Occupational Heat Exposure - Continued 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: 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. Occupational Heat Exposure - Continued 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. References 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. Current Trends Tuberculosis - United States, 1983 In 1983, 23,846 cases of tuberculosis were reported to CDC, for a rate of 10.2 cases per 100,000 population. Compared with 1982, this represents a 6.6% decrease in the number of cases reported and a decline of 7.3% in the rate. Rates for the 50 states ranged from 23.1/100,000 in Hawaii to 1.3/100,000 in North Dakota (Table 3). The rate increased in 13 states, remained unchanged in one, and decreased in 36. The rate among persons living in 56 cities with populations of 250,000 or more was 21.2/100,000-more than twice the national rate (Table 4). Urban rates ranged from 58.4/100,000 in Miami, Florida, to 2.5/100,000 in Toledo, Ohio. Eight cities had rates at least three times the national rate: Miami, Florida; Newark, New Jersey; Atlanta, Georgia; San Francisco, California; Tampa, Florida; Honolulu, Hawaii; Washington, D.C.; and Oakland, California. Tuberculosis - Continued TABLE 4. Tuberculosis cases and rates: cities with populations of 250,000 or more United States, 1983 and 1982 Tuberculosis - Continued In 1983, 1,360 tuberculosis cases were reported among children under 15 years of age, including 818 cases among children less than 5 years of age; in 1982, there were 1,349 and 789 such cases, respectively. Final tuberculosis mortality data for 1981 show 1,937 deaths. Compared with the final totals of 2,007 and 1,978 deaths in 1979 and 1980 and the 1982 provisional estimate of 1,980 deaths by the National Center for Health Statistics, there was essentially no change in tuberculosis mortality over the 4-year period 1979-1982. Reported by Div of Tuberculosis Control, Center for Prevention Svcs, CDC. Editorial Note: From 1968 through 1978, the average annual decrease in tuberculosis cases in the United States was 5.6%. From 1978 through 1981, when there was a large influx of Southeast Asian refugees, the average annual decline was only 1.4%. A 6.8% decrease in the number of cases in 1982 and the 6.6% decrease in 1983 indicate the previous downward trend has resumed. Three factors may have contributed to the decreased number of tuberculosis cases reported in 1983: (1) There was an increase in the number of states using the new individual case reporting system, which requires more accurate verification of cases before they are counted; (2) the number of refugees arriving in the United States with tuberculosis declined; and (3) the number of indigenous tuberculosis cases may have actually declined. Despite the decline in reported cases in 1983, tuberculosis persists as a public health problem. Transmission of infection continues, as evidenced by the continued occurrence and lack of decline of disease in young children. Tuberculosis mortality has not declined; moreover, in 1980, tuberculosis was the leading cause of death among 38 notifiable diseases for which mortality data were reported (1). The number of tuberculosis deaths that year exceeded the combined total of deaths for the other 37 notifiable diseases. It is estimated that more than 10 million persons in this country are infected with tubercle bacilli. They have a lifelong risk of developing disease, which can be minimized by giving preventive treatment. Additional cases will occur in new residents of this country who come from areas of the world where tuberculosis infection rates are much higher than in the United States. Unless otherwise contraindicated, these persons should receive a course of preventive therapy (2). State and local health departments are responsible for ensuring the control of tuberculosis in the community. It is estimated that 40,000 persons on health department registers are currently under treatment or medical supervision for tuberculosis and that each year, approximately 200,000 persons exposed to new cases must be examined. Many of these persons are placed on preventive treatment. Tuberculosis control has been complicated by the global emergence of organisms resistant to antituberculous drugs (3). Community outbreaks continue to occur in the United States (4,5). References 1. CDC. Annual summary 1982: reported morbidity and mortality in the United States. MMWR 1983;31:148. 2. American Thoracic Society/Centers for Disease Control (ATS/CDC). Treatment of tuberculosis and other mycobacterial diseases. Am Rev Respir Dis 1983;127:790-6. 3. Kleeberg HH, Boshoff MS. A world atlas of initial drug resistance. Tuberculosis Research Institute of the South African Medical Research Council, Pretoria, South Africa, 1980. 4. CDC. Interstate outbreak of drug-resistant tuberculosis involving children-California, Montana, Nevada, Utah. MMWR 1983;32:516-8. 5. Silverman PR. An outbreak of tuberculosis in southern Delaware: the meaning of surveillance and containment. Del Med J 1984;56:156-8. |