Summary

Why is it important to prevent heat illness?

• Heat illness can be a matter of life and death. Workers die from heat stroke every summer and every death is preventable.
• When heat stroke doesn’t kill immediately, it can shut down major body organs causing acute heart, liver, kidney and muscle damage, nervous system problems, and blood disorders.
• Having a serious injury or death occur at work affects everyone at a worksite.
• Workers suffering from heat exhaustion are at greater risk for accidents, since they are less alert and can be confused.

Although heat hazards are common in indoor and outdoor work environments, heat-related illness and fatalities are preventable. Many risk factors contribute to the risk for heat-related illness. A heat-related illness occurs when there is an increase in the worker’s core body temperature above healthy levels. As core temperature rises, the body is less able to perform normal functions. As core temperature continues to increase, the body releases inflammatory agents associated with damage to the liver and muscles. This process may become self-sustaining and generate a run-away inflammatory response, the “systemic inflammatory response” syndrome that often leads to death.

The terms heat stress and heat strain represent the relationship and difference between external factors and the body’s core temperature control mechanisms:

Heat Stress – The net heat load to which a worker is exposed. Physical exertion, environmental factors, and clothing worn all contribute to heat stress.

Heat Strain – The body’s physiological response to heat stress (e.g., sweating).

The body’s natural way to keep the core body temperature from rising to unhealthy levels is through an increase in heart rate and sweating. When these are not enough to keep the core body temperature from rising, the result is heat-related illness or death. Elevated core body temperatures may cause the following illnesses:

• Heat Stroke
• Heat Exhaustion
• Heat Cramps
• Heat Syncope
• Heat Rash

Outdoor workers who are exposed to hot and humid conditions are at risk of heat-related illness. The risk of heat-related illness becomes greater as the weather gets hotter and more humid.

Heat-related illness can be prevented.

OSHA does not have a specific standard that covers working in hot environments. Nonetheless, under the OSH Act, employers have a duty to protect workers from recognized serious hazards in the workplace, including heat-related hazards.