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NOTICE: This is an OSHA Archive Document, and may no longer represent OSHA Policy. It is presented here as historical content, for research and review purposes only.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

November 3, 1999

Mr. Joseph P. De Vito, P.E., CSP, RPIH
163 Stockton Street
Highstown, NJ 08520

Dear Mr. De Vito:

Thank you for your May 7, 1999 letter to the Occupational Safety and Health Administration's (OSHA's) Directorate of Compliance Programs regarding our April 10, 1991 interpretation letter to DOW Chemical U.S.A. (the "DOW letter"). In your letter, you addressed the use of generic procedures and the time period for implementing lockout/tagout procedures. The DOW letter summary, your questions, and our responses follow.

DOW Letter Summary: The DOW letter addresses the use of a "generic" procedure in conjunction with "work authorization permits" for protecting employees from various types of hazardous energy. A work permit is a control document that authorizes the performance of a specific task and establishes specific procedures for accomplishing that task.

The DOW letter discusses the specific information that must be included on a work permit and emphasizes that employers may not rely exclusively on generic energy control procedures. Rather, the company's energy control procedure must specify that the work permits identify: (1) the equipment to be serviced, (2) the types and unique energy characteristics to be encountered, (3) methods for working safely, and (4) the process or procedure which will be used to accomplish the task. If a company develops acceptable and specific work permits, and the work permits are used in conjunction with an appropriate set of "generic" procedures, this would constitute compliance with the control of hazardous energy standard, 29 CFR §1910.147. Please refer to the DOW letter for further details.

Issue #1: Several of our clients have taken this letter to mean that individual, equipment-specific, written lockout/tagout procedures identifying all of the hazards associated with each piece of equipment need not be developed, but that a generic procedure suffices. The OSHA lockout/tagout regulation [1910.147(c)(4)(ii)] requires specific steps to shutdown, isolate, block, secure, place and remove lockout or tagout devices, and to determine the effectiveness of those devices.

We believe that the generic procedures covering several pieces of equipment of the same type may be written where the equipment hazards, shut down procedures, and hazard controls are identical for each piece of equipment. Where this is not the case, however, we believe that individual procedures are required.

Response: The use of generic energy control procedures alone are unacceptable, since generic procedures do not meet the provisions set forth in §1910.147(c)(4)(ii). OSHA believes that a specific and documented procedure is necessary for most energy control situations because of the number of variables involved in controlling hazardous energy and the need for authorized employees to carefully follow the sequential steps in the energy control procedure.1

However, although employers may not rely exclusively on generic procedures, employers are not necessarily required to develop a separate procedure for every machine or piece of equipment. In appropriate situations, similar machines and/or pieces of equipment (i.e., those having the same type and magnitude energy) which have the same or substantially similar type of control(s) can be covered with a single procedure. A common procedure must include a method of identification (i.e., by type and location or by type and model number) which ensures that an authorized employee can determine which energy control procedure applies to the particular machine(s) or piece(s) of equipment. This clarification is further addressed in the enclosed letters of interpretation to Mr. Lawrence Halprin, Law Offices of Keller and Heckman, and Mr. Neil Wasser, Constangy, Brooks & Smith dated, September 19, 1995 and June 20, 1996, respectively.

Issue #2: OSHA requires [§1910.147(c)(1)] that prior to an employee performing service or maintenance on a machine where the unexpected energization could cause injury, that any potentially hazardous energy source be isolated from the machine. OSHA also requires [§1910.147(c)(4)(i)] the development of procedures to control potentially hazardous energy. We presume it is the intent that such written procedures are in place prior to performing the servicing or maintenance on the machine.

We believe the interpretative memorandum dated April 10, 1991 allows lockout/tagout procedures to be developed on an as-needed basis by personnel qualified to perform the repairs as long as they have received proper lockout/tagout training. These written procedures would, however, have to be in place and followed prior to actually beginning any repairs, even those of an emergency nature.

Response: Your reference to Section 1910.147(c)(1) correctly states that the employer is required to establish an energy control program, which includes procedures, training, and periodic inspections, before any employee performs any servicing or maintenance activity in situations where there might be exposure to injury from hazardous energy. This paragraph, as well as §1910.147(d)(3), further stipulates that the machine or piece of equipment must be isolated from the energy source and rendered inoperative prior to performing such work, including emergency servicing/maintenance operations.

Please note, however, that OSHA's policy regarding employee rescue activities, set forth in §1903.14(f), may apply in an imminent danger situation, if the emergency conditions described therein exist. The term "imminent danger" means the existence of any condition or practice that could reasonably be expected to cause death or serious physical harm before such condition or practice can be abated.

The DOW letter does not specifically address the referenced lockout/tagout training; it is nonetheless imperative that the employee who is utilizing the energy control procedure understands the hazards of the work and how to control them. It is for this reason that OSHA requires in §1910.147(d)(1) that the authorized employee(s) have knowledge of the type and magnitude of the energy, the hazards of the energy to be controlled, and the procedure to be used before the machine/equipment is turned off. OSHA also considers the training set forth in §1910.147(c)(7) to be of critical importance in ensuring that the applicable provisions of an employer's hazardous energy control procedures are known, understood, and strictly adhered to by the employees.

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 or obtain a copy of a referenced document, you may consult OSHA's website at 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

1The employer need not document the required procedure for a particular machine or piece of equipment when the eight specified conditions detailed in the §1910.147(c)(4)(ii) exception exist. The exception is intended to apply to situations in which the procedure for deenergizing, servicing/maintenance, and reenergizing can be carried out without detailed interactions of energy sources, machines/equipment, and employees. Please note that this exception applies only to the documentation requirement and not to the need for implementing and following specific procedures.(Back to text)