So exactly what is lockout tagout? Lockout Tagout (LOTO) was developed to prevent the release of hazardous energy during maintenance or repair work. Locking, tagging and isolating machinery and equipment from energy sources and residual energy protects workers against serious injury.

What's the purpose of LOTO?

LOTO involves the procedures required to disable plant and equipment safely, preventing any release of hazardous energy.

Machinery requiring service and/or maintenance may contain stored energy which could prove hazardous during the processes.

The term ‘energy’ does not refer just to electrical, mechanical or pneumatic sources. It could equally be chemical and thermal energy or another energy source.

 LOTO safety procedures create an energy control procedure which rules out the possibility for equipment to start up again intentionally, or otherwise release any residual form of energy.

OSHA lockout tagout standard

The Occupational Safety and Health Administration lockout tagout standard applies to all activities where the unplanned release of hazardous energy could present a danger to health, It sets out minimum performance standards in terms of hazardous energy control procedures to rule out the possibility of this happening. 


There are exceptions to the lockout tagout standard. These include:-

  • Construction, agriculture, and maritime work
  • Oil and gas well drilling and servicing 
  • Installations under the exclusive control of electric utilities for power generation, transmission and distribution
  • Work on plug-in electrical equipment which is unplugged and an authorized employee controls the plug
  • Operations where workers are sufficiently protected by other measures


Research suggests that typical annual violations to the OSHA lockout tagout standard exceed 1,400, with total penalties applied approaching $9.5M. , making the average cost of a violation in the region of $6,000.

Violations include:-

  • Failure to identify and isolate all energy sources
  • Failure to remove residual energy
  • Failure to provide adequate lockout tagout procedure training
  • Failure to create correct LOTO procedures
  • Failure to conduct LOTO inspections in line with guidelines
  • Failure to establish a lockout tagout program
  • Failure to develop and enforce lockout tagout policy

The history of lockout tagout

First established in 1982 and legally adopted in 1989, the OSHA standard for The Control of Hazardous Energy (Lockout/Tagout), Title 29 Code of Federal Regulations (CFR) Part 1910.147, was introduced to protect workers by setting out safe working practices controlling hazardous energy which include locking out and tagging out to prevent the accidental release of hazardous energy.

  • Lockout tagout is estimated to prevent over 50,000 lockout tagout injuries and 120 fatalities every year.
  • It benefits employers too by reducing insurance costs, employee days lost due to injury and equipment downtime.

What is the difference between lockout and tagout

Lockout and tagout are two distinctly different procedures providing a two-tier safety procedure.


Lockout safety practices involve using a padlock on equipment to isolate any potentially hazardous energy sources.

OSHA explains lockout as follows:-

“A device that utilizes a positive means such as a lock, either key or combination type, to hold an energy isolating device in the safe position and prevent the energizing of a machine or equipment.”


By contrast, tagout involves the placing of tags to ensure that all employees in the vicinity are aware that work is in progress on any individual piece of machinery and to warn against starting up the equipment.

OSHA explains tagout as follows:-

“A prominent warning device, such as a tag and a means of attachment, which can be securely fastened to an energy isolating device in accordance with an established procedure, to indicate that the energy isolating device and the equipment being controlled may not be operated until the tagout device is removed.”

OSHA, US Dept of Labor

Who is involved in lockout tagout procedures

The lockout program involves two sets of people; ‘authorized employees’ and ‘affected employees’.

Authorized employees are those entrusted with locking out and tagging out machinery for servicing and/or maintenance work, to control hazardous energy.

Authorized employees must receive regular training on hazardous energy sources in the workplace, including acceptable lockout tagout processes, the appropriate steps to take in every instance and also how to ensure the integrity of the lockout.

They will also assume responsibility for ensuring that all employees in the area are aware of the lockout and ensuring their safety. Authorized employees will also be trained to audit lockout tagout procedures.

By contrast, affected employees will not be involved in the service and maintenance work but will be in the vicinity of the operation. They must undergo awareness training to ensure they fully understand the implications of lockout tagout.

Lockout Tagout Tools and Devices

The OSHA lockout tagout standard requires employers to provide lockout tagout tools and devices that are fit for purpose, durable and easily identifiable.  Reuse of LOTO lockout devices is not permitted.

Energy isolating devices

Mechanical devices and energy control devices act to prevent the accidental release of hazardous energy, including circuit breakers and disconnect switches.

Lockout devices

Individually keyed padlocks to secure energy isolating devices in place, making sure once a piece of equipment is switched off it cannot be reactivated accidentally.

Safety Padlocks

Issued only by the employer, lockout tagout safety padlocks should have only one key and also have a key-retaining feature so the key cannot be removed if the padlock is not in the locked position.

Tagout devices

Tagout devices are clearly visible warnings which are fastened securely to the energy-isolating device, making it clear that the equipment must remain out of use


Tags are used to give individual information on the condition of the plant and equipment and may carry details on who is responsible for the lockout. Tagout devices must be able to withstand the environment in which they are used, attached by a self-locking and non-reusable method.

What is a Lockout Tagout box?

Some machinery may have more than one hazardous energy isolation point requiring lockout out and tagging out (group isolation). A group lockout box is used here.

How do they work?

The authorized employee will first complete the lockout tagout procedure on the isolation point. He will then place the key to this device in the LOTO box and attach his own personal padlock to this box.

Once all the personal padlocks have been attached to the LOTO box, he will use the recognised OSHA-recognized color coding system and place an orange or blue lock on the machinery, followed by an orange tag which confirms that all the isolation points have been secured.

What do the different color locks and tags mean?

The OSHA lockout tagout standard does not yet have a universally standardized color coding system. However, the following are generally recognized guidelines.

  • A red tag is a Personal Danger Tag (PDT)
  • An orange tag denotes a group isolation or lockbox tag
  • A yellow tag is an Out of Service Tag (OOS)
  • A blue tag is used for commissioning and testing
  • A red lock is used by authorized employees to lockout equipment
  • An orange lock is used by a group isolator to show that it is safe to carry out servicing and/or repair work
  • A yellow lock is used by an affected employee to lockout equipment before servicing
  • A blue lock is used instead of an orange lock for LOTO boxes with more than six
    isolation points

Procedure requirements

Developing a robust LOTO procedure is a vital consideration to avoid any unintentional energization of equipment which could prove fatal. A LOTO procedure is a documented list of steps or actions designed to guard against accidents during maintenance or servicing activities. Failure to comply with a LOTO procedure is one of the most common OSHA standards violations in the US.

7 Steps of lockout tagout procedures

It is generally recognized that there are seven individual steps in any LOTO procedure.

  • Step 1 involves preparation, where the authorized employee makes a qualified assessment of exactly what needs to be shut down, identifying the relevant energy sources and associated hazards.
  • Step 2 involves the authorized person ensuring that all affected employees are aware of the proposed lockout. They should be made aware of which equipment is being locked out, why this is happening, how long it will take and also a contact point if there are any questions.
  • Step 3 involves the actual powering down and shut down, following equipment manufacturers’ guidelines, and ensuring that all machinery is inactive.
  • Step 4 calls for isolation (also known as de-energization) where the plant and machinery are isolated from its energy source.
  • Step 5 is known as dissipation, which simply means ensuring any residual hazardous energy or stored energy which may remain in the equipment is removed.
  • Step 6 involves the authorized employee completing all approved lock out tag out procedures.
  • Step 7 is isolation verification, testing the equipment to ensure it is properly shut down and totally inactive.

Best practice for a lockout tagout program

Lockout Tagout programs call for a number of distinct steps, which must always be completed in the right order to ensure the correct energy control procedure.


A detailed risk assessment of all plant and equipment should be completed before implementing any LOTO procedures.

Organisations should develop robust LOTO programs identifying every step of the process.

The correct LOTO tools and devices should always be used.

Training plays an essential role in implementing safe and effective LOTO programs.


OSHA specifies that periodic inspections of LOTO procedures must be carried out at least annually. This is designed to ensure that the correct procedures are in place.  


Lockout tagout training should be provided to employees when they join the company, with retraining available if gaps in knowledge are identified or procedures are changed. The authorized employee should sign off on this training process.

Sufficient training documentation must be made available.

Contractors on site must also receive lockout tagout training.

Calculate the number of devices required

Lockout tagout devices required by organisations will differ, based on the plant and equipment they operate on a daily basis.

However, initial calculations can be made by:-

  • Assessing which and how many departments require lockable cabinets or LOTO boards.
  • Decide upon the location of the cabinets and boards related to the location of the equipment in question.
  • Identify any high-hazard areas and the total number of pieces of equipment. It is unlikely that it will ever be necessary to lock out every piece of equipment at any given time, so as a guideline stocking 10% of the total requirement is a good calculation.
  • Keep a close eye on the inventory to ensure the right equipment is always available.

Beyond lockout tagout compliance

Lockout procedures are integral to safety processes. It is advisable to go above and beyond general compliance and build an active and robust LOTO safety culture. Those responsible for LOTO should carry out the following:-

Communicate the LOTO policy

The LOTO policy should be clearly defined and communicated to ensure everyone involved understands the procedure and the benefits.

Consultation is important, and input from employees can play an important part.

Once the LOTO policy is established, make sure all relevant employees have access to a copy.

Create a system for submitting and receiving LOTO reports

Make sure employees have a defined route for raising questions or issues about the LOTO procedure, including the availability of equipment.

Perform frequent audits

Alongside the annual inspection required by OSHA, frequent evaluations of LOTO safety procedures should be carried out, including inspection of equipment held in stock.


LOTO procedures play a vital role in ensuring the safety of personnel during service and maintenance operations. It’s a life-saving process, and as well as legal obligations, employers have a moral duty to abide by the spirit of the OSHA lockout tagout standard to provide the right safety devices, ensure occupational safety and keep their facilities safe for all who work there.

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