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Heat-Related Illness Safety and Training Resources

This document provides an overview of heat-related illnesses and the resources available to reduce the risk of heat stress.

Agriculture, construction, and landscaping are all outdoor industries where, according to the Occupational Safety and Health Administration (OSHA), workers have suffered heat-related illnesses. To maintain a healthy body temperature in warm environments, the body relies on its ability to dissipate heat naturally through sweating and increased blood flow to the skin.  When the body is unable to dissipate heat quickly enough, the body’s internal temperature will continue to rise which may result in a heat-related illness. 

Heat related illnesses include: 

Heat Rash 

Excessive sweating during hot, humid weather can cause skin irritation. This irritation is known as heat rash.        

Symptoms of heat rash include:

  • Clusters of red bumps on skin
  • Can appear anywhere on the body including the neck, upper chest, and skin folds


  • When possible, try to work in a cooler, less humid environment
  • Keep the affected area dry


Heat Cramps 

Individuals who sweat a lot during strenuous activity are usually affected by heat cramps. Heavy sweating depletes the body's salt and moisture levels which causes painful cramps. 

Symptoms of heat cramps include:

  • Muscle cramps, pain or spasms in the abdomen, arms, or legs


  • Go to a cool location
  • Remove excess clothing
  • Drink water and a carbohydrate-electrolyte replacement liquid (sports drinks) every 15 to 20 minutes
  • Seek medical attention if cramps last more than an hour

Heat Syncope

Heat syncope is a fainting episode or dizziness. Heat syncope usually occurs with prolonged standing or sudden rising from a sitting or lying position. Dehydration and lack of acclimatization are factors that may contribute to heat syncope. 

Symptoms of heat syncope include:

  • Light-headedness
  • Dizziness
  • Fainting 


  • Sit or lie down in a cool place
  • Slowly drink water, clear juice, or a sports beverage


Heat Exhaustion

Heat exhaustion occurs when there is an excessive loss of water and salt, usually through excessive sweating, in the body. During heat exhaustion, the body can no longer keep blood flowing to supply vital organs and at the same time send blood to the skin to reduce body temperature.  

Symptoms of heat exhaustion include:

  • Rapid heart rate
  • Fatigue
  • Irritability
  • Thirst
  • Nausea 
  • Dizziness 
  • Heavy sweating
  • Elevated body temperature

Heat exhaustion treatment:

  • Call 911 and seek medical attention immediately
  • Remove employee from hot area
  • Provide liquids to drink
  • Remove unnecessary clothing
  • Have the employee wash their head, face, and neck with cold water


Heat Stroke

Heat stroke occurs when the body is unable to control its temperature. During a heat stroke, the body's temperature rises rapidly, the sweating mechanism fails, and the body is unable to cool down. 

Symptoms of heat stroke include:

  • Confusion
  • Unconsciousness
  • Red, hot, and dry skin 
  • Lack of sweating
  • Very high body temperature
  • Rapid heart rate

Heat stroke treatment:           

  • Call 911
  • Move worker to a shaded and cool area
  • Remove excess clothing and apply cold water to the body


To Prevent Heat-Related Illnesses:

  • Allow employees to acclimate to higher temperatures. According to OSHA, most outdoor fatalities (50-70%) occur within the first few days of working in a hot environment. This is due to the body’s need to gradually acclimatize to the heat. 
  • Encourage employees to frequently drink small amounts of water to stay hydrated. 
  • Schedule frequent rest periods with water breaks in shaded or cool areas. 
  • Ensure employees are aware of the signs of heat-related illnesses. 
  • Wear light-colored, loose fitting clothing and a hat to reduce exposure to the sun. 
  • Monitor weather reports daily and if possible, reschedule jobs with high heat exposure to cooler times of the day. 


Determining the Heat Index and Protective Measures: 

The heat index is a system that combines the air temperature and relative humidity to determine the apparent temperature or what the temperature feels like to the body. To determine protective measures for outside workers based on the heat index, OSHA developed the table shown below. By clicking on the links in the Risk Level column, you will be directed to a webpage that describes the precautions to take with each risk level. In addition to the table below, OSHA and the National Institute for Occupational Safety and Health (NIOSH) created the Heat Safety Tool phone app that will also provide information on the heat index and protective measures. 


Heat Index

Risk Level

Protective Measures

Less than 91°F

Lower (Caution)

Basic heat safety and planning

91°F to 103°F


Implement precautions and heighten awareness

103°F to 115°F


Additional precautions to protect workers

Greater than 115°F

Very High to Extreme

Triggers even more aggressive protective measures


Employees should be trained on how to recognize heat-related illnesses, what to do in the event someone is experiencing symptoms of a heat-related illness, and how to prevent heat-related illness. Training should be conducted prior to working in hot environments. To access heat stress safety training, click on the link below. 

CALS Heat Stress Safety Training


Additional Resources: 

OSHA Safety and Health Topics: Heat

OSHA Heat Index

OSHA Quick Card: Protecting Workers from Heat Stress

OSHA Fact Sheet: Protecting Workers from the Effects of Heat

Keywordsheat, stress, illness   Doc ID101692
OwnerNick G.GroupCALS Safety & Health Resources
Created2020-05-05 08:03:00Updated2020-05-05 08:08:09
SitesCALS Safety & Health Resources
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