario involving worker safety. If so, OSHA can be displaced in that particular instance.[1]

Discussion

In preparing our response to your inquiry, we consulted with PHMSA to determine whether, and to what extent, PHMSA has regulations covering working conditions at geological and underground storage facilities for gas and hazardous liquids. PHMSA explained that in general, the answer is no. PHMSA pointed out that unlike the standards promulgated under the OSH Act, the pipeline safety regulations were never designed to comprehensively protect workers in the pipeline industry.

Secondly, PHMSA noted that, while it (or its State agent) may regulate the aboveground piping at an underground natural storage facility, its regulations would apply only until the last valve, before the downhole injection equipment and piping, and would not resume until the first valve aboveground for withdrawal facilities (typically at the wellhead). In other words, to date, PHMSA has not exercised any authority to regulate working conditions in underground geological storage formations.[2]

If your inquiry concerns aboveground piping at such a facility, PHMSA does have a very limited number of regulations that apply to working conditions. These regulations primarily involve working conditions associated with pipeline operator personnel performing pipeline repairs in a surface trench (Note: PHMSA regulations cover pipeline operator employees, they do not cover contract employees.) For example, 49 CFR §192.605(b)(9) requires pipeline operators to take adequate precautions in excavated trenches to protect operator personnel from the hazards of unsafe accumulations of vapor or gas. As we already noted, however, the pipeline safety regulations were never designed to comprehensively protect workers in the workplace.

In contrast, OSHA's Process Safety Management Standard (29 CFR Part 1910.119) (PSM) was promulgated to require employers to utilize a comprehensive safety management approach to preventing and mitigating catastrophic releases of a large number of different highly hazardous chemicals which might impact worker safety across a broad spectrum of industrial processes — including those associated with geological storage facilities — such as gas processing.

Your inquiry did not specify the nature of the working conditions that you are seeking an interpretation for. Therefore, we are unable to perform the case-by-case analysis and provide you with a definitive response. We can say, however, that generally speaking PHMSA would likely displace OSHA in a scenario involving the safety of pipeline operator employees performing pipeline repairs in a trench. With respect to many other workplace safety issues, however, OSHA may not be displaced.[3]

Thank you for your interest in occupational safety and health. We hope you find this information helpful. 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. If you have any further questions, please feel free to contact the Office of General Industry Enforcement at (202) 693-1850.

Sincerely,

Richard E. Fairfax, Director

Directorate of Enforcement Programs

[1] Our former position reflected in the 1992 interpretation letter you referenced was issued prior to the Mallard Bay decision and is no longer operative.

[2] PHMSA does not dispute your assertion that because stored product will be re-injected into the stream of transportation, such storage is "part of the transportation system."

[3] In scenario 2 of your letter, you ask whether the PSM standards would be applicable given a geological underground facility which is "located remote from a manufacturing facility." Our overall response is based on the storage facility being remotely located from the manufacturing facility. If storage is entirely on the grounds of the manufacturing facility, presumably no transportation has taken place, and DOT/PHMSA jurisdiction would not be implicated to begin with. Additionally, if the geological underground facility is located in a distant location, but still on the employer's property or complex, it is considered "contiguous with" all other buildings, processes, or persons. Therefore, the geological underground facility would not be considered a normally unoccupied remote facility per 29 CFR 1910.119(b) and would not be an exempt process (29 CFR 1910.119(a)(2)(iii)).

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