Please enable javascript in your browser to view this site!

Heat Illness Prevention

Working in hot outdoor environments can result in heat illness and when left untreated, heat illness can rapidly lead to serious life-threatening situations.

To prevent heat illness, Company personnel, including maintenance and warehouse staff, along with their supervisors, must:

  • Understand the environmental and personal risk factors for heat illness.
  • Take the necessary preventative steps.
  • Recognize the early signs and symptoms of heat illness.
  • Know the Company’s established emergency response procedures for heat illness.

Basics of heat illness

Heat illness signs and symptoms

Early signs and symptoms of heat illness include:

  • Dehydration
  • Headache
  • Muscle cramps
  • Unusual fatigue

Heat illness may progress quickly to more serious illness (e.g. heat exhaustion and heat stroke). Symptoms include:

  • Cool, moist skin
  • Dizziness or lightheadedness
  • Nausea or vomiting
  • Fast heartbeat
  • Confusion or unusual behavior
  • Excessive sweating or red, hot, dry skin, and face
  • Convulsions or seizures
  • Fainting

If you notice signs or symptoms of heat illness, give first aid immediately, or follow emergency procedures. People with symptoms must not be sent home or left unattended without medical evaluation.

Risk factors


The main environmental risk factors for heat illness are:

  • Air temperature
  • Relative humidity
  • Radiant/conductive heat (from the sun and ground)
  • Air movement (safe when cooler than 95 degrees Fahrenheit)
  • Work intensity or duration
  • Clothing worn


The main personal risk factors for heat illness are:

  • Age
  • Degree of acclimatization
  • Medical conditions or use of prescription medicines (consult with personal physician)
  • Water consumption
  • Alcohol consumption
  • Caffeine consumption

Workplace emergency procedures

If any symptoms of serious illness are present, and trained personnel are not immediately available to make an assessment, call 911 immediately or if appropriate, transport the employee to:

University of Oklahoma Medical Center
Emergency Room
700 Northeast 13th Street
Oklahoma City, Oklahoma 73104
United States

When waiting for emergency help:

  • Move the person to a cool environment.
  • Loosen or remove excess clothing.
  • If the person is conscious and not nauseous, provide cool drinking water.
  • Fan and mist the person with water.
  • Apply a water-soaked towel (or an ice pack wrapped in a towel) to the head.
  • Apply ice packs (wrapped in a towel) to the armpits.
  • Wrap the person in a cooling blanket (if available).

Heat Illness Prevention Plan

Supervisors shall ensure that specific measures are taken to prevent heat illness amongst their staff.  These measures include:

Weather forecasts

Prior to assigning outdoor work during warm periods, supervisors shall check weather forecasts to assess the potential for heat-related stress or illness. View weather forecasts at:

Note that for unseasonably humid days, the heat load will be greater. For warmer periods, and especially during worker acclimatization, supervisors may:

  • Schedule outdoor work during cooler parts of the day.
  • Plan a staff rotation for strenuous work tasks as appropriate.
  • Encourage employees to maintain regular fluid intake.
  • Advise staff to wear lighter, loose-fitting clothing.
    • Include wide-brimmed hats if extended exposure to sunlight is expected.

Outdoor temperatures of 80 degrees Fahrenheit or warmer

  • Supervisors shall ensure that adequate shade is present at or near the work area for employees to take their rest/meal breaks.
  • Supervisors shall encourage employees to take a preventative cool-down rest when they feel it is needed to prevent overheating. Workers taking a cool-down rest may:
    • Be monitored for heat illness symptoms.
    • Take at least five minutes to rest in the shade or an air conditioned area.
    • Not be ordered back to work until any signs or symptoms of heat illness are gone.

Outdoor temperatures of 95 degrees Fahrenheit or warmer

  • Supervisor shall monitor employees for alertness and signs or symptoms of heat illness (either by direct supervision, a buddy system, phone communication, or other means).
  • Supervisor shall ensure that an adequate amount of cool drinking water is available and remind employees to drink plenty of water throughout the workday.

Supervisors, department or program managers, and/or Environmental Health and Safety (EH&S) may hold daily or weekly pre-shift meetings to remind workers of the required monitoring described above, including the need to drink plenty of water and the right to take cool-down rest breaks as needed.


The body needs a certain period of time to adjust to working in heat and humidity, especially when heavy physical exertion is required. Typically, people can adapt to significant increases in heat within 4 to 14 days of a progressively increasing workload. During this period additional cool-down rest breaks may permitted by a direct manager, especially with temperatures at or above 95 degrees Fahrenheit.


Heat Illness Prevention training shall include the general information described above, in a addition to department-specific procedures. Direct managers shall document local heat illness prevention procedures and these procedures shall be made available to employees in accordance with EH&S policies. Contact EH&S at for guidance on creating these procedures.

Have a question?