Archive Notice - OSHA Archive

NOTICE: This is an OSHA Archive Document, and may no longer represent OSHA Policy. It is presented here as historical content, for research and review purposes only.

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

September 9, 1993

Mr. Terry B. Armentrout
Project Officer
The Dalles
John Day Project
Portland District
Corps of Engineers
P.O. Box 564
The Dalles, Oregon 97058-9998

Dear Mr. Armentrout:

This is in response to your undated letter to Mr. Rolland Stroup of my staff. Your letter was received in early June. The stated purpose of your letter was to document your May 28 meeting with Mr. Stroup on the applicability of the lockout/tagout standards at 1910.333 and 1910.147 and on the proposed rulemaking for 1910.269 to the three, that is, Dalles, John Day and Willow Creek, powerhouse projects in the Columbia River basin. The question posed at the end of your letter and our reply follow.

Question: Assuming our "safe clearance procedure" meets all the requirements of applicable Occupational Safety and Health Administration (OSHA) lockout/tagout standards, can we continue to use our safe clearance procedure using tags only?

Rely: We cannot give you a definite answer to your question without onsite evaluation; however, the following information is provided to assist you. The Electrical Safety Related Work Practices, 29 CFR 1910.331-335 or the Control of Hazardous Energy Source (Lockout/Tagout), 29 CFR 1910.147 standards cover electric power generation, transmission and distribution facilities involving work on, or directly associated with, installations of utilization equipment used for purposes other than generating, transmitting, or distributing electric energy, and will continue to do so with respect to servicing and maintenance which are not explicitly addressed in the forth-coming specific standard for the power generation industry, 29 CFR 1910.269 Electric Power Generation, Transmission and Distribution (the "power generation standard") published as a Proposed Rule in the Federal Register, Volume 54, Number 19, on Tuesday, January 31, 1989.

The Occupational Safety and Health Administration (OSHA) accepts compliance with the proposed power generation standard, where it will apply, as equivalent to compliance with the aforementioned lockout/tagout standards. That is to say, OSHA will neither issue citations nor propose penalties where the employer has appropriately carried out the requirements of the proposed power generation standard within the intended scope. This policy is consistent with long-standing agency practice; specific procedures are spelled out in the OSHA Field Operations Manual (CPL 2.45B et seq.) whereby compliance with proposed standards in lieu of existing applicable standards is treated as a de minimis violation of the Occupational Safety and Health Act, carrying no penalties and resulting in no citations, as long as this practice affords equivalent protection to employees.

In your letter you reference Federal Register (FR), Volume 58, Number 59, published on March 30, 1993. This FR addresses OSHA's determination on further consideration of three issues of the 1910.147 lockout/tagout standard remanded by the Court of Appeals for the District of Columbia Circuit in UAW vs OSHA, 938 F.2d 1310. Specifically on page 16618, OSHA clarifies the intent of 1910.147(c)(3) by stating "this provision was specifically designed to permit those employers who had already developed and implemented effective tagout procedures to continue to use those procedures." To comply with 1910.147(c)(3)(ii), the level of safety achieved by your "safe clearance procedure" must be "equivalent to the level of safety obtained by using a lockout program." This equivalency will be determined on the basis of the employer's demonstrating "full compliance with all tagout-relate provisions of this standard together with such additional elements as are necessary to provide the equivalent safety available from the use of a lockout device. Additional means to be considered as part of the demonstration of full employee protection shall include the implementation of additional safety measures; such as the removal of an isolating circuit element, blocking of a controlling switch, opening of an extra disconnecting device, or the removal of a valve handle to reduce the likelihood of inadvertent energization."

As indicated in paragraph (a) of 1910.147, the standard covers the servicing and maintenance of machines and equipment..... but does not cover exposure to electrical hazards from work on or near or with conductors or equipment in electric utilization installations, which is covered by Subpart S - Electrical and specifically, Electrical Safety-Related Work Practices at 1910.331-335. By 1910.333(b)(2)(iii), both a lock and a tag are required when dealing with electrical hazards except as provided in (b)(2)(iii)(C) and (b)(2)(iii)(E). By the exception in (b)(2)(iii)(C), a tag may be used without a lock if the employer can demonstrate that tagging procedures will provide a level of safety equivalent to that obtained by the use of a lock. As you pointed out in your letter, this level of safety equivalency is clarified on page 32003 of the preamble to the Final Rule on Electrical Safety-Related Work Practices published in the Federal Register, Volume 55, Number 151, on Monday, August 6, 1990. As noted in this Final Rule, OSHA is not strictly requiring the opening of an additional disconnect or the removal of a circuit element if tags are used as an equivalent to locks. Any measure or combination of measures that will protect employees as well as the application of a lock can be used to supplement the tagging of disconnecting means. In determining whether an individual employer's "tagging only" program provides safety equivalent to a lock, OSHA will consider factors such as:

(1) The safety record under the employer's tagging program.

(2) Whether tagged disconnecting means are accessible to qualified persons only.

(3) Whether the tag and its attachment mechanism clearly identify the disconnecting means that is open and effectively inhibit reenerging the electric circuit.....

(4) Whether the employees are thoroughly familiar with tagging procedures......

As provided in Note 2 of 1910.333(b)(2), "lockout and tagging out procedures that comply with paragraphs (c) through (f) of 1910.147 will be deemed to comply with 1910.333(b)(2) provided that:

(1) The procedures address electrical safety hazards covered by Subpart S - Electrical; and

(2) The procedures also incorporate the requirements of paragraph (b)(2)(iii)(D) and (b)(2)(iv)(B) of 1910.333.

In your letter you stated that you are revising your tagout "procedure to fully comply with appropriate OSHA rules." When complying with 1910.147, you must have an energy control program consisting not only of energy control procedures but also training and periodic inspections applicable to tagout. When applicable you must also comply with the Electrical Safety-Related Work Practices which include training and inspection requirements in 1910.331 through 335 of Subpart S - Electrical.

Thank you for your interest in occupational safety and health. If we can be of further assistance, please contact us.


Roger A. Clark, Director
Directorate of Compliance Programs