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Safeguarding Against Hazardous Energy

Safeguarding Against Hazardous Energy


The Accidents

  • A sanitary landfill worker was killed when he tried to clear a jam in a large trash compactor. Unfortunately, he failed to stop, de-energize and lock out the equipment. When he slipped and fell into the hopper, the baling cycle automatically activated, amputating his legs.

  • A janitorial worker died after he was trapped inside a hospital laundry dryer. He had propped open the door and entered the dryer drum to begin cleaning, but he failed to de-energize or lock out the dryer. When a co-worker restarted the system, not knowing the victim was inside, an overhead conveyor dropped 200 pounds of wet laundry into the dryer, knocking out the prop holding the door open, trapping the victim inside and automatically starting the drying cycle.

  • A worker at a concrete pipe manufacturing facility died from injuries he suffered while cleaning a ribbon-type concrete mixer. The procedure was to shut off the power at the breaker panel, push the toggle switch by the mixer to make sure that the power was off and then enter the mixer to clean it. The victim didn’t know that the operator, who went to make a phone call, had already de-energized the mixer at the breaker. Thinking he was turning it off, the victim activated the breaker switch and energized the mixer. He then entered the mixer and began cleaning without first pushing the toggle switch to ensure the equipment was de-energized. The operator returned from making his call and pushed the toggle switch to check that the mixer was de-energized. When the mixer started and the operator heard the victim scream, he went immediately to the main breaker panel and shut off the mixer.

What do these accidents have in common? First, each is an actual case investigated by the National Institute for Occupational Safety and Health (NIOSH). Second, in each case, the resulting outcome was a fatality. Finally, each could have been prevented by implementing an effective lockout/tagout (LOTO) program.

According to the Occupational Safety and Health Administration (OSHA), LOTO refers to specific practices and procedures designed to safeguard employees from the unexpected energizing or startup of machinery and equipment, or the release of hazardous energy during service or maintenance activities. OSHA estimates about 3 million workers who service equipment face the greatest risk for injury if the appropriate LOTO standards are not in place. In addition, unprotected workers injured on the job from exposure to hazardous energy lose an average of 24 days of work time to recuperate. Organizations that comply with the LOTO standard prevent an estimated 120 fatalities and 50,000 injuries each year.

What is hazardous energy?

According to the NIOSH, hazardous energy is any type of energy that can injure or kill a worker should they be exposed to a sufficient quantity. Common sources include electricity, mechanical motion, pressurized air, and hot and cold temperatures. Workers can be exposed to hazardous energy releases during installation, maintenance, or service or repair of machines, equipment, processes or systems. The following are forms of hazardous energy:

  • Kinetic (mechanical) energy: Energy in the moving parts of the mechanical system.
  • Potential energy: Energy that is stored in pressure vessels, gas tanks, hydraulic or pneumatic systems, and springs (potential energy can be released as hazardous kinetic energy).
  • Electrical energy: Energy from generated electrical power, static sources or electrical storage devices (such as batteries or capacitors).
  • Thermal energy: Energy (high or low temperatures) resulting from mechanical work, radiation, chemical reaction or electrical resistance.

Prevention measures

On-the-job accidents, such as the ones described above, are all preventable. The key is for management to develop and implement a LOTO program that clearly delineates the standards and ensures those standards are strictly enforced at all worksites within the organization. Elements of a good LOTO program can protect workers from the forms of hazardous energy described and should consist of the following as a minimum:

  • Ensure LOTO plans are developed, established and implemented.
  • Ensure affected employees are properly trained in LOTO procedures.
  • Survey work areas to identify all sources of hazardous energy potentially impacting machines/equipment to be serviced, and lock out all sources.
  • Ensure any stored energy (mechanical, hydraulic, air, etc.) has been released or blocked before equipment is locked out for repairs.
  • Ensure employees working on a piece of equipment apply their personal (individually keyed) safety lock and tag to the lockout device, and that only the employee exposed to the hazard place or remove them.
  • When maintenance activities must extend beyond the current shift, replace the personal locks and tags of the leaving shift with the personal locks and tags of the arriving shift. The leaving shift must ensure the arriving shift understands the maintenance process and hazards.
  • Once locks and tags are in place, try to operate the equipment to ensure no lockouts have been missed.
  • Locks should not be removed until the maintenance workers and the authorizing employee are satisfied that the equipment is ready to be operated safely.

To develop your LOTO program, be sure to review OSHA Standard 1910.147, and the supplemental information available at https://safety.army.mil/ON-DUTY/Workplace/Lock-Out-Tag-Out.


Department of the Army Pamphlet 385-10, paragraph 14-3, Lockout/tagout, establishes the minimum requirements for the lockout or tagout of energy-isolating devices required to control hazardous energy. It ensures the machine or equipment is isolated from all potentially hazardous energy and locked or tagged out before employees perform any servicing or maintenance activities where the unexpected energization, startup or release of stored energy could cause injury.

  • 7 January 2024
  • Author: USACRC Editor
  • Number of views: 265
  • Comments: 0
Categories: On-DutyWorkplace