OSHA Lockout-Tagout Requirements Summary

Overview

29 CFR 1910.147 — The Control of Hazardous Energy, commonly known as the lockout-tagout (LOTO) standard, establishes requirements for preventing unexpected energisation or startup of machines and equipment, or the release of stored energy, during servicing and maintenance activities. The standard applies to general industry workplaces and is one of OSHA's most frequently cited standards, consistently appearing among the top ten violations issued each year.

The standard addresses hazardous energy in all its forms: electrical, mechanical, hydraulic, pneumatic, chemical, thermal, and gravitational. Any energy source that could cause injury to workers during servicing or maintenance must be effectively controlled before work begins. The fundamental requirement is straightforward — isolate the energy source, apply a lockout or tagout device, and verify isolation before servicing.

The scope of §1910.147(a)(1) covers the servicing and maintenance of machines and equipment in which the unexpected energisation or startup, or the release of stored energy, could harm employees. This includes activities such as constructing, installing, setting up, adjusting, inspecting, modifying, maintaining, and servicing machines. It applies whenever workers must remove or bypass a guard or other safety device, or place any part of their body into an area of a machine where work is performed on the material being processed. Lockout-tagout procedures are frequently required alongside other standards — for example, confined space entry typically requires energy isolation as part of the safe system of work, and maintenance at elevation must comply with OSHA fall protection requirements.

Scope and Exclusions

Section §1910.147(a)(2) defines specific exclusions from the standard. These exclusions apply only when certain conditions are met and do not represent blanket exemptions.

• Cord-and-plug equipment: Under §1910.147(a)(2)(ii), equipment that is connected to its energy source by a cord and plug is excluded when the plug provides effective isolation, the plug remains under the exclusive control of the servicing employee, and no additional hazards are created by the servicing work.
• Hot tap operations: Hot tap procedures on pressurised pipelines are excluded under §1910.147(a)(2)(iii) when the employer demonstrates that continuity of service is essential, shutdown is impractical, and documented procedures are followed that provide effective protection for employees.
• Normal production operations: The standard does not apply to normal production operations unless servicing activities require an employee to remove or bypass a guard or safety device, or place any part of their body into a point of operation or danger zone associated with the machine's operating cycle.

The construction industry (29 CFR 1926), agriculture (29 CFR 1928), and maritime industries (29 CFR 1915, 1917, 1918) are covered by separate standards and are outside the scope of 1910.147.

Energy Control Program

Section §1910.147(c)(1) requires employers to establish an energy control program consisting of energy control procedures, employee training, and periodic inspections. The program must document the employer's policy and methods for controlling hazardous energy.

Written energy control procedures are mandatory and must be developed for each machine or piece of equipment, unless the employer can demonstrate that a single generic procedure adequately addresses all foreseeable conditions. Each procedure must include:

• A statement of the intended use of the procedure
• Specific procedural steps for shutting down, isolating, blocking, and securing machines or equipment to control hazardous energy
• Steps for the placement, removal, and transfer of lockout or tagout devices, and the responsibility for them
• Requirements for testing a machine or equipment to determine and verify the effectiveness of lockout devices, tagout devices, and other energy control measures

Lockout vs. Tagout

Under §1910.147(c)(2), lockout is the preferred method of energy isolation. Each energy-isolating device must be locked out unless the employer can demonstrate that the use of a tagout system will provide full employee protection as specified in §1910.147(c)(3).

When tagout is used instead of lockout because an energy-isolating device is not capable of being locked out, the employer must demonstrate that the tagout program provides a level of safety equivalent to that obtained through the use of a lockout program. This demonstration requires compliance with all tagout-related provisions of the standard, including additional means of protection such as removing an isolating circuit element, blocking a controlling switch, opening an extra disconnecting device, or removing a valve handle.

Tags are warning devices and do not provide the physical restraint of a lock. Tags must clearly state that operation of the energy-isolating device from a safe or off position is prohibited. The standard emphasises that whenever an energy-isolating device is capable of being locked out, lockout must be used.

Energy Control Procedures — The Six-Step Sequence

Section §1910.147(d) establishes the required sequence for applying lockout-tagout. This procedure must be followed in order each time servicing or maintenance is performed.

1. Preparation

The authorized employee must identify all types and magnitudes of energy that the machine or equipment uses, understand the hazards of that energy, and know the methods to control it. This requires reviewing the energy control procedure, identifying all energy sources, and locating all energy-isolating devices.

2. Shutdown

The machine or equipment must be turned off or shut down using the procedures established for the machine. An orderly shutdown is required to avoid additional hazards. All affected employees must be notified before shutdown that a lockout-tagout procedure is being implemented.

3. Isolation

All energy-isolating devices must be physically located and operated to isolate the machine from its energy sources. This includes disconnecting electrical circuits, closing valves, blocking mechanical components, and any other actions necessary to prevent energy transmission.

4. Application of Lockout/Tagout Devices

Each authorized employee must apply their assigned lockout or tagout device to each energy-isolating device. Lockout devices must hold the energy-isolating device in a safe or off position. Tagout devices must be affixed at the same location where a lock would be placed and must clearly indicate that operation of the energy-isolating device is prohibited.

5. Release of Stored Energy

After isolation, all potentially hazardous stored or residual energy must be relieved, disconnected, restrained, or otherwise rendered safe. This includes discharging capacitors, relieving trapped pressure in hydraulic or pneumatic systems, releasing or blocking springs, and ensuring elevated components are lowered or blocked. If stored energy can re-accumulate, verification must continue until the servicing is completed or the possibility of accumulation no longer exists.

6. Verification

Before commencing servicing, the authorized employee must verify that isolation and de-energisation have been accomplished. This typically involves attempting to operate the machine's normal operating controls to confirm that it cannot be activated. The controls must be returned to the neutral or off position after the verification test.

Lockout/Tagout Device Requirements

Section §1910.147(c)(5) establishes four requirements for lockout and tagout devices:

• Durable: Devices must withstand the workplace environment for the maximum expected exposure period without deteriorating or becoming illegible.
• Standardised: Devices must be standardised within the facility by colour, shape, or size. Tagout devices must also be standardised in print and format.
• Substantial: Lockout devices must be substantial enough that removal requires excessive force or unusual techniques such as bolt cutters. Tagout devices and their attachments must be substantial enough to prevent inadvertent or accidental removal. Tag attachment means must be non-reusable, attachable by hand, self-locking, and non-releasable with a minimum unlocking strength of no less than 50 pounds.
• Identifiable: Each device must identify the employee who applied it. Tagout devices must warn against hazardous conditions if the machine is energised and must include a legend such as "Do Not Start," "Do Not Open," "Do Not Energize," or similar.

Each authorized employee must apply their own individual lockout or tagout device. No employee may remove another employee's device except under the limited circumstances described in §1910.147(e)(3), which requires verification that the employee who applied the device is not at the facility, reasonable efforts to contact that employee, and ensuring the employee knows the device has been removed before they resume work.

Periodic Inspection

Section §1910.147(c)(6) requires employers to conduct a periodic inspection of energy control procedures at least annually. The purpose is to ensure that the procedures and the requirements of the standard are being followed, and to correct any deviations or inadequacies.

The inspection must be performed by an authorized employee other than the one using the energy control procedure being inspected. For lockout procedures, the inspection must include a review between the inspector and each authorized employee of that employee's responsibilities under the energy control procedure. For tagout procedures, the review must also include each affected employee and all other employees working in the area.

The employer must certify that the periodic inspections have been performed. The certification must identify the machine or equipment on which the energy control procedure was used, the date of the inspection, the employees included in the inspection, and the person performing the inspection.

Training Requirements

Section §1910.147(c)(7) mandates training for three distinct categories of employees, each requiring different levels of instruction:

• Authorized employees: Workers who perform lockout-tagout. They must receive training in the recognition of applicable hazardous energy sources, the type and magnitude of energy available in the workplace, and the methods and means necessary for energy isolation and control. This is the most comprehensive training level.
• Affected employees: Workers who operate machines or equipment on which servicing is being performed under lockout-tagout, or who work in areas where such servicing is being performed. They must be instructed in the purpose and use of the energy control procedure, and must understand that they are prohibited from attempting to restart or re-energise machines that are locked or tagged out.
• Other employees: All other workers whose work operations are or may be in an area where energy control procedures are used. They must be instructed about the procedure and the prohibition against removing any lockout or tagout device and attempting to restart or re-energise equipment.

Retraining is required whenever there is a change in job assignments, machines, equipment, or processes that present a new hazard, or when a periodic inspection reveals that there are deviations from or inadequacies in the employee's knowledge or use of the energy control procedures. The employer must certify that employee training has been accomplished and is being kept up to date. The certification must contain each employee's name and dates of training.

Group Lockout/Tagout

When servicing or maintenance is performed by a group of workers, §1910.147(f)(3) requires specific procedures to ensure that each worker is afforded a level of protection equivalent to that provided by a personal lockout or tagout device.

A primary authorized employee must be designated to coordinate the group lockout-tagout. This employee is responsible for assessing the magnitude of the hazardous energy, ensuring all members of the group are informed about the status of the lockout-tagout, and coordinating the procedure's application and removal. Each authorized employee within the group must apply their own personal lockout or tagout device to a group lockbox or equivalent mechanism. This ensures that the machine cannot be re-energised until every worker has removed their personal device.

Shift and Personnel Changes

Section §1910.147(f)(4) addresses the continuity of lockout-tagout protection during shift changes. The standard requires specific procedures to ensure the orderly transfer of lockout-tagout device protection between outgoing and incoming employees. This prevents any gap in protection during the transition between shifts. The incoming shift must apply their devices before the outgoing shift removes theirs, maintaining continuous energy isolation throughout the handover. Employers must establish and document these transfer procedures as part of their energy control program.