Heat Illness in the Workplace

Working outside in the heat

Along with rising summer temperatures comes the risk of heat illnesses in workplaces across the country. Many of us have heard the terms “heat stroke” and “heat exhaustion” thrown around when the weather’s warm, but do you really know the difference and how to identify these illnesses?

Do you know if your workers are at risk and how to prevent these dangerous health situations in the first place? Let’s take a look at the basics of heat illnesses, as well as how to prepare your workplace for the hot summer months.

Workers at Risk for Heat Illnesses

Heat is just part of a typical summer day at many worksites, and it’s easy to assume workers will be fine, especially in climates where heat is present much of the year. Between 2008 and 2013, however, more than 100 heat-related fatalities occurred in the U.S. at worksites under OSHA jurisdiction.1 Therefore these summer hazards should not be taken lightly.

hot weather
Hot, humid weather can lead to high heat indexes. Photo: OSHA

Workers in many industries are at risk for heat illnesses, and these problems are most common in construction, agriculture, grounds maintenance, transportation, utilities and landscaping, according to OSHA. The Centers for Disease Control and Prevention (CDC) also reports that certain indoor jobs can get very hot and potentially dangerous, too.

These jobs include positions in bakeries, factories, boiler rooms and firefighting. In these workplaces heat sources like ovens or machinery can add to the already warm environment.

Managers also need to know about the situational factors that can contribute to heat illnesses including environmental issues and the employees themselves.

OSHA and the National Institute of Occupational Safety and Health (NIOSH) published a list of factors that put workers at risk for heat illnesses. Their list includes:

  • High temperatures
  • High level of humidity
  • Radiant heat sources (like ovens, furnaces)
  • Poor air movement
  • Physical labor
  • Not enough liquid consumption
  • Heavy PPE

In addition to these circumstances of the job site, certain employees may also be more susceptible to heat illnesses including workers in poor physical health, taking certain medications, 65 years of age or older and those who haven’t been exposed to hot temperatures recently (this could include new workers, temporary workers or workers who have been away from the worksite for more than a week due to illness or vacation).

Types of Heat Illnesses

Heat illnesses occur when the body cannot maintain its normal temperature. Not all heat illnesses are the same, though, and some are much more serious than others. Knowing how to identify each illness and how to respond to it is critical to avoiding a life-threatening situation.

Heat Stroke

Heat stroke, the most severe heat illness, occurs when the body loses control of its temperature regulation. A person suffering from heat stroke can have his or her body temperature rise to 106 degrees or higher as quickly as 10 minutes after heat stroke begins. Heat stroke is a highly dangerous situation, and you need to call 911 immediately.

heat stroke
Photo: OSHA

According to the CDC, a person suffering from heat stroke may experience either hot, dry skin or excessive sweating. Other symptoms include chills, headache, confusion, hallucinations, dizziness and slurred speech.

While waiting for medical personnel to arrive, try to cool the person off in any way possible. Get to a shady spot, then spray or shower the person with water, fan his body and apply cold compresses.

Heat Exhaustion

While slightly less serious than heat stroke, heat exhaustion is still a very concerning health problem. It occurs when the body sweats a lot and loses water and salt, which is often a common occurrence when employees are working in hot environments.

Managers and employees should keep an eye out for workers who feel weak, dizzy and nauseated or who have clammy skin, pale or flushed skin, shallow breathing or muscle cramps.

The same general first aid applies to heat exhaustion as to heat stroke, so get workers experiencing these symptoms out of the sun, try to cool them down and have them drink lots of water.

Heat Cramps

Heat cramps are common when doing physical work in the heat, and they happen when the body sweats out water and salt. If a worker is having muscle cramps, have him or her drink water and eat a snack. Sports drinks can also help reduce lost salt and fluids.

Heat Syncope

Some workers exposed to heat may faint, which is called heat syncope. Symptoms to watch out for before a fainting episode include dizziness and light-headedness. If someone does faint, have the person lie down in the shade and drink liquids.

Heat Rashes

The most prevalent heat illness is heat rash, which is when a cluster of red bumps or blisters appears on the skin. This can be caused by sweating and by wearing clothing that isn’t breathable. The best treatment for heat rash is to keep the area dry and to move out of the heat if possible. 

Other Risks Associated with Heat

Heat illnesses should be the primary focus in hot work environments, but safety managers and workers should also keep in mind that heat can lead to other related accidents. For example, safety glasses can fog up and hands can get sweaty in hot weather, which could cause a worker to not see a hazard or to drop a heavy object. In many hot, outdoor environments, sunburn is a real problem, too.

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Heat Illness Prevention

Managers and employees need to be aware of heat illnesses and their symptoms so anyone affected by these illnesses can receive prompt treatment. Make sure all employees are trained so they recognize symptoms in themselves and in others. Some workplaces even set up a buddy system so employees can check on each other during hot weather.

In 2011, OSHA began a campaign to raise awareness about heat illnesses, and their motto is “Water. Rest. Shade.” These three things should be emphasized at all hot worksites. Employees doing moderate activity in hot conditions should be drinking a cup of water every 15 to 20 minutes, according to OSHA. That may sound like a lot, but when workers are constantly sweating, those fluids really do need to be replaced.

Workers should also feel comfortable about taking regular breaks in the shade. Sometimes workers feel like taking breaks will make them look lazy, but in the heat, work performance and health can suffer if employees don’t rest frequently.

Additionally, new workers or workers not accustomed to the heat should be given time to acclimate. Allow them to gradually increase their workload over a week or so.


Extra precautions should be taken in outdoor work environments during hot weather. Whenever possible, try to schedule physically demanding tasks for early in the day when temperatures are cooler. Safety managers can also monitor weather reports or use OSHA’s heat safety smartphone tool that helps calculate heat indexes and recommends precautions. 


At indoor worksites, safety managers should consider whether the building is set up for maximum ventilation. Air conditioning, fans and windows should be used appropriately to prevent employees from getting overheated.

Additional Reminders for Workers

Safety managers must do everything in their power to keep the jobsite safe during warm months. They should also encourage their employees to properly prepare for the heat, too, even when they’re not at work. Remind employees to drink plenty of water at home so they stay hydrated.

Also inform them that caffeinated or alcoholic beverages can actually contribute to dehydration. Suggest employees also wear light-colored, breathable clothing to work and use sunscreen when appropriate.

Adjusting workplace practices to prevent heat illnesses is often necessary when it’s hot outside, but by keeping everyone in the workplace informed of how to prevent, recognize and deal with these problems, your workplace can stay safe and efficient.

1 Additional fatalities occurred at workplaces that did not fall under OSHA jurisdiction. Workers and workplaces not included under OSHA jurisdiction include family farms that only employ immediate family members, the self-employed and some public sector workers.


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