Lockout/Tagout Job Safety Analysis
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The failure to properly control hazardous energy during maintenance and servicing causes an estimated 120 fatalities and 50,000 injuries per year in the United States. Workers are killed or seriously injured when machinery unexpectedly starts, when electrical energy is released, when pressurized systems discharge, or when stored mechanical energy is released. OSHA's lockout/tagout standard (29 CFR 1910.147) has been among the top 10 most-cited violations for decades.
Lockout/tagout (LOTO) is the systematic process of isolating all energy sources that could cause harm, applying locks and tags to isolation devices, and verifying that the equipment is in a zero-energy state before work begins. This Job Safety Analysis covers the complete LOTO sequence for maintenance and servicing activities on machines and equipment with multiple energy sources.
Effective LOTO requires machine-specific procedures. A single machine may have electrical, hydraulic, pneumatic, mechanical, thermal, chemical, and gravitational energy sources. Missing even one source can be fatal. This JSA provides the framework; your site-specific energy control procedures must identify every energy source for each piece of equipment.
Disclaimer
This content is provided for general informational and educational purposes only. It is not a substitute for a site-specific Job Safety Analysis conducted by a qualified safety professional familiar with your workplace conditions, equipment, and personnel. OSHA citations, BLS statistics, and hazard controls referenced here may not reflect the most current standards or apply to your specific situation. Always consult current OSHA regulations, manufacturer guidelines, and a competent person before beginning work. Health & Safety Systems LLC assumes no liability for actions taken based on this content.
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Step 1: Identify all energy sources on the equipment
Hazards
- Unknown or hidden energy sources not addressed in the lockout procedure
- Stored energy (capacitors, springs, elevated components, pressurized systems) releasing after primary isolation
- Energy sources introduced by connected equipment or processes
Controls
- Review the machine-specific energy control procedure identifying all energy types: electrical, hydraulic, pneumatic, mechanical, thermal, chemical, gravitational
- Walk down the equipment and trace all energy sources including supply lines, connected machines, and auxiliary systems
- Identify stored energy sources: springs under tension, elevated components, pressurized accumulators, charged capacitors, heated surfaces
- Verify the procedure is current; update it if the equipment has been modified since last review
Step 2: Notify all affected employees
Hazards
- Workers unaware of the shutdown attempting to operate equipment
- Production personnel bypassing lockout to restore operations
Controls
- Notify all affected employees (operators, nearby workers, supervision) that the equipment will be locked out for maintenance
- Communicate the expected duration, what equipment is affected, and the name of the authorized employee performing the lockout
- Notify all shifts if the lockout will extend beyond the current shift
- Post notification signs on the equipment control panel and in the work area
Step 3: Shut down the equipment using normal procedures
Hazards
- Uncontrolled shutdown creating additional hazards (loss of cooling, ventilation, material flow)
- Residual material in process continuing to move or react after shutdown
Controls
- Follow the normal operating procedure to shut down the equipment in the proper sequence
- Allow moving parts to come to a complete stop before proceeding with lockout
- Verify process materials have stopped flowing and any reactions are complete or controlled
- Close valves, lower elevated components, and relieve pressure per the orderly shutdown procedure
Step 4: Isolate all energy sources
Hazards
- Isolation device not fully engaged (breaker not fully open, valve not fully closed)
- Wrong isolation point selected (adjacent circuit or valve)
- Gravity or spring energy not addressed by isolation alone
Controls
- Operate each energy isolation device (disconnect switch, circuit breaker, valve, block) to the fully isolated position
- Verify each device is at the correct equipment per the procedure; do not rely on labels alone
- Block or restrain components that could move under gravitational or spring force (chock wheels, lower press rams, support suspended parts)
- Bleed, vent, or drain residual energy from hydraulic, pneumatic, and steam systems; close bleed valves after draining
Step 5: Apply lockout and tagout devices
Hazards
- Unauthorized removal of lock and tag by another worker
- Lock applied to wrong device or not fully securing the isolation device
Controls
- Each authorized worker applies their own individually keyed lock to each energy isolation device
- Apply standardized lockout tags with the worker's name, date, department, and reason for lockout
- Use multi-lock hasps when multiple workers need to lock out the same isolation point
- Never use combination locks, shared keys, or master keys for lockout (except for documented shift transfer procedures)
Step 6: Verify zero energy state
Hazards
- Equipment not fully de-energized despite isolation device position
- Stored energy releasing when work contacts the equipment
- Instrument error giving false zero-energy reading
Controls
- Attempt to start the equipment using normal operating controls to verify it cannot be energized; return controls to off/neutral position after testing
- Use voltage testers, pressure gauges, and other instruments to verify zero energy at the point of work
- Test voltage detection equipment on a known live source before and after testing the locked-out circuit (live-dead-live method)
- Physically verify that moving parts are stationary, pressures are at zero, and temperatures are within safe working range
Step 7: Perform the maintenance or servicing work
Hazards
- Other workers removing locks before maintenance is complete
- Conditions changing during extended maintenance (shift changes, contractor overlap)
- Temporary energization needed for testing during maintenance
Controls
- Each worker maintains their own lock on all isolation points for the entire duration of their work
- If temporary energization is needed for testing, follow the specific procedure: remove tools, clear personnel, remove locks, energize, test, de-energize, re-lock, verify zero energy before resuming work
- For shift changes, the departing worker and arriving worker coordinate lock transfer; at no point should the equipment be unlocked without an authorized worker's lock in place
- Group lockout procedures must be used when multiple crafts or crews are performing maintenance simultaneously
Step 8: Remove lockout devices and restore equipment
Hazards
- Workers or tools still in contact with equipment during re-energization
- Equipment starting unexpectedly when locks are removed
Controls
- Verify the work area is clear: all tools removed, guards and safety devices reinstalled, workers positioned clear of the equipment
- Each authorized worker removes only their own lock after verifying the area is clear
- Notify all affected employees that lockout is being removed and equipment is about to be energized
- Re-energize equipment in the proper startup sequence; verify normal operation before returning to production
Required Personal Protective Equipment
Applicable OSHA Standards
29 CFR 1910.147
The Control of Hazardous Energy (Lockout/Tagout)
Primary LOTO standard requiring a written energy control program, machine-specific procedures, employee training, periodic inspections, and specific lockout/tagout device requirements.
29 CFR 1910.333(b)
Lockout and Tagging of Circuits
Electrical-specific lockout requirements for circuits and equipment. Establishes procedures for verifying de-energized state of electrical systems during maintenance.
29 CFR 1926.417
Lockout and Tagging of Circuits (Construction)
Construction-specific requirements for lockout and tagging of electrical circuits during construction activities. Requires de-energization and tagging before work begins.
ANSI/ASSE Z244.1
The Control of Hazardous Energy
Industry consensus standard providing additional guidance on energy control methods including alternative methods, control of hazardous energy during minor servicing, and risk assessment.
Injury and Fatality Statistics
Failure to properly control hazardous energy results in approximately 50,000 injuries per year, with amputations, crush injuries, burns, and electrocution being the most severe outcomes.
An estimated 120 workers die each year from failure to control hazardous energy during maintenance and servicing. OSHA estimates proper lockout/tagout procedures could prevent the majority of these deaths.
Source: Bureau of Labor Statistics, 2022
Frequently Asked Questions
What is the difference between lockout and tagout?
Lockout uses a physical lock placed on an energy isolation device (breaker, valve, disconnect) that prevents the device from being operated. Tagout uses a standardized tag attached to the isolation device that warns against operation. OSHA requires lockout whenever possible because it provides a physical barrier. Tagout alone is permitted only when the energy isolation device is not capable of being locked out, and additional safety measures must be taken because a tag can be removed without a key.
Who can remove a lockout lock?
Only the worker who applied the lock may remove it. This is a fundamental principle of LOTO. If a worker leaves the site without removing their lock, OSHA allows the employer to remove it under specific documented conditions: verification that the worker is not at the facility, reasonable efforts to contact the worker, and ensuring the worker knows their lock was removed before they return to work. This procedure must be documented in the energy control program.
What energy sources are covered by lockout/tagout?
OSHA 1910.147 covers all forms of hazardous energy: electrical (including stored charge in capacitors), mechanical (moving parts, flywheels), hydraulic (pressurized fluid), pneumatic (compressed air or gas), thermal (steam, hot surfaces, cryogenic systems), chemical (reactive chemicals, process fluids), and gravitational (elevated components, suspended loads). Every energy source on the machine must be identified in the machine-specific procedure and isolated before maintenance begins.
How often must lockout/tagout procedures be inspected?
OSHA requires a periodic inspection of the energy control program at least annually. The inspection must include a review of each authorized employee's responsibilities and the machine-specific procedures. An authorized employee other than the one using the procedure must conduct the inspection. For procedures involving only tagout, the inspector must also interview each affected and authorized employee. The inspection must be documented with the date, equipment, employees involved, and the inspector's identity.
Does lockout/tagout apply to minor servicing during normal production?
OSHA provides a limited exception for minor servicing activities performed during normal production operations if the work is routine, repetitive, and integral to the production process, AND the employer provides effective alternative protection. Examples include minor tool changes, adjustments, and lubrication that are routine. However, if the servicing exposes the worker to unexpected energization or release of stored energy, full LOTO procedures are required regardless of the task duration.