Preventing Heat Illness in Employees

The following article was first published in the CONN-OSHA Quarterly. It is reposted here with permission. 

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Heat is a recognized occupational hazard for outdoor and indoor workers that can cause serious or fatal illness when they are not provided with the necessary protection and training.

Thousands of workers every year become sick from occupational heat exposure, with some resulting in fatalities.

Heat is the leading cause of death among all weather-related deaths in the United States.

New employees whose bodies have not had time to adjust to working in the heat are most vulnerable.

Nearly three out of four workers who die from heat-related causes die in their first week on the job.

What is Heat Illness?

When outdoor and indoor temperatures increase, a person’s core body temperature may rise.

The body regulates temperature by sweating and increasing its heart rate, to help keep the body’s core temperature from rising to dangerous levels.

Heat illness can occur when these mechanisms cannot keep the core body temperature from rising.

There are several types of heat illness, with some being more severe than others.

There are several types of heat illness, with some being more severe than others.

• Heat rash often occurs on the neck, upper chest, and skin folds. It is characterized by red bumps on the skin.
• Heat syncope causes fainting and dizziness.
• Heat cramps, which often occur in the legs, arms, and stomach, are painful muscle spasms.
• Heat exhaustion symptoms include nausea and/or vomiting, dizziness, weakness, excessive sweating, irritability, thirst, and elevated body temperature.
• Heat stroke is a medical emergency and symptoms include confusion, slurred speech, unconsciousness, seizures, heavy sweating or hot, dry skin, very high body temperature, and rapid heart rate.

What Contributes to Heat Illness?

There are environmental factors that can contribute to heat illness including ambient air temperature, humidity, radiant heat from the sun, and air velocity.

Occupational risk factors include temperature and humidity in the work environment, time spent near heat sources, and direct sunlight encountered in the work environment.

Occupational risk factors include temperature and humidity, time spent near heat sources, and direct sunlight.

Other occupational risk factors include the physical exertion or workload required, being unaccustomed to or not used to working in the heat, and the clothing and or personal protective equipment being worn.

There are also personal risk factors that can contribute to heat illness.

These include the use of certain medications, such as antihistamines and diuretics; physical characteristics of the worker including age and fitness level; health conditions such as obesity, heart disease, high blood pressure, or diabetes; and recent alcohol or drug use.

How Can Employers Prevent Heat Illness?

Employers can take certain steps to prevent heat illness.

These include ensuring that workers take breaks in the shade or in a cooler location, drink water (1 cup every 15 minutes), reduce physical demands during hot weather, and wear hats and loose-fitting, light-colored clothing if possible.

Workers should be allowed to acclimatize to working in hot environments.

Workers should be encouraged to monitor themselves and others for signs of heat illness and take appropriate action.

In addition, workers should be encouraged to monitor themselves and others for signs of heat illness and take appropriate action if anyone begins experiencing symptoms.

Engineering controls can also help prevent heat illness.

Examples of engineering controls include the use of air conditioning in construction equipment cabs, cooling fans, local exhaust ventilation, and insulation of hot surfaces.

What Is Federal OSHA Doing to Prevent Heat Illness?

In April of 2022, OSHA initiated a National Emphasis Program on heat and continues to focus enforcement efforts in geographic areas and industries with the most vulnerable workers.

In July 2024, OSHA published a proposed rule for Heat Injury and Illness Prevention in Outdoor and Indoor Work Settings that would require employers to create a plan to evaluate and control heat hazards in their workplace.

This rule would require employers to develop and implement a heat injury and illness prevention plan, identify heat hazards for each work site, implement control methods when the worksite is at or above a heat index of 80 degrees, implement additional controls when the worksite is at or above heat index of 90 degrees, take steps if employee experiences signs and symptoms of heat illness, and develop a response plan, and provide training to employees.

Written Heat Illness Prevention Plan

Your written plan should address how you will:

1. Designate someone to oversee the heat illness prevention plan
2. Provide training on your heat illness prevention plan
3. Acclimatize workers
4. Modify work schedules to reduce exposures
5. Allow frequent rest breaks in shaded areas
6. Identify heat hazards
7. Check the temperature before work
8. Monitor for heat illness symptoms (including a buddy system)
9. Designate a break area and encourage hydration
10. Have workers dress for heat
11. Be prepared for an emergency

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About the author: Marigrace Riley is an occupational hygienist with the state of Connecticut.