The LOTO Standard At A Glance

Date First Published on SafetySmart Compliance: February 21st, 2012
Topics: Lockout Tagout | Machine Guarding |


The unexpected start-up of machinery during servicing, repair and maintenance is a common cause of fatal and serious injuries to workers working on the machine or in the danger zone. In 1994, OSHA adopted the Control of Hazardous Energy (or Lockout/Tagout) standard, 29 CFR 1910.147, to prevent these injuries. In addition to playing a key role in machine safety, LOTO has become a frequent source of OSHA citations.  Here’s a quick and dirty summary of LOTO requirements.


Lockout/Tagout (LOTO) is a safe work practice used when workers need to perform repairs or maintenance on equipment that’s energized by a source or multiple sources and establishes equipment-specific procedures (Energy Control Procedures) allowing the equipment to be completely de-energized so that it can be worked on without any possibility of unexpected start-up. The LOTO standard explains how this is to be accomplished.

When LOTO Is Required

LOTO must be used:

  • When performing other than routine maintenance or repetitive maintenance on machinery;
  • When clearing a jammed or blocked machine;
  • When rebuilding equipment;
  • During equipment set up;
  • When removing or disabling machine guards or safety interlocks; and/or
  • For tasks that require placement of a body part into a potentially hazardous area.

Exceptions: You don’t have to implement LOTO for:

  • Minor tool changes and equipment adjustments; or
  • Minor servicing activities which take place during normal production operations provided that the work is performed using alternative means of protection.


Energy Control Procedure

Each machine and piece of equipment that may need repairs or maintenance must have a unique written Energy Control Procedure (ECP) that details the specific steps by which a machine or piece of equipment can be physically isolated from one or more energy sources through the application of locks or locks and devices (chains, valve enclosures, etc.).

Because each piece of equipment or machinery has the potential for its own unique steps to isolate it, written ECPs are used to assist employees by providing clear directions on how to isolate. Otherwise, employees might err in their understanding and put themselves at risk for injury to themselves or their co-workers.

LOTO/Isolation of Energy Procedures

The basic steps of any LOTO procedure include:

  1. Locating hazardous energy sources;
  2. Notifying affected employees of planned shutdown;
  3. Use of normal procedures to shutdown machine or equipment;
  4. Disconnecting all energy sources;
  5. Applying locks and tags to all isolation devices;
  6. Blocking or dissipating all stored energy;
  7. Verifying lock out by testing machine controls; and
  8. Returning controls to neutral or off position.

The most common method of isolating is done through the use of a lock assigned to the worker performing the LOTO. He/she has the only key and while the machine is locked, it can’t be restarted until it’s unlocked by the worker performing the task. This provides the ultimate in control and protection to the worker. According to the OSHA standard, lockout locks must:

  • Be employer provided;
  • Be uniform and easily recognizable (e.g., Red lock);
  • Be identifiable;
  • Have a name, ID number, or both;
  • Be one lock/one key;
  • Be standardized and used for lockout only;
  • Lock differently from all others in plant.

Tagging and Tagout

Tags must also be used when performing LOTO and serve as an additional level of protection for the worker by warning others in the area that LOTO is occurring. Tags may also be used in lieu of locks, but only when the piece of equipment being worked on cannot be locked. The use of a lock is always the preferred method. In addition, tags must be durable, self-locking, non-releasable and non-reusable.

Procedures After Service Completed

When the service, repair or maintenance task is finished, workers must follow the LOTO procedures in reverse before releasing the equipment for use:

  • Check the machine to be sure it’s operationally intact, tools have been removed and guards have been replaced;
  • Check to be sure all employees are safely positioned;
  • Notify all affected employees that locks are being removed and the machine is ready for operation;
  • Remove all locks, blocks, or other restraints;
  • Restore all energy to the machine; and
  • Verify proper operation.

Group Lockout/Tagout

When more than one worker must perform service, repair or maintenance, each one must use a separate lock to lock out the equipment. That way, the equipment can’t be restarted until all workers in the area have removed their individual locks and are safe. Various devices exist for this type of group lockout, including hasps with multiple openings or a specific lock box that cannot be opened until all workers involved in the LOTO have removed their locks.

Sometimes an employee needs to leave the work area, perhaps for lunch or are finished working for the day.   If the work task is not completed at that time, the worker’s supervisor must be informed and will make the decision whether or not to leave the lock on or to have another worker’s lock put in place of the initial worker.  The equipment must never be unlocked until the work task is finished or it can be returned to its proper working condition through the steps above.

In the event that a worker accidentally leaves the work area without removing his/her locks and the work task has been completed, specific procedures must be followed before the lock can be removed by the organization. The best plan of action is to find the worker and have them return to remove the lock. But if they can’t be found or have gone home, a supervisor can remove the lock as long as they can reach the workers and let them know the lock is being removed either at that time or before they return to work.

(Click here for a Model Procedure for Group Lockout).


(Click here for more detailed analysis of Group Lockout requirements and procedures.)


LOTO and Outside Contractors

Each organization must determine whether it will permit outside contractors to perform LOTO using their own equipment and procedures or if their organization will have its own workers lock out the equipment being serviced on their won and remain in the area to supervise the work and LOTO implementation. If an organization chooses to allow an outside contractor to perform their own LOTO, they must take some responsibility to evaluate the contractors’ procedures and devices to assure they are following the US OSHA regulations so that their own workers are protected.


Audit and Monitoring of LOTO Procedures

At least once per year, an organization must audit its ECPs by having someone observe an actual LOTO being performed. Not every procedure needs to be audited but the purpose of the audit is to assure that the ECP is correct and that the workers performing the LOTO understand the procedure.  The audit must be documented by the person performing it and include the date of the audit, the ECP(s) audited, and the participating workers.

Training Requirements

All employees who may be required to perform LOTO must receive training on the general concepts of the practice and on the specific ECPs the organization has established.  Workers who perform LOTO are called “authorized” under the OSHA Standard. (More about the specific of training and how to conduct it are found in Part 3.)

All employees who may be working in the area where LOTO may be occurring or who are operators of equipment that may require LOTO, must also receive training. They’re called “affected” workers and are not trained or permitted to perform LOTO but are given basic information on what LOTO is and are instructed to follow instructions from authorized workers about staying out of the area when a LOTO is occurring and to never interfere with the procedures.