• Heat stress can occur within 15 minutes and is exacerbated by PPE, which traps body heat and moisture.
• Cold exposure can lead to frostbite and hypothermia and impair the ability to work.

Heat stress is a major hazard, especially for employees wearing protective clothing. The same protective materials that shield the body from chemical exposure also limit the dissipation of body heat and moisture. Personal protective equipment (PPE) and protective clothing can therefore create a hazardous condition.

Depending on the ambient conditions and the work being performed, heat stress can occur very rapidly — within as little as 15 minutes. It can pose as great a danger to employee health as chemical exposure can. In its early stages, heat stress can cause rashes, cramps, discomfort, and drowsiness, resulting in impaired functional ability that threatens the safety of both the individual employee and coworkers.

Continued heat stress can lead to heatstroke and death. Ways to protect against this hazard include:

• Avoiding overprotection,
• Careful training,
• Frequent monitoring of personnel who wear PPE,
• Judicious scheduling of work and rest periods, and
• Frequent replacement of fluids.

Cold exposure

Cold injury (frostbite and hypothermia) and impaired ability to work are dangers at low temperatures and when the wind-chill factor is low. Factors that guard against cold-exposure hazards include:

• Appropriate clothing;
• Warm shelter;
• Carefully scheduled work and rest periods; and
• Monitoring of employees’ physical conditions.

Please refer to the Heat and cold exposure subject for further information.