Education is paramount when dealing with high-temperature working conditions.

This chart outlines some of the health ailments excessive heat can cause.


According to the National Oceanic and Atmospheric Administration, heat is the number one weather-related killer in the United States resulting in hundreds of fatalities each year.

In fact, on average, excessive heat claims more lives each year than floods, lightning, tornadoes and hurricanes combined. It is the responsibility of every employer to ensure employees are kept safe during high heat conditions.

So, what is considered a high heat situation and what should we do about it? According to the National Weather Service, extreme caution must be taken when the heat index exceeds 90°F. The heat index is a measure of how hot it feels when relative humidity is added to the actual air temperature. A temperature of 90°F with 10% humidity will result in a heat index of 85°F, but with 60% humidity the heat index rises to 100°F.

Why is the heat index important? Our bodies dissipate heat by varying the rate and depth of blood circulation by losing water through the skin and sweat glands, and as a last resort, by panting when blood is heated above 98.6°F. Sweating cools the body through evaporation. However, high relative humidity retards evaporation, robbing the body of its ability to cool itself. When heat gain exceeds the level the body can remove, body temperature begins to rise and heat-related illnesses and disorders may develop.  OSHA has developed a mobile app that calculates heat index and offers reminders of protective measures for workers. It is available at

Heat cramps are painful muscle spasms generally in the legs and abdomen that are related to dehydration. Heat exhaustion occurs when a person is “overheating” and cannot sweat enough to cool the body. Symptoms can include profuse sweating, clammy skin, thready pulse, headache, dizziness, nausea and mood changes. Immediate treatment through cooling and hydration is necessary to prevent progression to heat stroke, the most severe of heat-related ailments. A heat stroke is a medical emergency and can lead to death even with aggressive treatment. Symptoms generally include hot, dry skin, no sweating, bright red or flushed skin, rapid and strong pulse, irritability, confusion or unresponsiveness.

OSHA has initiated a campaign to prevent heat illnesses in outdoor workers. The campaign is based upon three simple words: water, rest and shade. The principals of this campaign can be applied to any worker who must work in hot weather in a space that is not air conditioned. The primary concern is providing adequate cool water for a person to drink, teaching signs of dehydration (urine is dark and of a smaller quantity) and allowing sufficient break time for employees to obtain water and rest in a shaded or cool spot.

Other simple steps can be taken to protect workers including allowing employees to wear short pants and short-sleeved shirts to work, putting large paper cups next to the water source, moving the workday earlier to take advantage of cooler temperatures, or to schedule strenuous activities earlier in the day.  

Above all, it is critical for management to monitor the heat index and respond to that vital information.  Supervisors and employees need to be educated on how to best manage high heat situations and how to recognize the symptoms of and treatment for heat-related ailments.

A toolbox talk to facilitate this educational process is available at