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Heat Illness Prevention

Heat illness is a serious medical condition when heat exposure exceeds the physiological capacity of the body to cool itself, resulting in an increase in the core body temperature. This would result in a range of heat-related symptoms, from treatable heat cramps to heat stroke. Heat stroke can be fatal, especially if medical treatment is delayed.

Learn how to control the risk of heat-induced illness, train workers to protect themselves, recognize symptoms, and respond should a heat illness emergency occur.

UC Merced has developed a heat illness prevention program to plan for, prevent and respond to heat-related illness situations.

If you supervise employees who work outside in heat, you should know how to respond should a heat illness emergency occur.

Select a topic for more information:
     • Emergency response    
     • Identifying Heat Illness: Symptoms and First Aid
     • Reduce the risk
     • Regulations and policies
     • Risk factors
     • Safety training information
     • Supervisor’s responsibilities


Supervisor’s Responsibilities

Department Director/Chair Deans
     • Insure that Heat Illness Prevention Procedures Manual is implemented and available
     • Insure employees receive heat illness prevention training

     • Be aware of the risk factors that contribute to heat illness
     • Reduce the risk by taking special precautions to prevent heat illness
     • Be alert for the symptoms of serious heat illness
     • Train employees about heat illness risks and how to protect themselves
     • Know what to do and how to summon emergency responders should a heat illness emergency occur


Risk Factors

Personal Risk Factors
    • Age, weight, and physical condition
    • Acclimated to working in the heat
    • Consumption of water, alcohol and caffeine
    • Use of medications that affect tolerance to heat

Environmental Risk Factors
    • Air temperature and/or Relative Humidity
    • Direct exposure to the sun or heat sources
    • Limited air movement
    • Physical exertion and duration
    • Protective clothing and protective equipment worn by employees


Reduce the Risk

General Prevention
   • Rest in shaded or a cool, ventilated area
   • Stay hydrated
   • Avoid vigorous physical activities in hot and humid weather
   • At work, if you must perform physical activities in hot weather:
     - Drink plenty of fluids
     - Avoid alcohol, coffee and tea
     - Take frequent mini-breaks to hydrate yourself
     - As practical; wear hats, light colored and light/loose clothes


Identifying Heat Illness

Select an illness for information on definition, symptoms and first aid response/treatment options:

   • Heat Cramps
   • Heat Exhaustion
   • Heat Rash (prickly heat)
   • Heat Stroke
   • Transient Heat Fatigue



What is it? Heat cramps are painful spasms of the muscles.

Symptoms:  Heavy sweating and/or involuntary spasms

First Aid Response/Treatment:
      • Stop activity being performed, if not already
      • Find cool place to rest
      • Gently stretch cramped muscle
      • Drink water or an electrolyte beverage



What is it?  Heat exhaustion is characterized by loss of fluid from sweating when a worker fails to drink enough fluids.

      • Heavy sweating
      • Extreme thirst
      • Extreme weakness and fatigue
      • Giddiness, nausea, or headaches
      • Skin is cool, clammy and moist
      • Complexion is pale or flushed
      • Body temperature is normal or slightly higher

First Aid Response/Treatment:
      • Move victim into shade
      • Loose and remove clothing
      • Cool the victim (web cloth, spray mist)
      • Have victim slowly drink water
      • Elevate victim’s legs
      • Seek medical aid immediately if victim isn’t better

      * Caution: Persons with heart problems or with low sodium diet should consult a physician.



What is it?  Heat Rash or Prickly Heat is a skin condition caused by heat exposure or overheating

      • Small bumps or red/pink patches on skin
      • Large welts, hives or raised red bumps
      • Itching

First Aid Response/Treatment:
• Wash affected area with gentle soap
      • Rinse area with water and gently pat dry with towel
      • Remain in cool environment
      • Drink water
      • Use cortisone creams to treat rashes



What is it?  Heat stroke is the failure of the body's internal mechanism to regulate its core temperature.

    • Mental confusion, delirium, loss of concentration, convulsion or coma
   • Rapid pulse
   • A body temperature of 106° F or higher
   • Hot dry skin, which may be red, mottled or blush
   • Convulsions, seizures, unconsciousness, or death can occur

First Aid Response/Treatment:
   • Call for emergency help immediately
   • Move victim into shade
   • Loosen outer clothing
   • Lower body temperature (massage body with ice or damp cloth)
   • If victim is alert, have them slowly drink water or an electrolyte beverage, such as Gatorade

To print out hardcopy of full table with definitions, symptoms and first aid response/treatment options, click here.



What is it?  Transient Heat Fatigue is the temporary discomfort and mental or psychological strain

Symptoms:  Decline in task performance, coordination, alertness

First Aid Response/Treatment:
   • Drink fluids (water)
   • Rest in a cool environment



Emergency Response

When heat illness occurs:
   • Call 911 for emergency medical help
   • Tell the dispatcher this is a heat related illness
   • Notify your supervisor and contact UCM Worker’s Compensation, 877-6UC-RPRT (877-682-7778)
   • If an employee is hospitalized, notify the UCM Police dispatcher by calling 9-911 from a campus phone or 209-228-2677 (209-CAT-COPS) from cell phones


Regulations and policies

   • Heat Illness Prevention, California Code of Regulations, Title 8, Section 3395, Heat Illness Prevention


Safety training information

   • Heat-Related Illness Prevention and Information, Division of Occupational Safety and Health (DOSH)
   • To schedule group training, contact Environmental Health & Safety.