Lockout/tagout scope and purpose

This standard covers servicing and maintenance where unexpected energization, start up, or release of stored energy could injure employees. See 1910.147(a)(1)(i) and the general 1910.147 scope for context.

• Examples include repair, cleaning, adjustment, lubrication, and unjamming when those tasks could expose workers to sudden movement, electrical shock, or energy release.
• If the work can lead to unexpected energization or stored energy release, the standard applies.

The standard does not cover certain employment sectors and situations listed in the exceptions. See 1910.147(a)(1)(ii).

• Excluded are: construction and agriculture employment; activities covered by parts 1915, 1917, and 1918 of this title; electric utility generation/transmission installations; work covered by subpart S addressing electrical hazards (1910.147(a)(1)(ii)(D)); and oil and gas well drilling and servicing.

• If your activity falls into one of these categories, another OSHA standard or part may apply instead of 1910.147.

Normal production operations are not covered by the lockout/tagout standard unless specific servicing or maintenance conditions exist. See 1910.147(a)(2).

• The standard applies to control of energy during servicing/maintenance but excludes routine production operations.
• See the exceptions in 1910.147(a)(2)(ii) for when servicing during production becomes covered.

Servicing during normal production is covered if an employee must remove or bypass a guard, or must place any part of their body into the machine's point of operation or a danger zone. See 1910.147(a)(2)(ii)(A) and 1910.147(a)(2)(ii)(B).

• If either condition exists, the energy control requirements of the standard apply even during production.

Yes — work on cord-and-plug connected equipment is exempt if the hazard is controlled by unplugging and the plug is under the exclusive control of the employee performing the servicing. See 1910.147(a)(2)(iii)(A).

• The exemption applies only when unplugging and exclusive control of the plug effectively prevents unexpected energization or stored energy release.

Hot tap operations are excluded only if continuity of service is essential, shutdown is impractical, and documented procedures plus special equipment that provide proven effective protection are used. See 1910.147(a)(2)(iii)(B) and its conditions at 1910.147(a)(2)(iii)(B)(1), 1910.147(a)(2)(iii)(B)(2), and 1910.147(a)(2)(iii)(B)(3).

• If your hot tap operation cannot meet all three conditions, then 1910.147 requirements apply.

An employer must establish a program with procedures to affix appropriate lockout or tagout devices and otherwise disable machines or equipment to prevent unexpected energization or release of stored energy. See 1910.147(a)(3)(i) and the program requirements in 1910.147(c).

• The program must include written procedures, employee training, and periodic inspections as described in the standard.

An affected employee uses or works in the area of equipment being serviced under LOTO; an authorized employee is the person who actually applies or removes lockout/tagout devices to perform the servicing or maintenance. See the definitions in 1910.147(b).

• An affected employee becomes an authorized employee only when their job duties include performing servicing or maintenance covered by this section.

An energy isolating device is "capable of being locked out" if it has a hasp or other means of attachment for a lock, or a built-in locking mechanism, and lockout can be achieved without dismantling, rebuilding, replacing, or permanently altering the device. See the definition in 1910.147(b).

• If lockout would require major alteration of the isolating device, it is not considered capable of being locked out.

An energy isolating device is a mechanical device that physically prevents energy transmission or release (for example, a manually operated circuit breaker, disconnect switch, line valve, block). Push buttons, selector switches, and other control-circuit devices are not energy isolating devices. See the definitions in 1910.147(b).

• Use lockout/tagout on true energy isolating devices; do not rely on control-circuit devices as the sole isolation method under this standard.

Tagout may be used instead of lockout only if the employer can demonstrate the tagout program provides full employee protection equivalent to lockout, following the requirements in 1910.147(c)(2)(ii) and 1910.147(c)(3).

• The tag must be attached where the lock would have been attached 1910.147(c)(3)(i).
• The employer must comply with all tagout provisions and add any extra measures needed to achieve equivalent safety 1910.147(c)(3)(ii).

After January 2, 1990, replacement or major repair, renovation, or installation of new machines must use energy isolating devices designed to accept a lockout device. See 1910.147(c)(2)(iii).

• This requirement helps ensure future capability for lockout devices to be used on new or significantly altered equipment.

The employer must attach tags where a lock would be attached and show the tagout program provides an equivalent level of safety to lockout by following all tagout provisions plus any additional elements (such as blocking switches or removing handles) needed for equivalence. See 1910.147(c)(3)(i), 1910.147(c)(3)(ii), and consider the additional means listed in 1910.147(c)(4).

• Examples of additional measures that can help demonstrate equivalence include removal of an isolating element, blocking a switch, opening an extra disconnect, or removing a valve handle 1910.147(c)(4).

Written energy control procedures must be developed and must clearly outline scope, purpose, authorization, rules and techniques for controlling hazardous energy, including steps for shutting down, isolating, blocking, securing equipment, placement/removal/transfer of devices, responsibilities, and testing requirements. See 1910.147(c)(4)(i) and 1910.147(c)(4)(ii) with subparts A–D.

• The procedure must include the sequence of actions for safe shutdown, isolation, application and removal of devices, and verification that the energy control is effective.

An employer need not document a procedure for a specific machine only if all eight listed conditions are met, including no stored energy hazard, a single readily identified energy source that can be isolated and locked out by a single lock under exclusive control of the authorized employee, no hazard to other employees, and no prior accidents involving unexpected activation. See the exception in 1910.147(c)(4)(i).

• The eight conditions are strict; if any are not met, the employer must document and use a full energy control procedure.

Locks and tags must be durable enough to withstand the environment of use and maintain legibility; tags must resist weather, wet/damp locations, and corrosive environments so messages remain readable. See 1910.147(c)(5)(ii)(A) and its subparts (1)–(3).

• Choose hardware and tags that will not deteriorate under expected exposure conditions.

Lockout and tagout devices must be standardized so they are identifiable and uniformly used for energy control, and they must be the only devices used for that purpose and not used for other functions. See 1910.147(c)(5)(ii)(B).

• Standardization reduces confusion and ensures everyone recognizes which devices control hazardous energy.

Procedures must specify the exact steps for placement, removal and transfer of lockout/tagout devices and clearly assign responsibility for those actions. See 1910.147(c)(4)(ii)(C).

• The document should state who applies locks/tags, who removes them, how to transfer control between authorized employees, and any supervisor responsibilities for oversight.

The employer must establish a program that includes written energy control procedures, employee training, and periodic inspections to ensure machines are isolated from energy sources and rendered inoperative before servicing. See 1910.147(c) and the program description at 1910.147(c)(2).

• Training must cover authorized and affected employees; inspections must verify procedures are followed.

You may temporarily remove lockout/tagout to re-energize machinery for testing or positioning, but you must follow a specific sequence to protect employees: clear tools/materials, remove employees from hazardous areas, remove LOTO devices as specified, energize for the minimum time while using effective protections, then de-energize and reapply LOTO if further servicing is needed. See the OSHA letter Minor servicing exception clarification which describes these steps and references the requirements in 1910.147 (see the letter's discussion of 1910.147(f)(1)).

• These steps are required each time temporary re-energization is needed and cannot be used to avoid full LOTO during other servicing phases.

No, OSHA does not automatically accept ANSI "alternative methods" as compliant with 1910.147; while ANSI standards can provide useful guidance, OSHA has not determined they universally meet the standard's requirements. See the OSHA letter Minor servicing exception clarification.

• Employers may use consensus standards for guidance, but must ensure their procedures meet OSHA's explicit requirements in 1910.147.

Lockout and tagout devices must be standardized by at least one clear criterion such as color, shape, or size, and tags must also have standardized print and format. See 1910.147(c)(5)(ii).

• Use a single, consistent system across the facility (for example, all locks red and of a certain shape).
• For tagout devices, make sure the printed legend and layout are uniform so messages are immediately recognizable.
• Standardization helps employees quickly identify energy control devices and reduces the chance of mistakes.

Lockout devices must be substantial enough to prevent removal without excessive force or unusual techniques (for example, they should not be removable with bolt cutters or simple metal cutting tools). See 1910.147(c)(5)(ii)(C)(1).

• Choose locks and devices made of robust materials and designs appropriate to the environment and the energy-isolating hardware.
• The intent is to provide a reliable physical barrier so an unauthorized or accidental removal is very difficult.

Tagout device attachments must be non-reusable, attachable by hand, self-locking, non-releasable, have a minimum unlocking strength of at least 50 pounds, and be generally equivalent to a one-piece, all-environment-tolerant nylon cable tie. See 1910.147(c)(5)(ii)(C)(2).

• Use attachment materials and methods that resist accidental detachment in your workplace environment.
• Avoid reusable or weak attachments (e.g., simple string or tape) that could fail or be removed unintentionally.

Lockout and tagout devices must indicate the identity of the employee who applied the device. See 1910.147(c)(5)(iii).

• Typical identification methods include the employee's name, initials, employee number, or company-assigned ID on the lock or tag.
• Maintain a clear policy so authorized employees consistently label their devices and others can readily determine who applied them.

Tagout devices used when equipment is energized must warn against hazardous conditions and include a legend such as "Do Not Start, Do Not Open, Do Not Close, Do Not Energize, Do Not Operate." See 1910.147(c)(5)(iii).

• Ensure tag text is legible and visible in the workplace lighting and environmental conditions.
• Use the standardized print and format required by 1910.147(c)(5)(ii).

The employer must conduct a periodic inspection of the energy control procedure at least annually, and the inspection must be performed by an authorized employee other than the one(s) using the procedure being inspected. See 1910.147(c)(6) and 1910.147(c)(6)(i)(A).

• Inspections must identify and correct deviations or inadequacies found during the review (1910.147(c)(6)(i)(B)).
• Employers must certify that the periodic inspections have been performed and include the machine or equipment identity, date, employees included, and the inspector's name (1910.147(c)(6)(ii)).

When lockout is used, the periodic inspection must include a review between the inspector and each authorized employee of that employee's responsibilities under the energy control procedure; when tagout is used, the review must include each authorized and affected employee and the elements in paragraph (c)(7)(ii). See 1910.147(c)(6)(i)(C) and 1910.147(c)(6)(i)(D).

• For lockout: review individual responsibilities and practice to confirm authorized employees understand their duties.
• For tagout: include affected employees in the review and cover tag limitations listed in 1910.147(c)(7)(ii).
• Correct any deviations identified during the inspection (1910.147(c)(6)(i)(B)).

Authorized employees must be trained to recognize hazardous energy sources, the type and magnitude of energy, and methods to isolate and control it; affected employees must be instructed in the purpose and use of the energy control procedure; all other employees who work where energy control procedures may be used must be instructed about the procedures and the prohibition on attempting to restart locked-out or tagged-out machinery. See 1910.147(c)(7)(i)(A)-(C).

• Tailor training to job duties: authorized employees require hands-on procedural skill, affected employees need to know how procedures protect them.
• Document training per 1910.147(c)(7)(iv).

Employees must be trained that tags are warning devices (not physical restraints), must not be removed or bypassed without authorization, must be legible and understandable, must withstand workplace environmental conditions, can create a false sense of security, and must be securely attached so they cannot be inadvertently detached. See 1910.147(c)(7)(ii)(A)-(F).

• Emphasize that a tag does not physically prevent operation the way a lock does (1910.147(c)(7)(ii)(A)).
• Ensure tags and attachments are appropriate for outdoor or harsh environments (1910.147(c)(7)(ii)(D)).

Retraining must be provided whenever there is a change in job assignments, machines, equipment, or processes that present a new hazard, or when the energy control procedures change; additional retraining is required if periodic inspections reveal, or the employer believes, that an employee's knowledge or use of the procedures is inadequate. See 1910.147(c)(7)(iii)(A)-(B).

• Retraining should reestablish proficiency and introduce new or revised methods as needed (1910.147(c)(7)(iii)(C)).
• Keep retraining records as part of your program documentation.

The employer must certify that employee training has been accomplished and kept up to date, and the certification must contain each employee's name and dates of training. Lockout or tagout shall be performed only by authorized employees. See 1910.147(c)(7)(iv) and 1910.147(c)(8).

• Maintain a written training certification that includes the employee's name and the date(s) of training (1910.147(c)(7)(iv)).
• Restrict application of energy isolation to employees who have been trained and designated as authorized (1910.147(c)(8)).

Affected employees must be notified by the employer or authorized employee before lockout or tagout controls are applied and after the devices are removed from the machine or equipment. See 1910.147(c)(9).

• Provide clear, timely notifications so affected employees know when equipment is out of service and when it will be returned to operation.
• Notifications can be verbal, written, or by other effective means appropriate to the workplace.

Before turning off a machine, the authorized employee must know the type and magnitude of the energy, the hazards to be controlled, and the method to control the energy; then the employee shall perform the machine or equipment shutdown. See 1910.147(d)(1) and 1910.147(d)(2).

• This means train and equip authorized employees so they can identify all energy sources and proper isolation methods prior to shutdown.
• Follow your written energy control procedure step-by-step to ensure consistent, safe shutdowns.

Lockout or tagout devices must be affixed to each energy isolating device by authorized employees; lockout devices must hold isolating devices in a safe or off position; tagout devices must clearly indicate that operation or movement of the isolating device from the safe or off position is prohibited and, where locks could be used, tags must be attached at the same point a lock would have been. See 1910.147(d)(4)(i)-(iii) and 1910.147(d)(4)(iii)(A)-(B).

• If a tag cannot be directly affixed, place it as close as safely possible to the isolating device so it is obvious to anyone attempting operation (1910.147(d)(4)(iii)(B)).
• Only authorized employees should apply or remove these devices (1910.147(d)(4)(i)).

After affixing lockout or tagout devices to energy isolating devices, all potentially hazardous stored or residual energy must be relieved, disconnected, restrained, or otherwise rendered safe; if stored energy could reaccumulate to a hazardous level, verification of isolation must be continued until servicing is completed or the possibility ends. See 1910.147(d)(5)(i)-(ii).

• Examples: bleed hydraulic lines, dissipate capacitors, block suspended parts, or vent pneumatic systems.
• If reaccumulation is possible (e.g., spring tension, charging accumulators), continuously verify isolation as required by 1910.147(d)(5)(ii).

An authorized employee must verify that isolation and deenergization have been accomplished before starting work; each lockout or tagout device must be removed by the employee who applied it, except under a documented employer procedure for removal when that employee is not available. See 1910.147(e) and 1910.147(e)(3).

• The exception to removal by the applying employee requires written procedures, verification that the original authorized employee is not at the facility, attempts to contact them, and ensuring they know the device was removed before they resume work (1910.147(e)(3)(i)-(iii)).
• Always verify isolation using methods appropriate to the energy (e.g., attempt start, test voltmeter) while following safety measures.

When locks or tags must be temporarily removed to test or position equipment, the employer must follow the sequence: clear tools/materials from the machine, remove employees from the area, remove the lockout/tagout devices per 1910.147(e)(3), energize and test/position, then deenergize and reapply energy controls if servicing continues. See 1910.147(f)(1)(i)-(v).

• The OSHA letter of interpretation on the minor servicing exception clarifies that the employer must provide equivalent employee protections (such as guarding or removing employees from hazard areas) during these temporary energized steps and that the exception is limited to the time needed for testing or positioning.
• Follow the sequence strictly and document the protective measures used while the machine is energized.

Whenever outside servicing personnel will perform work covered by the standard, the on-site employer and the outside employer must inform each other of their respective lockout or tagout procedures, and the on-site employer must ensure its employees understand and comply with the outside employer's program restrictions and prohibitions. See 1910.147(f)(2)(i)-(ii).

• Coordinate procedures, communication methods, and responsibilities before work begins.
• Consider written agreements or a pre-job briefing to confirm mutual understanding and protect all employees.

Group lockout/tagout must provide equivalent protection to personal devices by assigning primary responsibility to an authorized employee, allowing that employee to ascertain each group member's exposure status, assigning overall control when multiple crews are involved, and requiring each authorized employee to affix and remove their personal lock or tag on the group device when they start and stop work. See 1910.147(f)(3)(ii)(A)-(D).

• Use group lockboxes, multiple hasp arrangements, or comparable mechanisms so each worker can apply a personal device.
• Ensure clear assignment of who coordinates and communicates changes or transfers of control.

Employers must use specific procedures during shift or personnel changes that provide for the orderly transfer of lockout or tagout protection between off-going and oncoming employees to ensure continuity of protection and minimize exposure to unexpected energization or release of stored energy. See 1910.147(f)(4).

• Procedures typically include verifying isolation, transferring responsibility in writing or via log, using group lockout devices or lockboxes, and ensuring incoming employees affix their personal devices before outgoing employees remove theirs.
• Document the transfer steps and train employees on the shift-change procedure to avoid gaps in protection.