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.

May 25, 1994

David J. Muchow, Esq.
General Counsel and Corporate Secretary
American Gas Association
1515 Wilson Boulevard
Arlington, VA 22209

Dear Mr. Muchow:

This letter is in response to the American Gas Association's (A.G.A) Request For Clarification, Or In The Alternative, Petition For Administrative Stay, dated March 5, 1993. A.G.A. has requested that OSHA clarify that, in light of the preemption provision in Section 4(b)(1) of the Occupational Safety and Health Act, the final rule on Permit-Required Confined Spaces (PRCS), which requires employers to implement safety precautions prior to and during entry into confined spaces whenever serious atmospheric, mechanical or other types of hazards are present, does not apply to gas utility vaults. The Department of Transportation's Office of Pipeline Safety (OPS) has issued regulations covering natural gas distribution and transmission facilities, including vaults and related spaces. 49 C.F.R. 191, 192 (1991).

At a meeting on April 8, 1993 between OSHA and Solicitor of Labor staff and A.G.A. representatives concerning the March 5 submission, A.G.A. engineers stated that the presence of gas was the only hazard ordinarily encountered by employees in conducting inspections and performing normal maintenance work in vaults. A.G.A. expressed concern that broad application of the PRCS standard to vaults would require significant changes in its members' operating procedures, which conform to OPS procedures for minimizing the hazards of gas in such spaces. According to A.G.A., this would subject gas utility companies to conflicting federal requirements and could lead to disruption of services.

As A.G.A. has pointed out, section 4(b)(1) of the OSH Act, 29 U.S.C. 653(b)(1) (1988), precludes OSHA from applying its standards to working conditions that are regulated by other federal agencies. The phrase "working conditions" encompasses both a worker's surroundings and the hazards incident to his work. See, Columbia Gas of Pennsylvania v. Marshall, 636 F.2d 913 (3d. Cir. 1980); Southern Railway Co. v. OSHRC, 539 F.2d 335 (4th Cir. 1976; Southern Pac. Transp. Co. v. Usery, 539 F.2d 386, 390 (5th Cir. 1976). See also in reinspection of Norfolk Dredging Co., 783 F.2d 1526, 1530-32 (11th Cir. 1986). Thus, an OSHA standard does not apply to the extent that another federal agency prescribes or enforces standards addressing the same general working conditions.

Current OPS regulations contain requirements for adequately ventilating large vaults and for providing a means for testing the atmospheres of sealed vaults prior to entry, 49 C.F.R. 192.187 (1991); for designing and locating vaults to minimize the entrance of water, 49 C.F.R. 192.85, 189 (1991), for periodically inspecting vault equipment and for repairing leaking or faulty equipment, 49 C.F.R. 192.749 (1991), and for minimizing the danger of fire, or explosion in any structure or area in which gas might be present, 49 C.F.R. 192.751 (1991). Operators must also report to OPS any incident involving a death or serious injury associated with the release of gas from a pipeline. 49 C.F.R. 191.5 (1991). While these provisions are primarily directed to the hazards of fire and explosion, they appear sufficiently related to the general problem of hazardous vault atmospheres to preempt all OSHA regulation of such hazards under the PRCS, including fire, explosions, toxicity and oxygen deficiency. Southern Pac., 539 F.2d at 391 (noting that comprehensive Federal Railroad Administration treatment to the general problem of railroad fire protection would displace all OSHA regulation on fire protection even if the FRA regulations differed from OSHA's).

Furthermore, OSHA recognizes that the application of the PRCS standard to atmospheric hazards in vaults, even if limited to hazards such as toxicity or oxygen deficiency, could impair a pipeline operator's ability to respond quickly to protect the public safety in a gas emergency, a result in apparent conflict with OPS's overall scheme. See 49 C.F.R. 192.615, 192.711 (1991). Cf. Southern Pac., 539 F.2d at 392 (dominant agency regulations may displace OSHA regulations by articulating a formal position that a given working condition should go unregulated or that certain regulations - and no others - should apply to a defined subject). For these reasons, OSHA does not intend to enforce the PRCS standard in vaults to the extent that such enforcement would be based on hazards that relate to gas or other hazards that are addressed by DOT/OPS regulations.

However, enforcement of the PRCS standard in vaults is not entirely preempted. Because the OPS regulatory scheme primarily relates to the hazards of gas in vaults, the more comprehensive PRCS standard may apply to these spaces to the extent that hazards other than those related to gas are involved. Norfolk Dredging Co. 783 F.2d at 1531; Southern Pac., 539 F.2d at 391. As an example, if a vault contains no gas but employees encounter other, unusual hazards which could impair the entrant's ability to escape from the space, some of the procedures in the PRCS standard may apply. Based on A.G.A.'s representation that such other hazards are not reasonably predictable in its vaults, A.G.A.'s members need not develop a permit-required confined space program to address such hazards in advance. If such unusual hazards are encountered, they should be dealt with by following sound industrial hygiene and safety procedures, including the procedures set forth in 1910.146(d) that are relevant in light of the particular hazards involved. The discovery of such hazards initially by workers, where the employer could not reasonably have known of the existence of the hazard, will not constitute a violation of the OSH Act or the PRCS standard.

This interpretation addresses the concerns raised in A.G.A.'s March 5, 1993 submission and discussed during the meeting of April 8, 1993 and is consistent with the agency's prior enforcement policy. Based upon the information A.G.A has provided, OSHA expects that the PRCS standard would apply only in unusual circumstances in which hazards not normally encountered in day-to-day operations are present.

The policy stated in this letter applies to employers and vaults regulated by current OPS regulations. Should relevant OPS regulations be repealed or modified, it would be necessary for OSHA to reconsider its position. However, as long as current OPS regulations remain in effect, OSHA will not apply the PRCS standard to working conditions addressed by DOT/OPS regulations in vaults.


Joseph A. Dear
Assistant Secretary