When Is it Dangerously Hot to Work?

High heat and construction work are simply not compatible. Yet, the work must get completed. Workers must wear protective clothing and gear which diminishes the body's capacity to shed heat. This fact combined with high heat creates specific exposures which require vigilant monitoring.

For related guidance on managing heat risks at work sites, see Heat Exposure in Construction and Host Liquor Liability.

Short-term exposures to heat and humidity

  • Prevention: Drink plenty of water — a good test is that the employee should urinate at least every three hours, two hours is better. If they do not need to urinate, they are not getting adequate fluids. Wear breathable clothing such as cotton. Work in the shade or indoors as much as possible and take frequent water breaks in the shade.
  • Heat exhaustion: This is the stage before heat stroke when many symptoms from dehydration appear. Any dizziness, nausea or vomiting, cramping, or sudden weakness requires immediate attention. Headaches, blurred vision, or unusual fatigue can be signs of heat exhaustion. Rest the worker in the shade, loosen tight clothing and provide water. Observe the employee for several minutes; if they stop sweating or any symptom worsens, or they breathe rapidly or have a quick pulse, seek emergency medical help immediately.

Heat stroke

Heat stroke: LIFE THREATENING. Add these to the heat exhaustion symptoms:

  • Hallucinations, confusion, disorientation, or illogical behavior
  • High body temperature, red or pale skin, or difficulty breathing
  • Unconsciousness or coma

Seek immediate professional help for these symptoms.

Bacteria-carrying insects also thrive in hot weather. Lyme disease and West Nile Virus are not uncommon in many areas; prevention includes using mosquito deterrent and checking for ticks after outdoor work.

Long-term exposures include skin cancer. Wear protective clothing and use sunscreen on exposed skin.

Common sense goes a long way to prevent over-taxing workers. If a concrete pour is scheduled for an extremely hot day, postpone it — you'll spare your employees heat-related discomfort, and the odds of getting the concrete placed before it sets are low.

Remember your machine operators too. Check on them throughout the day and carefully observe their performance. Any signs of erratic behavior need to be addressed immediately, since even air-conditioned cabins can create dehydrating conditions in the hot sun. If your crew works in entertainment or live events, review Theatrical Producers Insurance for venue-specific considerations.

If you want your crew working on a Friday, supply plenty of water and shaded rest breaks Monday through Thursday; the body can only take so much heat. If you are unsure about risks or controls, talk to an agent.

Frequently Asked Questions

How much water should workers drink on hot days?

Workers should drink water regularly and be able to urinate every two to three hours; lack of urine is a practical sign of insufficient hydration.

What are the early signs of heat exhaustion?

Early signs include dizziness, nausea, muscle cramps, sudden weakness, headache, blurred vision, and unusual fatigue.

When should I call emergency services for a worker?

Call emergency services immediately if a worker loses consciousness, stops sweating, becomes confused or delirious, breathes rapidly, or has a very fast pulse.

How can I reduce insect-borne disease risk on the job?

Use insect repellent, remove standing water near work areas, and perform regular tick checks after outdoor work to reduce disease risk.

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