Heat stress in hazardous waste workers: evaluation and prevention.

The risk of heat stress for hazardous waste workers is high due to the unique aspects of their work, particularly the use of vapor-barrier clothing. Such garments interfere with one of the body's principal mechanisms for dissipating heat, that is, evaporative cooling. Under such conditions the body's heat load rapidly increases and heat-related illness may occur. The medical surveillance examination is an important tool for identifying those workers with risk factors for developing heat stress or underlying diseases that may be exacerbated by heat strain. Further testing to determine fitness for duty, e.g., exercise stress testing, needs to be individualized with respect to the patient's specific work situation and/or clinical status. Appropriate medically related recommendations regarding an individual's ability to perform hazardous waste work can then be determined by the examining physician. Finally, preventive strategies, such as training, physiological and environmental monitoring in the field, judicious scheduling of work and rest periods, appropriate hydration, and use of cooling equipment and canopies, are available and should be employed to reduce the occurrence of heat-related illness in hazardous waste workers.