Lockout/Tagout: Energy Control Programs

The Control of Hazardous Energy standard, commonly known as Lockout/Tagout (LOTO), is found at 29 CFR 1910.147 and is consistently among OSHA's Top 10 most cited standards. LOTO protects workers from the unexpected energization, startup, or release of stored energy during service and maintenance activities. OSHA estimates that LOTO compliance prevents approximately 120 fatalities and 50,000 injuries per year. The standard applies when workers must bypass or remove a guard, place any part of their body in a machine's point of operation, or otherwise be exposed to energy hazards.

A complete energy control program includes three components: written energy control procedures for each piece of equipment, training for authorized employees (those who perform lockout), affected employees (those who work in areas where LOTO is used), and other employees (everyone else who might be near LOTO equipment), and a periodic inspection (at least annual) of the energy control procedures. Each piece of equipment must have an equipment-specific written procedure unless a general procedure adequately covers it.

The six-step LOTO sequence is: (1) Notify affected employees that servicing will occur and the machine will be shut down. (2) Identify all energy sources — electrical, pneumatic, hydraulic, mechanical (springs, gravity), thermal, and chemical. (3) Shut down the equipment following normal stopping procedures. (4) Isolate each energy source by opening disconnects, closing valves, or blocking mechanical components. (5) Apply lockout devices — each authorized employee applies their own lock so that the machine cannot be started without their personal key. (6) Release or restrain stored energy (bleed pneumatic/hydraulic lines, block elevated parts, discharge capacitors, allow thermal cooldown). Verify zero energy state by attempting to start the machine.

Tagout is used only when a specific piece of equipment cannot be locked out because it has no lockout capability. A tag alone provides less protection than a lock — it is a warning, not a physical barrier. When tagout is used instead of lockout, OSHA requires equivalent protection measures such as removing an isolating circuit element, blocking a control switch, opening an extra disconnect, or removing a valve handle. Group lockout (multiple authorized employees work on one machine simultaneously) requires a group lockout box where each employee applies their own lock. Contractors performing LOTO must coordinate with the host employer's LOTO program.