THURSDAY, June 19 (HealthDay News) -- Crop workers, most of them foreign-born, have the highest rate of death from heat-related illness, a new U.S. report released Thursday found.

From 1992 to 2006, 68 of the 423 workers in the United States who died from heat-related illness were involved in crop production, U.S. health officials said.

Their death rate is 0.39 per 100,000 people compared with 0.2 per 100,000 other workers, according to the U.S. Centers for Disease Control and Prevention (CDC).

"Heat-related deaths among crop workers were about 20 times higher than the rates for the general work force," Dawn Castillo, chief of the Surveillance and Field Investigations Branch in the Division of Safety Research at CDC's National Institute for Occupational Safety and Health, said during a midday teleconference Thursday.

"Such deaths are preventable," she added. "It is important to ensure that appropriate steps are taken to ensure that workers who toil to put food on our table are not placed at unnecessary risk."

Most of the workers who died from heat-related illness were foreign-born, Castillo added. "From 2003 to 2006, 71 percent of the crop workers who died of heat-related illness were foreign-born," she said.

"The high proportion of these deaths among foreign-born workers in recent years is striking and suggests a need to ensure that communications on the risk of heat-related illnesses be in workers' native languages," Castillo said.

By comparison, she added, 148 of the 423 workers who died from heat-related illness in the time period studied were in the construction industry, which represents 35 percent of all heat-related deaths in the United States.

Agriculture, forestry and fishing accounted for the next highest number of deaths, with 102, or 24 percent of total number, Castillo said.

But in terms of the rate at which workers in a certain occupation die from heat, crop workers appear to be at special risk, the researchers say. In fact, the rate of deaths for crop workers is 2.5 times greater than that of workers in the entire agricultural industry, 3.5 times greater than those in the construction industry and 20 times higher compared with all workers, Castillo added.

The report is published in the June 20 issue of the CDC's Morbidity and Mortality Weekly Report.

Heat-related illnesses range from minor problems such as heat cramps and rashes to serious problems such as heat exhaustion and heat stroke. In heat stroke, body temperature rises to a dangerous level. This can be deadly if medical care is not provided immediately.

People with heat stroke can have body temperatures of 103°F or more. The condition is also characterized by red hot and dry skin, with no sweating, rapid pulse, throbbing headache, dizziness, nausea, confusion and unconsciousness.

Crop workers can be at increased risk for heat stroke, because they often wear extra or protective clothing, along with equipment to protect them against pesticide poisoning or nicotine poisoning, the CDC reports.

To illustrate the point, the CDC reported the details of one case in particular.

A male Hispanic was harvesting tobacco in North Carolina in July 2005. The temperature that day reached 93°. In the afternoon, a little before 3 p.m., the man's son saw his father working slowly and advised him to rest. The man ignored the advice.

A short time later, other workers noticed that the man appeared confused. They carried him to shade and tried to get him to drink water. About 4:30 p.m., the man was taken by ambulance to the local emergency department, where his body temperature was recorded at 108°F.

He died, from what officials determined to be heatstroke.

Although the man had been given safety and health training on pesticides, there had been no training given on the dangers and prevention of heat-related illness.

To prevent heat-related deaths among crop workers requires educating both employees and employers of the dangers of working in hot weather. Such education should include recognizing symptoms of heat-related illness, and what to do should these symptoms occur, Castillo said

In addition, workers should be monitored for signs of heat-related illness and proper medical attention should be available, she added.

More information

For more information on heat-related illness, visit the U.S. Centers for Disease Control and Prevention.