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Standard Interpretations - Table of Contents
• Standard Number: 1910.147(b); 1910.147(c)(4); 1910.147(c)(7)(i); 1910.147(d); 1910.147(d)(4)(i); 1910.147(f)(3)(ii); 1910.147(f)(3)

February 10, 2004

[Name and Address Withheld]

Dear [Name Withheld]:

Thank you for your October 15, 2003 letter to the Occupational Safety and Health Administration's (OSHA's) Directorate of Enforcement Programs. This letter constitutes OSHA's interpretation only of the requirements discussed and may not be applicable to any questions not delineated within your original correspondence. You posed two specific scenarios and three questions regarding regulations related to the Control of hazardous energy (lockout/tagout) standard, 29 CFR §1910.147. The paraphrased inquiries and our responses follow.

Scenario: At the plant where I work, we implement our lockout/tagout (LOTO) as follows: The maintenance group leader (authorized employee) contacts the plant operator to work on a piece of equipment. The plant operator radios the auxiliary operator to come to the control room to retrieve the locks/tags and prints out the lockout sheet. The auxiliary operator isolates the valves, breakers, etc., and places the keys in the lock box. The auxiliary operator also places a control lock/tag on the box, informs the plant operator that the equipment is ready to be worked on, and then resumes what he or she was doing before the LOTO. The maintenance man (group leader) places his personal lock on the lock box and signs onto the lockout form. The maintenance man is now ready to work. The auxiliary operator and maintenance man signed the tags.

Comment: With regard to your two scenarios (this scenario and the scenario below), our office did not perform a detailed review of the energy control procedures that you provided. OSHA does not review procedures in this manner or certify that procedures comply with the provisions of the LOTO standard.
1 Additionally, your brief description lacks sufficient detail to thoroughly evaluate your company's energy control procedure with respect to the requirements of the LOTO standard. Nonetheless, the following comments with respect to the first scenario are provided based on the information provided.

It appears that your company utilizes lockout, has documented energy control procedures, and employs a group lockbox with an operations lock type of energy control system.
2 Although your scenario does not contemplate group lockout, as only one employee is performing the maintenance, the above procedure does appear to have an organizational structure commonly used with group lockout situations.3 It appears that the plant operator exercises overall hazardous energy control responsibility, in accordance with 1910.147(f)(3)(ii)(C), to coordinate impacted work forces and ensure continuity of employee protection. This person is sometimes referred to as the primary authorized employee. If the maintenance group leader were to have the responsibility for supervising a number of authorized employees and ascertaining the exposure status of individual group members with regard to the lockout or tagout of the machine or equipment, the maintenance group leader would be identified as the principal authorized employee [1910.147(f)(3)(ii)(A) and (B)].

In other words, your company's lockout management system appears to be structured similarly to some of the performance responsibilities contained in Section 1910.147(f)(3)(ii). These provisions require the employer to develop and implement procedures for determining the exposure status and coordination of work forces and individual crewmembers.

Based upon the limited information available, the following comments are provided:
  1. The procedure described in your scenario does not include all of the energy control measures required by paragraph (d) of the LOTO standard. For example, as described, the procedure does not include a step to determine the presence of (and if present, to relieve, disconnect, and/or restrain) all potentially hazardous stored or residual energy. Another apparent deficiency involves the failure to verify that the hazardous energy isolation and de-energization of the machine or equipment have been accomplished. The placement of a personal lock on any energy-isolating device, without verifying that the system has been effectively isolated (e.g., dissipating residual energy), may pose a serious hazard for the maintenance employee [§§1910.147(d)(5) and (d)(6)].

  2. Although not included in your scenario, the other applicable requirements of the LOTO standard (e.g., paragraph (c)(8) for affected employee notification; paragraph (e) for the release of equipment from lockout) also would need to be met.
Scenario: The maintenance group leader contacts the plant operator and requests to work on a piece of equipment. The plant operator informs all affected employees (operators) that the piece of equipment is being taken out of service and prints out the lockout sheet and the equipment specific energy control procedure. The authorized employee obtains the locks/tags and locks out the valves, breakers, etc., according to the equipment specific energy control procedure. The authorized employee signs the tags and verifies zero state by pressing the start button and also by having the plant operator try to start the equipment. The authorized employee returns to the control room and places the keys in the lock box. The authorized employee installs a control lock on the lock box and gives the key to the plant operator. The group leader verifies the locks/tags are in the proper place by also signing the tags; he then signs onto the lockout sheet.4 The authorized employee also places this personal lock on the lock box.

Comment: This second scenario appears to be similar to the first, except that affected employee notification and isolation and de-energization verification steps are included. Should you have any further questions, please do not hesitate to telephone the OSHA Regional Office at:
U.S. Department of Labor - OSHA
JFK Federal Building, Room E340
Boston, MA 02203
(617) 565-9860
Question #1: Can the authorized employee lockout the equipment if he is not working on it?

Reply: Yes. A worker is considered an authorized employee if they either: (1) lock out or tag out machinery/equipment in order to perform servicing or maintenance, or (2) implement a lockout and/or tagout system procedural element on machines or equipment (in order to permit servicing or maintenance). Employees implement a lockout/tagout procedural element if they: (a) perform energy source isolation; (b) implement lockout and/or tagout on machines or equipment; (c) dissipate potential (stored) energy; (d) verify energy isolation; (e) implement actions to release LOTO; or (f) test or position machinery or equipment. Thus, in your first scenario, the auxiliary operator performed the lockout and is an authorized employee, even though he/she did not perform the maintenance work. 5

Question #2: The group leader is the person responsible for all activities leading to the completion of a specific job, task, or project. Should this person be the affected employee, the authorized employee, or a manager?

Reply: The answer to your general question depends on the group leader's responsibilities. He/she must be an authorized employee if his/her responsibilities, for example, include managing the protection of a set number of employees under group LOTO [§1910.147(f)(3)(ii)]. An affected employee, on the other hand, is one who does not perform servicing or maintenance work on the machine or a piece of equipment and does not implement the LOTO system procedural elements. Rather, the affected employee's job responsibilities include operating the machine or equipment or performing other work in an area where the servicing or maintenance work is being performed. Please refer to the above comment and reply for the responsibilities of an authorized employee, principal authorized employee, and primary authorized employee to better determine the manner in which the group leader would be classified.

Question #3: If I am normally an affected employee, but I am also the person working on the equipment, can I be both the affected employee and the authorized employee?

Reply: Yes. An affected employee becomes an authorized employee when the affected employee's duties are enlarged to include performing servicing or maintenance on a machine or piece of equipment which must be locked or tagged out. See the definition of an Authorized employee in paragraph 1910.147(b). Before performing service or maintenance, that employee must receive the training detailed in 1910.147(c)(7)(i)(A).

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.


Richard E. Fairfax, Director
Directorate of Enforcement Programs

1 OSHA does not test, approve, certify, or endorse any procedure, equipment or product. [ back to text ]

2 OSHA Instruction, STD 1-7.3 (September 11, 1990), provides guidelines to assist you in the evaluation of your employer's energy control program. For example, Appendix C provides various group lockout/tagout procedure examples using lockbox procedures, including the use of operations locks (also known as Job Locks) which ensure the continuity of employee protection during shift or personnel changes. This instruction may be found in the Directives section (under the Laws and Regulations title) at the OSHA Home Page (http://www.osha.gov). Also, please refer to §§1910.147(c)(4) and (f)(3) for details related to energy control procedure and group lockout/tagout provisions. [ back to text ]

3 If this is a misunderstanding of your scenario and other employees are involved in the servicing and maintenance activities, all of the provisions of 1910.147(f)(3) are applicable. [ back to text ]

4 Checking that the locks/tags are in the proper place is an important step, but checking alone may not sufficiently verify that the machine or equipment is effectively isolated from the hazardous energy source(s). In your second scenario, both the authorized employee and the plant operator perform a verification step by trying to start the machinery once it has been locked out. However, given the limited detail in your scenario, we cannot determine whether these steps are adequate to verify de-energization and isolation of the machinery. [ back to text ]

5 Any person isolating energy sources and/or applying lockout devices is considered an authorized employee and must have the requisite knowledge of an authorized employee, regardless of whether he/she performs servicing or maintenance work [§§1910.147(c)(7)(i) and (d)(4)(i)]. [ back to text ]

Standard Interpretations - Table of Contents

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