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Toolbox talk · 10 min · Electrical

Lockout/Tagout Basics

Hazards: Unexpected start-up or reenergization during servicing · Release of stored energy — hydraulic, pneumatic, spring, gravity, steam · Electrocution and arc flash while working on a circuit believed dead · Caught-in, crushing or amputation from a machine that restarts

Why it matters

Control of hazardous energy, 29 CFR 1910.147, was the fourth most cited OSHA standard in fiscal year 2025. OSHA lists what these injuries look like: "electrocution, burns, crushing, cutting, lacerating, amputating, or fracturing body parts." The machine does not have to be running to hurt you — only able to start, or still holding something back.

Key points

  • Know every energy source before you touch the switch. 1910.147(d)(1): type and magnitude, the hazards, how it is controlled. Electrical, hydraulic, pneumatic, mechanical, thermal, chemical, gravity, spring — the second control circuit or the shared air header is the one that gets missed.
  • Shut down in order, isolate at the device. (d)(2) orderly shutdown, (d)(3) every isolating device located and operated. Use this machine's written procedure: a generic one does not know where your disconnect is.
  • Bleed, block and drain the stored energy. (d)(5): relieved, disconnected, restrained, rendered safe — accumulators, capacitors, raised rams, loaded springs, hot lines. Where it can build back up, keep verifying.
  • Verify with an instrument, not an opinion. (d)(6): verify isolation and deenergization before work starts. Meter the conductors, read the gauge, try the start once the area is clear.
  • One person, one lock, one key. (d)(4)(i) and (e)(3): you affix your own device and you remove it. Four people in there, four locks on.
  • Restart is a procedure too. (e)(1)-(e)(2): area inspected, parts back together, everybody clear, affected employees told before it comes back on.
  • On a jobsite, 1926.417 is the rule. 1910.147 does not cover construction: tag the controls, render deenergized circuits inoperative, tag every point where they can be energized.

Do / Don't

Do

  • Read this machine's procedure before you start.
  • Put your own lock and tag on every isolation point.
  • Test dead with a meter proved on a known source.
  • Tell the operator and the next shift what is locked out.

Don't

  • Cut, bypass or "borrow the key" for someone else's lock.
  • Trust an E-stop, interlock or selector switch as isolation.
  • Reach past a guard to clear a jam, even for a second.
  • Leave a lock on and go home without telling anyone.

Quick site check

  • Is today's machine procedure on hand, and does it name the disconnects?
  • Enough locks, tags and hasps for everyone working in there?
  • Meter and gauges available, and the meter proved?
  • Who is accountable for the group lockout on this job?
Discussion — ask the crew
  1. Name the machine you serviced most recently. How many separate energy sources does it have, and can you name every one?
  2. Where is the disconnect for it, and what is the label on that disconnect?
  3. What on that machine holds pressure, spring force or a raised weight after the power is off?
  4. How did you verify it was actually dead — a meter reading, a gauge, or hitting the start button?
  5. If your lock is still on it at the end of shift and you go home, what happens next?
Refs: 29 CFR 1910.147 — The control of hazardous energy: (c)(2)-(c)(4) procedures, (d) application of control, (e) release · 29 CFR 1910.147 App. A — Typical minimal lockout procedure · 29 CFR 1926.417 — Lockout and tagging of circuits (construction) · OSHA — Control of Hazardous Energy (Lockout/Tagout): energy types and harmful effects · OSHA — Top 10 Most Frequently Cited Standards, FY 2025 (1910.147 ranked 4th)Sign-in sheet included in the printed version

Frequently asked questions

1910.147(d) requires them in this order: prepare for shutdown, shut the machine down, isolate every energy source, apply lockout or tagout devices, relieve stored energy, then verify isolation before work starts. The order is mandatory, not a suggestion.

Only if the isolating device cannot accept a lock, or if the employer can demonstrate the tagout provides full employee protection under 1910.147(c)(3) — tag where the lock would have gone, plus extra measures like removing a valve handle or opening a second disconnect. A tag warns; it holds nothing shut.

You are — 1910.147(e)(3) says each device is removed by the employee who applied it. Removal by anyone else takes a documented procedure in the energy control program: verify you are off site, make all reasonable efforts to reach you, and make sure you know before you resume work at that facility.

Not on its own. (d)(6) requires the authorized employee to verify that isolation and deenergization have been accomplished. On an electrical source that means a meter reading at a named point; on hydraulics or air it means a gauge at zero after the bleed.

No. 1910.147(a)(1)(ii)(A) says the standard does not cover construction employment. Construction circuits fall under 1926.417: controls to be deactivated shall be tagged, deenergized equipment rendered inoperative with tags at every point where it can be energized, and tags placed to plainly identify what is being worked on.

That is when most of these injuries happen. Minor servicing during normal production is outside 1910.147 only when it is routine, repetitive, integral to production and done with alternative measures that give effective protection. Reaching past a guard into a machine that can start is not one of those cases.

Sources & references

Content checked against these sources — last reviewed August 28, 2026.

Results are estimates for planning purposes and do not replace a competent person's evaluation or an engineer's design. Follow the OSHA standards that apply to your work and your employer's written program.

By — Editorial team of SteelToeTools.com (published by LSEA SAS) Updated