Workers who are exposed to extreme cold or work in cold environments may be at risk of cold stress. Extreme cold weather is a dangerous situation that can bring on health emergencies in susceptible people, such as those without shelter, outdoor workers, and those who work in an area that is poorly insulated or without heat.

Cold stress refers to environmental conditions (e.g., air temperature/humidity, windchill temperature, rain, and inadequate clothing for protection) in which body heat is lost to the environment at a rate that is faster than the body can produce heat. Consult the US Customary Windchill Chart, an integration of air temperature and wind velocity, to provide an estimate of the cooling power of the environment. (Note that persons riding in open vehicles may be subjected to dangerous wind chills even when the natural wind velocity is low).

Cold strain refers to the physiological responses (e.g., attempts to compensate for body heat loss through vascular changes, increased metabolic production of heat, and shivering) involved in preventing or limiting body heat loss. Cold stress may progress to cold injury and illness. Cold injuries may include hypothermia, frostbite, redness, swelling, and cracking of exposed skin. As the victim becomes colder, they may experience muscle rigidity, reduced blood pressure, cardiovascular effects and a decrease in respiratory rate. Cold strain may also involve psychological impact to body heat loss, such as cognitive decline, poor judgment , and clouded consciousness.

Reference Regulations: OSHA Cold Stress Guide