Heat stress happens when the body cannot cool itself fast enough. Early signs include heavy sweating, headache, dizziness and fatigue; confusion or collapse is a medical emergency.
Plan work for the cooler parts of the day, provide shaded rest areas and cool drinking water close to the work, and build regular rest breaks into the schedule. New and returning workers need time to acclimatise.
Supervisors should check on crews frequently, use a buddy system, and stop work when conditions exceed the site heat-stress plan. Anyone showing symptoms must be moved to shade, cooled and given first aid immediately.