Ninth Circuit Upholds EPA’s Approval of Enlist Duo Pesticide

On Wednesday the Ninth Circuit mostly upheld a decision by the Environmental Protection Agency (EPA) to register Enlist Duo—a pesticide to kill weeds on corn, soybeans, and cotton fields—in 2014, 2015, and 2017.  The panel ultimately held remand without vacatur was warranted, as the panel found the EPA’s error “in failing to consider harm to monarch butterflies caused by killing target milkweed was not ‘serious.’”

The three-judge panel consisted of Circuit Judges N. Randy Smith, Paul J. Watford, and Ryan D. Nelson.  Judge Nelson wrote the opinion and a concurrence, while Judge Watford wrote a dissent.  The petitioners, National Family Farm Coalition (NFFC); Family Farm Defenders; Beyond Pesticides; Center For Biological Diversity; Center For Food Safety; Pesticide Action Network North America, alleged the EPA’s decision violated the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) and the Engendered Species Act (ESA).

The opinion first noted the significance of corn, soybeans, and cotton as “three of the most important agricultural commodities in the United States.”  They added that “[d]omestically, these three crops together have a gross production value of approximately $103 billion per year.” 

The pesticide at issue, Enlist Duo, was invented by Dow Agrosciences LLC.  Enlist Duo combines two chemicals—2,4-dischlorophenoxyacetic acid (2,4-D), choline salt and glyphosate.  In the past, both 2,4-D and glyphosate have been registered for certain uses as weed killers in the past decades.  During studies to test Enlist Duo, the EPA found that the type of 2,4-D used “[was] less volatile than other forms of 2,4-D.”  Ultimately the EPA concluded, “Enlist Duo’s registration would ‘not generally cause unreasonable adverse effects on the environment’ under FIFRA and would comply with the ESA, subject to certain use restrictions.”

In reviewing the EPA’s compliance with FIFRA, the court held several of the petitioners’ arguments were non-persuasive and agreed with the EPA.  For example, NFFC argued the EPA incorrectly applied FIFRA’s “‘cause any unreasonable adverse effects’ unconditional registration standard in its 2017 registration decision rather than the ‘significantly increase the risk of any unreasonable adverse effect’ conditional registration standard.”  The EPA conceded that it “cited the wrong standard,” but asserted the error was “harmless” because the standard for unconditional registration is higher, not lower, than the standard for conditional registration.  The court agreed with the EPA. 

However, petitioners were successful in arguing the EPA failed to properly “assess harm to monarch butterflies from increased 2,4-D use on milkweed in target fields.”  Specifically, petitioners argued the EPA should have considered how the destruction of milkweed on target fields would affect monarch butterflies, and the court agreed this argument “carries some force.”  The EPA did not acknowledge or address those risks in its briefing.  This leads to evidence that the monarch butterflies could be “adversely affected” by Enlist Duo on target fields where it is used.  The EPA is required under FIFRA to determine whether any effect on the environment was “unreasonable.”  All of the petitioners’ other FIFRA arguments were denied.

Under the ESA, the petitioners first asserted that the EPA’s “no effect” findings for plants and animals in allowing use of Enlist Duo in permitted capacities was legally erroneous—the court disagreed.  The EPA used “risk quotients” and interpretative “levels of concern” developed as part of compliance with FIFRA, but applied much more conservative assumptions.  The court agreed once again with the EPA, stating “[t]his methodology applies the correct legal standard.” 

The petitioners also argued under the EPA’s ESA compliance, that its rationale for limiting the “action area” to the treated field where Enlist Duo would be used was “not sound.”  The court accorded deference to the EPA in the way it decided to define the action area because this requires the application of scientific methodology, which is within the EPA’s discretion.

The final argument under the ESA that petitioners made was that the EPA violated its duty to ensure no “adverse modification” of “critical habitat” by relying on its 2015 risk assessment.  However, the court held “[t]his methodology did not misapply the “may affect” standard as to critical habitats.”

The case was remanded without vacatur because although the EPA made an error by failing to consider harm to monarch butterflies caused by killing target milkweed, “it is not serious.”  Petitioners were represented by Center For Food Safety, while Respondent-Intervenor Dow was represented by Arent Fox, Kirkland & Ellis, Quinn Emanuel Urquhart & Sullivan, and Wiley Rein.  Several additional parties filed amicus briefs.