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Integrity Path
Category: Health, Safety and Environment

Lockout/Tagout

Also known as: LOTO, Lock Out Tag Out, Lockout Tagout, Lockout-Tagout, Control of Hazardous Energy
Simply put

Lockout/Tagout (LOTO) is a safety procedure used to make sure dangerous machinery or equipment is properly shut off and cannot be turned back on while someone is working on it. It works by physically disabling the equipment and applying locks and warning tags so that stored or incoming energy cannot be released and cause injury. Its purpose is to protect workers from unexpected startup or the release of hazardous energy during servicing and maintenance.

Formal definition

Lockout/Tagout (LOTO) refers to the practices and procedures used to control hazardous energy by disabling machinery or equipment to prevent the unexpected release of that energy during servicing or maintenance. The procedure ensures that equipment is stopped, isolated from all potentially hazardous energy sources, and locked out before employees perform work, using lockout devices to hold energy-isolating mechanisms in a safe position and tagout devices to provide warning that the equipment must not be operated. As addressed in OSHA guidance on the control of hazardous energy, LOTO is a specific safety control procedure and does not by itself constitute a complete workplace safety or hazardous-energy program; readers should confirm applicable regulatory requirements, which are jurisdiction-specific, against primary sources. This entry is educational and not a substitute for professional safety or legal advice.

Why it matters

Servicing and maintenance work often requires employees to place themselves in close proximity to machinery that can cause serious injury if it starts unexpectedly or releases stored energy. Lockout/Tagout addresses this specific hazard by ensuring that equipment is stopped, isolated from all potentially hazardous energy sources, and physically locked out before work begins. Without such a procedure, workers face the risk of unintentional exposure to hazardous energy from equipment and machinery.

LOTO is one specific safety control procedure and does not by itself constitute a complete workplace safety or hazardous-energy program. Organizations typically implement it alongside broader elements such as training, hazard assessment, and ongoing oversight. Its effectiveness depends on correct implementation in context rather than on the mere existence of a written procedure.

Regulatory requirements for controlling hazardous energy are jurisdiction-specific. In the United States, OSHA provides guidance on the control of hazardous energy, but readers operating in other jurisdictions should confirm the applicable requirements against primary sources. This entry is educational and not a substitute for professional safety or legal advice.

Who it's relevant to

Occupational Health and Safety Managers
Safety leaders responsible for controlling hazardous energy need to understand LOTO as a defined procedure within a larger workplace safety program. They should confirm the specific regulatory requirements applicable in their jurisdiction against primary sources rather than assuming LOTO alone satisfies broader obligations.
Maintenance and Servicing Personnel
Workers who service or maintain machinery are the individuals LOTO is designed to protect from unexpected startup or the release of hazardous energy. Their correct application of lockout and tagout devices is central to whether the procedure achieves its intended protective effect.
Learning and Development and Training Staff
Those who design and deliver safety training may need to build LOTO instruction that reflects how the procedure isolates and locks out energy sources. Training is a distinct component and does not by itself constitute a complete hazardous-energy program; it should be paired with the underlying procedures and applicable regulatory requirements.
Compliance and Audit Teams
Teams verifying adherence to internal policies and applicable external requirements may assess whether LOTO procedures are documented and followed. Because requirements are jurisdiction-specific and may involve matters best addressed by qualified legal or safety professionals, findings should be validated against primary sources.

Inside LOTO

Energy Isolation
The practice of disconnecting or blocking hazardous energy sources (electrical, mechanical, hydraulic, pneumatic, chemical, thermal, and others) before servicing or maintaining equipment, so that stored or residual energy cannot cause unexpected startup or release.
Lockout Device
A physical mechanism, such as a lock, that holds an energy-isolating device in a safe or off position, preventing the equipment from being energized until the device is removed by an authorized person.
Tagout Device
A prominent warning tag affixed to an energy-isolating device to indicate that the equipment must not be operated. Tagout communicates a prohibition but does not physically prevent re-energization the way a lockout device does.
Authorized Employee
A worker who performs the actual application and removal of lockout/tagout devices to service or maintain equipment, and who is trained to recognize and control the hazardous energy sources involved.
Affected Employee
A worker who operates or works in the area of equipment being serviced under lockout/tagout, but who does not perform the lockout/tagout procedure itself. This person must be aware of the procedure and its purpose.
Energy Control Procedure
A documented, equipment-specific procedure describing the steps to shut down, isolate, block, secure, and verify the de-energization of a machine before service, and the sequence for safely restoring energy afterward.
Verification of Isolation
The step of confirming that energy has actually been isolated and that stored energy has been dissipated or restrained, typically by attempting to operate controls or testing before beginning work.

Common questions

Answers to the questions practitioners most commonly ask about LOTO.

Is Lockout/Tagout a compliance requirement or an ethics practice?
Lockout/Tagout sits firmly on the compliance side of the spectrum. It concerns adherence to occupational safety regulations and internal energy-control policies with defined obligations and consequences, rather than values-based judgment that exceeds legal minimums. In the United States it is addressed by OSHA's Control of Hazardous Energy standard; because the specific regulatory citation and requirements are jurisdiction-specific, confirm the applicable rules against primary sources for your location. This entry is educational and not a substitute for qualified legal or safety counsel.
Does completing a Lockout/Tagout training module make an organization compliant with hazardous energy requirements?
No. A training module is only one component of a hazardous energy control program, not the whole of it. Training is intended to build awareness and competency, but a compliant program generally also requires written energy-control procedures, appropriate devices, periodic inspections, and other elements defined by the applicable standard. Treating training completion as equivalent to full program compliance is a common misconception. Because obligations vary by jurisdiction and facility, consult the applicable regulation and qualified safety professionals.
Who should receive Lockout/Tagout training within an organization?
Training is generally structured around the roles a person plays relative to hazardous energy control, for example, those who perform the energy-control procedures and those who work in or around areas where such procedures are used. The specific scope, depth, and frequency of training for each role depend on the applicable regulation and the organization's own procedures. Determine role definitions and training requirements by reference to the governing standard and your internal policy rather than assuming a single uniform approach.
How should Lockout/Tagout training be documented?
As with other compliance training, documentation typically records who was trained, on what content, and when, so the organization can demonstrate that training occurred and identify when refreshers may be due. Documentation supports but does not by itself establish program effectiveness, which also depends on how procedures are applied in practice. Confirm the specific recordkeeping expectations against the applicable regulation, as these are jurisdiction-specific.
How does Lockout/Tagout training connect to the written energy-control procedures?
Training and written procedures are distinct but interdependent components. The written procedures define how hazardous energy is to be controlled for specific equipment or situations, while training is intended to ensure that affected personnel understand and can apply those procedures. Training built on generic content without alignment to the organization's actual procedures and equipment is unlikely to prepare personnel adequately. Coordinate training design with the individuals responsible for maintaining the underlying procedures.
How can an organization assess whether its Lockout/Tagout training is working?
Assessment generally combines training-level measures, such as completion and demonstrated competency, with program-level review, such as periodic inspection of how procedures are applied in the field. No training method or completion rate guarantees that unsafe practices are prevented; outcomes depend on implementation, supervision, and context. Effectiveness evaluation should be treated as part of the broader monitoring and review function rather than as a property of the training module alone.

Common misconceptions

A tagout device provides the same level of protection as a lockout device.
A tag is a warning that communicates that equipment should not be operated, but it does not physically prevent re-energization. A lockout device physically holds the isolating device in a safe position. Where feasible, lockout is generally regarded as providing greater protection than tagout alone.
Turning off a machine at its normal operating controls is sufficient before servicing it.
Using an on/off switch or normal operating control is not the same as isolating energy at the source. Effective lockout/tagout requires isolating the energy source, securing it, and verifying isolation, because stored or residual energy can still cause unexpected startup or release.
Lockout/tagout is a training topic that, once delivered, satisfies the workplace safety obligation.
Training is only one component. Lockout/tagout also depends on documented energy control procedures, proper devices, verification steps, and the distinct roles of authorized and affected employees. Training supports the program but does not by itself constitute the full system.

Best practices

Develop and maintain written, equipment-specific energy control procedures that identify each hazardous energy source and the steps to isolate, secure, and verify it.
Clearly distinguish and train the roles of authorized employees who apply and remove devices from affected employees who work in the area, so each understands their responsibilities.
Use lockout devices rather than tagout alone wherever the energy-isolating device is capable of accepting a lock, since a physical lock prevents re-energization while a tag only warns against it.
Include a verification step in every procedure to confirm that energy is isolated and that stored or residual energy has been dissipated or restrained before work begins.
Ensure each authorized employee applies their own personal lock and controls its removal, so equipment cannot be re-energized while anyone remains at risk.
Periodically review and confirm energy control procedures against the actual equipment and configurations in use, and consult qualified safety or legal counsel where jurisdiction-specific requirements apply.