|E.P.A. Denies an Environmental Group’s Request to Ban a Widely Used Weed Killer
The Environmental Protection Agency
on Monday said that the widely used herbicide 2,4-D would remain on the
market, denying a petition from an environmental group that sought to
revoke the chemical’s approval.
The E.P.A. said that the environmental group, the Natural Resources Defense Council, had not adequately shown that 2,4-D would be harmful under the conditions in which it is used.
“At best, N.R.D.C. is asking E.P.A. to take a revised look at the
toxicity of 2,4-D,” the E.P.A. said in its decision, which was posted on its Web site.
“Yet the ground for tolerance revocation is a lack of safety.”
First approved in the late 1940s, 2,4-D is one of the most widely used
weed killers in the world. It is an ingredient of numerous home
lawn-care products, and it is used by farmers.
Dow Chemical is thought to be the major manufacturer, though the E.P.A.
has also approved versions from Nufarm, an Australian company, and
Agro-Gor, a joint venture of PBI/Gordon of Kansas City, Mo., and Atanor
Use of the chemical is expected to grow substantially in the coming
years because Dow is seeking federal approval to sell seeds of corn
genetically engineered to be resistant to 2,4-D.
Farmers planting that corn would be able to spray 2,4-D on their fields
to kill weeds without hurting the crop. Now, 2,4-D is not used much on
corn, the nation’s most widely grown crop.
The council filed its petition in 2008 asking that the registration of
the herbicide, as well as the permissible residue levels on various
foods, be revoked. In February, it sued the E.P.A., saying the agency
had not acted on the petition fast enough.
The group cited various studies suggesting that exposure to 2,4-D could
cause cancer, hormone disruption, genetic mutations and neurotoxicity.
It also said the E.P.A., in previous assessments, had underestimated how
much people, especially children, might be exposed to the chemical
through dust, breast milk and skin contact.
In its ruling, the E.P.A. said that while some studies cited suggested
that high doses of the chemical could be harmful, they did not establish
lack of safety, and in some cases they were contradicted by other
The agency in particular cited a study, financed by the 2,4-D
manufacturers and conducted by Dow, in which the chemical was put into
the feed of rats. The study did not show reproductive problems in the
rats or problems in their offspring that might be expected if 2,4-D were
disrupting hormone activity, the E.P.A. said.
James W. Gray, executive director of the industry task force that sponsored the study, hailed Monday’s decision.
“E.P.A. has done a thorough job in evaluating all the evaluable data and found no cause for concern,” he said.
Mae Wu, a lawyer with the council, said the group was “disappointed that
it has taken this long to deny our petition” and also “disappointed
that they are not protecting public health by getting this toxic
chemical off the market.” She said it was too soon to say what the
group’s next step would be, though it will have the right to object to
The E.P.A. has reviewed the safety of 2,4-D several times, particularly with regard to an increased risk of cancer.
Some studies have shown a higher risk of non-Hodgkin’s lymphoma among
farmers who use the chemical. But E.P.A. reviewers have said the farmers
might have been exposed to many things, making it difficult to state
that 2,4-D was the cause.
After reviewing the data, the agency renewed the registration for 2,4-D
in 2005. In 2007, it declined to conduct a special review of the cancer
risk, saying that it had “determined that the existing data do not
support a conclusion that links human cancer to 2,4-D exposure.”
2,4-D was an ingredient of Agent Orange, a defoliant used in the Vietnam
War that is said to have harmed many Vietnamese civilians and American
soldiers. Most experts say the main health problems came from
contamination of 2,4,5-T, the other major ingredient in Agent Orange.
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