What Is Lockout/Tagout?
Lockout/tagout (LOTO) is a set of safety procedures designed to protect workers from the unexpected release of hazardous energy during equipment servicing and maintenance. The process involves placing locks and tags on energy isolating devices to ensure machinery cannot be started, energized, or release stored energy while a worker is performing maintenance.
LOTO is governed by OSHA standard 29 CFR 1910.147, "The Control of Hazardous Energy." Failure to comply is consistently among OSHA's top 10 most-cited violations, with serious penalties exceeding $15,000 per instance.
Why LOTO Matters
The Bureau of Labor Statistics estimates that failure to properly control hazardous energy accounts for nearly 10% of serious workplace accidents in industrial settings. Workers performing maintenance on machinery that unexpectedly starts up or releases stored energy face risks including electrocution, amputation, crushing injuries, burns, and death.
A properly implemented LOTO program eliminates these risks by ensuring that every energy source is identified, isolated, and verified before any work begins.
Who Is Involved in LOTO?
OSHA defines three categories of employees in the LOTO process:
- Authorized employees: Workers who actually perform the lockout/tagout. They apply locks and tags, verify isolation, and perform the servicing or maintenance work. They receive the most comprehensive training.
- Affected employees: Workers who operate or use the equipment being serviced, or who work in areas where LOTO is being performed. They must be notified before and after LOTO is applied.
- Other employees: Anyone who works in or near the area where LOTO is in effect. They must understand the prohibition against restarting or reenergizing equipment.
The Six-Step LOTO Sequence
OSHA 1910.147(d) prescribes a specific sequence for applying energy controls. Every LOTO procedure must follow these steps in order:
- Preparation: The authorized employee identifies all energy sources, their type and magnitude, and the methods required to control them.
- Shutdown: The machine or equipment is shut down using the established operating procedure. An orderly shutdown prevents additional hazards from an uncontrolled stop.
- Isolation: All energy isolating devices are physically located and operated to disconnect the equipment from its energy sources.
- Lock/Tag Application: Lockout or tagout devices are affixed to each energy isolating device by the authorized employee. Each lock must identify the worker who applied it.
- Stored Energy Release: All stored or residual energy (springs, capacitors, elevated components, pressurized lines) is relieved, disconnected, restrained, or otherwise rendered safe.
- Verification: The authorized employee verifies that the equipment is fully deenergized by attempting to start it using normal operating controls, then returning controls to the off position.
Lockout vs. Tagout
A lockout device uses a lock to physically hold an energy isolating device in the safe position. A tagout device is a warning tag attached to the isolating device indicating that it must not be operated.
OSHA strongly favors lockout over tagout. If an energy isolating device is capable of being locked out, the employer must use lockout unless they can demonstrate that tagout provides equivalent protection. Tagout alone requires additional safety measures (removing a circuit element, blocking a switch, using an extra disconnect) and additional employee training on the limitations of tags.
Building a Complete LOTO Program
A compliant LOTO program under OSHA 1910.147 consists of three components:
1. Written Procedures
Every piece of equipment with hazardous energy requires a documented energy control procedure (see our writing guide). Each procedure must include the specific steps for shutdown, isolation, lock/tag application, stored energy release, and verification. There is a narrow exception for equipment with a single, readily identifiable energy source, but documenting all procedures is the recommended practice.
2. Employee Training
Training must be role-specific. Authorized employees need technical training on energy source recognition, type and magnitude, and control methods. Affected employees need instruction on procedure purpose and use. All training must be certified with employee name and training date. See our full training requirements guide.
3. Periodic Inspections
Every energy control procedure must undergo a periodic inspection at least annually. The inspection must be performed by an authorized employee other than the one who normally uses the procedure. Inspection certifications must record the machine, date, employees included, and inspector name.
Common LOTO Mistakes
- Incomplete energy source identification: Missing a secondary energy source (gravity, stored pneumatic pressure, thermal energy) is the most dangerous oversight in any LOTO program.
- Using control circuits instead of isolation devices: Push buttons and selector switches are not energy isolating devices. Only mechanical devices that physically prevent energy transmission qualify.
- Skipping verification: Attempting to start the equipment after lockout is the critical step that confirms isolation is complete. Skipping it defeats the purpose of the entire procedure.
- Inadequate training documentation: Training must be certified with names and dates. "Toolbox talks" without documentation do not satisfy OSHA requirements.
- Overdue inspections: Annual inspection deadlines are frequently missed, especially in organizations managing procedures with spreadsheets or paper files.
Managing LOTO with Software
Paper-based LOTO programs work for small facilities with a handful of procedures. As programs grow, version control, inspection tracking, and consistent formatting become increasingly difficult to manage manually.
LOTO management software like LOTOBuilder centralizes procedure creation, automates inspection scheduling, tracks training records, and generates OSHA-compliant documentation on demand. Explore LOTOBuilder features or start a free trial.
