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Fact Sheet

(29 CFR 1910.147)


The OSHA standard concerning lockout/tagout is formally known as Control of Hazardous Energy. The standard applies to all general industry employers, regardless of number of employees. Its purpose is to ensure that employees are protected from the release of stored energy and unexpected start-up of machines and equipment during servicing and maintenance work. The full text of the standard can be accessed from

The standard applies when servicing or performing maintenance on machines or equipment. The lockout/tagout standard does not apply to: (1910.147 (a)(1)-(2))
  • Construction, maritime or agricultural employment
  • Work on cord and plug-connected equipment if the plug is under the control of the employee performing the work
  • Utility transmission, generation and distribution equipment or hot taps (see 1910.147(a)(2)(iii)(B))
  • Electrical hazards from conductors or equipment in electric utilization installations (covered by 1910 Subpart S)
  • Oil and gas well drilling and servicing
Normal production operations, covered by the Machine Safeguarding standards in 1910 Subpart O, are not covered UNLESS an employee must bypass or remove a guard or safety device or an employee must place part of their body into a point-of-operation area or other danger zone. (1910.147(a)(2)(ii)) Bypass or remove a guard, and lockout applies.

The employer must establish a program and procedures to control all types of energy that could cause employee injury during service and maintenance work. Possible energy sources include electrical, pneumatic, hydraulic, chemical, and thermal; stored/potential energy from capacitors, springs and even gravity must also be controlled.

The self-check on the following pages addresses the major requirements of the lockout/tagout standard. Consult the standard references listed for further details and specific regulatory text. All references (e.g., (e)(2)(i)) refer to paragraphs from 29 CFR 1910. 147 unless otherwise noted.

General Requirements
All sources of potentially hazardous energy on all machines and equipment have been identified.
The energy isolating devices (EID's) that control the flow of energy to the machines/equipment have been identified. "On/Off" switches and control circuits are NOT EID's; the EID must physically prevent the transmission or release of energy. EID's include manual circuit breakers, line valves and blocks.
Work practices have been evaluated to identify tasks where LOTO is required. This includes service and maintenance work, as well as tool changes or other production tasks that require employees to bypass guards or otherwise be exposed to potentially hazardous energy.

Energy Control Program (c)(1-3)
There is a program that ensures all machines and equipment will be isolated from energy sources and rendered inoperative before employees perform any servicing or maintenance work where the unexpected energizing, startup or release of stored energy could occur and cause injury.
Where it is possible to use lockout (placement of a lock and tag on the energy isolating device, e.g., circuit breaker), lockout is used instead of tagout alone UNLESS a tagout procedure can be shown to provide the equivalent safety of a lockout device.
All machines and equipment that were installed or underwent major modifications since 1/2/90 are designed to accept lockout on all energy isolating devices.

Energy Control Procedures (c)(4)
A generic lockout procedure may be followed for machines/equipment that meet all of the following:
___ no potential for stored or residual energy or re-accumulation of energy after shutdown.
___ single, readily identifiable energy source.
___ isolating and locking out the sole energy source completely de-energizes the equipment.
___ a single lockout device achieves the locked-out condition.
___ the lockout device is under the exclusive control of the employee performing the work.
___ the servicing/maintenance work creates no hazards for other employees.
___ no accidents have occurred when utilizing this exception to the requirement for specific, documented lockout procedures.
For machines/equipment NOT meeting the above criteria, specific procedures for lockout of individual equipment types are developed and documented.
Documentation (written program) includes:
___ scope and purpose of lockout procedures
___ personnel authorized to perform lockout
___ procedures for controlling hazardous energy, including:
___ statement of intended use of the procedure
___ specific steps for shutting down and isolating equipment
___ specific steps for the placement, removal and transfer of lockout devices
___ specific requirements for verifying effectiveness of lockout (affirming a zero-energy state)
___ responsibilities and the means to enforce compliance
Materials & Hardware (c)(5)
Materials and hardware for lockout are provided by the employer; a sufficient # of devices are available to cover all foreseeable repair situations.
Lockout devices are standardized by color, shape or size and be identifiable and used only for lockout purposes.
Devices are capable of withstanding the environment to which they are exposed and substantial so as not be removable without excessive force/unusual methods.
Tagout devices are durable enough to not deteriorate or become illegible in the conditions they are exposed to, and are secured with non-reusable, non-releasable attachment means with a minimum unlocking strength of 50 pounds.
LOTO devices indicate the identity of the employee applying the device(s).
Tagout devices are standardized in print and/or format, and contain words of warning such as "Do Not Start" or "Do Not Operate".

Periodic Inspection (c)(6)
An annual inspection/audit of energy control procedures is conducted to ensure the that procedures are being followed, are adequate and that all authorized employees understand their responsibilities.
The inspection is conducted by an authorized employee other than the person utilizing the procedure being inspected.

Training & Communication (c)(7)
Authorized employees (those performing lockout) have knowledge of:
___ recognition, types and magnitude of applicable energy sources
___ means and methods of energy isolation and control
Affected employees (those operating or working around machines/equipment undergoing lockout) understand the purpose and use of lockout.
All employees are able to recognize a lockout situation and understand the prohibitions on attempting to start or use locked out equipment.
Where tagout is used alone, employees are additionally trained on the following limitations of tags:
___ tags are only warnings and do not provide physical protection.
___ tags may not be removed, except by authorized persons placing them.
___ tags may not be bypassed, defeated or ignored.
___ tags must be understood by all employees in the work area to be effective.
___ tags must be made of materials that withstand the environment.
___ tags may evoke a false sense of security.
___ tags must be securely attached to energy isolating devices.
Retraining is provided whenever there is a change in assignments, change in procedures, changes to equipment that present a new hazard, or when the periodic inspection or experience shows that there are deficiencies in employee knowledge.
Training demonstrates proficiency and is documented with names, dates and the employer's certification that training has been conducted.

Application/Removal of Lockout (c)(8-9),(d), (e)
Lockout or tagout is only performed by authorized employees performing servicing or maintenance.
Energy control procedures contain these elements and are done in the following sequence prior to servicing/maintenance work:
___ affected employees are notified by authorized employees prior to the application or removal of lockout or tagout.
___ prior to LO/TO, machines are shut down/turned off using normal procedures
___ energy isolating devices (circuit breakers, valves, etc.) are placed in the "off" position to isolate the machine/equipment form the energy source.
___ locks and tags are applied to hold energy isolating devices in the off position; if tags only are used, they are placed in the same place as a lock, or as close as possible, and indicate that operating the EID is prohibited.
___ all residual or stored energy is released or rendered safe, and if it can re-accumulate, steps are taken to verify isolation until work is completed
___ verify that the machine/equipment is at a zero energy state.
Before removing LOTO and restoring energy to the machine, these steps are followed:
___ work area is inspected to ensure that machine/equipment components are intact, employees are notified and safely positioned, and it is safe to restart. Verify that machine controls are in the "off" position.
___ LOTO devices are removed by the employee who placed them unless alternate procedures have been developed for removing the LOTO of an employee who is unavailable. (see (e)(3)(i-iii))
Additional Requirements (f)(1-4)
If machines must be tested, positioned or otherwise re-energized during a LOTO, the procedures described in (d) and (e) for removal and (re)application of LOTO are followed.
Whenever outside contractors perform servicing/maintenance work, host and contractors shall inform each other of their LOTO procedures. The host employees understand and comply with the contractor's program (e.g., prohibition on starting equipment under LOTO).
Group LOTO situations follow procedures that provide protection to that of a personal LOTO procedure (i.e., every authorized employee involved has complete control over all energy sources). (See (f)(3)(ii)(A-D))
Specific procedures to ensure continuity of protection during shift/personnel changes are utilized.

The standard contains a brief appendix that provides a template for a basic lockout procedure - see 1910.147 Appendix A.

For more information, training resources or compliance assistance on Lockout/Tagout issues, contact the South Dakota Safety Council at 605-361-7785 or 800-952-5539.

Contact the South Dakota Safety Council at
or phone 605-361-7785 or 1-800-952-5539.