Lockout Tagout (LOTO): What It Is, OSHA Requirements, and How It Works

OSHA 1910.147: What Employers Must Do

The standard requires employers to develop and document an energy control program, provide energy-isolating devices that can be locked out, conduct annual inspections of each energy control procedure by an authorized employee, and train all authorized and affected employees. Each inspection must be certified in writing with the equipment name, date, and inspector. Each procedure must be reviewed with each authorized employee it covers.

Employee Classifications

Authorized employee: performs the lockout or tagout and holds the key. Must be trained in hazard recognition and the specific procedure for each piece of equipment they service.

Affected employee: operates or works near equipment that is being locked or tagged out. Must understand that they cannot attempt to restart or operate equipment under lockout or tagout under any circumstances.

Other employee: works in an area where lockout tagout is in use. Must understand that locked or tagged equipment cannot be operated or re-energized.

Types of Hazardous Energy

Lockout tagout covers all forms of hazardous energy, not only electrical. Each type must be identified in the written procedure and controlled with a specific isolation method before work begins.

Electrical: de-energize and lock out circuit breakers, disconnects, or fused switches. Mechanical: block, pin, or restrain rotating shafts, flywheels, coiled springs, and counterweights. Hydraulic: block cylinders and bleed system pressure to zero. Pneumatic: close supply valves, bleed lines, and block residual pressure. Thermal: close supply valves and allow heated components to cool before entry. Gravitational: block or lower suspended loads and raised machine members before workers enter the zone. Chemical: close and blank supply lines, purge, and test the atmosphere.

The most common field failure is thermal and hydraulic stored energy. Workers isolate the electrical source, assume the job is done, and fail to bleed down hydraulic lines or to allow heated components to cool to a safe temperature. Stored energy incidents account for a disproportionate share of LOTO injuries.

The 8-Step Procedure

OSHA requires each energy control procedure to be equipment-specific and documented. The framework below applies to all compliant procedures. For a detailed walkthrough of each action and documentation requirements, see Lockout Tagout Procedure – OSHA Safety & NFPA 70E Compliance.

1. Prepare for shutdown. Identify all energy sources. Review the written procedure for the specific equipment. Gather required locks, tags, and devices before approaching the equipment.

2. Notify affected employees. Tell all workers in the area that the equipment will be shut down and locked out. State the expected duration.

3. Shut down equipment. Follow the sequence in the written procedure. Use normal stopping procedures.

4. Isolate all energy sources. Operate every energy-isolating device to the off or closed position. Each circuit breaker, disconnect, and valve must be addressed individually.

5. Apply lockout or tagout devices. Each authorized employee applies their personal lock or tag to each energy-isolating device. Where a single point requires multiple locks, use a hasp. Each worker keeps the only key to their lock. For a full comparison of device types and applications, see Lockout Tagout Devices – OSHA NFPA 70E Safety Tools.

6. Release or restrain stored energy. Bleed hydraulic and pneumatic lines to zero. Block or lower suspended loads. Allow heated components to cool. Discharge capacitors. This step fails more often than any other.

7. Verify zero energy state. Use a calibrated voltage tester on each conductor. Attempt to start the equipment using normal controls. Do not rely on indicator lights or instrument readings. Verify at the point of isolation, not from the control panel.

8. Perform the work. Each authorized employee controls their own lock. If a shift changes before work is complete, the outgoing employee must not remove their lock until the incoming authorized employee has applied their own.

Restoration reverses the isolation sequence. Each authorized employee removes their own lock after verifying that tools and personnel are clear and affected employees have been notified. Removing another worker's lock is a violation of the standard, regardless of the reason given.

What a Compliant LOTO Program Requires

Written procedures: one per piece of equipment where unexpected energization could cause injury. Generic procedures are not acceptable unless the employer can demonstrate that all covered equipment is similar enough that a single procedure provides equivalent protection. Each procedure must be specific enough to follow without additional instruction.

Annual inspections: required by OSHA 1910.147(c)(6) at least once every 12 months. Performed by an authorized employee other than the one who uses the procedure. Must include a review with each authorized employee covered by it. Must be certified in writing. In practice, inspections should verify that the written procedure still matches the current equipment configuration. A modified machine invalidates a procedure that was accurate when written.

Group lockout: when more than one authorized employee services the same equipment, each worker applies their own personal lock to a hasp. The equipment cannot be re-energized until every worker has removed their lock. Designating one employee to apply a single lock on behalf of the crew violates the personal lock requirement and is a common audit finding.

Contractors: the host employer must inform contractors about the on-site LOTO program and any unique hazards. The contractor must share their program. Where both run simultaneously, procedures must be coordinated. The host employer remains responsible for verifying that protection is in place for everyone on site.

Most Common Violations

No written program: assuming a generic procedure covers all equipment. Equipment-specific procedures are missing, leading to the use of a single procedure for machines with different energy sources. Annual inspections were not conducted: treating the requirement as administrative rather than operational. Stored energy not addressed: failing to bleed lines, discharge capacitors, or block suspended loads. Improper verification: relying on indicator lights instead of direct voltage testing at the point of isolation. Tagout is used when lockout is feasible: applying tags is faster.

Lockout Tagout and NFPA 70E

OSHA 1910.147 governs energy control across all industries. NFPA 70E specifically governs electrical safety in the workplace. Under NFPA 70E, establishing an electrically safe work condition before any electrical task is the first requirement. That sequence is the electrical application of OSHA 1910.147: identify all electrical supply sources, interrupt the load current, open the energy-isolating device, visually verify it is open, release or restrain stored electrical energy, apply LOTO devices, and test with a rated-voltage tester to verify the absence of voltage. For a full explanation of what NFPA 70E requires on energized electrical work, see NFPA 70E Arc Flash Requirements For OSHA Electrical Safety.

Organizations that train their workforce in both LOTO and NFPA 70E together, rather than treating them as separate programs, consistently achieve better compliance results and fewer incidents.

Training Requirements

OSHA 1910.147(c)(7) requires training for authorized employees, affected employees, and any other employees who work in areas where LOTO is used. Retraining is required when job assignments change, when inspections reveal procedural gaps, or when there is reason to believe an employee lacks the required knowledge or skills. OSHA Lockout Tagout Training - Electrical Safety Course covers all three employee classifications, energy control procedures, stored energy identification, and verification methods in a 6-hour live online or in-person course.

Facilities that need to qualify their full maintenance and operations workforce can access group training, live online delivery, and customized program development through Electrical Safety Training – NFPA 70E and CSA Z462 Courses.

Lockout Tagout in Canada: CSA Z460

CSA Z460, the Control of Hazardous Energy standard, parallels OSHA 1910.147 in structure and intent. It requires written procedures, equipment-specific energy control programs, training for authorized and affected workers, and annual program audits. Provincial occupational health and safety legislation references CSA Z460 as the applicable standard in most jurisdictions. Employers operating across the Canada-US border must address the requirements of both standards.