Heat stress is the net heat load on the body from the combined effect of hot environmental conditions (air temperature, radiant heat, humidity and air movement), internal body heat due to physical activity, and clothing requirements. Workplaces and occupations associated with excessive heat exposure include: foundries, steel mills, bakeries, construction sites, kitchens, grounds maintenance, dishwashing and steaming. Heat stress is largely preventable by engineering and administrative control methods. As a last resort or in extreme conditions, the use of personal protection is warranted. These measures include establishing procedures for acclimatization of new workers, training in safe work practices, reducing the duration of work in hot environments and providing plenty of drinking water. Workers and supervisors must receive adequate training and education to be able to recognize early symptoms of health disorders and seek timely medical help. Employers can prevent or minimize heat stress hazards by implementing appropriate policies and programs. A workplace heat stress policy must include clearly defined procedures for working safely in hot environments and for providing care to potential heat stroke victims.