Lockout Tagout Steps: How the LOTO Procedure Works and Why
What Are the Lockout Tagout Steps?
Lockout/tagout (LOTO) is the safety procedure used to shut down machinery and physically prevent it from starting up or releasing stored energy while someone is working on it. The procedure is commonly taught as six steps: prepare for shutdown, notify affected workers and shut the machine down, isolate every energy source, apply locks and tags, release or restrain any stored energy, and verify zero energy before work begins. When the job is done, a separate restoration sequence brings the machine back online in a controlled way.
Those six steps look simple on paper. Every one of them exists because skipping it has injured or killed someone. This guide walks through what each step actually involves, why the order matters, and who is allowed to remove a lock once it's on.
What Is Lockout/Tagout? (LOTO Meaning)
Lockout/tagout is the common name for hazardous energy control — the practice of isolating a machine from every source of energy that could move it, energize it, or release something dangerous while a person is inside its guards or working on its systems.
"Energy" here means more than electricity. A machine can hurt you through:
- Electrical energy — live circuits, motors, control power
- Mechanical energy — moving parts, flywheels still spinning after shutdown
- Hydraulic and pneumatic pressure — fluid or air trapped in lines and cylinders
- Gravity — raised rams, blades, counterweights, or platens that can fall
- Stored energy — compressed springs, charged capacitors, pressurized accumulators
- Thermal and chemical energy — hot surfaces, steam, reactive materials in process lines
In the United States, LOTO programs are driven by OSHA's control of hazardous energy standard, and consensus guidance also comes from bodies like ANSI and ISO. We deliberately don't quote clause numbers or threshold values here — those details change and vary by industry, so always rely on your employer's written procedures and the current official publications.
Lockout vs. Tagout: What's the Difference?
The two words describe two different levels of protection:
| Lockout | Tagout | |
|---|---|---|
| What it is | A physical lock holds the energy-isolating device (breaker, valve, disconnect) in the safe position | A prominent warning tag attached at the isolation point |
| What it prevents | Physically blocks the device from being operated | Warns people not to operate the device |
| Strength of protection | Positive restraint — the device cannot be moved without removing the lock | Relies entirely on people reading and obeying the tag |
| When it's used | Whenever the equipment can accept a lock — the strongly preferred method | Generally only when a device physically cannot be locked, with extra precautions added |
The short version: a tag is a warning; a lock is a barrier. Tags tear, fade, fall off, and get ignored under deadline pressure. Locks don't. That's why lockout is the default and tagout alone is the narrow exception.
The 6 Lockout Tagout Steps in Detail
The exact sequence at your facility comes from a machine-specific written procedure. But nearly every LOTO procedure follows the same six-step skeleton.
Step 1: Prepare for Shutdown
Before touching anything, the authorized worker identifies every energy source feeding the machine — electrical, hydraulic, pneumatic, gravity, springs, and anything else — along with its magnitude, its hazards, and exactly how each source is isolated and controlled. This is where the machine-specific written procedure earns its keep: complex equipment often has energy sources that aren't obvious from where you're standing, like a second electrical feed or an accumulator that stays pressurized after the pump stops.
Why it matters: most serious LOTO failures aren't people skipping the lock — they're people locking out the sources they knew about and missing one they didn't.
Step 2: Notify Affected Workers and Shut Down
Everyone who operates the machine or works around it is told that it's going down for service and why. Then the machine is shut down using its normal stopping procedure — the standard operator controls, in the normal sequence — not by yanking a disconnect under load.
Why it matters: notification prevents a confused operator from trying to restart "their" machine, and an orderly shutdown avoids creating new hazards (arc flash at a loaded disconnect, a process left in an unstable state).
Step 3: Isolate All Energy Sources
Now every energy-isolating device gets moved to the safe position: main disconnects opened, breakers switched off, supply valves closed, lines blanked or blocked as the procedure requires. One critical point trips up newcomers: a stop button, selector switch, or other control-circuit device is not energy isolation. Controls tell the machine to stop; isolation physically removes the machine's ability to run. A machine that's "off" at the control panel can still start from a fault, a sensor, or someone else's finger.
Step 4: Apply Lockout/Tagout Devices
Each authorized worker attaches their own personal lock to each isolation point, with a tag identifying who applied it and why. When several people work on the same machine, group lockout hardware — a hasp or lock box — lets every worker attach a personal lock, so the equipment can't be re-energized until the last person has removed theirs.
Why it matters: one lock per person is the whole logic of the system. Your lock is your personal guarantee that nobody can start the machine while your hands are inside it — a guarantee that evaporates if people share locks or keys.
Step 5: Release or Restrain Stored Energy
Isolating the supply doesn't remove energy already stored in the machine. This step dissipates or restrains it: venting trapped air or hydraulic pressure, allowing flywheels and rotating parts to come to a complete stop, discharging capacitors, releasing or blocking spring tension, and physically blocking anything gravity can move — raised rams, blades, and platens get pinned or cribbed, never trusted to hydraulics alone. If stored energy can rebuild (a slowly re-pressurizing line, for instance), the procedure has to keep it controlled the whole time work continues.
Step 6: Verify Zero Energy (Try It)
The step most often skipped, and the one that saves lives: prove the machine is dead before anyone reaches in. After checking that no one is exposed, press the start buttons and cycle the controls — the machine should do nothing. Where the hazard is electrical, a qualified person tests circuits with a meter that has itself been verified against a known live source. Then return the controls to neutral or off so nothing lurches when power is eventually restored.
Why it matters: verification is the only step that catches every earlier mistake — the wrong disconnect, a mislabeled panel, a second feed nobody knew about. "Try before you pry" is the habit that turns a paperwork exercise into actual protection.
Restoring Equipment to Service
Bringing a machine back up is its own controlled sequence, not just "pull the locks":
- Inspect the work area — tools, blocking, and spare parts out of the machine; guards reinstalled.
- Clear personnel — confirm everyone is safely away from the equipment.
- Remove devices — each worker removes their own lock and tag.
- Notify affected workers — announce that the machine is going back into service before re-energizing.
Who Can Remove a Lockout/Tagout Lock?
Only the person who applied it. That single rule is the backbone of the whole system. A supervisor cannot remove your lock, a coworker cannot remove your lock, and cutting someone's lock off casually is treated in most facilities as a firing-level offense — because the only thing that lock means is "a specific human being may be inside this machine."
There is one narrow, formal exception. When the worker who applied the lock is genuinely unavailable — left the site, unreachable — the employer may remove it, but only under a documented procedure that typically requires:
- Verifying the worker is actually away from the facility
- Making reasonable efforts to contact them
- Ensuring the worker is informed before they return to work
The details of that exception process live in your employer's written program. The everyday rule stays simple: your lock, your key, your life.
Common LOTO Mistakes to Avoid
- Treating "off" as "isolated." Stop buttons and interlocks are controls, not isolation.
- Missing an energy source — the second feed, the accumulator, the raised load overhead.
- Skipping verification because the job "will only take a minute." Short jobs are where shortcuts concentrate.
- Sharing locks or keys, which quietly destroys the one-person-one-lock guarantee.
- Ignoring stored energy after the supply is isolated — pressure, springs, and gravity don't read tags.
- Relying on tags alone when a lockable device exists.
Where LOTO Fits in Shop Safety
Lockout/tagout is the maintenance-side companion to machine guarding: guards protect people during normal operation, LOTO protects them when the guards come off. It applies across virtually every type of manufacturing process — servicing a CNC mill, clearing a jam in a press, or maintaining the wire feeder and gas system on the equipment used in MIG and TIG welding all begin with the same six steps. Whatever the machine, the logic never changes: identify every energy source, isolate it, lock it, drain what's stored, and prove it's dead before anyone reaches in.
One final reminder: this article is an educational overview, not training. LOTO authorization requires formal, employer-provided training on machine-specific procedures. If your facility's written procedure differs from the outline here, your procedure wins — and current publications from OSHA and ANSI are the authoritative sources for requirements in your jurisdiction.