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Fatalities from Occupational Heat Exposure

Presented below are two of several fatalities from occupational heat stroke reported to the National Institute for Occupational Safety and Health (NIOSH) since 1977.

Indiana: In July 1980, a 24-year-old white male, who was employed at a surface coal mine, collapsed and later died after performing heavy labor in a hot environment. The worker, 5 feet 9 inches tall and weighing about 200 pounds, had been employed at the mine for 1H weeks. On the day of the reported incident, he was assigned to load 40-pound bags of explosives into vertically drilled holes in preparation for blasting the material overlying the coal seam. He began work at 6:00 a.m., and at 3:40 p.m., informed a co-worker that he did not feel well. He walked about 50 yards to a shady area and collapsed. The outdoor dry bulb temperature was 39.4 C (103 F).

The worker was moved to a nearby hospital where his rectal temperature registered 42.2 C (108 F). By the time he was transferred to the intensive care unit (ICU), his temperature exceeded 43.3 C (110 F). He was treated with an ice pack and intravenous fluids but died at 6:30 p.m. The autopsy report listed systemic hyperthermia with extreme generalized dilation of capillaries (cardiovascular shock) and cerebral edema as the immediate causes of death.

Wisconsin: In September 1981, a 39-year-old black male, 5 feet 7 inches tall and weighing 165 pounds, was employed as a furnace attendant at an aluminum foundry. He had worked at the foundry for 2 weeks and was responsible for turning on and attending a furnace used to melt aluminum. On the afternoon of the reported incident, he had pressed the wrong button and accidentally spilled molten aluminum on the floor. He spent about 15 minutes removing the spill and wore a silver reflective suit for protection against the radiant heat emanating from the metal. The outdoor dry bulb temperature was 28.3 C (83 F), and the worksite temperature was about 29.4 C (84 F); the estimated temperature of the molten aluminum in the furnace was 982.2 C (1,800 F).

After removing the spilled material, the worker described the accident to his supervisor and, still wearing the suit, left the workplace without explanation. He was discovered 15 minutes later having seizures in the foundry parking lot. Paramedics transported him to a hospital at 5:40 p.m.; on arrival, his body temperature was 41.7 C (107 F). Medication controlled the seizures, but he remained comatose. He was treated with rubbing alcohol and an ice pack, and at 7:00 p.m., when his body temperature was 35.6 C (96 F), he was placed on a hyperthermic machine in the ICU. He began bleeding from the rectum at 9:30 p.m., and fresh, frozen plasma was administered. The bleeding apparently stopped but then recurred with hematuria. He died the next day at 9:30 a.m. in cardiac arrest. The autopsy report listed the causes of death as hyperthermia, disseminated intravascular coagulation, and coronary arteriosclerosis.

The worker had a history of treatment for alcoholism and reportedly had been drinking heavily in the days before his death; however, at the time of hospitalization, he had no alcohol in his blood. Four days before the heatstroke, he had severely lacerated his toes in a lawnmower accident and was treated with antibiotics and tetanus toxoid. Reported by Div of Respiratory Disease Studies, Div of Biomedical and Behavioral Science, National Institute for Occupational Safety and Health, CDC.

Editorial Note

Editorial Note: Illness and death from environmental heat are important public health problems (1). This is especially true in the occupational setting when workers performing physical labor outdoors are exposed to higher-than-normal ambient temperatures and when such temperatures have an additive effect on heat generated by the jobs themselves. The fatalities reported here illustrate, in both outdoor and indoor settings, the circumstances that may lead to heatstroke and, subsequently, to death.

Occupational heat-related conditions include heat cramps, heat exhaustion, dehydration, and skin disorders. In addition, the risk of unintentional injuries increases substantially with exposure to heat stress (2). An estimated six million workers in the United States may be exposed to occupational heat stress. Estimates of deaths and illnesses associated with occupational heat exposures are difficult to obtain, because worksite conditions and occupation are usually not listed on hospital records or death certificates; moreover, heatstroke may not be recognized as the primary cause of illness or death. However, for 1973-1976, annual reports from the California Department of Health Services alone show seven fatalities among 1,128 acute occupational heat-related illnesses (3). About 10%-15% of these patients required hospitalization, and an additional 40% were absent from work for varying periods after their illnesses; the remainder returned to work after medical treatment.

The health status of a worker is important in determining the response to heat exposure (4). Certain preexisting conditions can render a person more susceptible to heatstroke; these include obesity, drug abuse, alcoholism, acute or chronic illnesses, fatigue, poor physical condition, overeating, use of anticholinergic and certain psychotropic drugs, lack of sleep, and lack of acclimatization (5). The first worker described here was moderately obese and in poor physical condition; the second had a history of treatment for alcoholism and may have been affected by the wound and the medication he received 4 days before his death.

In 1969, an international panel of scientists convened by the World Health Organization recommended keeping a worker's deep body temperature at or below 38 C (100.4 F) to prevent heat illnesses (6). In response to this, NIOSH developed in 1972 a Criteria Document for Occupational Exposure to Hot Environments, which recommended the following preventive measures (7): (1) acclimatizing new workers and workers returning from vacation or absence because of illness; (2) implementing a work/rest regimen matched to the severity of the workers' heat exposure. (The Threshold Limit Value for Heat Stress adopted by the American Conference of Governmental Industrial Hygienists can be used as a guide to establish a suitable work/rest regimen (8)); (3) scheduling hot operations for the coolest part of the day; (4) making drinking water and salt readily available to replace the water and salt lost by sweating; (5) making protective clothing available to workers, as appropriate; (6) reducing environmental heat by engineering controls; (7) monitoring environmental heat at the job site; (8) performing pre-employment and periodic medical examinations to define those at increased risk; and (9) instructing workers and supervisors about preventive measures and early recognition of the symptoms of heat-related disorders.


  1. CDC. Illness and death due to environmental heat--Georgia and St. Louis, Missouri, 1983. MMWR 1984;33:325-6.

  2. Ramsey JD, Burford CL, Beshir MY, Hensen RC. Effects of workplace thermal conditions on safe work behavior. Journal of Safety Research 1983;14:105-14.

  3. State of California, Department of Health, Occupational Health Branch. Occupational disease in California. Annual Reports 1973-1976.

  4. Dukes-Dobos FN. Hazards of heat exposure. A review. Scand J Work Environ Health 1981;7:73-83.

  5. Bartley JD. Heat stroke: is total prevention possible? Milit Med 1977;142:528,533-5.

  6. World Health Organization. Health factors involved in working under conditions of heat stress. WHO Technical Report Series 1969; no. 412.

  7. National Institute for Occupational Safety and Health criteria for a recommended standard. Occupational exposure to hot environments. Cincinnati: National Institute for Occupational Safety and Health 1972 (Document #HSM 72-10269).

  8. American Conference for Governmental Industrial Hygienists. TLV's Threshold Limit Values for chemical substances and physical agents in the work environment with intended changes for 1983-1984. Heat Stress 62-9.

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