This page is dedicated to the memory of Brother Jeff Wolf who was a member of IBEW Local #16. Jeff lost his life on a job site in August, 2001.

What is Lockout /Tagout?

Commonly referred to as LO/TO, this procedure blocks the flow of energy from the power source to the equipment. It also provides a means of warning to others by attachment of a tag.


All employees are affected by LO/TO and a LO/TO program is required by federal law. Training must be done for all authorized personnel who maintain or service equipment. This training must be done initially and annually.

LO/TO Devices

Your employer provides all individual locks, keys, tags and other lockout/tagout materials that you need to conduct a lockout/tagout. The goal is for these items to be immediately recognizable so that everyone will know not to operate locked and tagged equipment.

There are many different types of LO/TO devices depending on its use. These are:

  • Locks
  • Multi lock devices
  • Blocks
  • Chains
  • Wheel valve covers
  • Ball valve covers

Check the manufacturers requirements for each LO/TO device These devices must be durable and, though there are no specific requirements for each type of device, they must be lockable. Tags should be attached to the device. Tags alone are not a LO/TO device because they do not prevent the energizing of equipment. Check with your customer safety representative for proper procedures.

Types of Energy Sources

There are different types of energy sources that require LO/TO devices when working on equipment. Be sure that you understand that not all sources are ones that you can see. Each of these energy sources must have a lockout/tagout device. Take the time to familiarize yourself with the equipment to ensure that you have isolated each potential energy source. Hazardous energy comes in many forms and each form must be controlled. On some types of equipment more than one form of energy must be controlled and LO/TO applied before work begins.

Common types of energy that are subject to LO/TO include:

  • Electrical – Can be a direct source, such as a machine that used an electric motor, or an indirect source such as the electricity that runs a pneumatic or hydraulic motor
  • Pneumatic – Uses air pressure
  • Hydraulic – Uses fluid under pressure
  • Potential – Stored energy such as the energy in capacitors, compressed air, hydraulics and springs
  • Pressurized liquids or gases – Including steam and chemicals present in pipes and supply lines, storage tanks and vessels
  • Any other energy – Including thermal or mechanical energy, gravity, pressurized systems and elevated parts which must be dissipated or restrained by grounding, blocking, bleeding, blanking, or some other type of control

Requirements for devices

All locks and tags must be:

  • Durable
  • Able to resist easy removal
  • Readable even if exposed to water or chemicals
  • Easily identifiable
  • Standardized by color, shape or size
  • Used only for LO/TO procedures
  • Marked to identify the person who attached it

Your safety – and that of your coworkers – depends on proper recognition and use of locks and tags. So remember:

Never use your LO/TO equipment for locking personal or unauthorized items.
Never lend or borrow a lock or tag
Never remove someone else’s lock or tag

Devices must be durable enough to withstand any situation in which they are used and that they cannot be removed accidentally. They should be of the same color or size to avoid any confusion. They should also be identified by markings which state “Do Not Start” or “Do Not Operate”.

Equipment requiring LO/TO

Any piece of equipment with any of the aforementioned energy sources is subject to LO/TO. Following is a list of equipment requiring LO/TO. This list is, by no means, complete. That is why it is very important to aware of all sources of energy connected to the equipment.

  • Conveyors
  • Motors
  • Lathes
  • Compactors
  • Pumps
  • Welders

When Do I Need LO/TO?

An analysis of all hazards associated with the equipment should be done prior to LO/TO to ensure that all sources of potential energy have been identified and that LO/TO is necessary. LO/TO should be used where any hazardous energy exists or unexpected startup of equipment could occur. Where there is doubt or if there is a possibility of injury to anyone – LOCK IT OUT!

If you are required to remove a safety device,
If you are to put any part of your body in harms way,
If you are exposed to any type of hazardous energy,

Are there exceptions?

Yes. If there is no potential energy sources associated with the equipment, then LO/TO is not required.
If routine maintenance or adjustments on the equipment are necessary, then LO/TO is not required. However, a second employee should be nearby a disconnecting means in case of trouble.
If the equipment is cord-connected, then LO/TO is not required. The cord should be disconnected from the energy source before servicing.
If an operation requires a hot tap where shutdown is not feasible, then LO/TO is not required.

Who is an “affected” employee?

Employees who normally work around, operate or make adjustments on equipment are affected employees. Any one who works in the company can be an affected employee. Affected employees should check to make sure that the equipment is safe and if adjustments are needed they should notify the appropriate individuals. They should follow all safety rules associated with the equipment and should not tamper with any LO/TO devices.

Who is an “authorized” employee?

Employees who are trained to use LO/TO and are in danger of being harmed while repairing equipment are authorized employees. Authorized employees must make affected employees aware of the danger and what work will be done to the equipment. They should ensure that that all energy sources are locked out and that all stored energy has been released. Assistance with any repairs or maintenance may be needed and can be a valuable aid for safety. Placing a “Danger” tag on the equipment is a responsibility of an authorized employee. They should also remove any LO/TO devices when completed or coordinate with other shifts if the repairs are not completed.

LO/TO Procedures

Installing or removing lockout devices, shutting down equipment or removing energy sources from the equipment are types of LO/TO procedures. The release of any type of stored energy is also a LO/TO procedure.

Responsibilities of the Company

The company is responsible for administration and maintenance of the LO/TO program. They will provide training and awareness programs for the employees and review the success of the program. They are also responsible for any disciplinary actions needed to prevent further incidents. Annual reviews will be conducted to make sure the LO/TO program is being followed.

Requirements for Training

The employer is required to train “authorized” employees initially and at least once a year. “Affected” employees are to be trained initially. All employees are to be trained if the procedures or job requirements change or if there are any deficiencies in the program.

Performing LO/TO

Fatalities in industry can be greatly reduced if LO/TO procedures are followed:

  • Do not take shortcuts that could cause injury or death
  • Refer to LO/TO procedures for your company
  • Refer to lockout procedures for each piece of equipment
  • Ensure that everyone knows of repairs in progress

Six steps to Lockout/Tagout and de-energizing

  1. Preparation
    Know the equipment and it energy sources before working on it. Does it have multiple energy sources that must be controlled? Check with your supervisor for a written procedure or checklist that details the shutdown of the equipment you are working on.
  2. Shutdown
    Turn off the equipment as directed by the written procedure. This may by use of an OFF switch or a more complicated method. Check with your supervisor if you are unsure of any part of the shutdown.
  3. Isolation
    Find and isolate any form of energy that the machine uses. This includes pulling fuses, throwing disconnects, and capping any secondary sources of energy. Don’t stop with simply pulling a fuse. Fuses can be replaced.
  4. Application
    Locks and tags must be applied to all energy-isolating equipment, valves, and switches. Anything that might restore the flow of energy to the work areas must be locked and tagged out.
    Locks with tags help other employees identify a lockout situation. Tags explain the work being done and name the “authorized” employee who placed the lock. Place tags with the lock or as close to it as possible.
    If the equipment cannot be locked, place tags as close as possible to the energy-isolating device. Newer equipment and any that is being updated must now be capable of being locked.
    However, in the event that an energy source is not capable of being locked out, a tag may be used without a lock as long as it is supplemented by at least one additional safety measure that provides a level of safety equivalent to that obtained by use of a lock. Examples of additional safety measures include the removal of an isolating circuit element, blocking of a controlling switch, or opening of an extra disconnecting device.
  5. Control
    Even after equipment has been locked out, you must control stored energy:
    Relieve, disconnect, or restrain and residual hazardous energy that could be present
    Check that all moving parts have stopped
    Relieve trap pressure
    Blank pipe flanges
    Install ground wires to discharge electrical capacitors
    Block or support elevated equipment
    While performing service, check continuously if energy buildup is possible
  6. Verify
    Make sure each energy source is shutdown, blocked off, controlled, and locked and tagged out
    Warn everyone in the lockout area and be sure they are moved to a safe place
    Activate all controls that might restore power to the machine you are working on
    If equipment does not start, restore all controls to the OFF position and begin work

Three steps to removal and reenergizing

  1. Restore work area
    Restore the work area to operating conditions:
    Remove all tools
    Double-check all equipment components
    Replace all safety features, such as machine guards
    Close access panels that were opened to perform service on equipment
  2. Notify personnel
    Notify all employees that LO/TO devices are being removed. Remove employees from the area or make sure they are a safe distance from the equipment.
  3. Remove Lockout/Tagout devices
    The person who placed each device must be the one to remove it. If someone who placed the LO/TO device is not present, notify your supervisor who will follow specific procedures. Never remove it yourself.

Restarting the equipment

After all devices are removed, tell affected employees that the LO/TO is ended and that the equipment is being reenergized.


Remember the LO/TO steps:

  1. Preparation
  2. Shutdown
  3. Isolation
  4. Application
  5. Control
  6. Verification

Is the job done? Not until you have followed the last three steps to restore energy:

  1. Restore work area
  2. Notify
  3. Remove

Whether you are the person applying locks and tags or the person waiting to use the equipment being serviced, you cannot afford to by-pass or skip any steps when it comes to your safety – or that of your co-workers.

If you are required to remove a safety device
If you are to put any part of your body in harms way
If you are exposed to any type of hazardous energy


When you have completed reviewing the materials presented here, click on the LO/TO Exam button to complete the examination.