OSHA Lockout/Tagout Explained: Your Comprehensive Guide to LOTO Compliance

Written by Staff Writer

OSHA LOTO is about one simple idea. Before someone services or maintains equipment, the energy that could hurt them needs to be controlled.

That sounds basic until you picture a real worksite: 

• A mechanic reaches into a jammed conveyor
• A maintenance worker opens a machine guard
• A technician drains a pressurized line

An unexpected startup in that situation can lead to serious injuries.

What Is Lockout/Tagout? 

Lockout/tagout, commonly called LOTO, is used to keep equipment from starting or releasing energy while maintenance work is being performed.

The “lockout” part uses a lock to hold an energy-isolating device in a safe position. The “tagout” part uses a warning tag to show that equipment must not be operated until the tag is removed.

Common energy sources include:

1. Heat, chemicals, gravity or stored tension
2. Electrical power
3. Mechanical movement
4. Hydraulic pressure
5. Pneumatic pressure

Why Lockout/Tagout Matters for Control of Hazardous Energy

Some maintenance tasks require employees to work around equipment that could start unexpectedly. Lockout/tagout helps prevent that from happening.

A strong program helps crews avoid dangerous assumptions. For example:

1. “The switch is off, so it’s safe”
2. “This repair will only take a minute”
3. “Everyone knows not to restart it”

Those thoughts can turn risky fast. LOTO adds structure, proof and accountability before work begins.

When 1910.147 from the Occupational Safety and Health Administration Applies

The requirements in 29 CFR 1910.147 apply to servicing and maintenance activities where unexpected startup, energization or energy release could injure workers. Typical covered tasks include:

1. Clearing jams
2. Repairing machines
3. Replacing parts
4. Cleaning equipment near danger zones
5. Adjusting or setting up machinery

OSHA 1910.147 Requirements for Lockout/Tagout and Energy Control Programs

Under 29 CFR 1910.147, the employer’s program includes energy control procedures, employee training and periodic inspections.

The real test is simple: Can a machine operator walk up to a machine, follow the procedure and know the equipment cannot restart unexpectedly?

Written Energy Control Procedures

OSHA requires written hazardous energy control procedures to identify the scope, purpose, authorization, rules and techniques used to control hazardous energy.

A strong written procedure usually explains these items:

• The equipment covered
• The energy sources involved
• The shutdown and isolation steps
• The lock or tag placement steps
• The method for verifying isolation

Need a practical training foundation for your team? A lockout/tagout certificate course helps workers understand key hazardous energy control concepts and includes a certificate of completion.

Lockout and Tagout Devices

Locks and tags need to be more than visible. OSHA requires lockout and tagout devices to be used only for energy control and they must be durable, standardized, substantial and identifiable.

That means a faded paper tag on a greasy valve is not a dependable system. Good device control includes a few everyday habits:

1. Keep devices consistent by color, shape or size
2. Replace damaged locks, tags, hasps and attachments
3. Store devices where authorized employees can find them

Authorized Employees, Affected Employees and Other Workers

Employees have different responsibilities under a lockout/tagout program. Authorized employees apply locks or tags during servicing. Affected employees operate or work near equipment being serviced. Other workers need to understand that locked or tagged equipment cannot be restarted.

Confusion here causes real risk. Who can remove a lock? Who needs notification before startup? Who should stop work when something looks wrong?

Periodic Inspections and Program Review

OSHA requires employers to inspect energy control procedures at least annually. The inspection must be done by an authorized employee other than the one using the procedure being inspected.

Use that review to catch weak points:

• Missing machine-specific steps
• Outdated equipment names
• New energy sources
• Workers who need retraining

A good review is not about blame. It is how a LOTO program stays alive as machines, crews and work conditions change.

How the LOTO Procedure Works Step-by-Step

A good lockout/tagout procedure should feel boring in the best way. Same order, same checks, no guesswork. OSHA’s standard lays out an energy control sequence that covers preparation, shutdown, isolation, device application, stored energy control, verification and safe restoration.

1. Prepare for Shutdown

Before anyone touches a switch or valve, the authorized employee needs to understand the equipment. What energy sources are present? Where are the isolation points? What could still move after shutdown?

A smart pre-check looks at a few details:

1. The machine being serviced
2. The type and magnitude of energy
3. The correct shutdown sequence
4. Any affected employees nearby

This is where written procedures save time. They keep workers from relying on memory during a rushed repair.

2. Shut Down and Isolate the Equipment

Next, the machine is shut down using normal stopping procedures. Then the authorized employee operates the energy-isolating devices.

That may include disconnects, breakers, line valves, blocks or other isolation points. Control buttons alone are not enough because they do not physically isolate energy.

3. Apply Lockout Devices or Tagout Devices

Once isolation points are set, locks or tags are applied. Each device should clearly identify the employee who applied it.

This step sends a clear message. Do not start, open, close, energize or operate this equipment. OSHA’s standard also requires tagout devices to warn against hazardous conditions if equipment is energized.

4. Release or Control Stored Energy

Stored energy can be the hidden problem. A machine can be disconnected and still dangerous.

Watch for these sources:

1. Trapped pressure
2. Suspended parts
3. Charged capacitors
4. Springs under tension
5. Hot materials or surfaces

OSHA requires potentially hazardous stored or residual energy to be relieved, disconnected, restrained or otherwise made safe.

5. Verify Isolation Before Work Begins

Verification is the point where assumptions stop. Before work begins, the authorized employee must verify that the equipment has been isolated and de-energized.

Would you bet your hands on a switch position alone? A better answer is to test, check and confirm.

Restore Equipment Safely After Service

Before restarting, workers should remove tools, replace guards, clear employees from the area and remove devices in the proper order.

Common LOTO Violations and Practical Prevention Tips

Most lockout/tagout problems start small. A missing step. A rushed repair. A worker who “knows the machine” but follows memory instead of the written procedure.

1. Skipping Machine-Specific Procedures

A one-page generic checklist rarely works across a full facility. The baler, mixer, press and conveyor may all hide energy in different places.

Before work starts, ask three questions:

1. What potentially hazardous energy sources are present?
2. What stored energy could remain?
3. What exact device isolates each source?

A smart prevention step is to walk the procedure with an authorized worker at the machine, not at a desk. The best written steps reflect the real work area.

2. Treating Tagout as a Shortcut

Tags warn. Locks physically prevent movement. That difference matters.

OSHA allows tagout in certain cases, but the employer must follow the standard’s tagout requirements and provide equivalent protection where lockout would otherwise be expected.

Use this simple habit:

1. Lock out when the equipment can accept a lock
2. Use tags only under a controlled program
3. Train workers not to treat tags like reminders

3. Failing to Retrain Workers When Conditions Change

Retraining may be required when job assignments, equipment or procedures change. It may also be necessary when inspections identify gaps in employee knowledge.

Did a new valve get added during a repair? Did production move a machine to another line? Those changes can create new hazards.

4. Overlooking Contractors, Shift Changes and Group LOTO

Complex jobs need tighter communication. Contractors, night crews and multi-person equipment maintenance tasks can all create handoff risks.

OSHA requires specific procedures during shift or personnel changes and group lockout/tagout must include overall responsibility and personal protection for employees involved in the work.

Building LOTO Into a Stronger Safety Program with Employee Training

Strong hazardous energy control comes from several parts working together:

1. Written procedures
2. Worker training
3. Annual inspections
4. Supervisor follow-through
5. Clear correction of unsafe habits

Employers can also pair equipment-specific instruction with broader OSHA 30-Hour General Industry Outreach training, offered through the University of South Florida. Outreach training provides general safety education and does not replace employer-required, equipment-specific LOTO training.