The Fifteen Most Common Lockout Tagout Mistakes and How to Prevent Them

The Machine Is Off—but Is It Safe?

A maintenance technician prepares to clear a jam or repair equipment. Pressing the stop button may stop normal operation without physically isolating electrical energy, hydraulic pressure, pneumatic pressure, mechanical movement, thermal energy, gravity, springs, capacitors, or stored pressure.

A machine that has stopped is not necessarily safely isolated.

This examination explores the most common lockout tagout mistakes and how to prevent them.

What Are the Most Common Lockout Tagout Mistakes?

The most common lockout tagout mistakes include incomplete procedures, missed energy sources, failure to control stored energy, skipped verification, inadequate training, weak group accountability, unsafe shift transfers, and premature lock removal. Most failures occur when workers treat shutdown as isolation or depart from the approved energy-control procedure.

What Does OSHA Require for Lockout/Tagout?

OSHA's standard addresses unexpected energisation, startup, or release of stored energy during covered servicing and maintenance activities. Key definitions include:

Lockout/Tagout: A safety procedure combining physical restraint and warning identification.

Hazardous energy: Any energy source capable of injuring a worker.

Authorised employee: Worker trained to apply energy controls and perform maintenance.

Affected employee: Worker who operates equipment or works in affected areas.

Energy-isolating device: Physical device such as disconnect, breaker, or valve that isolates hazardous energy.

International readers must follow applicable local laws and organisation-specific energy-isolation procedures.

1. Using a Generic or Incomplete LOTO Procedure

A broad procedure may fail to identify the exact equipment, isolation points, shutdown sequence, stored-energy controls, verification method, and restart steps.

Prevention: Develop and maintain machine-specific or equipment-specific procedures wherever required.

Target keywords: incomplete LOTO procedure, generic LOTO procedure, machine-specific LOTO procedure.

2. Failing to Identify Every Hazardous Energy Source

Cover primary, secondary, hidden, and interconnected energy sources including electricity, hydraulic pressure, pneumatic pressure, gravity, springs, flywheels, steam, chemicals, and thermal energy.

Prevention: Conduct an energy-source survey before shutdown and confirm it against drawings, labels, manuals, and physical equipment.

3. Using a Stop Button Instead of Isolating Energy

Stop buttons, selector switches, software controls, emergency stops, and interlocks are generally control-circuit devices, not necessarily energy-isolating devices.

Prevention: Locate and operate the appropriate disconnect, breaker, valve, blank, block, or other approved energy-isolating device.

4. Failing to Notify Affected Employees

Poor notification can cause confusion, production interference, attempts to restart equipment, and unsafe interaction with isolated machinery.

Prevention: Notify affected employees before applying LOTO and again before equipment is returned to service.

5. Applying the Wrong Lockout or Tagout Device

Problems include incompatible breaker locks, loose valve lockouts, damaged tags, unidentified locks, ordinary maintenance locks, and improvised devices.

Prevention: Use durable, standardised, identifiable, and fit-for-purpose LOTO devices approved by the organisation. A warning tag provides warning and identification but does not provide the same physical restraint as a lock.

6. Failing to Control Stored or Residual Energy

Isolation does not automatically remove pressure, heat, electrical charge, raised components, compressed springs, rotating parts, or reaccumulating energy.

Prevention: Relieve, disconnect, restrain, discharge, block, or otherwise render stored energy safe. Continue verification when hazardous energy could reaccumulate.

OSHA expressly requires stored or residual energy to be rendered safe before work begins.

7. Skipping Zero-Energy Verification

Locks and tags show that a procedure has been applied, but verification confirms whether the isolation is effective.

Possible verification methods include:

• Trying normal operating controls
• Testing for absence of voltage
• Checking pressure gauges
• Observing mechanical movement
• Confirming blocked or restrained components

Prevention: Require the authorised employee to verify isolation and de-energisation before work starts.

Bold Warning: No verification means no confirmed zero-energy state.

8. Allowing Untrained Workers to Perform LOTO

Distinguish between:

Authorised employees: Apply energy controls and perform maintenance.

Affected employees: Operate equipment or work in affected areas.

Other employees: Work nearby where LOTO is in use.

Each group requires role-appropriate knowledge.

Prevention: Provide initial training, practical procedure instruction, competency checks, and retraining whenever assignments, equipment, hazards, or procedures change—or when deficiencies are identified. OSHA does not simply require automatic annual retraining; retraining is triggered by specified changes or deficiencies.

Workers and safety professionals can develop practical hazardous-energy control knowledge through structured Lockout/Tagout training.

9. Sharing Locks or Failing to Use Personal Locks

Each authorised worker should apply and control their own personal device under the organisation's approved individual or group LOTO procedure.

Unsafe practices include sharing padlocks, one employee locking out for everyone without a compliant group system, using another employee's key, and failing to identify the person protected by the lock.

Prevention: Establish personal accountability through individual device application and control.

10. Weak Accountability During Group Lockout Tagout

Group work becomes dangerous when no coordinator is designated, workers are not accounted for, personal protection is unclear, multiple crews use conflicting procedures, or sign-on and sign-off processes are incomplete.

Prevention: Designate a primary authorised employee, maintain individual accountability, and establish a reliable group lockbox or equivalent system.

OSHA requires primary responsibility to be assigned and coordinated when multiple crews, departments, or groups are involved.

11. Poor Protection During Shift or Personnel Changes

Protection can be lost when an outgoing worker removes a lock before an incoming worker applies theirs.

Prevention: Use a documented handover process that maintains uninterrupted protection between outgoing and incoming employees. Include face-to-face handover where practical, status confirmation, personal lock transfer sequence, updated personnel records, and reverification when required.

OSHA requires specific procedures to preserve continuity during shift and personnel changes.

12. Failing to Coordinate LOTO With Contractors

Host employers and outside employers may use different devices, terminology, permit systems, isolation procedures, and responsibilities.

Prevention: Exchange procedures before work, identify the controlling party, communicate restrictions to affected workers, and agree on verification and restoration responsibilities.

13. Removing Another Employee's Lock Improperly

The employee who applied the lock or tag should normally remove it. Exceptional removal must not become a shortcut.

Prevention: Establish a documented employer-directed removal procedure that verifies the employee is absent, confirms the person cannot reasonably return to remove the device, ensures the area is safe, and informs the employee before they resume work.

OSHA permits employer-directed removal only under specific developed, documented, and trained procedures.

14. Restarting Equipment Without a Final Safety Check

Common restoration mistakes include tools left inside machinery, guards not replaced, components not operationally intact, employees remaining in danger zones, workers not notified, and controls left in an unsafe position.

Prevention: Inspect the equipment and work area, confirm workers are clear, restore guards, remove devices correctly, notify affected employees, and re-energise through the approved restart sequence.

OSHA requires inspection of the work area and confirmation that employees are safely positioned before restoring energy.

15. Failing to Inspect and Improve the LOTO Programme

Even a well-written procedure can become outdated because of equipment modifications, new isolation points, changed tasks, new employees, repeated shortcuts, audit findings, and contractor arrangements.

Prevention: Conduct periodic inspections, document findings, correct deviations, update procedures, and retrain employees when deficiencies are discovered.

OSHA requires covered energy-control procedures to be inspected at least annually, with certification identifying the machine, inspection date, employees included, and inspector.

Lockout Tagout Mistake-Prevention Checklist

• Use an equipment-specific procedure
• Identify every energy source
• Notify affected employees
• Shut down equipment safely
• Operate every required isolation device
• Apply personal locks and tags
• Control stored and residual energy
• Verify the zero-energy state
• Maintain individual accountability
• Protect workers during shift changes
• Coordinate with contractors
• Inspect the area before restart
• Conduct and document periodic inspections
• Retrain workers when deficiencies arise

Preventing LOTO Mistakes Requires More Than a Padlock

Effective LOTO depends on planning, complete energy identification, physical isolation, stored-energy control, verification, personal accountability, communication, training, and inspection.

Whether you manage workplace safety, maintain industrial equipment, supervise contractors, or are preparing for a safety-related career, structured training can help you recognise hazardous-energy control failures before they lead to an incident. Explore comprehensive Lockout/Tagout training to strengthen your LOTO safety and compliance skills.

Always follow your organisation's approved energy-control procedures and the occupational safety requirements applicable in your jurisdiction.