Heat Stress Toolbox Talk: Signs, Water, Rest and Shade

Heat illness can go from "feeling a bit rough" to a medical emergency in a short time, and the person affected is often the last to notice. This heat stress toolbox talk is for crews working outdoors in warm weather, or indoors near ovens, furnaces, boilers or in unventilated spaces. Everyone should leave knowing the warning signs, the three basics of prevention, and what to do if a coworker goes down.

Why does a heat stress toolbox talk matter?

OSHA states that thousands of US workers become sick from heat exposure every year, and some cases are fatal. Heat illness is preventable, and it isn't just a summer problem. It can happen indoors or out, in any season, wherever heavy work, hot conditions and heat-trapping clothing combine.

New starters face the greatest danger. OSHA reports that almost half of heat-related deaths happen on a worker's first day on the job, and over 70 percent during the first week. The same applies to people returning after a week or more away, because their bodies have lost their tolerance to heat.

In the UK, HSE lists the symptoms of heat stress as poor concentration, muscle cramps, heat rash, severe thirst, fainting, heat exhaustion and heat stroke. It notes that severe thirst is a late symptom, so don't wait for it.

Talking points for your heat illness safety talk

• Drink before you're thirsty. OSHA advises drinking water frequently, not just when you feel thirsty. For jobs lasting more than two hours, electrolyte drinks help replace the salt lost in sweat.
• Rest in the shade, and don't skip breaks. OSHA says breaks should get longer and more frequent as heat stress rises. Resting somewhere cool means you recover faster.
• Know the early signs. Heavy sweating, dizziness, nausea, headache, cramps and unusual tiredness or irritability all point to the body struggling to cool down.
• Treat confusion as an emergency. Confusion, slurred speech, seizures or collapse can mean heat stroke. OSHA's first aid advice is to cool the worker immediately and call emergency services.
• Watch out for each other. Use the buddy system, especially for new, temporary or returning workers, who need time to build tolerance to the heat.
• Lighten the load in peak heat. Where possible, schedule the heaviest work for cooler parts of the day and slow the pace.
• Follow the site heat plan. Know where water, shade and first aid are, and who to tell.

Example to share with the crew

Picture this: it's the first hot week of the year, and a temporary labourer is on his second day, shifting materials on an exposed roof. He's keen to make a good impression and skips the mid-morning break. By 11 a.m. he's pale, sweating heavily and says he feels sick.

His buddy notices, gets him into the shade, gives him water and tells the supervisor, who starts cooling him and keeps him under watch. When he starts slurring his words, they call emergency services. Because someone was watching, the response started early.

Heat stress checklist

• Cool drinking water is available close to the work, in enough quantity
• A shaded or cool rest area is set up and everyone knows where it is
• Break schedule is adjusted for today's heat
• New and returning workers are paired with a buddy and eased in
• Heaviest tasks are scheduled for cooler parts of the day where possible
• Everyone can name the signs of heat exhaustion and heat stroke
• First aid arrangements and emergency numbers are known on site

Questions to ask the crew

1. What signs of heat illness would you look out for in a coworker?
2. Where is the nearest water and shade from where you're working today?
3. Who here is new or just back from time off, and who is their buddy?

How to close the talk

If the crew remembers one thing from this heat stress toolbox talk, make it this: water, rest and shade, every hour, and look out for each other. If anyone feels unwell, stop work and tell your supervisor straight away. If someone is confused or collapses, cool them and call emergency services. For more on fluids, see our hydration and nutrition talk, and find more safety topics for toolbox talks in our library.