Lockout/Tagout (LOTO) Procedure: Complete Guide to OSHA 1910.147 Compliance (2026)

Lockout/Tagout (LOTO) is one of the most critical safety procedures in industrial environments. It protects workers from the unexpected energization or startup of machinery and equipment, or the release of stored energy, during servicing and maintenance. Failure to follow LOTO procedures is a leading cause of serious injuries and fatalities in manufacturing, oil and gas, and process industries. This guide covers the complete LOTO procedure, from OSHA 1910.147 requirements to the six-step process and common mistakes.

What Is Lockout/Tagout (LOTO)?

Lockout/Tagout (LOTO) is a safety procedure used to ensure that dangerous machines are properly shut off and not able to be started up unexpectedly before maintenance or servicing work is performed. The term refers to:

• Lockout — placing a physical lock on an energy-isolating device to prevent the equipment from being energized
• Tagout — placing a warning tag on the energy-isolating device indicating that it must not be operated until the tag is removed

LOTO protects workers from hazardous energy including electrical, hydraulic, pneumatic, mechanical, thermal, chemical, potential, and kinetic energy.

OSHA LOTO Standard: 29 CFR 1910.147

OSHA 29 CFR 1910.147, "The Control of Hazardous Energy (Lockout/Tagout)," is the primary US standard governing LOTO. It requires employers to:

• Establish an energy control program
• Use lockout devices for equipment that can be locked out
• Ensure that tagout devices are used alone only if lockout is not possible
• Develop, document, and use procedures for isolating energy
• Train employees on the energy control program
• Conduct periodic inspections of the energy control procedures

When Is LOTO Required?

LOTO is required when:

• Servicing or maintaining machines where unexpected energization could cause injury
• Clearing jammed equipment
• Installing or setting up new equipment
• Performing major repairs or overhauls
• Performing maintenance on electrical circuits
• Cleaning equipment where energization could cause injury

When Is LOTO NOT Required?

LOTO is not required for:

• Normal production operations (if the operator is protected by standard guards)
• Minor tool changes and adjustments (if they are routine, repetitive, and integral to production)
• Work on cord-and-plug-connected equipment (if the plug is under the exclusive control of the worker)

The 6 Steps of LOTO

Step 1: Notify Affected Employees

Before shutting down equipment, notify all affected employees (those who work in the area or use the equipment) that LOTO is about to be applied. This ensures that no one is surprised by the shutdown or attempts to use the equipment during maintenance.

Step 2: Shut Down the Equipment

Shut down the equipment using its normal stopping procedure (stop button, shutdown sequence, valve closure). Do not use emergency stops for normal shutdown — they may leave the equipment in an unsafe state.

Step 3: Isolate Energy Sources

Isolate all energy sources using energy-isolating devices:

• Electrical — open circuit breakers, disconnect switches
• Hydraulic — close valves, block cylinders
• Pneumatic — close valves, vent air pressure
• Mechanical — block moving parts, release spring tension
• Thermal — allow equipment to cool, or isolate heat sources
• Chemical — close valves, blank lines, drain systems
• Potential/Gravity — block raised loads, lower elevated equipment

Step 4: Apply Locks and Tags

Apply individual locks and tags to each energy-isolating device:

• Each authorized employee applies their own personal lock
• The lock must be uniquely keyed (no master keys)
• The tag must identify the worker, the date, and the reason for lockout
• If multiple workers are involved, each applies their own lock (group lockout)
• Use lock boxes for group lockout scenarios

Step 5: Verify Zero Energy State

This is the most critical — and most often skipped — step. After applying locks and tags, verify that the equipment is at zero energy state:

• Try to start the equipment using normal controls (it should not start)
• Test for voltage on electrical circuits
• Check for residual pressure in hydraulic and pneumatic systems
• Check for stored mechanical energy (springs, elevated loads)
• Check for residual heat in thermal systems

Critical safety note: Never assume that because the lock is applied, the equipment is de-energized. Always verify the zero energy state before beginning work.

Step 6: Perform the Work and Remove LOTO

After maintenance is complete, remove LOTO in the correct sequence:

• Ensure all workers are clear of the equipment
• Remove all tools and materials from the work area
• Reinstall all guards and safety devices
• Remove each worker's personal lock and tag (each worker removes their own lock)
• Notify affected employees that LOTO is being removed
• Restore energy and test equipment operation

LOTO Roles and Responsibilities

Authorized Employees

Authorized employees are those who apply locks and tags and perform the servicing or maintenance. They must:

• Be trained on LOTO procedures
• Use their own personal locks (no sharing)
• Verify zero energy state before beginning work
• Remove their own locks when work is complete

Affected Employees

Affected employees are those who work in the area or use the equipment being serviced. They must:

• Be notified when LOTO is applied and removed
• Not attempt to operate equipment that is locked out
• Not attempt to remove locks that are not theirs

Other Employees

Other employees who work in the area but do not use the equipment must:

• Be aware that LOTO is in progress
• Not attempt to operate locked-out equipment
• Report any concerns about LOTO procedures

Types of Hazardous Energy

Electrical Energy

• Source — power supplies, capacitors, batteries
• Isolation — circuit breakers, disconnect switches
• Verification — voltage tester, multimeter
• Special concern — stored energy in capacitors must be discharged

Hydraulic Energy

• Source — hydraulic pumps, accumulators, pressurized lines
• Isolation — valves, blank flanges
• Verification — pressure gauge, bleed valve
• Special concern — accumulators store energy even when pumps are off

Pneumatic Energy

• Source — air compressors, pressurized tanks, air lines
• Isolation — valves, blank flanges
• Verification — pressure gauge, vent valve
• Special concern — vent all air pressure before working

Mechanical Energy

• Source — rotating shafts, gears, flywheels, springs
• Isolation — blocks, pins, chocks
• Verification — visual inspection, try to move
• Special concern — springs can release suddenly; flywheels have rotational inertia

Thermal Energy

• Source — steam lines, heated equipment, hot process materials
• Isolation — shut off heat source, allow to cool
• Verification — temperature gauge, infrared thermometer
• Special concern — equipment may remain hot long after heat source is removed

Potential/Gravity Energy

• Source — elevated loads, raised equipment, counterweights
• Isolation — blocks, supports, chains
• Verification — visual inspection
• Special concern — raised loads can fall if not properly blocked

LOTO in Oil and Gas Process Facilities

In oil and gas facilities, LOTO carries additional complexity:

• Process isolation — pipelines and vessels may contain hazardous fluids under pressure
• Positive isolation — requires blinding or double block and bleed in addition to valve closure
• H2S exposure — equipment may contain toxic H2S gas requiring purging before LOTO
• Complex systems — multiple energy sources in a single piece of equipment
• Permit systems — LOTO is often part of a permit-to-work system

Saudi Aramco's Construction Safety Manual (CSM) Chapter II-1 and ADNOC's Code of Practice provide specific LOTO requirements for Gulf-based operations.

LOTO Training Requirements

OSHA requires three levels of LOTO training:

Training for Authorized Employees

• Recognition of applicable hazardous energy sources
• Methods and means necessary for energy isolation and control
• Purpose and use of the energy control procedure
• The importance of verifying zero energy state

Training for Affected Employees

• The purpose of the energy control procedure
• The importance of not attempting to restart or re-energize locked-out equipment

Training for Other Employees

• The purpose of the energy control procedure
• The prohibition on attempting to restart or re-energize locked-out equipment

Retraining is required when:

• Job assignments change
• New equipment or processes are introduced
• Procedures change
• Periodic inspections reveal deficiencies

Common LOTO Mistakes

Mistake 1: Skipping Zero Energy Verification

The most dangerous LOTO mistake is not verifying zero energy state after applying locks. Workers assume that because the lock is applied, the equipment is de-energized — but residual energy, stored energy, or isolation failures can leave the equipment energized.

Mistake 2: Using Tagout Without Lockout

Tags alone do not provide physical protection. A tag can be removed or ignored. If lockout is possible, it must be used. Tagout alone is only acceptable when lockout is not physically possible.

Mistake 3: Sharing Locks

Each authorized employee must use their own personal lock. Sharing locks or using a master key eliminates the individual protection that LOTO provides. If a worker forgets to remove their lock, the equipment cannot be started — which is exactly the point.

Mistake 4: Not Isolating All Energy Sources

Equipment often has multiple energy sources (electrical, hydraulic, pneumatic, mechanical). Failing to isolate all sources leaves the worker exposed to unexpected energization from the unisolated source.

Mistake 5: Not Training All Employees

LOTO training is required for authorized, affected, and other employees. Untrained workers may attempt to remove locks or restart equipment, creating serious hazards.

LOTO Periodic Inspections

OSHA requires periodic inspections of LOTO procedures at least annually. The inspection must:

• Be conducted by an authorized employee other than the one using the procedure
• Identify any deficiencies in the procedure or its implementation
• Correct any deficiencies identified
• Include a certification record of the inspection

How SkillJet.co Supports LOTO Training

SkillJet.co's HSE Certification Module includes LOTO scenarios in the Oil & Gas Process Safety and Construction & Occupational Safety disciplines. Practice questions cover the 6-step LOTO procedure, energy types, verification requirements, and OSHA 1910.147 compliance. Use our diagnostic assessment to identify your knowledge gaps and practice drills to build exam-ready reflexes.

Conclusion

Lockout/Tagout is one of the most important safety procedures in any industrial environment. It protects workers from the unexpected release of hazardous energy during maintenance and servicing. The key to effective LOTO is: notify all affected employees, shut down equipment properly, isolate all energy sources, apply individual locks and tags, verify zero energy state, and follow the correct removal sequence. Never skip the zero energy verification — it is the step that catches isolation failures before they cause injuries. Follow the procedure, train all employees, and conduct periodic inspections to ensure the procedure remains effective.