What is lockout tagout? A plain-language definition and OSHA guide

Last updated 2026-07-10

What does lockout tagout actually mean?

Lockout tagout is how you kill the power to a machine and keep it dead while a worker has hands inside it. It applies before maintenance, cleaning, unjamming, or any task that puts a person in contact with moving parts or an energized system. "Lockout" means clamping a physical lock onto an energy-isolating device (a disconnect switch, valve, or circuit breaker) so the machine cannot restart. "Tagout" means attaching a warning tag to that device when a lock physically will not fit, telling other workers not to restore energy.

The two words ride together because the standard requires one or both depending on the equipment. A lock beats a tag every time. A tag can be peeled off. A lock cannot, not without the key.

The idea is dead simple: zero energy reaching the machine while someone works on it. That covers electrical energy, hydraulic pressure, pneumatic pressure, gravity (a suspended load), thermal energy, and stored mechanical energy like a compressed spring. Every bit of it gets released or blocked before the work starts.

OSHA runs this under the Control of Hazardous Energy standard at 29 CFR 1910.147, which applies to general industry. ^[1] Construction has separate rules. Maritime has separate rules. If you're general industry, 1910.147 is your standard.

Why does OSHA say lockout tagout matters?

OSHA estimates full compliance with 29 CFR 1910.147 would prevent about 120 deaths and 50,000 injuries every year in the United States. ^[2] That figure comes from OSHA's own regulatory analysis and has anchored enforcement guidance for decades. Nobody has a clean dataset here, because a "failure to lockout" event often gets coded as the machine that did the damage rather than the energy-control failure that let it happen. Fifty thousand is the closest published number.

On citations, 1910.147 lands in OSHA's top-ten most-cited standards year after year. ^[3] In fiscal year 2023 it ranked fifth, with 2,554 violations cited. That put it above respiratory protection. Serious violations can run up to $16,131 each under 2024 penalty limits, and willful violations up to $161,323. ^[4]

The fines are not the real reason the rule exists. Amputations are the injury most tied to bad energy control. A press, a conveyor, a mixer, a compactor: every one of them has killed a worker who never knew the machine could restart.

See our broader piece on lockout tagout for implementation walkthroughs.

What are the different types of hazardous energy that LOTO covers?

OSHA's definition of hazardous energy is broad on purpose. The standard defines an energy source as "any source of electrical, mechanical, hydraulic, pneumatic, chemical, thermal, or other energy." ^[1] That "other energy" catchall is where gravity lives.

Here's what each type looks like on a real shop floor:

Energy Type	Common Source	Control Method
Electrical	Motors, panels, control circuits	Disconnect switch + lockout hasp
Hydraulic	Presses, lifts, injection molders	Valve closure + pressure bleed
Pneumatic	Air tools, cylinders, conveyors	Valve closure + line depressurization
Mechanical	Compressed springs, flywheels	Block or restrain the part
Gravitational	Suspended loads, raised dies	Block or lower before work
Thermal	Steam lines, heated platens	Valve closure + cooldown time
Chemical	Process lines under pressure	Valve closure + purge/vent

Gravity causes more confusion than any other type. A die raised on a press weighs hundreds or thousands of pounds. Cut the electrical power and that die can still fall and kill. You have to physically support it.

Same logic on a truck bed lifted during maintenance. Power's off, but gravity is still pulling on several tons of steel. A prop or mechanical block is not optional.

Who is required to follow a lockout tagout program?

29 CFR 1910.147 sorts workers into two groups: authorized employees and affected employees. ^[1]

Authorized employees are the ones who actually lock out or tag out the equipment. They do the service or maintenance. They get the full training: how to spot energy sources, how to apply lockout devices, how to verify a zero energy state, and how to release equipment back to service. OSHA requires this training to be documented.

Affected employees run the equipment that gets locked out, or work in the area where LOTO is happening. They don't apply locks, but they need to know lockout is in progress and that they cannot try to restart anything. Their training is lighter. It is still real.

There's a third bucket too. "Other" employees are anyone else in the building who might walk past LOTO in progress. They need the basics: what a lockout device looks like, what it means, and that they never touch it.

For small shops the lines blur. A five-person operation might have all five as both authorized and affected employees, depending on the day. The standard does not care about your headcount. If your people service equipment with hazardous energy, they need documented training. ^[2]

What are the six steps in the lockout tagout procedure?

OSHA lays out a specific sequence for shutting down and locking out equipment. The steps come straight from 29 CFR 1910.147(d). Here's how they run in plain language:

1. Prepare for shutdown. Identify every energy source for the machine. Know where each disconnect, valve, and switch sits. Read the equipment-specific LOTO procedure before you start.

2. Notify affected employees. Tell the operators and anyone nearby the machine is going down for maintenance. This stops someone from restarting it because they didn't know work was in progress.

3. Shut down the equipment. Use the normal stopping procedure. Power it off.

4. Isolate energy sources. Open every disconnect, close every valve, unplug the machine. All of them. Missing one energy source is how people die.

5. Apply lockout or tagout devices. Put a lock on each energy-isolating device. If several workers are on the job, each one applies their own personal lock. This is not optional. One lock from a supervisor does not protect the technician who shows up later.

6. Release or restrain stored energy. Bleed hydraulic lines, discharge capacitors, block suspended parts, vent pneumatic pressure, let hot surfaces cool. Then verify. Push the start button. Try to move the part. Confirm a zero energy state before you touch anything.

When the work's done, the sequence runs backward: pull the tools, clear workers from the area, remove LOTO devices in reverse order, notify operators, restore energy.

One thing people get wrong. Removing your own lock is yours alone to do. An authorized employee removes their own lockout device, nobody else's. If a worker heads home without pulling their lock, the standard has a specific procedure for that, and it's cumbersome by design. The whole point is that nobody casually strips off another worker's lock.

What must a written lockout tagout program include?

29 CFR 1910.147(c)(1) requires an energy control program in writing. ^[1] The program has to cover a written scope and purpose, the rules for employees, and the techniques you use to enforce compliance.

Beyond the program document, you need equipment-specific procedures for every machine with hazardous energy. OSHA's standard at 1910.147(c)(4) lists what each procedure must contain: the machine name and type, the steps to shut it down and isolate energy, the type and magnitude of each energy source, and how to control each one.

There's a narrow exception. Under 1910.147(c)(4)(i) you can skip a written machine-specific procedure only if the equipment has no potential for stored or residual energy, has a single energy source, isolates completely with one lock, fully de-energizes at lockout, cannot re-accumulate stored energy, and the employee keeps their personal lock in view and control the whole time. That's tighter than most employers assume. A standard three-phase motor with a disconnect switch might qualify. A hydraulic press never does.

Training records are required too. Document that each authorized and affected employee got training, and recertify when procedures change, when an inspection turns up deficiencies, or when you have reason to believe an employee doesn't understand the program. ^[1]

Want to skip the blank-page problem? SafetyFolio's safety program generator walks you through your machinery list and produces the documentation in about 15 minutes.

Annual inspections of your energy control procedures are mandatory. 1910.147(c)(6) requires a periodic inspection at least once a year for each procedure, done by an authorized employee other than the one who uses it. ^[1] The inspection has to be certified in writing: the date, the equipment covered, the workers involved, and who performed the review.

What is the difference between a lockout and a tagout?

A lockout uses a physical lock to hold an energy-isolating device in the off or open position. The device cannot move without removing the lock, and removing the lock takes the key. This is the preferred method under 1910.147.

A tagout uses a tag on the energy-isolating device. The tag reads something like "Do Not Operate" and names who placed it and when. Tags protect less because a tag can be removed or ignored. OSHA allows tagout-only programs, but the employer has to demonstrate the program gives "a level of safety equivalent" to lockout. ^[1] Proving that equivalency is harder than just using locks.

The standard's language is blunt: "Whenever possible, lockout shall be used." Tagout fits when an energy-isolating device cannot accept a lock, say an older valve with no provision for a hasp. Even then you pile on extra protection: pull the valve handle, open an additional disconnect, add a second tag.

Tagout-only programs are still common in older facilities running legacy equipment. They're not prohibited. But they draw more scrutiny during an OSHA inspection, and they give workers less real protection.

What OSHA training is required for lockout tagout?

Training is not a one-time checkbox. 29 CFR 1910.147(c)(7) spells out separate requirements by employee type. ^[1]

Authorized employees need to understand the purpose and function of the energy control program, plus the specific energy hazards, methods, and means of isolation for every piece of equipment they service. That training gets documented, and the documentation has to name each employee who received it.

Affected employees need to understand the purpose of the program and the ban on restarting locked-out equipment. Their training can be shorter. It cannot be zero.

Retraining kicks in when: (a) a procedure changes, (b) an inspection reveals a gap in a worker's knowledge or practice, or (c) the employer has reason to believe an employee doesn't understand the program. There's no mandatory annual retraining interval beyond the annual inspection, but most safety pros build annual refreshers into the calendar anyway, because equipment changes and people forget.

Workers who need a broader foundation can start with OSHA training, including the OSHA 30 course, which covers energy control in both its construction and general industry tracks.

The Bureau of Labor Statistics tracks nonfatal occupational injuries involving machinery. Contact-with-object injuries, the category that captures LOTO-preventable events, hit manufacturing workers hard, and newer and younger workers show up in those numbers at a disproportionate rate. ^[5] Training gaps are the common thread.

How does lockout tagout apply to contractors and outside workers?

This is where small businesses get blindsided. Bring in a contractor to service your equipment and you pick up obligations under 1910.147(f)(2). ^[1]

The host employer (that's you) has to inform the contractor about your energy control procedures and any unusual hazards your equipment carries. The contractor has to inform you about theirs. Then both sides review those procedures to confirm they don't create hazards for each other's people.

In practice: before the contractor touches your compressor, CNC machine, or conveyor, sit down and walk through whose locks go on which devices, in what order, and how you coordinate the work. A contractor running their own LOTO procedures on your equipment is fine, as long as their procedures are at least as protective as yours.

The scenario that kills people is when the contractor and host each assume the other has it covered. Nobody coordinates. The contractor pulls their lock thinking the job's done, but a host employee is still inside the machine. Or a host employee bypasses a contractor's lock because they figure the contractor already left.

Document the coordination talk. A signed contractor coordination form takes about five minutes and creates a record if OSHA shows up.

What are the penalties for violating OSHA's lockout tagout standard?

OSHA raises its civil penalty limits each year for inflation under the Federal Civil Penalties Inflation Adjustment Act. ^[4] As of 2024, the numbers are:

• Serious violation: up to $16,131 per violation
• Other-than-serious: up to $16,131 per violation
• Willful or repeated: up to $161,323 per violation
• Failure to abate: up to $16,131 per day past the abatement deadline

A single LOTO audit at a mid-sized plant can spin off multiple violations: one per machine missing a written procedure, one for missing training records, one for no annual inspection certification. They add up fast.

Willful classification lands when OSHA determines the employer knew about the hazard and chose to leave it. That's not a hard case to make if a prior inspection flagged LOTO issues and nothing got fixed.

Beyond the civil side, a worker death from bad energy control can trigger a criminal referral under Section 17(e) of the OSH Act, which allows a fine up to $10,000 and up to six months in prison for a willful violation that causes a worker's death. ^[6] Those criminal cases are rare. They still happen.

For context on how OSHA citations work more broadly, see our piece on what OSHA stands for and the enforcement framework.

Does lockout tagout apply to small businesses?

Yes. 29 CFR 1910.147 has no small-employer exemption. One employee who services a machine with hazardous energy is enough to trigger the whole thing: a written energy control program, a procedure for that machine, documented training, and annual procedure inspections. ^[1]

Business size changes how complex the program is, not whether you need one. A five-person machine shop needs a simpler program than a 500-person manufacturer. They both need a program.

Small employers fall into two traps. The first is leaning on verbal procedures: "everybody knows to unplug it before opening the guard." That does not satisfy the written program requirement, and it will not survive an injury investigation. The second is skipping machine-specific procedures because writing them feels like a mountain. One procedure per machine sounds like a paperwork flood until you write your first one. A procedure for a simple bandsaw is one page.

If you already keep written documentation under OSHA's hazard communication standard, LOTO fits the same habit. Same discipline, different hazard.

What is a group lockout, and when do you need one?

Group lockout is what you use when several workers service the same machine at the same time. Each worker gets independent protection. One person's lock does not cover the crew.

29 CFR 1910.147(f)(3) covers group lockout specifically. ^[1] The common tool is a lockout hasp, a hinged plate with multiple holes, each sized for one lock. Every authorized employee clips their personal lock onto the hasp. The equipment cannot re-energize until every lock is off, and every lock takes its owner's key.

For bigger jobs there's a group lockbox. The authorized supervisor drops the keys to the energy-isolating device locks inside the lockbox, then every worker on the job puts their personal lock on the box. Nobody gets the equipment keys back until all the personal locks come off.

The principle underneath is the same: no single person, supervisor included, can restore energy while any worker's lock stays on. This is personal protection, and it's the whole point of the system.

Group lockout procedures have to be written into your energy control program. Run maintenance shifts where multiple technicians work the same machine and a vague general policy will not hold up. You need a documented process that names who applies the primary lockout, how workers add their personal locks, and what happens at shift change.

How do you build a lockout tagout program from scratch?

A LOTO program stops feeling intimidating once you break it into four concrete deliverables: a written policy, an equipment inventory with procedures, training documentation, and an annual inspection log.

Start with the equipment inventory. Walk your facility and list every machine or system with hazardous energy. Include HVAC units, air compressors, conveyors, and any vehicle hoists or lifts. You're hunting for anything that stores or releases energy that could hurt a worker servicing it.

For each piece, write a machine-specific procedure. It lists the machine name, every energy source (type, location, magnitude), the steps to isolate each one, and how to verify a zero energy state. OSHA's 1910.147 Appendix A includes a sample energy control procedure as a non-mandatory guide. ^[1] Read it before you write yours.

Then write the program-level policy. It explains the scope, defines your authorized and affected employee classifications, describes the LOTO devices you use and where they live, and covers your coordination procedures for contractors.

Train your employees. Document it. Date the records. Keep them.

Set a calendar reminder for annual procedure reviews. Each procedure gets reviewed, and the review gets certified in writing: the date, who did it, the equipment covered, and which employees were involved.

Want this done without hiring a consultant? SafetyFolio's program generator is built for exactly this workflow. You answer questions about your equipment and workforce, and the tool produces a program document you can finalize and put into use.

For the recordkeeping habits that work alongside a LOTO program, our piece on writing an incident report covers the documentation side.

Frequently asked questions

What does LOTO stand for in safety?

LOTO stands for lockout tagout. It's the OSHA-required procedure for controlling hazardous energy before workers service or maintain machinery. Lockout means applying a physical lock to energy-isolating devices. Tagout means attaching a warning tag when a lock cannot be applied. The governing standard is 29 CFR 1910.147, the Control of Hazardous Energy standard.

Is lockout tagout required by OSHA?

Yes. OSHA's 29 CFR 1910.147 requires a written energy control program, machine-specific procedures, documented employee training, and annual procedure inspections for any general industry employer whose workers service equipment with hazardous energy. There's no small-business exemption. The standard covers all private-sector general industry workplaces under federal OSHA, plus states with their own OSHA-approved plans.

What is the difference between lockout and tagout?

Lockout uses a physical lock to hold an energy-isolating device in the safe position. Tagout uses a warning tag when a lock cannot be applied. OSHA prefers lockout because a tag can be removed or ignored. Tagout-only programs are allowed only when the employer demonstrates equivalent protection, which takes extra measures like removing valve handles or isolating additional disconnects.

What are the six steps of a lockout tagout procedure?

The six steps under 29 CFR 1910.147(d) are: (1) prepare for shutdown by identifying all energy sources, (2) notify affected employees, (3) shut down the equipment using its normal stop procedure, (4) isolate all energy sources by opening disconnects and closing valves, (5) apply lockout or tagout devices to each isolating point, and (6) release or restrain stored energy, then verify a zero energy state before beginning work.

What types of energy does lockout tagout cover?

OSHA's definition covers electrical, mechanical, hydraulic, pneumatic, chemical, thermal, and gravitational energy. Every energy source has to be controlled, not only the electrical connection. A pneumatic press with the power off can still crush a worker if the air lines stay pressurized. A suspended load can still fall if nobody blocks it.

How often does lockout tagout training need to be done?

OSHA sets no fixed annual retraining interval, but 29 CFR 1910.147(c)(7) requires retraining when procedures change, when an inspection reveals a deficiency, or when an employee appears not to understand the program. Most safety managers run annual refreshers anyway. Initial training has to be finished before an employee performs any service covered by the standard.

Does lockout tagout apply to plug-in equipment?

Equipment that plugs into a standard outlet may qualify for a limited exception under 1910.147(a)(2)(ii) if it uses cord-and-plug connection and the authorized employee keeps exclusive control of the plug during servicing. That means the plug stays in the employee's hand or sight the entire time. The moment it goes out of reach, the exception drops and full lockout kicks in.

What happens if a worker leaves before removing their lockout device?

The standard intends each worker to remove their own lock. If a worker leaves with the lock still on, 29 CFR 1910.147 lets the employer remove it only after verifying the employee is out of the facility, making all efforts to contact them, and documenting the entire process. The procedure is deliberately inconvenient, to discourage anyone from casually pulling another person's lock.

How many machine-specific procedures does a company need?

You need one procedure per piece of equipment, or per group of similar machines with identical energy sources and control methods. OSHA allows combining machines into a single procedure when their energy sources and control steps match. There's a limited exemption for very simple single-energy-source equipment, but most industrial machines don't qualify. OSHA inspectors read that exemption narrowly.

What OSHA standard covers lockout tagout in construction?

Construction electrical work falls under 29 CFR 1926 Subpart K rather than the general industry 1910.147 standard. Construction employers control hazardous energy under those provisions. Some states with their own OSHA plans apply 1910.147-style requirements more broadly, so checking your state plan is worth doing if you straddle construction and general industry work.

Can a supervisor remove a worker's lockout device?

No, not without following a specific documented exception procedure. Each authorized employee's lock is personal protection for that specific worker. A supervisor pulling an employee's lock without verifying the employee is clear and off-site puts that worker at risk and violates 1910.147. OSHA takes this seriously, and incident investigations almost always look for evidence of unauthorized lock removal.

What should lockout tagout devices look like?

OSHA requires lockout devices to be durable, standardized, substantial, and identifiable under 29 CFR 1910.147(c)(5). They have to withstand the workplace environment. Lockout hasps, padlocks, valve lockouts, and circuit breaker lockouts are all common. Tags have to hold up to weather and use without degrading. Many employers color-code devices by department or employee for quick visual accountability.

Is there a lockout tagout standard for utilities and power generation?

Yes. Electric utility and power generation workers fall under 29 CFR 1910.269 rather than 1910.147. The two standards share goals but carry different specific requirements. Utility workers follow 1910.269 for generation, transmission, and distribution work. 1910.147 covers the broader industrial base, including facilities that consume power but don't generate or distribute it.

Sources

1. OSHA, 29 CFR 1910.147 Control of Hazardous Energy (Lockout/Tagout): Full text of the LOTO standard including definitions, scope, written program requirements, employee training, and annual inspection requirements
2. OSHA, Control of Hazardous Energy (Lockout/Tagout) Safety and Health Topics page: OSHA estimates LOTO compliance prevents approximately 120 fatalities and 50,000 injuries per year
3. OSHA, Top 10 Most Cited Standards FY2023: Lockout/tagout ranked fifth among most-cited OSHA standards in FY2023 with 2,554 violations
4. OSHA, Penalties page: 2024 civil penalty amounts: serious violations up to $16,131; willful or repeated violations up to $161,323
5. U.S. Bureau of Labor Statistics, Injuries, Illnesses, and Fatalities program: BLS data on contact-with-object injuries in manufacturing, used for context on the distribution of LOTO-preventable events
6. OSHA, OSH Act of 1970, Section 17 Penalties: Willful violations causing worker death can carry criminal penalties of up to $10,000 fine and six months imprisonment under Section 17(e)
7. OSHA, LOTO Compliance Directive CPL 02-00-147: OSHA compliance directive clarifying enforcement policy for 1910.147 including the cord-and-plug exception and group lockout procedures
8. OSHA, 29 CFR 1910.269 Electric Power Generation, Transmission, and Distribution: Separate energy control standard applicable to electric utilities rather than 1910.147
9. OSHA, 29 CFR 1926 Subpart K Electrical (Construction): Construction industry electrical safety requirements distinct from general industry 1910.147
10. OSHA, Penalties page (Federal Civil Penalties Inflation Adjustment Act table): Annual inflation adjustment basis for OSHA civil penalty maximums