Center for Biological Diversity

For Immediate Release, January 5, 2017

Contact: Nathan Donley, (971) 717-6406,

Public Records Sought on EPA's Sudden Reversal, Approval of Highly Toxic Pesticide

Enlist Duo Among Growing Number of Pesticides With Heightened Toxicity

PORTLAND, Ore.— The Center for Biological Diversity submitted a Freedom of Information Act request today seeking public records illuminating the Environmental Protection Agency's decision in November to suddenly expand its approval of the highly toxic pesticide Enlist Duo, despite an earlier decision to revoke approval after determining it was likely more harmful than first believed.

Specifically the Center is seeking information regarding four unpublished studies from the chemical giant Dow Agrosciences, the maker of Enlist Duo.

“The public has every right to know how the EPA decides which pesticides are sprayed on our land and our food,” said Nathan Donley, a senior scientist with the Center. “It's the EPA's job to ensure that people and wildlife are protected from toxic chemical mixtures like Enlist Duo, and we shouldn't be kept in the dark about how that work is carried out.”

The convoluted approval process came after the EPA backtracked on its initial 2014 approval of Enlist Duo when regulators belatedly discovered a Dow patent application indicating interaction between the pesticide's two components — glyphosate and 2,4 D — cause “synergy” that can greatly increase the pesticide's potential harm to nontarget species of plants, such as neighboring farmers' crops and endangered species.

After a court ordered the EPA to reconsider its approval of the pesticide, the agency reviewed the four unpublished studies from Dow and dramatically altered course, expanding its original approval of Enlist Duo from 15 states to 34 states and broadening its use beyond corn and soy to cotton.

“The EPA's about-face on Enlist Duo was very sudden and came only after it received a handful of unpublished studies on the pesticide from Dow,” Donley said. “This is extremely troubling because it suggests Dow's studies painted a completely different picture of the pesticide's potential toxicities than data the company submitted in earlier applications to another federal agency, the U.S. Patent and Trademark Office.”

Dow was pushing the EPA to fast-track approval of Enlist Duo to combat the superweed epidemic fueled by overuse of glyphosate. During research for comments to the EPA on the new pesticide, the Center found that in both of Dow's patent applications regarding 2,4-D and glyphosate, 99 out of 99 experimental conditions showed synergy — or heightened toxicity — between the two ingredients. Yet the four Dow studies that are at the heart of this new FOIA request somehow resulted in the EPA no longer believing there is synergy between glyphosate and 2,4-D.

“You don't get positive indications of harmful synergy in 99 of 99 cases unless the effect you're seeing is real,” said Donley. “It's unclear how a simple set of experiments later given to the EPA so easily contradicted such an extensive demonstration of synergy made to the patent office.”

Last year the Center released a groundbreaking report, Toxic Concoctions, finding that more than two-thirds of new pesticides registered in the past six years by the four major pesticide companies had patents demonstrating their new products' potentially harmful synergistic effects with other pesticides — effects the EPA failed to consider when approving the products. Prior to 2016 the agency had not considered patents showing pesticide synergy or incorporated the publically available patent information into their analyses of these new pesticides. The Center followed this report with a petition to the EPA asking that it require information on pesticide synergy to be included in pesticide-registration applications. The EPA has yet to act on that petition.

The Center for Biological Diversity is a national, nonprofit conservation organization with more than 1.1 million members and online activists dedicated to the protection of endangered species and wild places.

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