Summer heat can be especially harmful for those who work outdoors in direct sunlight or in hot environments, making them susceptible to heat-induced illnesses such as heat stress, heat exhaustion or the more serious heat stroke, says the Occupational Safety and Health Administration.

"Working in extreme temperatures is not only uncomfortable, it can be life-threatening," said acting Assistant Secretary of Labor for OSHA Jordan Barab. "As we move into the summer months, it is important for workers and their employers to minimize the chances of heat-induced illnesses, and imperative that they recognize the signs of heat stress and take proper precautions to reduce the chances of illness or death."

High temperature and humidity, physical exertion and lack of sufficient water intake can lead to heat-related stress. Symptoms of heat exhaustion or heat stroke include confusion, irrational behavior, loss of consciousness, abnormally high body temperature and hot, dry skin. OSHA advises workers to take preventive measures such as reducing physical exertion and wearing light, loose-fitting clothing. The agency advises employers to provide workers with water and regular rest periods in a cool recovery area. OSHA offers fact sheets on protecting workers from heat effects; working outdoors; and sun protection.