Back to Basics, Lockout-Tagout

Back to Basics: Lockout/Tagout

Back to Basics is a weekly feature that highlights important but possibly overlooked information that any EHS professional should know. This week, we examine lockout/tagout and OSHA’s recommendations for controlling hazardous energy.

Workers are exposed to hazardous energy in a number of different industries, especially during equipment and machinery maintenance and servicing. According to OSHA, the unexpected startup or release of stored energy that can happen during maintenance and servicing could result in serious injuries or fatalities. Proper lockout/tagout (LOTO) practices and procedures must be implemented to protect employees from the release of hazardous energy.

Hazardous energy

Hazardous energy is electrical, mechanical, pneumatic, chemical, thermal, or other sources of energy in equipment or machinery that have the potential to harm workers. OSHA says that workers who are servicing or maintaining machines with hazardous energy could be seriously injured or killed if the hazardous energy is not properly controlled. Injuries can include electrocution, burns, crushing, cutting, lacerating, amputating, or fracturing body parts.

Craft workers, electricians, machine operators, and laborers are among the 3 million workers who service equipment regularly and face the highest risk of injury. According to OSHA, compliance with the LOTO standard prevents an estimated 120 fatalities and 50,000 injuries each year. Examples of these kinds of injuries include a steam valve that is automatically turned on burning the repair workers, a jammed conveyor system releasing and crushing a worker, and internal wiring shorting and shocking the worker who is fixing the piece of equipment.

For employers

OSHA’s LOTO procedures are outlined in the Control of Hazardous Energy standard for general industry, and it contains the practices and procedures that employers should implement to keep their workers safe from the release of hazardous energy. The standard outlines the employer’s responsibility to protect employees from hazardous energy sources on machines and equipment during service and maintenance, says OSHA.

Employers should develop an energy control program that serves the needs of the particular workplace and machines and equipment being serviced and maintained in that workplace. The program should consist of energy control procedures, employee training, and periodic inspections to ensure that before any servicing or maintenance is done on equipment that presents hazardous energy risks, the equipment is isolated from the energy source and rendered inoperative.

The appropriate lockout or tagout devices should be affixed to energy-isolating devices, and machines and equipment should be deenergized. Employers must determine which system is better to use in each situation. If an energy isolating device is capable of being locked out, then the energy control program should use a lockout system, unless they can demonstrate that a tagout system will provide full employee protection. If an energy isolating device is not capable of being locked out, employers must implement a tagout system, and if a tagout device is used on an energy isolating device that is capable of being locked out, the tagout device should be attached at the same location that the lockout device would have been attached.

Employers need to make sure that new or overhauled equipment is capable of being locked out. They should only choose LOTO devices that are authorized for the particular equipment or machinery present in the workplace, and ensure that the devices are durable, standardized, and substantial. LOTO devices should also be able to identify the individual users.

The established energy control procedures should be inspected at least annually, and employers must comply with the additional energy control provisions in OSHA standards when:

  • Machines or equipment must be tested or repositioned
  • Outside contractors work at the site
  • In group lockout situations
  • During shift or personnel changes

Employers should document, implement, and enforce energy control procedures and establish a policy that only permits the employee who installed a LOTO device to remove it.


In terms of training, employees need to know, understand, and follow the applicable the provisions of the hazardous energy control procedures. Training must cover at least these three areas:

  • Aspects of the employer’s energy control program
  • Elements of the energy control procedure relevant to the employee’s duties or assignment
  • The various requirements of the OSHA standards related to LOTO

All employees who are authorized to lockout machines or equipment and perform the service and maintenance operations need to be able to recognize the applicable hazardous energy sources in their workplace, the type and magnitude of energy, and the means and methods of isolating and controlling the energy. Employers should also retrain all employees to maintain proficiency and to introduce new or changed control methods.  

For the full OSHA standard for lockout/tagout, click here.

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