Heat

Heat-Related Illnesses and First Aid

Several heat-related illnesses can affect workers. Some of the symptoms are non-specific. This means that when a worker is performing physical labor in a warm environment, any unusual symptom can be a sign of overheating.

Heat-Related Illness	Symptoms and Signs
Heat stroke	Confusion Slurred speech Unconsciousness Seizures Heavy sweating or hot, dry skin Very high body temperature Rapid heart rate
Heat exhaustion	Fatigue Irritability Thirst Nausea or vomiting Dizziness or lightheadedness Heavy sweating Elevated body temperature or fast heart rate
Heat cramps	Muscle spasms or pain Usually in legs, arms, or trunk
Heat syncope	Fainting Dizziness
Heat rash	Clusters of red bumps on skin Often appears on neck, upper chest, and skin folds
Rhabdomyolysis (muscle breakdown)	Muscle pain Dark urine or reduced urine output Weakness

Employers and workers should become familiar with the heat symptoms. When any of these symptoms is present, promptly provide first aid. Do not try to diagnose which illness is occurring. Diagnosis is often difficult because symptoms of multiple heat-related illnesses can occur together. Time is of the essence. These conditions can worsen quickly and result in fatalities.

When in doubt, cool the worker and call 911.

See below for further first aid recommendations.

First Aid

OSHA’s Medical Services and First Aid standard and the Medical Service and First Aid in Construction require the ready availability of first aid personnel and equipment. First aid for heat-related illness involves the following principles:

Take the affected worker to a cooler area (e.g., shade or air conditioning).
Cool the worker immediately. Use active cooling techniques such as:
- Immerse the worker in cold water or an ice bath. Create the ice bath by placing all of the available ice into a large container with water, standard practice in sports. This is the best method to cool workers rapidly in an emergency.
- Remove outer layers of clothing, especially heavy protective clothing.
- Place ice or cold wet towels on the head, neck, trunk, armpits, and groin.
- Use fans to circulate air around the worker.
Never leave a worker with heat-related illness alone. The illness can rapidly become worse. Stay with the worker.
When in doubt, call 911!

Confusion, slurred speech, or unconsciousness are signs of heat stroke. When these types of symptoms are present, call 911 immediately and cool the worker with ice or cold water until help arrives.

Workers who are new to working in warm environments are at increased risk of heat-related illness. See the Protecting New Workers section of this website for more details. Especially during a worker's first few days, absolutely all symptoms should be taken seriously. Workers who develop symptoms should be allowed to stop working. They should receive evaluation for possible heat-related illness.