A storm can roll in fast on a hot July afternoon. One worker on a crane or a steel deck is the tallest thing around — and lightning tends to find the tallest thing. The good news is that this hazard announces itself. The whole job is acting early, before the first drop of rain.
The hazard
Lightning can reach well beyond the rain — a strike out of a sky that still looks clear overhead. So it arrives before the storm looks close. On a site you're often the high point: scaffolds, rebar, cranes, lifts, and wet ground all carry current. A strike can stop a heart or throw someone off a height. And it isn't only the lightning — the same storm brings winds that topple lifts and cranes, flying debris, and downpours that flood excavations and wash out footing.
What to do
- When thunder roars, go indoors. That's the rule, and it's simpler than counting. If you can hear thunder at all, you're within reach of a strike — stop exposed work and get to shelter. Waiting to count seconds keeps people outside inside the danger zone.
- Wait 30 minutes after the last thunder before going back out. The tail of a storm still strikes.
- Get to real shelter. A substantial building with wiring and plumbing, or a fully enclosed all-metal vehicle with the windows up. A lone tree, an open shed, a tent, or an open vehicle are not shelter.
- Get down early. Off heights, cranes, lifts, and scaffolds before the rain starts, not after. Coming down a wet ladder in a gust is its own hazard, so the decision has to be made with time in hand.
- Secure the site. Lower or secure cranes and lifts to the manufacturer's wind limits, and stow or tie down loose material before it becomes a missile.
- Watch the forecast and the radar, and agree in the morning who is watching and how they'll warn everyone at once.
- Stay off and away from metal — drop hand tools, keep clear of rebar, fences, wet ropes, and standing water.
If someone is struck
- Call 911.
- It's safe to touch them — a struck person carries no electrical charge.
- Check whether they respond and whether they're breathing normally. If not, start CPR immediately and use an AED if there's one available. Don't spend time hunting for a pulse — for an untrained responder that's unreliable and it costs the minutes that matter.
- Move them to shelter if you can do it safely. The area is still dangerous and lightning can strike the same place twice.
Watch out for
- A clear blue sky overhead while a dark cell builds in the distance — strikes still reach you.
- Sheltering under a lone tree or in an open shed. Both can make it worse.
- Being caught out and trying to "ride it out" in a crouch. The old advice to crouch low is no longer given — it doesn't meaningfully protect you, and it keeps you outside. Keep moving to real shelter.
- The wind and the water doing the damage while everyone is watching the sky.
Talk it over
- Where's our nearest real shelter from where we're working today, and how long does it take to get there — including getting someone down off height?
- Who's watching the weather, and how do they warn the whole crew at once?
- When thunder starts, what stops first, and who calls it?