Definition of LOTO: What is Lockout Tagout Safety?

Lockout Tagout (LOTO) is a safety procedure used to prevent machines from starting up or releasing hazardous energy during servicing and maintenance. It ensures equipment stays completely de-energized so workers aren’t exposed to unexpected movement, electrical currents, stored pressure, or other energy sources. In short, LOTO keeps a machine “off” and proven safe, before anyone works on it. 

Without proper LOTO, equipment can re-energize in seconds and cause serious injuries.  In this guide, we’ll break down OSHA hazardous energy basics, when it’s required, common energy sources to watch for, the basic steps of a compliant LOTO procedure, and how to find Lockout Tagout Training. 

What Is Lockout Tagout?  

Lockout tagout is a safety procedure that protects workers from OSHA hazardous energy during equipment servicing and maintenance. In other words, it keeps a machine from turning on or releasing stored energy while someone is working on it.  

LOTO helps prevent injuries caused by:  

• Unexpected startup 

• Re-energizing equipment too soon 

• Stored energy (pressure, gravity, heat, spring tension, etc.) 

Lockout vs. Tagout: What’s the Difference?  

People often say “lockout tagout” as one phrase, but the two components serve different purposes: 

Quick rule of thumb: 
Lockout stops the energy. Tagout communicates the risk. 

Why Lockout Tagout Is Important  

LOTO is one of those safety programs you only notice when it’s missing — usually right after a near-miss or an injury. When equipment starts unexpectedly (or releases stored energy), the damage can happen fast and leave no room for “we thought it was off.”  

OSHA’s Control of Hazardous Energy standard (29 CFR 1910.147) requires employers to have an energy control program with procedures to control hazardous energy during servicing and maintenance.  

And it’s not a “paperwork only” rule. OSHA regularly cites employers for LOTO issues. In fact, 1910.147 has been in OSHA’s Top 10 most frequently cited standards list (FY 2024 shows it in the top five).  

OSHA estimates that compliance with the lockout tagout standard prevents about 120 fatalities and 50,000 injuries each year.  

When lockout tagout safety fails, common outcomes can include:  

• Electrocution 

• Burns 

• Amputations 

• Crush injuries or fractured body parts 

• Lacerations and cuts  

When Is Lockout Tagout Required?  

Lockout tagout is required when employees service or maintain machines or equipment and there’s a risk of unexpected energization or startup, or release of stored energy (pressure, spring tension, gravity, heat, etc.).  

If the work involves equipment being worked on while it could still move, be energized, or release energy, LOTO should be in place. OSHA’s definition of servicing/maintenance is broad and includes tasks like:  

• Installing or setting up equipment 

• Inspecting or adjusting 

• Repairing, replacing, modifying, or maintaining 

• Cleaning, lubricating, or unjamming 

• Adjusting or tool changes when an employee could be exposed to startup or hazardous energy  

OSHA’s LOTO standard is centered on servicing/maintenance, not normal production operations. But servicing during production can still fall under LOTO when employees are exposed to hazardous energy. For example, if guards are bypassed or someone reaches into a danger zone.  

29 CFR 1910.147 is the general industry LOTO standard associated with manufacturing, warehousing, utilities, and general industry settings. It does not cover construction and agriculture employment, or maritime work covered by OSHA Parts 1915, 1917, and 1918, plus a few other specific exclusions (like certain utility-controlled installations and oil & gas well drilling/servicing).  

Even if your operation falls outside 1910.147, controlling hazardous energy is still a smart baseline safety move because employers must provide a workplace free from recognized hazards under OSHA’s General Duty Clause.  

Common Sources of Hazardous Energy  

OSHA makes it clear that hazardous energy can come from many sources. Here are the most common types of energy that can cause injury:  

• Electrical: Live wiring, control circuits, and stored electrical energy in things like capacitors, batteries, or UPS systems.  

• Mechanical: Moving parts (belts, gears, blades), rotating shafts, flywheels, and gravity hazards (e.g., a raised load or machine component that can drop).  

• Hydraulic & Pneumatic: Stored pressure in lines, cylinders, tanks, or compressed air systems that can release suddenly, even after the equipment is “off.”  

• Chemical: Hazardous energy created by chemical reactions, pressure buildup, or volatile substances that can release energy unexpectedly.  

• Thermal: Extreme heat or cold retained in equipment (steam lines, hot surfaces, heated fluids, cryogenic systems).  

The Basic Steps of a Lockout Tagout Procedure  

Employers must develop equipment-specific LOTO procedures that eliminate guesswork. While the exact steps vary by machine, OSHA requires a process that ensures equipment cannot restart or release stored energy. 

5 Core Steps of a LOTO Procedure 

Many facilities expand this into 8 or more steps, but these five form the foundation of a compliant LOTO process. 

Who Needs Lockout Tagout Training?  

If someone services equipment, works around it while it’s being serviced, or could be impacted by a shutdown, they need LOTO training. OSHA’s lockout tagout standard requires training that matches the employee’s role in the energy control program because “one training for everyone” usually leaves gaps.  

The 3 training categories OSHA expects are:  

1. Authorized Employees  

Authorized employees are the people who do the lockout tagout. They need training on hazardous energy sources, the type/magnitude of energy in the workplace, and the exact methods for isolation and control.  

2. Affected Employees  

Affected employees are the people who work with or near the equipment being serviced. They need to understand the purpose of the energy control procedure and how to work safely around equipment that’s locked/tagged out.  

If an affected employee’s duties expand and they start performing servicing/maintenance, they become an authorized employee and must be trained accordingly before doing that work.  

3. Other Employees  

This refers to anyone who may be in the area. They must understand what LOTO devices mean and that they can’t remove locks/tags or try to restart equipment.  

When Is Retraining Required?  

OSHA does not require LOTO retraining on a fixed annual schedule. Retraining is necessary when something changes or performance shows a problem. For example: 

• Job assignment changes 

• Machines/equipment/processes change and create new hazards 

• Energy control procedures change 

• Periodic inspections (or observation) show employees aren’t following the procedure or using LOTO safely  

Online Lockout Tagout Training for Compliance  

If your team needs lockout tagout training online, it’s worth choosing a course that reinforces the why behind energy control. Strong training helps employees recognize hazardous energy sources, follow equipment-specific procedures consistently, and verify a true zero-energy state before work begins.  
Ready to train your team? Explore our Lockout Tagout Training Courses or Lockout Tagout General Industry.

Why is LOTO important?

OSHA imposes some pretty substantial fines if you fail to follow the Lockout/Tagout standard. This standard, CFR 1910.147, is one of the top ten most frequently cited violations.

But that's nothing compared to the human cost.

According to OSHA, there are up to 3 million U.S. workers who face the greatest risk while servicing equipment, including craft workers, machine operators, and other laborers.

Injuries from hazardous energy releases are typically quite serious – examples include electrocution, burns, crush injuries, lacerations, amputations, or fractures. Workers injured this way lose an average of 24 days away from work while they recover. That's more than a month for those that work 5 days a week.

And OSHA estimates that LOTO compliance prevents 50,000 of these injuries each year, as well as 120 deaths.

They also estimate that up to 10% of industrial safety accidents are related to a LOTO failure. In other words, the Lockout/Tagout standard saves lives, but it's only as good as its implementation.

When Is Lockout Tagout Required?

Any time a worker is going to work on or around a machine or piece of equipment that can cause an injury, then Lockout/Tagout regulations apply. This includes equipment that could smash, cut, shock, trap, burn, or otherwise injure a person.

LOTO procedures must be applied during a wide range of activities, including construction, installation, setup, adjustment, inspection, modification, maintenance, and service.

Some situations call for LOTO procedures even if you're not working directly on the equipment itself. For example, if workers are entering an area with moving machine parts, those machines must be completely deenergized and locked out / tagged out before entry.

Many times, hazardous energy release accidents happen because people fail to apply LOTO procedures to tasks they think are safe, like cleaning, lubricating, or unjamming equipment. There are some specific routine tasks where LOTO doesn't apply, but the exception isn't as broad as you think, and it's better to assume safety precautions are necessary.

Technically, CFR 1910.147 doesn't apply in agriculture, construction, maritime industries, or oil/gas drilling and servicing. However, the control of hazardous energy is also addressed in a number of other OSHA standards that affect those industries, including but not limited to §1926 Subparts K, Q, and V, §1917 Subpart C, and §1918 Subpart G.

Even if no specific regulations apply, the General Duty clause will, and LOTO can save thousands in worker's compensation and medical expenses.

What Are the Lock Out / Tag Out Steps?

The goal of Lockout/Tagout procedures is to ensure that relevant equipment is inoperable, all power sources are isolated, all stored energy is released before work begins, and that no one can or will try to reenergize the equipment before work is complete.

To accomplish all of those things effectively, specific LOTO procedures should be tailored to your particular company, workflow, and equipment.

However, there are five basic lockout/tagout steps.

Step 1: Communicate the shut-off to relevant employees

Before the LOTO begins, you should inform all employees who work near or with the affected equipment of the shut-down plan and likely timeline.

While you're going to put locks and tags in place as reminders, proactive communication sets expectations and helps minimize confusion.

Step 2: Identify all hazardous energy sources

Identifying all hazardous energy sources can be more difficult than it sounds, especially for complex equipment.

Many machines have residual or stored energy separate from the primary energy source. When designing your lockout/tagout practices, you need to consider all possible sources of hazardous energy and make a plan to control each that exists in the most effective way.

Hazardous energy sources may include:

• Electrical. Consider all sources of electrical energy, including backup systems and stored energy in batteries and capacitors.
• Mechanical. This is energy created by motion, and it's easy to overlook – consider any moving parts, including the potential effects of gravity or an accidental bump that translates to momentum.
• Hydraulic. When hydraulic equipment's electrical system is deenergized, the breaks will disengage, and stored hydraulic energy may be released. Even if spontaneous release seems unlikely, hydraulic energy must be released before safe work can begin.
• Pneumatic. Similar precautions must be taken with pneumatic equipment as hydraulic systems.
• Chemical. The unexpected release of chemical energy can occur for many reasons, like if chemicals change temperature, pressure, or come into contact with one another. The most common example is an internal combustion engine burning gasoline.
• Thermal. Consider whether the machinery can become active from thermal energy. Thermal energy (hot or cold) may be stored in the equipment from mechanical work, radiation, chemical reaction, and electrical resistance, among others. Also consider external sources like the sun.

Step 3: Isolate all hazardous energy sources

Before working on any machinery or equipment, each potential source of hazardous energy you identified above must be isolated.

For primary sources of energy, this will mean disconnecting the equipment completely from all potential inputs.

For electrical lockout/tagout, this will involve electrical circuit breakers, plugs, or disconnect switches. For chemical, hydraulic, or pneumatic energy, you typically isolate the fluid or gas using ball or gate valves, blind flanges, blocks, or something similar. Make sure there's no way that pressure can reaccumulate during work.

You should NOT consider an energy source to be properly isolated through the use of push buttons, e-stops, selector switches, or control panels.

You'll also need to release any form of stored energy, like properly discharging hydraulic or pneumatic pressure. Additionally, you need to block, isolate, or remove any form of potential and kinetic energy. For example, you'll want to lock any movable machine parts.

Step 4: Lock and tag the hazardous energy sources

The purpose of both locks and tags is to ensure equipment isn't reenergized before it's safe. Locks and tags are usually applied at breakers or electrical disconnects, traditional plugs, and battery backups because electrical lockout/tagout is the most common. However, any source of power will need a lockout device.

A lock physically prevents power from being restored (and/or otherwise renders the equipment inoperable), while a tag indicates that the equipment shouldn't be turned on, along with additional information on who engaged LOTO protocol and when.

Ideally, you use a lockout device in conjunction with a lockout tag. OSHA allows tagout devices when lockout isn't possible, but the tagout program needs additional layers to provide equivalent employee protection.

The LOTO standard has been in effect since 1990, so many manufacturers of potentially hazardous equipment design for and recommend specific lockout devices. It's important to use a lockout device that's appropriate to your equipment. It should fit in such a way that equipment can't be reenergized.

Lockout devices come in many forms. They're usually red with prominent labels. The most common types are padlocks of all shapes and sizes, clamp-on breaker devices, and boxes that enclose an electrical plug. However, many specialty lockout devices also exist.

Step 5: Ensure the equipment has been effectively isolated

Before work begins, you should confirm all sources of energy have been dealt with. Typically this involves trying to operate the equipment to make sure you can't.

It should also include steps like checking pressure gauges and double-checking.

LOTO Training

LOTO training is required for workers involved in or working in areas where they might be affected. Initial training has to start before they begin relevant work. The standard doesn't require regular refresher training, but you do need to retrain if you have reason to believe an employee is failing to use LOTO appropriately

Specifically, §1910.147(c)(7) requires that authorized employees are trained in the general concepts, as well as your specific procedures. Employees who work in an area where LOTO procedures apply also need general training.

Online training from an OSHA-authorized provider can be an effective and efficient way to train workers on the general concepts of lockout/tagout. It enables you to provide a low-cost but thorough foundation in the requirements so your training can focus on the hands-on stuff.

Looking for broader help with your compliance training? Check out our business solutions and learn how we can keep you compliant and safe while saving you money!