Lockout/Tagout Basics: Control the Energy Before It Controls You

The machine doesn't care that you were only reaching in for a second.

Lockout/tagout exists for one reason: machines hold energy, and energy doesn't announce itself. A press that looks "off" can still hold hydraulic pressure. A conveyor that stopped can restart when someone upstream clears a fault. A raised load is stored energy waiting on gravity. The injuries lockout/tagout prevents rarely come from dramatic failures — they come from routine work: clearing a jam, changing a blade, reaching in "for just a second."

OSHA's standard for the control of hazardous energy, 29 CFR 1910.147, requires employers to run an energy control program: documented, equipment-specific procedures, locks and tags applied by trained authorized employees, and verification before work begins. The standard is detailed, but its core sequence fits in six steps. Here they are, in the order the standard lays them out — every time, no shortcuts.

Step 1: Notify the people affected

Before anything is shut down, tell the people who use the equipment — and the people around it — that it is being locked out and why. Surprises cause injuries in both directions: an operator who doesn't know a machine is down may try to restart it, and a coworker who doesn't know work is happening inside a guard may not expect anyone to be there. Notification is a step in the standard, not a courtesy.

Step 2: Shut the equipment down in its normal order

Stop the machine using its regular stopping procedure — the sequence the manufacturer and your facility's procedure specify. A controlled shutdown leaves equipment in a predictable state. Yanking a disconnect on a running machine can create its own hazards and its own damage; the point of lockout is control, and control starts with an orderly stop.

Step 3: Isolate every energy source

This is the step that gets skipped, because it requires knowing the machine. Isolate means physically separating the equipment from every source of energy that can reach it: electrical, hydraulic, pneumatic, mechanical, thermal, chemical — and gravity, in the form of raised parts and suspended loads. One switch rarely does all of that. Your equipment-specific procedure exists precisely because each machine's sources are different, and "I turned it off" is not the same as "it is isolated."

Step 4: Apply your lock and your tag

The authorized employee applies a personal lock to each energy-isolating device, plus a tag that says who locked it and warns against operating it. The lock is the physical control — it holds the device in the safe position. The tag is the communication. Neither substitutes for the other, and the standard requires both where devices are lockable.

Step 5: Release or block any stored energy that's left

Isolation stops new energy from arriving; it does nothing about the energy already stored. Pressure in a line, a charged capacitor, a spring under tension, a load held in the air — all of it has to be released, drained, bled, blocked, or restrained before hands go in. Stored energy is the quietest item on this list and the one behind some of the worst surprises, because a machine can pass every other step and still move.

Step 6: Verify — try it, and confirm nothing moves

The final step is proof. After lockout, the authorized employee tries the operating controls to confirm the equipment will not start, checks that no movement occurs, and returns the controls to the off position. Verification is what separates "I believe it's dead" from "I tested it." If you only have discipline for one step on a hard day, this is the one that catches the mistakes made in all the others.

The lock is personal

One rule holds the whole sequence together: the person who applied the lock removes it. Your lock is your statement that you are the one exposed, and nobody else gets to decide your exposure is over. The standard does allow an employer to remove an absent employee's lock, but only under a specific, documented procedure with verification that the employee is not at the facility — it is an exception with paperwork, not a shortcut for a busy afternoon.

Who does what — and who has to be trained

The sequence above is performed by authorized employees — the people trained and designated to lock out equipment and do the servicing work. But they are not the only people the standard expects you to train. Affected employees — the operators who run the equipment — must be instructed on the purpose of lockout and why they must never attempt to restart a locked machine. And every other employee in the area needs to understand enough not to touch a lock or tag that isn't theirs. Under 29 CFR 1910.147(c)(7), that training has to happen before people work around the equipment, and again whenever procedures, machines, or job assignments change in ways that introduce new hazards. Most small operations get the mechanical steps right and let the training side slide — which is how you end up with a perfect lockout performed by one person and defeated by another who was never told what the lock meant.

Forty-five seconds of discipline, in exchange for everybody going home the way they came in. Lockout/tagout is not paperwork and it is not theater. It is the sequence that stands between stored energy and the person reaching in — and it only works when every step happens, every time.