Sep 14, 2007

EPA Rules 2,4-D Herbicide Doesn’t Lead to Cancer

More than 20 years after the controversy began, EPA has determined that the herbicide 2,4-D does not cause cancer in people. It announced its decision Aug. 8.

The cheap and easy to manufacture herbicide, which kills many broadleaved weeds without injuring grasses, was invented in the 1940s and is considered the first chemical herbicide. It is widely used worldwide on grain crops and by homeowners to control weeds in lawns. It also is used in orchards and vineyards and in vegetable production.

“This notice announces EPA’s decision not to initiate a special review for 2,4-D, 2,4-DB and 2,4-DP,” according to the EPA announcement. “Based on extensive scientific review of many epidemiology and animal studies, the agency finds that the weight of the evidence does not support a conclusion that 2,4-D, 2,4-DB and 2,4-DP are likely human carcinogens. The agency has determined that the existing data do not support a conclusion that links human cancer to 2,4-D exposure.”

During the 1980s, 2,4-D came under a cloud of suspicion when studies in Kansas and Nebraska reported a possible link between farmers who applied 2,4-D to wheat fields and non-Hodgkin’s lymphoma. The link was not confirmed by other studies, but EPA has been looking closely at the herbicide since 1986.

The Industry Task Force II on 2,4-D Research Data was formed in 1988 to fund research studies to respond to EPA’s need for data in the re-registration process.

That task force reviewed more than 300 studies and concluded that 2,4-D and related compounds does not cause cancer, genetic damage or birth defects. The task force report says 2,4-D is “less toxic than caffeine and slightly more toxic than aspirin.”

The acid formulation of 2,4-D is, however, irritating to the skin, more so than the ester formulation and – just as with aspirin and caffeine – 2,4-D poisoning can occur.

Symptoms of poisoning with chlorophenoxy compounds include irritation to skin, eyes and respiratory tract, a burning sensation in the chest, coughing, headache, dizziness, vomiting, diarrhea, confusion, bizarre or aggressive behavior, increased heart rate, metabolic acidosis and kidney failure.

The EPA decision should provide mental relief to farmers – and to homeowners whose families enjoy weed-free yards because of 2,4-D.