Heat-Related Deaths Among Crop Workers --- United States, 1992--2006

Workers employed in outdoor occupations such as farming are exposed to hot and humid environments that put them at risk for heat-related illness or death. This report describes one such death and summarizes heat-related fatalities among crop production workers in the United States during 1992--2006. During this 15-year period, 423 workers in agricultural and nonagricultural industries were reported to have died from exposure to environmental heat; 68 (16%) of these workers were engaged in crop production or support activities for crop production.

The heat-related average annual death rate for these crop workers was 0.39 per 100,000 workers, compared with 0.02 for all U.S. civilian workers. Data aggregated into 5-year periods indicated that heat-related death rates among crop workers might be increasing; however, trend analysis did not indicate a statistically significant increase. Prevention of heat-related deaths among crop workers requires educating employers and workers on the hazards of working in hot environments, including recognition of heat-related illness symptoms, and implementing appropriate heat stress management measures.

Case Report

In mid-July 2005, a male Hispanic worker with an H-2A work visa (i.e., a temporary, nonimmigrant foreign worker hired under contract to perform farm work) aged 56 years was hand-harvesting ripe tobacco leaves on a North Carolina farm. He had arrived from Mexico 4 days earlier and was on his third day on the job. The man began work at approximately 6:00 a.m. and took a short mid-morning break and a 90-minute lunch break. At approximately 2:45 p.m., the employer's son observed the man working slowly and reportedly instructed him to rest, but the man continued working. Shortly thereafter, the man's coworkers noticed that he appeared confused. Although the man was combative, his coworkers carried him to the shade and tried unsuccessfully to get him to drink water. At approximately 3:50 p.m., coworkers notified the employer of the man's condition. At 4:25 p.m., the man was taken by ambulance to an emergency department, where his core body temperature was recorded at 108°F (42°C) and, despite treatment, he died. The cause of death was heat stroke. On the day of the incident, the local high temperature was approximately 93°F (34°C) with 44% relative humidity and clear skies. The heat index was in the range of 86°--101°F (30°--38°C) at mid-morning and 97°--112°F (36°--44°C) at mid-afternoon.¶ Similar conditions had occurred during the preceding 2 days.

The man had been given safety and health training on pesticides but nothing that addressed the hazards and prevention of heat-related stress. He reportedly only spoke Spanish. Fluids, such as water and soda, were always available to the workers in the field; however, whether the man drank any of these fluids is unknown.

Heat-Related Fatalities, 1992--2006

During 1992--2006, a total of 423 worker deaths from exposure to environmental heat were reported in the United States, resulting in an average annual fatality rate of 0.02 deaths per 100,000 workers. Of these 423 deaths, 102 (24%) occurred in workers employed in the agriculture, forestry, fishing, and hunting industries (rate: 0.16 per 100,000 workers), and of these, 68 (67%) occurred in workers employed in the crop production or support activities for crop production sectors, resulting in an average annual fatality rate of 0.39 deaths per 100,000 crop workers (Table). Analysis of fatality rates by 5-year periods suggests an increase in rates over time; however, those rates were based on small numbers of deaths, and the increase over time was not statistically significant (Figure).

During 1992--2006, nearly all deceased crop workers were male,** and 78% were aged 20--54 years (Table). During 1992--2006, the birth country was unknown for 46% of the decedents; however, during 2003--2006, approximately 20 (71%) of the 28 deceased crop workers were from Mexico or Central and South America. Nearly 60% of all heat-related deaths among crop workers occurred in July, and most deaths occurred in the afternoon. Although 21 states reported heat-related deaths among crop workers, California, Florida, and North Carolina accounted for 57% of all deaths, with North Carolina having the highest annualized rate.

Reported by: RC Luginbuhl, MS, North Carolina Dept of Labor. LL Jackson, PhD, DN Castillo, MPH, Div of Safety Research, National Institute for Occupational Safety and Health; KA Loringer, ND, EIS Officer, CDC.

Editorial Note:

During 1992--2006, a total of 68 crop workers died from heat stroke, representing a rate nearly 20 times greater than for all U.S. civilian workers. The majority of these deaths were in adults aged 20--54 years, a population not typically considered to be at high risk for heat illnesses (3). In addition, the majority of these deaths were among foreign-born workers.

Persons who work outside in hot and humid conditions are at risk for heat-related mortality and morbidity. Heat-related illnesses range from minor heat cramps or rash to heat exhaustion, which is more serious and can lead to heat stroke, which can result in death if medical attention is not provided immediately. Heat stroke is characterized by a body temperature of >103°F (>39°C); red, hot, and dry skin (with no sweating); rapid, strong pulse; throbbing headache; dizziness; nausea; confusion; and unconsciousness. Crop workers might be at increased risk for heat stroke because they often wear extra clothing and personal protective equipment to protect against pesticide poisoning or green tobacco illness (transdermal nicotine poisoning). Employers and workers must be aware that heat-related illness, which can have symptoms similar to pesticide poisoning and green tobacco illness, requires immediate attention. The high proportion of heat-related deaths among foreign-born workers indicates that training and communications regarding the risk for heat-related illnesses should be provided in the workers' native language.