Fact Sheet


“Lockout/tagout” refers to specific practices and procedures to safeguard employees from the unexpected energizing or startup of machinery and equipment, or the release of hazardous energy during service or maintenance activities. This requires that:

  1. an assigned person turns off and disconnects the machinery or equipment from its energy source(s) before performing service or maintenance and
  2. the authorized employee either locks or tags the energy-isolating device(s) to prevent the release of hazardous energy and take steps to verify that the energy has been isolated effectively.

Lockout devices hold energy-isolation devices in a safe or “off” position. These devices prevent machines or equipment from becoming energized, because they can only be removed with a key or other unlocking mechanism, or through extraordinary means, such as bolt cutters.

Tagout devices are prominent warning devices that an authorized employee fastens to energy-isolating devices to warn employees not to re-energize the machine or equipment while that employee services or maintains it. Tagout devices are easier to remove and, by themselves, provide employees with less protection than do lockout devices.

OSHA Standards

OSHA’s standard for The Control of Hazardous Energy (Lockout/Tagout), Title 29 CFR Part 1910.147, spells out steps employers must take to disable machinery or equipment that will prevent the release of hazardous energy while employees perform servicing and maintenance activities. The standard outlines ways for controlling hazardous energies: electrical, mechanical, hydraulic, pneumatic, chemical, thermal and other energy sources.

In addition 29 CFR 1910.333, sets forth requirements to protect employees working on electric circuits and equipment. This section requires safe work practices be used, including lockout and tagging procedures. The provisions apply when employees are exposed to electrical hazards while working on, near, or with conductors or systems that use electric energy.

The standard gives each employer the flexibility to develop an energy-control program suited to the particular workplace and types of machines and equipment being used, maintained or serviced. Generally this is done by affixing appropriate lockout or tagout devices to the energy-isolating devices, and by de-energizing machinery and equipment.


Employees need to be trained minimally in:

  1. aspects of the employer’s energy control program,
  2. elements of the energy control program relevant to the employee’s duties or assignment, and
  3. the various requirements of the OSHA standards related to lockout/tagout.


The standards establish requirements that employers much follow when employees are exposed to hazardous energy while servicing and maintaining equipment and machinery. Some of the most critical requirements from the standards as outlined in OSHA’s Fact Sheet are:


Control of Hazardous Energy: Lockout/Tagout, OSHA 3120, 2002 Revised

OSHA Fact Sheet: Lockout/Tagout

OSHA Lockout-Tagout Interactive Training Program. Includes a tutorial, hot topics and case studies.

OSHA Safety and Health Topics: Control of Hazardous Energy (Lockout/Tagout)