Farm Pesticide May Be Linked to Cancer, Study SaysMay 6, 2003 | AP A federal study of 31,000 North Carolina farmers and their wives concludes that a widely used farm pesticide may increase the risk of prostate cancer in people exposed to it.
The study found that over a four-year period 14 percent more of the subjects developed prostate cancer than would be expected in the general population.
Of 45 pesticides evaluated, the study found possible connections to prostate cancer in seven of them, and methyl bromide was most widely linked to cancer.
Applied as a gas, methyl bromide is used before planting to kill insects, nematodes, weeds and pathogens.
Six other pesticides chlorpyrifos, coumaphos, fonofos, phorate, permethrin and butylate appeared to increase risks only among those with a family history of cancer.
Prostate cancer was the most common cancer in the late 1990s in North Carolina, with about 144 cases in 100,000 people, according to state health statistics.
"Obviously, we're concerned about these results," said Anne Coan, natural resources director of the N.C. Farm Bureau Federation.
Fewer North Carolina farmers now use methyl bromide to prepare soil for tobacco transplants, said Coan, who serves on a state advisory panel for the health study.
Millions of pounds of methyl bromide still are used each year, but it is being phased out of use worldwide because it depletes the protective ozone layer of the atmosphere.
Its use in developed nations, including the United States, is to end in 2005.
The United States has been prodded by North Carolina's strawberry, tobacco and pepper growers to ask the United Nations for exemptions to allow continued use of the chemical on a smaller scale. The request says there is no practical alternative.
"Methyl bromide is a heavy hitter and it's been on a lot of target lists for phase-out," said Fawn Pattison of the Agricultural Resources Center in Raleigh, which promotes alternatives to toxic pesticides. "We've been concerned about it both for health effects and ozone depletion."
The new report is part of the Agricultural Health Study and involves the National Cancer Institute, the National Institute of Environmental Health Sciences and the Environmental Protection Agency.
The study tracked more than 55,000 men in North Carolina and Iowa, most of them farmers, who apply pesticides. North Carolina was chosen because of its diversity of agriculture.
Between 1993 and 1999, 566 new prostate cancers developed among the 55,000 farmers, compared to the 495 predicted by its incidence rate in the two states.
The risk of cancer increased the more often farmers used methyl bromide, and the longer they were exposed to it over a lifetime, the report said. Officials said the findings would be confirmed if more cancers than normal continue to appear among study subjects.