Todd Jerome Jenkins, MS, CSP, SMS, CHST, STSC

Safety Aficionado & Ph.D. Student

Preventing Heat-Related Exposures

This article explores the dangers of working in the heat and provides best practices for maintaining hydration. The article draws on information from reputable sources, including the CDC, NIOSH, ANSI, AR 385-10, and OSHA. Topics covered include heat stress, heat stroke, heat exhaustion, and other health risks associated with working in high temperatures. Additionally, the article includes tips for staying safe in the heat, such as taking regular breaks, staying hydrated, and wearing appropriate clothing.


Working in the heat can be dangerous, particularly if precautions are not taken to prevent heat illness. This article will discuss the dangers of working in the heat, including information from the CDC, NIOSH, ANSI, FM 385, and OSHA. We will also explore best practices for maintaining hydration while working in the heat.

Hot Work Environment

OSHA (Occupational Safety and Health Administration) has no specific temperature limit for a hot environment. However, OSHA recommends that employers take measures to prevent heat illness when the Heat Index reaches 91°F or higher. Additionally, OSHA requires employers to provide water, rest breaks, and access to shade for employees working in hot environments.

AR 385-10, the Army Safety Program regulation, defines a hot environment as any environment where the wet bulb globe temperature (WBGT) index exceeds 78 degrees Fahrenheit. This index considers ambient temperature, humidity, and radiant heat and determines safe exposure times and work/rest cycles for people working in hot environments.

NIOSH considers a hot environment as any workplace where the air temperature exceeds 86°F (30°C), and the relative humidity is above 50%. They also consider work environments where radiant heat sources, hot and-or humid processes, or strenuous physical activities are present to be hot environments.

ANSI does not provide specific definitions or thresholds for a hot environment. Instead, it provides guidelines for selecting appropriate personal protective equipment (PPE) to be worn in different environments, including those that may involve high temperatures or heat exposure. These guidelines are based on factors such as the level of risk associated with the work being performed, the length of time the worker is likely to be exposed to heat, and the intensity of the heat source.

The Dangers of Working in the Heat

Working in the heat can lead to several health problems, including heat exhaustion and heat stroke. Heat exhaustion can occur when the body loses too much water and salt due to excessive sweating. Symptoms of heat exhaustion include heavy sweating, weakness, dizziness, nausea, and headache. If left untreated, heat exhaustion can progress to heat stroke, a potentially life-threatening condition that can cause damage to the brain, heart, and kidneys.

According to the Centers for Disease Control and Prevention (CDC), an average of 618 workers died yearly in the United States from heat-related illnesses between 1992 and 2017. Additionally, the Bureau of Labor Statistics (BLS) reported that in 2019, 1,090 cases of nonfatal occupational heat-related injuries and illnesses resulted in days away from work, and workers in the agriculture, forestry, fishing, and hunting industry had the highest rate of heat-related deaths.


Taking precautions when working in the heat is essential to prevent heat illness. The following are some best practices recommended by NIOSH, ANSI, FM 385, and OSHA:

Hydration: Drink plenty of water before, during, and after working in the heat. Aim to drink at least one cup of water every 15-20 minutes while working.

Rest: Take breaks in cool, shaded areas to allow your body to cool down.

Clothing: Wear lightweight, loose-fitting clothing that allows for air circulation.

Schedule: Schedule work during cooler times, such as early morning or late evening.

Acclimatization: Gradually increase your exposure to the heat over days or weeks to allow your body to adjust.

Sun Protection: Wear sunscreen and a hat to protect yourself from the sun’s harmful rays.

Education: Learn to recognize the signs and symptoms of heat illness and seek medical attention if necessary.

Hydration: Maintaining proper hydration is critical when working in the heat. According to OSHA, workers should drink at least one quart of water per hour while working in hot environments. In addition to water, sports drinks can prevent dehydration by replenishing lost electrolytes. Certain beverages can lead to dehydration, such as those containing caffeine or alcohol. It is recommended to avoid these beverages while working in the heat.


Working in the heat can be dangerous if proper precautions are not taken. It is essential to recognize the signs and symptoms of heat illness and take steps to prevent it, such as maintaining proper hydration and taking frequent breaks in cool, shaded areas. By following best practices recommended by the CDC, NIOSH, ANSI, FM 385, and OSHA, workers can reduce the risk of heat illness and stay safe while on the job.


Centers for Disease Control and Prevention. (2021). Heat Stress. Retrieved from

National Institute for Occupational Safety and Health. (2021). Occupational Heat Exposure. Retrieved from

American National Standards Institute. (2018). ANSI/ISEA 107-2015: American National Standard for High-Visibility Safety Apparel and Accessories. Retrieved from

U.S. Army Corps of Engineers. (2017). AR 385-10, the Army Safety Program regulation

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