The Environmental Protection Agency said Wednesday that it will re-evaluate the health effects of a popular weed killer that has been found in drinking water supplies in the United States.
The EPA will take another look at the science on atrazine, a herbicide commonly used on corn and other crops, and decide whether further restrictions are needed to protect human health. Research has shown that runoff after rainstorms can wash the chemical into streams and rivers, where it can enter drinking water supplies.
EPA monitoring of 150 drinking water systems in the American Midwest, where the chemical is used most heavily, have not detected it at concentrations that would trigger health problems, including cancer. But new studies have shown that even at low levels atrazine in drinking water can cause low birth weights, birth defects and reproductive problems.
In 2003, under the George W. Bush administration, the EPA allowed the continued use of atrazine with few restrictions.
"We are taking a hard look at the decision made by the previous administration on atrazine," said Steve Owens, an assistant administrator, in a statement released Wednesday. "Our examination of atrazine will ... help determine whether a change in EPA's regulatory position on this pesticide is appropriate."
Environmentalists on Wednesday hoped the new review would lead to the chemical being phased out.
"The hope is that they will decide at the end of the day that they should be regulating it more stringently, or they will just take if off the market," said Mae Wu, an attorney with the Natural Resources Defense Council. The NRDC sued the EPA in 2003 for failing to evaluate adequately atrazine's effects on endangered species.
More recently, operators of drinking water systems in six Midwestern states sued manufacturers, seeking reimbursement for the cost of removing the chemical from their water supplies.
Calls to the Swiss company Syngenta, the largest manufacturer of atrazine, were not immediately returned.