• Heat stress refers to heat-related illnesses that occur when the body can’t maintain a normal temperature.
• All employers with employees exposed to hot work environments must take steps to mitigate heat stress, as a hazard covered under the General Duty Clause of the OSH Act of 1970.

Heat stress can occur in both indoor and outdoor work settings. Indoor operations involving high air temperatures, radiant heat sources, heavy lifting and other strenuous physical activities, and direct physical contact with hot objects increase the potential for heat stress. Outdoor work during the hot summer months, especially activities that require workers to wear semipermeable or impermeable protective clothing, also increases the likelihood of heat stress.

What’s the standard number?

Heat exposure is covered under the Occupational Safety & Health (OSH) Act of 1970, Section 5(a)(1), known as the General Duty Clause. This requires employers to provide all of their employees with work and a workplace that are free from recognized hazards that are likely to cause death or serious harm.

Who must comply?

All employers with employees exposed to hot work environments must take steps to mitigate heat-related illness due to heat stress. The term heat stress is used to describe a number of heat-related illnesses that occur when the body is not able to maintain a normal temperature. Heat-related disorders include heat stroke, heat exhaustion, heat cramps, and heat rashes.

Key definitions

• Acclimatization means exposing the employee to the hot environment for progressively longer periods to allow the body to adapt.
• Administrative controls means reducing specific job hazards through changes in work procedures (e.g., written safety policies, schedule changes, training, and supervision).
• Conduction means the heat exchange between the heat and a surface.
• Convection means the exchange between the skin surface and the surrounding air.
• Engineering controls means reducing or eliminating specific job hazards through the use of or substitution of machinery or equipment (e.g., ventilation, air cooling, fans, shielding, and insulation).
• Fluid replacement means providing cool water to employees and encouraging them to drink small amounts frequently.