fast facts 

advancing safety, health, and workplace rights in the legislative branch April 2008
 

Lockout/Tagout 

Employers must establish and implement

an energy control program whenever an 

employee services or maintains machinery, 

equipment, or systems whose unexpected

energizing, start up, or release of energy has 

potential to injure them. All forms of energy 

are covered by the Occupational Safety and 

Health Administration (OSHA) standards, 

including the Control of Hazardous Energy 

(Lockout/Tagout) and the Electrical 

Safety-Related Work Practices. The 

most common type is electrical energy, 

whether from generated power, storage 

devices (batteries and capacitors), or static. 

However, the program must also protect

against injury from thermal energy (high or

low temperature). Sources of kinetic energy

(mechanical energy from moving parts), as 

wellaspotentialenergy(storedinpressurized 

vessels, hydraulic and pneumatic systems, 

and springs), must also be addressed. 

The energy control program requires that 

an authorized person must disconnect 

the machinery or equipment from its 

energy sources and block it as necessary to

prevent any unexpected movement before 

Figure 1: A Proper Circuit Breaker Lock and Tag 

service or maintenance work is performed. 

Additionally, the program requires that 

authorized employees either lock or tag its

energy-isolating device(s) to prevent the 

release of hazardous energy and take steps to 

verify effective isolation of the energy. 

Energy-isolating devices prevent the 

transmission or release of energy. They

include items such as electrical switches, 

circuit breakers, disconnect switches, line

valves, slide gates, slip blinds, and mechanical

blocks. Because procedures are required 

for applying lockout or “tagout” devices to

energy-isolating devices, these programs are 

often referred to as lockout/tagout (LOTO) 

programs. 

It is crucial that personnel developing the

LOTO program identify every energy 

source and energy-isolating device for each

piece of machinery or equipment included 

in the program. The steps to be followed to 

provide absolute control of each source and

isolating device must be incorporated into 

the specific procedures developed for each 

piece of machinery or equipment. 

As the name implies, lockout devices are 

items such as locks that are used to keep 

energy-isolating devices in safe positions.

Their function is to secure energy-isolating

devices in positions that prevent machines 

from becoming energized during servicing 

and similar activities. 

Tagout is used when it is not possible to 

apply a lockout device. It involves attaching 

a danger tag on or as close as possible to 

an energy-isolating device. The tag must 

indicate that the machine being serviced 

www.compliance.gov
 

Figure 2: A Plug LO/TO on Metal Working Lathe 

cannot be operated until it is removed by the 

person who applied it. The tag must identify

who applied it and indicate when the tag 

was applied. It may only be removed by the 

authorized person who applied it. Use of 

tagout alone creates potential for premature 

activation of an energy-isolating device, so it 

is less safe than using a lockout procedure. 

LocksandtagsusedintheLOTOprogram 

must be standardized in color, shape, or size 

so they are readily recognizable by anyone in 

the work area. Additionally, all employees 

withaccesstotheareawheretheyareapplied 

must betrained torecognizethese itemsand 

their purpose. 

Locks and tags used in LOTO programs 

must also be durable and unable to be 

removed without excessive force or unusual 

techniques. Nylon tie-wraps may be easily 

cut off, so they may not be used as lockout 

devices. 

Authorized personnel must verify that all 

energy sources are effectively controlled 

before servicing work begins. When the 

work is finished, they must remove their 

control devices. 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

All authorized employees must be provided 

withtrainingthatallowsthemtounderstand 

the purpose and function of the energy

control program. Their training must also 

allow them to develop the knowledge and 

skills needed for safe implementation of 

the program. Mere distribution of lockout/

tagout procedures is not adequate. 

An employee other than the one using the 

individual energy control procedure must 

evaluate and certify it at least annually. Each 

evaluation must include a review by the 

inspector and each employee authorized

to implement the program, and include a 

reviewoftheemployee’sresponsibilities.Any 

identified deviations from the procedure or 

inadequacies in it must be corrected. 

Figure 3: An Untagged LO Device on a Pipe 

Valve Handle 

Going Beyond the Basics 

Whenmultipleworkersmustsimultaneously 

service a machine, each should be assigned 

a separate lock and key. If work is not 

completed before the end of a shift and new

workers are to continue the work, the new 

arrivals should apply their locks before the 

departing ones remove theirs. Each worker 

must move away from the machine before it 

is re-energized. 

Though a combination lock may be used in 

a LOTO program, it is possible for many 

people to know its combination. This enables

multiple people to remove it prematurely, 

potentially injuring anyone still working on 

the machine. Instead, key-operated locks 

are more controllable lockout devices. By 

providing one copy of the key to the user 

and one to the program’s coordinator for 

use only during unusual circumstances 

after confirming that the person assigned 

to the lock is safely away, the opportunity to 

remove the lock prematurely is much more 

limited. 

Whenever an outside contractor or 

employees from other divisions or 

jurisdictions are involved with the work, 

all affected groups must inform each other 

of their LOTO procedures. Further, if 

a program for entry of confined spaces 

is needed, the hazardous energy control 

Figure 4: A LO/TO Device Prevents Use of Plug 

Shown in Figure 2 

program must be integrated with it when 

needed. 

OSHA also has a similar standard 

mentioned above that primarily 

concentrates on electrical energy. 

Specifically, OSHA requires the deenergization and disconnection of electrical 

equipment. This includes removal of 

isolating circuits and the opening of extra

power disconnect devices. It also includes 

minimum safe distances for approach to

high voltage. Steps to safely re-energize 

during maintenance and the removal of 

LOTO devices are also addressed. 

fast stats 

· OSHA requires employers to develop and implement procedures and practices to protect employees during servicing and maintenance of machines and equipment. 

(29CFR§1910.147 and 1910.333(b)(2)). 

· OSHA Accident Investigation Summaries from OSHA-170 forms for 2000-2002 on Lockout lists a total of 355 incidents investigated. This includes 63 killed workers and 121 

amputated. Death and amputation account for 52% of the Lockout incidents investigated, indicating severe trauma where machines or equipment started unexpectedly. 

If you spot a safety hazard in your legislative branch 
 The Office of Compliance advances safety, health,
 workplace, contact the Office of Compliance to report it: and workplace rights in the U.S. Congress and the Room LA 200, John Adams Building Legislative Branch. Established as an independent

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www.compliance.gov Editor 

This information does not constitute advice or an official ruling of the Office of Compliance or the Board of Directors and is intended for educational 

purposes only. For further information, please refer to the Congressional Accountability Act (2 U.S.C 1301 et seq.) and the regulations issued by the 

Board, or you may contact the Office of Compliance.