EPA Seeks to Vacate Dow Herbicide Registration

Turn to the nation's most objective and informative daily environmental news resource to learn how the United States and key players around the world are responding to the environmental...

By Pat Rizzuto

Nov. 25 — The Environmental Protection Agency is asking a federal appellate court to vacate and remand the agency's 2014 registration of Dow Agrosciences' Enlist Duo™ herbicide (Natural Res. Def. Council v. EPA, 9th Cir., No. 14-73353, motion filed 11/24/15).

“[Because] EPA is in receipt of new information regarding potential synergistic effects between the two ingredients [in Enlist Duo] on non-target plants, EPA seeks a voluntary remand in order to reconsider the Enlist Duo registration in light of the new information,” the agency said in a motion filed Nov. 24 with the U.S. Court of Appeals for the Ninth Circuit.

Claims Dow Agrosciences LLC made in a patent application for its Enlist Duo herbicide led the EPA to request the vacatur, the agency said.

The two active weed-killing ingredients in Enlist Duo—glyphosate and 2,4-D—“are more effective in combination than when applied individually,” Dow wrote in its patent application.

The EPA did not have the information about Enlist Duo's synergistic action when it assessed the risks of the herbicide, wrote Donald Brady, director of the EPA Pesticide Office's Environmental Fate and Effects Division, in a declaration filed with the vacatur motion.

New information the EPA has received from Dow after reading the claims the company made in its patent application suggest the herbicide may pose greater environmental risks than the agency previously realized, including risks to threatened or endangered species, it said.

Dow Confident in Herbicide's Safety

Dow AgroSciences issued a statement declaring itself “confident in the extensive data supporting Enlist Duo herbicide.”


“We are working with EPA to quickly provide further assurances that our product's conditions of registered use will continue to protect the environment, including threatened and endangered plant species,” Dow's statement continued.


“Recognizing the pressing needs of U.S. farmers for access to Enlist Duo to counter the rapidly increasing spread of resistant weeds—and in light of the comprehensive nature of the regulatory assessments already conducted to support the Enlist Duo registration—we expect that these new evaluations will result in a prompt resolution of all outstanding issues,” the statement said.


Tim Hassinger, Dow AgroSciences president and CEO, said in the statement, “We believe the questions that have been raised about any potential synergy between 2,4-D choline and glyphosate can be promptly resolved in the next few months, in time for the 2016 crop use season.”


Hassinger added, “It's possible that we could see some changes to use conditions on the existing Enlist Duo label. However, based on the ongoing dialogue with EPA, we do not expect these issues to result in the long-term cancellation of the Enlist Duo product registration. We continue to prepare for commercial sales of Enlist Duo for the 2016 growing season, with enthusiastic grower adoption.”


“EPA now has all of the data developed by Dow AgroSciences on observed potential synergies between 2,4-D choline and glyphosate in Enlist Duo,” Hassinger added. “From these data, EPA will readily see—after evaluating all of the efficacy data on the final formulation—why these data support the registration of Enlist Duo.”


The EPA registered the herbicide in 2014 for use on corn and soybeans in six states: Illinois, Indiana, Iowa, Ohio, South Dakota and Wisconsin (200 DEN A-14, 10/16/14)


On March 31 the EPA expanded the number of states where Enlist Duo could be used to include Arkansas, Kansas, Louisiana, Minnesota, Missouri, Mississippi, Nebraska, Oklahoma, and North Dakota.


Dow AgroSciences, a subsidiary of the Dow Chemical Co., announced its first U.S. sale of Enlist Duo on May 21.


The herbicide is designed to be used in tandem with genetically modified corn and soybean crops that Dow developed and were approved by the U.S. Department of Agriculture in 2014 (182 DEN A-4, 9/19/14).


The combination of the genetically engineered crops and herbicide allows farmers to spray Enlist Duo widely without fear of crop damage.


Greater Scrutiny Predicted for Biotech Herbicides

Andrew Kimbrell, an attorney with and executive director of the Center for Food Safety, an advocacy group, told Bloomberg BNA he doubts the agency will promptly resolve the issues. The center and the Natural Resources Defense Council have led the litigation challenging the EPA's registration of the herbicide.

The EPA's motion acknowledges the agency has important questions about a high-profile pesticide that Dow designed as the “next generation” solution in biotechnology, Kimbrell said.

The Monsanto Co. introduced the first generation in 1974 with glyphosate, sold under the name of Roundup®, along with Roundup Ready crops, he said.

Dow designed Enlist Duo along with corn, soybeans and cotton that are resistant to the herbicide to be the second generation biotech package, Kimbrell said. The agrochemical company has marketed Enlist Duo as a solution to weeds that have grown resistant to Roundup.

Monsanto already is working on the third generation product, an herbicide with glyphosate and dicamba, he said. However, EPA's motion puts a serious road block in these second- and third-generation products, Kimbrell told Bloomberg BNA.

“Whether it's a permanent road block or delay, we don't know,” Kimbrell said.

It should mean, at least, that these new types of herbicides with more than one active ingredient are going to get closer scrutiny by the agency, he said.

Next Steps

The NRDC issued a statement applauding the agency's motion, but criticizing the original registration.

Dow AgroSciences has until December 7 to respond to the agency's vacatur motion, the NRDC said.

The court would then decide whether to pull the herbicide from the market, it said.

Kimbrell said given the high-profile status of Enlist Duo, he expects the EPA to allow public comment on any future registration decision it may propose.

The EPA also will have to decide whether it would require Dow to take back herbicide stocks it already has sold, Kimbrell said.

The EPA said in an emailed statement that it expects to complete its review “in a timely manner.”

The agency said it could not discuss whether Dow would be subject to enforcement for failing to disclose the synergistic information to the agency.

Dow Aims at $1 Billion Revenue

Dow Agrosciences' 2014 annual report provides evidence of the importance it placed on Enlist Duo and its complementary crops.

Approximately 84 million acres of American farmland are infested with hard-to-control and resistant weeds that Enlist would address, it said.

Dow described its Enlist technology as a key catalyst for growth. “We expect this technology to lead Dow AgroSciences’ drive to $1 billion in incremental revenue from the sale of new products by 2018,” Dow wrote.

To contact the reporter on this story: Pat Rizzuto in Washington at prizzuto@bna.com

To contact the editor responsible for this story: Larry Pearl at lpearl@bna.com

For More Information


The EPA's vacatur motion is available at http://src.bna.com/bf2.



Dow Agrosciences' patent application is available at http://src.bna.com/bgp.


Request Environment & Energy Report