May 14, 2026 Updated June 18, 2026 Steven Eaton

What Is Lockout Tagout (LOTO)? OSHA 1910.147 Explained (2026 Guide)

What is lockout tagout (LOTO) and why does OSHA require it?

Short answer: Lockout tagout (LOTO) is the safety procedure used to isolate and de-energize hazardous energy sources before maintenance, servicing, or repair work on machinery and equipment. The controlling OSHA standard is 29 CFR 1910.147 — "The Control of Hazardous Energy." LOTO prevents the unexpected release of stored energy — electrical, hydraulic, pneumatic, mechanical, thermal, chemical, and gravitational — that kills approximately 120 workers per year in the United States and injures thousands more.

What Is Lockout Tagout (LOTO)? OSHA 1910.147 Explained (2026 Guide)

Lockout tagout is one of OSHA's most consistently cited standards. 29 CFR 1910.147 appeared in OSHA's Top 10 Most Cited Standards in every year for the last decade, generating thousands of citations annually across manufacturing, construction, utilities, and service industries. The standard exists because hazardous energy — electricity, compressed air, hydraulic pressure, stored mechanical energy, gravity — can release without warning during equipment maintenance, causing amputations, crush injuries, electrocution, and fatalities that are entirely preventable with proper procedure.

This guide is written for safety managers, maintenance supervisors, facilities directors, and compliance officers who need to understand what LOTO requires, how the standard's procedures work, what constitutes an authorized vs. affected employee, and how to build and document a compliant program. The governing framework is OSHA 29 CFR 1910.147 and the companion standard ANSI/ASSE Z244.1.

Why this matters.
OSHA estimates that compliance with 29 CFR 1910.147 prevents approximately 120 fatalities and 50,000 injuries annually in the U.S. alone. Hazardous energy releases account for roughly 10% of serious industrial accidents — and nearly all are preventable. OSHA willful citation penalties for LOTO violations can reach $165,514 per violation as of 2026, with repeat violations carrying equal maximums per occurrence. Beyond the citations, failure to implement LOTO is the kind of violation that appears in wrongful death litigation because the standard is explicit, the procedure is known, and the deviation is documentable.

Part 1 — What is hazardous energy?

OSHA 1910.147 defines hazardous energy as any energy source capable of causing injury during equipment servicing or maintenance. The standard covers six categories:

Energy type	Examples	Isolation method
Electrical	AC/DC circuits, capacitors, batteries, uninterruptible power supplies	Circuit breaker lockout, plug lockout, disconnect lockout
Hydraulic	Pressurized fluid systems, hydraulic cylinders, accumulators	Valve lockout, pressure bleed-down, accumulator discharge
Pneumatic	Compressed air lines, air cylinders, pneumatic actuators	Valve lockout, line vent/bleed, pressure gauge verification
Mechanical	Flywheels, springs under compression, counterweights, gravity-loaded components	Blocking, pinning, chocking, restraint devices
Thermal	Steam lines, hot surfaces, process heat systems, cryogenic lines	Valve lockout, thermal bleed-down with temperature verification
Chemical	Process chemical lines under pressure, reactive materials in feed systems	Valve lockout, line isolation, double-block-and-bleed

Part 2 — Lockout vs. tagout: the distinction

OSHA 1910.147 defines two control methods:

Lockout

Lockout is the application of a lockout device (typically a padlock) to an energy-isolating device (a circuit breaker, a valve, a disconnect) in the OFF or SAFE position, preventing the energy-isolating device from being operated. Lockout is the primary and preferred method under OSHA 1910.147 because it physically prevents re-energization — a lock cannot be bypassed without visible destruction.

Tagout

Tagout is the placement of a warning tag on an energy-isolating device to indicate it must not be operated until the tag is removed. Tagout alone is permitted only when the energy-isolating device is not capable of being locked out (i.e., it has no hasp or locking point). When tagout only is used, OSHA 1910.147(c)(3)(ii) requires additional protective measures to provide protection equivalent to lockout — including removing an isolating circuit element, blocking a control switch, opening an extra disconnect device, or removing a valve handle.

The lockout preference rule

OSHA 1910.147(c)(1) states that lockout is preferred over tagout whenever equipment "can be locked out." If equipment has been installed or modified after January 2, 1990, and it is capable of being locked out, lockout is required. Tagout-only programs are only acceptable for legacy equipment with no locking provisions — and even then, the tagout must include the supplemental protective measures above.

Part 3 — The six types of LOTO personnel

Personnel type	OSHA 1910.147 definition	Training required
Authorized employee	The person who applies the lockout/tagout device and performs the servicing. Only authorized employees apply and remove locks.	Full LOTO procedure training, including all six steps, energy verification, and equipment-specific procedures
Affected employee	An employee whose job requires them to operate equipment that has been locked out, or who works in an area where servicing is performed.	Instruction on LOTO purpose, their prohibition from restarting locked equipment, and what to do if they see a lock they don't recognize
Other employee	Employees who work in areas where LOTO is used but are not authorized or affected.	Instruction that they must not remove, bypass, or ignore lockout/tagout devices

Part 4 — The six-step LOTO procedure

OSHA 1910.147 establishes a required sequence for applying LOTO. Every equipment-specific LOTO procedure must follow this sequence:

Prepare for shutdown. The authorized employee identifies all energy sources for the equipment — electrical, hydraulic, pneumatic, mechanical, thermal, chemical. Reviews the equipment-specific LOTO procedure. Notifies affected employees that the equipment will be shut down and locked out.
Shut down the equipment. The authorized employee uses the normal stopping procedure to bring the equipment to a complete stop. All moving parts must be at rest; all process conditions must be at a stable state before proceeding.
Isolate all energy sources. The authorized employee operates every energy-isolating device (circuit breaker, disconnect switch, valve, plug, etc.) to the OFF or SAFE position. For complex equipment with multiple energy sources, every source must be isolated — partial isolation is not compliant.
Apply lockout/tagout devices. The authorized employee applies a lockout padlock (or tagout device where lockout is infeasible) to each energy-isolating device. Each authorized employee involved in the work applies their own lock. A lockout hasp allows multiple locks to be applied to a single energy-isolating device in group lockout situations.
Release/restrain stored energy. The authorized employee releases, restrains, or otherwise renders safe all stored energy. This means: bleeding compressed air lines; discharging hydraulic accumulators; blocking suspended machine elements against gravity; disconnecting capacitors; waiting for hot surfaces to cool below thermal injury threshold; neutralizing spring-loaded components. This step is the most frequently skipped and the most frequently responsible for injuries.
Verify isolation (the zero-energy verification). Before beginning work, the authorized employee verifies that isolation is complete and effective. For electrical: attempt to restart the equipment using the normal control (the equipment must not start); use a properly rated voltage tester to confirm zero electrical potential at the work point. For pneumatic/hydraulic: confirm zero pressure on gauges. For mechanical: attempt to move gravity-loaded elements. Verification is not optional — it is the final confirmation step that the energy is actually absent.

Part 5 — LOTO device requirements

Lockout padlocks

OSHA 1910.147(c)(5)(ii) requires lockout devices to be: substantial, durable, standardized (uniform in color, shape, or size), and identifiable (with each authorized employee's name or other identifier). Each authorized employee must have their own personal lock — padlocks cannot be shared because only the person who applied the lock can remove it. Lockout padlocks should be keyed individually (one key per lock) so that one employee's lock cannot accidentally be opened with another's key.

Lockout hasps

Lockout hasps are multi-hole devices that allow multiple padlocks to be applied to a single energy-isolating point simultaneously. They are essential for group lockout procedures where multiple authorized employees are working on the same equipment — each worker applies their own lock to the hasp; the equipment cannot be re-energized until every worker's lock has been removed. Hasps are available in aluminum and steel, typically accepting 6-12 individual locks.

Tagout tags

Lockout/tagout tags must be: standardized, legible, understandable, durable (rated for environmental conditions including moisture and temperature extremes), and attached by a means that is non-reusable, attachable by hand, self-locking, and with a minimum unlocking strength of no less than 50 lbs. Tags must include the warning "Do Not Start," "Do Not Open," "Do Not Energize," "Do Not Operate" or equivalent language.

Cable lockouts

Cable lockouts use a flexible steel cable to loop through multiple energy-isolating devices — useful when a single lock or hasp cannot reach all isolation points on large or complex equipment. A single lockout padlock threads through the cable loop, effectively locking out all devices threaded on the cable.

Circuit breaker lockouts

Circuit breaker lockout devices clamp over the breaker toggle handle in the OFF position, providing a hasp point for a padlock without requiring modification to the breaker. Available in configurations for standard toggle breakers, larger industrial breakers, and panel-mount breakers. Essential for any electrical LOTO program.

Part 6 — Equipment-specific procedures

OSHA 1910.147(c)(4)(i) requires the employer to develop, document, and utilize a written procedure for each piece of equipment with more than one energy source where lockout or tagout will be used. The procedure must:

Identify all energy sources for the equipment (type, magnitude)
List each energy-isolating device and its location
Specify the steps to achieve zero energy state in the correct sequence
Specify what stored energy must be released or restrained and how
Specify the verification method to confirm zero energy state

Equipment with a single energy source, clearly visible and completely controlled by the normal stopping procedure, may use a general lockout procedure rather than an equipment-specific one — but this exception is narrow. Most industrial machinery has multiple energy sources and requires a written equipment-specific procedure.

Part 7 — Group lockout and contractor LOTO

Group lockout

When multiple authorized employees are working on locked-out equipment simultaneously, each must apply their own lock to a hasp at each energy-isolating point. OSHA 1910.147(f)(3) permits a group lockout procedure where one individual serves as the "primary authorized employee" who applies the group lockout device, and each worker in the group applies their personal lock to the group hasp or a group lockout box. The equipment cannot be re-energized until all personal locks are removed.

Contractor LOTO coordination

When outside contractors perform work on employer equipment, OSHA 1910.147(f)(2) requires the host employer and the contractor to inform each other of their respective LOTO procedures and to ensure that each party understands and complies with the restrictions and prohibitions. This coordination must be documented. The host employer's LOTO procedures typically take precedence; contractors must comply or receive written authorization for their alternative procedures.

Part 8 — Lock removal: who can remove a LOTO device

OSHA 1910.147(e)(3) is explicit: the authorized employee who applied the lockout/tagout device must be the one to remove it. No other person may remove another person's lockout device. This rule prevents the most common re-energization accident — a supervisor or coworker removing a lock because the authorized employee has left the area or ended their shift.

Emergency lock removal procedure

If an authorized employee leaves the facility without removing their lock, OSHA permits emergency removal only under a documented procedure that includes: verifying that the authorized employee is not in the facility; making all reasonable efforts to contact the employee; and ensuring that the employee knows their lock has been removed before they return to work. This procedure must be documented in the written LOTO program and executed by a supervisor, not by another worker.

Part 9 — Periodic inspection requirements

OSHA 1910.147(c)(6)(i) requires the employer to conduct an annual inspection of each energy control procedure. This is a documented review — not just a check that the procedure exists, but a hands-on audit of how authorized employees actually perform the procedure on each piece of equipment. The annual inspection must:

Be performed by an authorized employee other than the one using the procedure
Include certification that it was performed (date, equipment identifier, employees involved, inspector name)
For group lockout procedures, include a review with all authorized employees in the group

Part 10 — Worked example: locking out a hydraulic press in a metal stamping operation

A maintenance technician at a metal stamping facility needs to clear a jam in the die area of a 100-ton hydraulic press. The press has three energy sources: electrical (motor and controls), hydraulic (main cylinder and accumulator), and mechanical (gravity-loaded upper die). Using the equipment-specific LOTO procedure:

Prepare. Technician reviews the equipment-specific LOTO procedure for this press (required by 1910.147(c)(4)). Notifies the press operator and nearby workers that the press will be locked out. Gathers personal lockout padlocks, a lockout hasp, and lockout tags from the LOTO station.
Shut down. Initiates normal stop sequence on the press control panel. Confirms all motion has stopped and the upper die is in the up/home position.
Isolate electrical. Opens the main electrical disconnect for the press. Applies a circuit breaker lockout device to the disconnect handle and applies personal padlock. Tags the disconnect with a lockout tag reading "Do Not Energize — Maintenance in Progress."
Isolate hydraulic. Closes the hydraulic supply valve feeding the press cylinder. Applies a valve lockout device and personal padlock. Tags the valve.
Release stored energy. Opens the hydraulic accumulator bleed valve to discharge residual pressure. Confirms pressure gauge reads zero. Installs die block (mechanical restraint) under the upper die assembly to prevent gravity-driven descent if hydraulic hold fails. For the electrical circuit, confirms no capacitors in the control system (per equipment-specific procedure — capacitors would require discharge time).
Verify zero energy state. Attempts to restart the press using the normal START button — no response (electrical isolated). Checks hydraulic pressure gauge at the cylinder — confirms zero. Physically attempts to push the upper die block (it does not move — mechanical restraint confirmed). Proceeds with clearing the die jam.

At the conclusion of the maintenance work, the technician removes the die block, closes all bleed valves, removes all lockout devices in reverse order, and notifies the press operator before re-energizing. The full LOTO product lineup — padlocks, hasps, tags, cable lockouts, and lockout stations — is available in our Lockout / Tagout collection.

Frequently asked questions

What is lockout tagout (LOTO)?

Lockout tagout (LOTO) is a safety procedure used to isolate hazardous energy sources before maintenance, servicing, or repair of machinery and equipment. The procedure involves shutting down equipment, isolating all energy sources, applying lockout padlocks and/or tagout tags to energy-isolating devices, releasing stored energy, and verifying zero energy state before work begins. The governing OSHA standard is 29 CFR 1910.147.

What OSHA standard covers lockout tagout?

OSHA 29 CFR 1910.147 — "The Control of Hazardous Energy (Lockout/Tagout)" — is the primary standard for general industry. Construction is covered under 29 CFR 1926.417. Maritime is covered under 29 CFR 1915.89. Electrical work in general industry also involves interaction with OSHA 29 CFR 1910.333 (electrical safety-related work practices), which has its own de-energization requirements that overlap with but are distinct from 1910.147.

What is the difference between lockout and tagout?

Lockout is the application of a physical padlock to an energy-isolating device, preventing re-energization. Tagout is the application of a warning tag on an energy-isolating device indicating it must not be operated. Lockout is required whenever the energy-isolating device can accept a lock. Tagout-only is permitted only for legacy equipment with no provision for a lock, and requires additional protective measures to compensate for the reduced security of a tag vs. a lock.

Who is an authorized employee under OSHA 1910.147?

An authorized employee is an employee who implements the LOTO procedure — applies the lock or tag, performs the work, and removes the devices. Only authorized employees may apply and remove lockout/tagout devices. Authorized employees must be trained in the recognition of applicable hazardous energy sources, the type and magnitude of energy in the workplace, and the methods and means to isolate and control that energy.

Can a supervisor remove a worker's lockout padlock?

Not without following a documented emergency lock removal procedure. OSHA 1910.147(e)(3) requires that only the authorized employee who applied the lockout device may remove it. If emergency removal is required (the employee has left the facility without removing their lock), the employer's written program must specify the procedure: verify the employee is not present, make all reasonable efforts to contact them, and ensure they are notified before returning to work.

How often does OSHA require LOTO procedures to be audited?

OSHA 1910.147(c)(6) requires an annual inspection of each energy control procedure. The inspection must be performed by an authorized employee other than the one using the procedure and must be documented with the date, the equipment, the employees involved, and the inspector's name. Annual inspection is one of the most commonly missed LOTO requirements during OSHA inspections.

What is group lockout?

Group lockout is the procedure used when multiple authorized employees work on the same locked-out equipment simultaneously. A primary authorized employee applies the group lockout device (typically to a lockout hasp or a group lockout box), and each worker in the group applies their personal padlock. The equipment cannot be re-energized until every worker has removed their personal lock.

Does LOTO apply to cord-and-plug connected equipment?

OSHA 1910.147(a)(2)(iii)(A) provides an exception for cord-and-plug connected equipment where "unplugging the equipment from the energy source" and the authorized employee maintains "exclusive control of the plug" constitutes adequate lockout. This exception applies only when: the equipment can be de-energized by unplugging; the plug is the only energy source; and the authorized employee maintains physical control of the plug throughout the servicing. If the employee must set the plug down and cannot maintain exclusive control, a lockout device on the plug is required.

What LOTO training does OSHA require?

1910.147(c)(7) requires training for all employees covered by the standard: authorized employees must be trained in recognition of hazardous energy sources, type and magnitude of energy present, and the methods for isolation and control. Affected employees must be trained on the purpose of the LOTO program and the prohibition against restarting or re-energizing locked equipment. Retraining is required when there is reason to believe an employee does not understand the procedure or when there is a change in job assignment, machinery, or processes that presents a new hazard.

What is stored energy and why is it the most dangerous LOTO step?

Stored energy is energy that remains in a system after the primary energy source has been isolated — hydraulic pressure in a cylinder or accumulator, a compressed spring, a suspended load subject to gravity, thermal energy in a heated system, or charge in a capacitor. Stored energy is the most dangerous step because it is invisible and non-obvious: the main power is off, the machine appears inert, but the stored energy can release violently without any operator input. OSHA's requirement to release or restrain all stored energy before beginning work (1910.147(d)(5)) exists specifically because workers are killed by stored energy even when they correctly locked out the primary source.

What is a LOTO station?

A LOTO station is a centralized, fixed storage location for lockout/tagout devices — padlocks, hasps, tags, cable lockouts, valve lockout devices, and other hardware. OSHA does not mandate LOTO stations, but they are industry best practice for ensuring lockout devices are available, organized, and inventoried. Stations should be located near the equipment they serve, labeled, and stocked with sufficient devices for every authorized employee on the crew.

Does OSHA require lockout or tagout for electrical panel work?

Yes. Electrical panel servicing (replacing breakers, rewiring circuits, working in live panel areas) requires either OSHA 1910.147 LOTO or the electrical-specific de-energization requirements of OSHA 1910.333. The two standards overlap for electrical equipment maintenance. In general, the more protective standard (1910.147's full zero-energy verification) applies; qualified electrical workers may additionally reference NFPA 70E for arc flash protection requirements during the verification step. Circuit breaker lockout devices are designed for this application.

What Is Lockout Tagout (LOTO)? OSHA 1910.147 Explained (2026 Guide)

What is lockout tagout (LOTO) and why does OSHA require it?