Hazards: Heat stroke in unacclimatized workers · Heat exhaustion · Dehydration · Delayed recognition of symptoms
Why it matters
OSHA states that over 70 percent of heat-related deaths happen during a worker's first week on the job. Not the hottest week — the first one. A body needs days of repeated exposure before it sweats early enough and hard enough to keep up.
On May 16, 2022, a helper installing interior walls at a commercial site collapsed and died of heat stroke. It was his first day of work. There was no shade except the trucks, the heat index that day only ran between 71 and 96 °F, and he had been drinking water and Gatorade. He had not been trained to recognize the symptoms, and he was not acclimatized. (OSHA Accident Search, Summary Nr 149868.015.)
Key points
- New to heat: start at 20 percent. No more than 20 percent of a normal shift's heat exposure on day one, then 40, 60, 80, and a full shift on day five.
- Done hot work before, just not lately? OSHA's guide gives 50 percent on day one, 60 on day two, 80 on day three, full shift on day four.
- A week off puts you back at the start. Vacation, sick leave, a rained-out stretch, a move from an indoor job — all of it counts. Say so out loud at the tailgate instead of proving something.
- The first heat wave gets everybody. When the temperature jumps well above what we have been working in, even long-timers are back to being unacclimatized for a few days.
- Pair the new person with somebody. Confusion and staggering are things a coworker sees first — the person in trouble is usually the last to know.
- Water does not replace acclimatization. The man who died on his first day had been drinking. Drink about a cup every 15 to 20 minutes anyway, and use the shade.
- Stopped sweating, confused, or acting strange is a 911 call. That is heat stroke until proven otherwise. Cool the person and call — do not drive them home.
Do / Don't
Do
- Tell the foreman if you are new or coming back from time off
- Give new people the shaded and indoor tasks for the first days
- Take the breaks in shade or air conditioning — it does not cost you heat tolerance
- Speak up the moment a coworker looks off
Don't
- Put a brand-new hire straight onto the heaviest job in full sun
- Send someone back to the same work after they cramped or got dizzy
- Assume a fit young worker is safe — fitness is not acclimatization
- Wait for someone to ask for water or shade
Quick site check
- Who on this crew is in their first week, or back after more than a week away?
- Is there real shade within a short walk of where we are working, or only truck cabs?
- Is cool water in place and close, and does everyone have a bottle?
- Does each new person have a named buddy for the shift?
- Does everybody here know the site address to give to 911?
- Who on this crew is in their first week of hot work, or just back from more than a week off?
- If someone here started stumbling or acting confused this afternoon, who would notice first, and what would they do in the next two minutes?
- What work on this job could a new person do in the shade for the first couple of days without holding the crew up?
- Where is the closest shade or air-conditioned break area from where we are working right now?
- Have any of you felt heat symptoms on this job and kept working? What made you keep going?