OSHA 29 CFR 1910.147

OSHA 29 CFR 1910.147 establishes requirements for controlling hazardous energy during the servicing and maintenance of machines and equipment. Known as the Lockout/Tagout (LOTO) standard, OSHA estimates it prevents about 120 fatalities and 50,000 injuries each year by ensuring machines cannot unexpectedly start up, energize, or release stored energy while workers are performing maintenance.

The standard ranked #4 on OSHA's Top 10 most cited standards in FY 2025 with 2,562 violations. Most violations stem from missing written procedures, inadequate training, and skipped annual inspections — all preventable with a properly implemented energy control program.

1910.147 applies to general industry — any workplace where employees service or maintain machines and equipment that could expose them to hazardous energy. This covers manufacturing, utilities, warehousing, food processing, and commercial building maintenance, among others.

Whole industries sit outside the standard's scope — construction and agriculture, maritime (parts 1915/1917/1918), electric utility installations covered by 1910.269, electrical-hazard work under Subpart S, and oil and gas well drilling and servicing. Within covered workplaces, three key application exceptions apply:

• Cord-and-plug equipment: If the equipment is unplugged and the plug remains under the exclusive control of the employee performing the work, LOTO is not required.
• Hot tap operations: Welding on pressurized pipelines, vessels, or tanks to install connections or branch lines, when continuity of service is essential, shutdown is impractical, and documented procedures with special equipment provide proven effective protection.
• Minor servicing: Routine, repetitive tasks like tool changes and adjustments during normal production, provided alternative protective measures (such as machine guarding) are in place.

The standard covers all forms of energy that could cause injury during servicing. Machine-specific LOTO procedures must identify every energy source present:

Many machines have multiple energy sources. A hydraulic press, for example, has electrical energy (motor), hydraulic energy (pressurized fluid), and gravitational energy (raised ram). The written procedure must address all of them.

1910.147(d) defines the sequence for applying energy controls. Every machine-specific written procedure must follow these steps. Separately, 1910.147(c)(9) requires notifying affected employees before the controls are applied and again after they are removed — notification bookends the sequence rather than being one of the (d) steps:

• Preparation: The authorized employee identifies all energy sources, types, and magnitudes for the machine, and understands the methods to control them.
• Shutdown: The machine is shut down using normal stopping procedures (e.g., pressing the stop button, closing valves).
• Isolation: All energy-isolating devices are located and operated to disconnect the machine from every energy source (disconnect switches, valves, etc.).
• Lock/Tag application: Each authorized employee applies their personal lockout device (padlock) and/or tagout device to each energy-isolating device. Each worker must have their own lock — no sharing.
• Stored-energy release: All stored or residual energy (capacitors, springs, elevated components, rotating flywheels, pressurized fluids and gases) is relieved, disconnected, restrained, or otherwise rendered safe. If re-accumulation is possible, verification must continue until servicing is complete.
• Verification: After confirming no personnel are exposed, the authorized employee verifies isolation by operating the normal start controls or testing with instruments as appropriate, then returns the controls to neutral or off.

Removing LOTO devices (1910.147(e)): Before removing locks, inspect the work area to ensure all tools are removed and components are intact. Verify all employees are safely clear. Each employee removes only their own lock. Notify affected employees that servicing is complete and the machine is being re-energized.

1910.147(c)(5) requires employers to provide lockout and tagout devices that are standardized, durable, substantial, and identifiable. Devices must withstand the environment where they are used (heat, moisture, corrosives) and must not be used for any other purpose; tag attachment means must be non-reusable, self-locking, and attachable by hand.

Devices and tags support an employer's written energy-control program; no product by itself makes a machine compliant. If you are outfitting or replenishing a program, our collection covers lockout tagout devices (padlocks, hasps, and valve, cable, breaker, and plug lockouts) alongside lockout tagout tags with the DO NOT OPERATE legend, including US-made options.

1910.147(c)(7) establishes three tiers of training based on an employee's relationship to the locked-out equipment:

Retraining is mandatory when job assignments change, machines or processes change, energy control procedures are updated, or the periodic inspection reveals deviations or knowledge gaps. OSHA does not require annual retraining on a fixed schedule.

Where tagout is used, 1910.147(c)(7)(ii) adds training on tag limitations: tags are warning devices that do not physically restrain, must never be bypassed, ignored, or defeated, must be legible and understandable to all employees in the area, and may be removed only by the person who applied them.

Documentation: Employers must certify that training is accomplished and current. Certification records must include each employee's name and dates of training.

1910.147(c)(6) requires at least one inspection per year of each energy control procedure. This is one of the most commonly cited subsections because employers either skip inspections entirely or fail to document them properly.

The inspection must:

• Be performed by an authorized employee other than the one using the procedure being inspected
• Include a review of responsibilities with each authorized employee for lockout; where tagout is used, the review extends to each affected employee and covers tag limitations
• Correct any deviations or inadequacies observed

Required documentation: Machine/equipment identification, date of inspection, employees included in the inspection, and the name of the person performing the inspection.

When multiple employees service the same machine, 1910.147(f)(3) requires group lockout/tagout procedures. The key principle: each employee must have personal control over their own protection.

• A designated primary authorized employee coordinates the group lockout and takes overall responsibility
• Each crew member applies their own personal lock — typically to a group lockout box or multi-hole hasp
• The machine cannot be re-energized until every employee has removed their personal lock

Shift changes (1910.147(f)(4)): When one shift relieves another during ongoing servicing, the employer must have specific procedures that ensure continuity of protection through an orderly transfer. The standard method is for the incoming shift to apply their locks before the outgoing shift removes theirs, so protection never lapses.

For a worked example of group LOTO in a live-infrastructure environment, see our data center lockout tagout procedures guide.

LOTO violations are among the most frequently cited and most severely penalized OSHA standards. A single inspection can yield multiple citations — one per machine without a procedure, one for missing training records, and so on.

The 2026 federal maximums remain at the 2025 levels shown (OSHA made no 2026 inflation adjustment). Actual penalties depend on employer size, good faith, violation history, and gravity of the hazard. An employer with 10 machines and no written procedures could face over $165,000 in serious violations alone.

Most Cited Subsections

• (c)(4)(i) — Written procedures: No machine-specific energy control procedures, or using a single generic procedure for all equipment
• (c)(7)(i) — Training: Missing training records, no initial training, or no retraining after procedure changes
• (c)(6)(i) — Periodic inspection: Inspections not done, not documented, or performed by the same person who uses the procedure
• (d)(6) — Verification of isolation: Workers skip the "try" step to confirm zero energy state after applying lockout devices
• (c)(1) — Energy control program: No formal program exists or key components are missing

If your workplace also handles first aid and medical services (1910.151), energy release incidents during maintenance are a key reason to have adequate first aid supplies and trained responders on-site.

For electrical hazard warning signs required near lockout/tagout locations, see our ISO 7010 W-Series Warning Signs guide (W012 Electricity).

LOTO procedures are frequently required as part of OSHA 1910.146 permit-required confined space entry, where energy isolation is a prerequisite before workers enter the space.

OSHA references

• 29 CFR 1910.147 Full Regulation Text
• OSHA Control of Hazardous Energy Overview
• OSHA Lockout/Tagout eTool (Interactive)
• OSHA Lockout/Tagout Fact Sheet (PDF)

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