The Natural Resources Defense Council filed a petition Monday asking the EPA to take the chemical off the market, charging its leading manufacturer did not properly disclose that 17 workers had developed prostate cancer. The group also said the chemical had been linked to deformities in frogs.
The petition also asks that the Environmental Protection Agency and Justice Department investigate the manufacturer, Swiss-based Syngenta, the world's biggest agribusiness. The company's North American headquarters is in Greensboro, N.C.
The EPA has been drafting new rules for the use of atrazine, one of the nation's most widely used herbicides, and is expected to issue any changes by late summer.
After the chemical is sprayed onto crops and grass, it can enter the food chain through rainwater, snow runoff and groundwater. EPA rules permit up to 3 parts per billion of atrazine in drinking water.
The resources council contends new research shows the chemical – already banned in France, Germany and Italy – is more dangerous than previously thought and is unfit for public use.
The petition maintained that reports from the manufacturer last year on the result of a prostate-cancer screening program for employees at its plant in St. Gabriel, La., demonstrate that the weedkiller should be taken off the market.
The group also cited research made public in April from the University of California, Berkeley, that showed as many as 20 percent of male frogs exposed to very low doses of atrazine can develop multiple sex organs or both male and female organs. Many had small, feminized larynxes.
The researchers concluded the effects resulted from atrazine's causing cells to produce the enzyme aromatase, which is present in vertebrates and converts the male hormone testosterone to the female hormone estrogen. It happened from doses as small as 0.1 part per billion.
The NRDC also said the EPA's risk assessment for atrazine violates the agency's own policy because it relies partly on "an unlawful and unethical experiment in which human volunteers were intentionally exposed to atrazine."
Syngenta spokeswoman Sherry Duvall said the NRDC was misusing preliminary data on frogs to draw insupportable and "outrageous" conclusions, needlessly alarming the public with exaggerated claims about the cancer risk and making a "desperate, ill-conceived attempt" to discredit the EPA's review process for pesticides.
"In all cases, Syngenta has been completely forthcoming with information on atrazine to employees and to EPA as it became available," she said. "Farmers have relied on atrazine for 40 years as an effective weed-control tool in corn and for conservation tillage."