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Locking out and tagging equipment is one of the most basic safety procedures in general industry and maintenance work, especially in larger commercial buildings with several complex systems. We see it most commonly in electrical systems, but HVAC and refrigeration systems should also be treated with the same caution. Those systems have many moving parts, electrical circuits, and other hazards that could cause severe injury or death if someone energizes equipment that's actively being worked on.

Lockout/tagout (or LOTO) notifies other people in the area that equipment is de-energized and being actively worked on and/or provides an obstacle that prevents the equipment from being re-energized. However, despite LOTO's safety benefits, improper LOTO procedures remain one of the most common OSHA violations. According to OSHA’s official data and statistics, lockout/tag-out violations were the 4th most common source of citations in the 2025 fiscal year.

Proper LOTO could be the difference between life and death on a job site, so we should know how to do it right, what equipment we need for LOTO, and LOTO training requirements for companies.

Lockout vs. Tagout

Although lockout and tagout are very similar and fall under the same safety umbrella, there is a critical distinction between them. 

Lockout is when a worker completely locks a machine out of its power source. Unless someone removes or breaks that lock, the machine cannot be energized while it is locked out. Lockout devices may only be removed by the person who applied the lockout device. That person should be the only one with the key (though there is a multi-step emergency exception).

Many lockout kits have a hasp with several holes. These hasps allow multiple employees to lock out a piece of equipment, such as when more than one person is involved in a repair or maintenance. Nobody can energize the equipment until ALL workers have removed their locks.

Tagout is when a worker fastens a tag near the power source. This tag warns other workers that somebody is working on the system. It exists to deter other workers from powering the machine on, but it doesn’t physically stop them in the same way a lock does; it relies on other workers’ observational skills (and good intentions). Tagging out can only offer similar protection to a lockout program if everyone complies with the tagout program’s safety standards. As such, it is not as ideal as the lockout method. Tagout materials must also have text with clear instructions, such as “Do Not Start” or “Do Not Open,” and it should have the information of the person who placed the tag.

If locking a system out is possible, it must be locked out. However, if a lockout isn’t possible, such as on some older equipment that hasn't been designed or modified to be locked out, you MUST tag it out. OSHA recognizes the lockout method’s superiority, but if tagout is the only option, OSHA requires employers to have a tagout procedure that has been demonstrated to be as effective as a lockout.

LOTO Procedure

The LOTO procedure in OSHA Standard 1910.147(d) has six main steps, regardless of whether you use the lockout or tagout method:

1. Prepare for shutdown.
2. Shut down the system.
3. Disconnect or isolate the machine from the energy source(s).
4. Apply the lockout or tagout device(s) to the energy-isolating device(s).
5. Release, restrain, or otherwise render safe all potentially hazardous stored or residual energy. If a possibility exists for reaccumulation of hazardous energy, regularly verify during the service and maintenance that such energy has not reaccumulated to hazardous levels.
6. Verify the isolation and de-energization of the machine.

In some training materials, you may see a variation of the procedure with more steps, including notifying employees and releasing a system from lockout/tagout. (That's what we did in our LOTO training video.) Those additional steps are still important and covered in other OSHA standards: OSHA 1910.147(c)(9) and 1910.147(e)(3), respectively.

LOTO Programs and Products

OSHA requires employers to have a LOTO program in place with documented LOTO procedures for each specific piece of equipment. One of the main components of a LOTO program is proper training before working on equipment that must be locked or tagged out. Employers are also required to issue retraining under some circumstances, such as whenever they modify their LOTO program or the employees change job assignments or equipment. Employers must also have each LOTO procedure annually reviewed by an authorized employee other than the one(s) utilizing the energy control procedure being inspected, such as a designated safety officer.

You can also purchase LOTO kits with lockout materials (locks, keys, and hasps), writable and waterproof tagout devices, and compliant non-reusable attachments for tagout devices. These can be a bit expensive, but you’ll certainly be a lot safer if you carry one on your truck and use them in compliance with your company’s LOTO program.

Regardless of whether you're an employee trying to leave a job with all your limbs intact or an employer who wants to create a safe and OSHA-compliant working environment, LOTO is something we all should know and practice. We all want to protect human life on the job, and LOTO is a simple and effective way to do it. 

If you would like to learn more about OSHA’s standards or your rights as a worker, please visit OSHA’s website. Some of the links below are OSHA resources specific to lockout/tagout:

Link to OSHA’s Control of Hazardous Energy Lockout/Tagout publication

Link to OSHA’s overview of lockout/tagout and directory resources