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.


July 10, 2000

Mr. Edward Ayscue, Chief
Facilities Management Branch
Federal Bureau of Prisons
500 First Street, NW
Washington, DC 20534

Dear Mr. Ayscue:

Thank you for your November 22, 1999 letter to the Occupational Safety and Health Administration's (OSHA) Office of Federal Agency Programs. You requested OSHA's opinion regarding proposed modifications to the Bureau of Prisons' (BOP) Lockout/Tagout (LO/TO) procedures that you would like to implement at BOP correctional facilities in order to minimize a possible security risk to prison staff and inmates. Please pardon the delay in our response.

Under the BOP's present procedures, inmate electrical workers are allowed exclusive control over locking devices, ensuring that any deenergized circuit cannot be re-energized until the locking device is removed by the person who applied it. Special provisions are made for the limited types of machinery and equipment requiring a locking device other than a combination lock, such as hydraulic and pneumatic presses or pressurized steam pipes. You believe that allowing inmates to have exclusive control over these locks poses a potential security problem, since inmates could use the locks to the impede prison staff from gaining access throughout the facilities.

In order to address this concern, the BOP plans to use combination locks equipped with master key access as the locking devices in its facilities. Each lock will have an attached laminated tag, which identifies the protected inmate electrician and warns against hazardous conditions created, if the machine, equipment, or circuit is energized. The tag will also be labeled with instructions permitting removal of the tag and lock only by the authorized inmate electrical worker.

In addition, the BOP's proposed policy would allow for the removal of locks in accordance with the 1910.147(e)(3) exception when an authorized inmate is unavailable because: he or she has been transferred to segregation for disciplinary or administrative reasons; he or she is incapacitated due to illness or injury; or conditions during an institutional disturbance (e.g., a prison riot) prevent the release of the lockout device by the authorized inmate. Pursuant to the BOP's proposed policy, a management representative would have the authority to remove a lock when any of these three conditions exists and the provisions stated in 29 CFR 1910.147(e)(3)(i)-(iii) are followed. The BOP believes that this program change would provide prison management with the ability to better maintain security in BOP facilities under the circumstances identified in your letter.

OSHA recognizes that prison environments are very different from traditional employment environments. We appreciate your efforts to fully apply LO/TO procedures, given the unique demands of the prison environment, and to develop a program that is consistent with the provisions of 1910.147(e)(3) in those situations in which an inmate who applied a locking device is not available to remove that device. Section 1910.147(e)(3) contemplates situations in which an employee in a traditional employment environment, who affixed a lock or a tag to an energy control device, is not available to remove that lock or tag. This provision provides that, when the employee is not available, the tag or lock may be removed under the employer's direction, as long as the employer complies with the requirements of 1910.147(e)(3). We believe that the three circumstances that you have described in your letter would constitute situations in which an inmate is "not available to remove" his or her locking device and that these circumstances are the institutional equivalent to a determination an authorized employee is "not at the facility." See 1910.147(e)(3)(i).

The BOP classifies its inmate workers who perform LOT0 operations as "electrical workers." When inmate electricians and other inmates are working on or around live electric parts they need to comply with 1910.333(a)(l) and 1910.333(b)(2), if lockout and tagging is involved. This response will address the requirements for implementing the one exception to the removal of a lock used for energy control by the authorized employee pursuant to 1910.147(e)(3) or 1910.333(b)(2)(v)(C). These requirements need to be integrated into your written procedures on energy control.

In certain, limited situations, a master key may be used to remove locks used in controlling the release of hazardous or electrical energy. Pursuant to 1910.147(e)(3), an employer is required to implement and follow specific procedures for the removal of locks by someone other than the worker who applied the lock. For re-energizing electrical parts, the employer must follow the 1910.333(b)(2)(v)(C) requirements. However, although the standards require an employer to establish lock removal and training procedures, the specific means for removing a lock is not prescribed. Therefore, the BOP may remove an inmate's locking device using a master key in the situations in which an inmate is not available to remove his or her own locking device, as long as the BOP has, and follows, its specific procedures that include the elements detailed in the exception to 1910.147(e)(3) and 1910.333(b)(2)(v)(C).

The BOP's proposed policy appears to be consistent with the requirements enumerated in 1910.147(e)(3) and 1910.333(b)(2)(v)(C). In order to reliably prevent the inadvertent removal of a lock securing an energy isolating device, we concur with your proposed control which strictly restricts access to the master key to a management representative, who is trained to understand fully the provisions of your policy regarding the removal of a locking device with a master key. For your energy control program to be effective, you must integrate the policy into written energy control procedures; each correctional facility must incorporate these procedures into its LOTO program; you must provide adequate training on these procedures; and you must perform periodic inspections to determine the effectiveness of this policy.

You also identified circumstances where locking devices could be misused for purposes other than the control of hazardous energy, thereby disrupting prison security. The removal of these locks would be an institutional security matter, and the standards do not apply to locks that are not attached to energy isolating devices and that are not used to protect inmates from hazardous energy. However, in order to effectively ensure the integrity of your LO/TO program, it may be prudent to assign responsibility for all removal of all locking devices to the management representative identified in the energy control procedures.

Thank you for your interest in occupational safety and health. We hope this provides the clarification you were seeking. Please be aware that OSHA's re-examination of an issue may result in the clarification or correction of previously stated enforcement guidance. If you have any further questions, please feel free to contact the Office of Federal Agency Programs at 202-693-2122.


Richard E. Fairfax, Director
Directorate of Enforcement Programs