Lockout/Tagout (LOTO): The Zero-Energy Steps Students Keep Mixing Up

29 CFR 1910.147 · Control of Hazardous Energy

Keywords: lockout tagout, LOTO procedure, zero energy state, energy isolation, authorized employee, affected employee, energy control program, OSHA 1910.147

The Six-Step LOTO Sequence

1. Notify affected employees the equipment is being shut down.
2. Identify all energy sources (electrical, pneumatic, hydraulic, gravity, thermal, chemical).
3. Shut down the equipment using normal stopping procedure.
4. Isolate — operate each isolating device to disconnect the equipment from its energy source.
5. Lock/Tag out the isolating devices with assigned individual locks.
6. Release/Restrain stored or residual energy (bleed lines, block parts, discharge capacitors, etc.).

Authorized vs. Affected vs. Other Employees

• Authorized: performs the lockout; installs and removes their own lock.
• Affected: operates the equipment; must be notified, never removes the lock.
• Other: works in the area; must know not to restart locked-out equipment.
• Only the authorized employee who applied the lock may remove it — a supervisor may only remove in a documented emergency procedure.

Common Exam Traps

• Tagout alone is not equivalent to lockout — tags are a warning only, not a physical barrier. Use lockout whenever possible.
• Verification is required after lockout — try to operate the equipment or use a meter to confirm zero energy before work begins.
• Re-energization has its own sequence: remove tools, replace guards, notify employees, then remove locks/tags.
• Complex/group lockouts require each worker to apply their own personal lock — one "group lock" applied by a supervisor is a violation.
• Gravity is an energy source. Blocking raised equipment (dies, ram, conveyor) against unexpected descent is required.

Memory Aid — LOTO Order

N-I-S-I-L-R

• Notify affected employees
• Identify all energy sources
• Shut down equipment
• Isolate energy
• Lock/Tag the isolating devices
• Release residual energy, then verify

Key Definitions to Know