What the lockout/tagout standard covers
Section 1910.147 covers servicing and maintenance of machines and equipment where unexpected energization or start-up, or the release of stored energy, could injure employees. The employer must establish an energy control program consisting of energy control procedures, employee training and periodic inspections. Before servicing, the equipment must be isolated from its energy source and rendered inoperative.
The standard is not limited to electricity. Stored hydraulic or pneumatic pressure, a raised load, or a spring under tension can all injure a worker after the power is off, which is why the standard requires stored or residual energy to be relieved, disconnected or restrained. See our guide to machinery injury claims for how these accidents happen.
The required sequence, step by step
Paragraph (d) requires the control steps to be performed in this order:
- Preparation: before shutdown, the authorized employee must know the type and magnitude of the energy, its hazards and how to control it
- Shutdown: the equipment is turned off using the established procedure, in an orderly way that avoids creating added hazards
- Isolation: all energy isolating devices needed to separate the equipment from its energy sources are operated
- Lockout or tagout devices are applied: a lockout device holds the isolating device in the "safe" or "off" position; a tagout device clearly indicates that operation is prohibited
- Stored energy is relieved, disconnected, restrained or otherwise made safe, and isolation is kept under verification if energy could build back up to a hazardous level
- Verification: before work begins, the authorized employee confirms that the equipment is isolated and de-energized
Training, inspections and group lockout
The standard requires training so that authorized employees can recognize hazardous energy sources and the means of isolating them, affected employees understand the purpose and use of the procedure, and other employees in the area know not to restart locked or tagged equipment. Retraining is required after job changes, new hazards, changes to the procedure, or when an inspection or the employer has reason to believe the procedure is not being followed. Employers must keep certification of training that lists each employee's name and training dates.
The energy control procedure must be inspected at least annually by an authorized employee other than the ones using the procedure; deviations must be corrected, and the certification must identify the equipment, the date, the employees included and the inspector. Where a crew or department works under group lockout, the procedure must give protection equivalent to personal locks: one authorized employee has primary responsibility for the group, and each authorized employee attaches a personal device to the group device or lockbox when starting work and removes it when stopping.
A tag is not the equivalent of a lock in practice. The standard requires employees trained on tagout to be taught that a tag provides no physical restraint and may create a false sense of security.
Where the standard does not apply
Paragraph (a)(1)(ii) excludes construction and agriculture; employment covered by the shipyard, marine terminal and longshoring standards; certain electric utility installations; electrical work covered by subpart S; and oil and gas well drilling and servicing. Other OSHA rules may apply in those settings instead.
Within covered workplaces, paragraph (a)(2) generally leaves out normal production operations, with two exceptions that bring the work back in: where an employee removes or bypasses a guard or other safety device, or places a body part in the point of operation or a danger zone. Cord-and-plug equipment that is unplugged and under the employee's exclusive control is also excluded. Whether the standard applied to a particular job is often disputed after an accident and depends on the facts.
How a lockout/tagout failure can matter to a claim
For most employees, workers' compensation is the remedy against the employer and does not depend on proving fault; see workers' compensation vs a lawsuit. Lockout/tagout records can still matter. Written procedures, training and inspection certifications, the lock and tag logs, and any OSHA inspection file can show what actually happened before the machine moved, and may be relevant to a third-party claim against, for example, a contractor that serviced the machine or a manufacturer whose equipment lacked a practical way to isolate energy (see defective equipment claims).
A violation of an OSHA standard does not by itself give a worker a right to sue, and how such evidence is used differs by state. Our page on OSHA violations and workplace claims explains the general picture. If you or a family member was hurt, preserve the evidence early, including the machine, any locks and tags, and your own written account. For amputations and crush injuries specifically, see crush injuries and amputations.
Sources
Regulation text cited on this page, checked on 23 October 2026. This is a federal regulation; state rules and state-plan variations may also apply.
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