Skip to content
STEELTOETOOLS
Toolbox talk · 10 min · Heat & Cold Stress

Lightning and Severe Weather

Hazards: Direct lightning strike in the open, on a roof or on a lift · Ground current and side flash from a strike nearby, not overhead · Falls caused by a strike — paralysis, shock or a startled step at height · Conduction through rebar, plumbing, cords, scaffold and crane steel · High winds on scaffolds, forms, walls and suspended loads

Why it matters

On May 13, 2024, a plumber was walking back to the van at the end of the day when lightning struck him. He died three days later (OSHA Summary Nr 166742.015). In August 2021 two carpenters were on fiberglass stepladders inside a partly finished building when lightning hit nearby — one died, the other took third-degree burns to the arms (Nr 138467.015). NOAA counted 21 lightning deaths in the U.S. in 2025. It does not have to hit you, and it does not have to be overhead.

Key points

  • Thunder is the alarm. OSHA and NOAA: when thunder roars, go indoors — a distant rumble counts. There is no 30-second count to make first, and lightning strikes up to 10 miles from any rain.
  • Thirty minutes after the last thunder. Not after the rain stops, not after the sky clears. Going back out early is how people get caught.
  • Shelter is a real building or a hard-topped vehicle. Fully enclosed, with wiring and plumbing, windows up in the truck. A shed, a tent, a pavilion or a framed-up shell is not shelter.
  • Ground current kills the most people. NOAA's own finding: you do not have to be the tallest thing around. Get off rebar, scaffold, plumbing and cords.
  • Do not start what you cannot stop. With storms in the forecast, no pour, no pick, no roof deck you cannot walk away from in the time it takes to reach shelter.
  • Wind has its own rules. No scaffold work in storms or high winds without a competent person's call plus fall arrest or secured wind screens (1926.451(f)(12)).

Do / Don't

Do

  • Check the NOAA forecast before the shift and name who watches it all day.
  • Know the shelter and the walk time from the furthest crew, in minutes.
  • If caught out: get off high ground, away from isolated trees, poles and equipment — and never lie flat.
  • Call 911 for anyone struck; start CPR and use an AED. They carry no charge.

Don't

  • Wait for rain, or for the storm to look close, before going in.
  • Shelter under a tree, in a trailer doorway, or in an open equipment cab.
  • Touch cords, plumbing, rebar or a concrete wall while sheltering.
  • Trust a handheld detector to buy you one more lift.

Quick site check

  • Point at today's shelter from where we stand, and time the walk from the furthest work face.
  • Confirm who has authority to call everybody in, and how they will do it — horn, radio, phone.
  • List the tasks on today's schedule that cannot be stopped in that many minutes, and decide now.
Discussion — ask the crew
  1. Where is our safe shelter from here, and how many minutes does it take the furthest crew to reach it?
  2. Who is watching the weather today, and how do the rest of us hear about it?
  3. Which task on this job cannot be stopped quickly once it starts, and what does that mean for a morning forecast of storms?
  4. Who has kept working after hearing thunder because the sky overhead was still clear?
  5. Whose call is it to send everybody in, and does anybody here doubt they would back it?
Refs: OSHA/NOAA Fact Sheet FS-3863 (06/2021), Lightning Safety When Working Outdoors — shelter, hard-topped vehicles, and 30 minutes after the last sound of thunder · NOAA/NWS — Five Ways Lightning Strikes People: direct strike, side flash, ground current (the most deaths and injuries), conduction, streamers · NOAA/NWS with the National Lightning Safety Council — U.S. lightning deaths: 21 in 2025, 14 in 2024 · 29 CFR 1926.451(f)(12) — No work on or from scaffolds during storms or high winds unless a competent person determines it is safe and employees have fall arrest or wind screens · 29 CFR 1926.1431(k)(8) — Hoisting personnel: (i) wind over 20 mph at the platform, (ii) other dangerous weather; a qualified person decides · 29 CFR 1926.854(c) — No work on top of a wall when weather constitutes a hazard; 29 CFR 1926.35 — emergency action plans · OSHA Accident Search — Summary Nr 166742.015, 05/16/2024: a plumber walking back to the work van was struck by lightning and died three days later · OSHA Accident Search — Summary Nr 138467.015, 08/24/2021: two carpenters on fiberglass stepladders in a partly finished building when lightning struck nearby; one died, the other had third-degree arm burnsSign-in sheet included in the printed version

Frequently asked questions

That is not what OSHA and NOAA publish, and the difference matters. The joint OSHA/NOAA fact sheet FS-3863 gives no flash-to-bang count. Its rule is: when thunder roars, go indoors — if you hear thunder, even a distant rumble, get to a safe place immediately — and remain in the shelter or the vehicle for at least 30 minutes after hearing the last sound of thunder. There is one 30 in the rule, and it is at the end, not the beginning.

Yes. The same fact sheet states that lightning can strike outside the heaviest rainfall areas or even up to 10 miles from any rainfall, and that NOAA advises nowhere outside is safe when thunderstorms are in your area. Thunder is audible at roughly the distance lightning can already reach. Hearing it is the trigger. For scale, the same fact sheet counts 20 to 25 million cloud-to-ground strikes a year in the United States and over 300 people struck.

No, and this is the part crews underestimate. NOAA lists five ways people are struck: a direct strike, a side flash jumping from a taller object a foot or two away, ground current traveling outward through the ground from the strike point, conduction along wires or metal, and streamers. NOAA states plainly that ground current causes the most lightning deaths and injuries. In OSHA Summary Nr 138467.015 lightning struck nearby while two carpenters worked on fiberglass stepladders in a partially finished building; one died and the other took third-degree burns.

A fully enclosed, substantial building with electrical wiring and plumbing, which act as an earth ground — and you stay off anything conductive inside it: cords, electrical equipment, plumbing fixtures, corded phones, and concrete walls or floors that may have metal in them. If no such building is reachable, a hard-topped metal vehicle with the windows rolled up. The fact sheet is explicit that sheds, pavilions, tents and covered porches do not provide adequate protection.

There is no standard titled lightning. Employers are covered by the General Duty Clause, Section 5(a)(1) of the OSH Act, for recognized hazards that can cause death or serious harm. Three specific paragraphs also bite in bad weather: 1926.451(f)(12) prohibits work on or from scaffolds during storms or high winds unless a competent person determines it is safe and employees are protected by a personal fall arrest system or wind screens; 1926.1431(k)(8) puts hoisting personnel on hold on a qualified person's judgment in wind over 20 mph at the platform or other dangerous weather; and 1926.854(c) prohibits work on top of a wall when weather conditions constitute a hazard.

Not by a blanket rule, and it is worth being precise. 1926.1431 is titled Hoisting personnel, so its (k)(8) environmental-conditions paragraphs govern lifting people on a personnel platform, not every material hoist. For material lifts the controls are the manufacturer's limits, 1926.1417 operating procedures and the General Duty Clause. Either way the practical answer on a jobsite is the same: nobody is in the air, on the boom or on the load line when thunder is audible.

FS-3863 recommends a written lightning protocol inside the emergency action plan required by 1910.38 or 1926.35. It should tell supervisors and workers to act on thunder, lightning or other warning signs; say how workers are notified; identify the safe shelters; state the response time needed to reach them; specify how the decision to suspend and to resume outdoor work is made; and account for the time needed to move the public as well as the crew.

No detector predicts the first strike. The fact sheet states that no system can detect the first strike, detect all lightning or predict strikes, and that handheld detectors typically miss strikes, cannot locate them and are less accurate than commercial services. NOAA recommends relying first on NOAA weather reports and NOAA Weather Radio, and notes that simply listening for thunder or watching the sky is sometimes the better indication.

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