On December 7, 2020, eleven states filed a brief with the Ninth Circuit Court of Appeals, opposing a request from the Environmental Protection Agency (“EPA”) to keep the registration for sulfoxaflor in place while the agency comes into compliance with Endangered Species Act (“ESA”) requirements. This move is the latest development in on-going litigation over sulfoxaflor, an insecticide that was first registered for use by the EPA in 2013. The current lawsuit, challenging the current 2019 sulfoxaflor registration, argues that EPA violated both FIFRA and the ESA. EPA has asked that the registration be sent back to the agency for review, but several parties oppose that request, including the eleven states.

Background on Sulfoxaflor

Sulfoxaflor is a member of a new class of pesticide known as sulfoximines which are extremely effective against sap-feeding insects, including those which have grown resistant to other pesticides. EPA notes that sulfoxaflor has been useful in combating both aphids and tarnished plant bugs.

In 2013, EPA registered two sulfoxaflor products manufactured by Dow AgroSciences LLC (“DOW”) for use under FIFRA. According to FIFRA, EPA may only register a pesticide if doing so will not cause “unreasonable adverse effects on the environment.” 7 U.S.C. § 136a(c)(5)(c). After EPA registered the two sulfoxaflor products in 2013, a coalition of beekeeper’s associations filed suit, alleging that EPA had violated FIFRA by registering sulfoxaflor without showing that use of the pesticide would not cause unreasonable adverse effects. Specifically, the plaintiffs in Pollinator Stewardship Council v. U.S. Envtl. Prot. Agency, 806 F.3d 520 (9th Cir. 2015) argued that although EPA had initially proposed to conditionally register sulfoxaflor while reviewing additional studies on the pesticide’s effects on honeybees, the agency instead unconditionally registered sulfoxaflor without obtaining any further studies. In other words, the plaintiffs argued that EPA had originally planned to register sulfoxaflor temporarily while it acquired additional data to better assess the pesticide’s impact to honeybees, but instead registered sulfoxaflor permanently without any additional data in violation of the agency’s duty under FIFRA to ensure that registered pesticides will not adversely affect the environment.

The Ninth Circuit agreed with the plaintiffs in the 2015 case, concluding that EPA’s decision to unconditionally register sulfoxaflor was not supported by substantial evidence. Accordingly, the court vacated the registration, and remanded the issued back to EPA so the agency could obtain further data on the effects of sulfoxaflor on bees.

EPA once again registered sulfoxaflor for use in 2016. The 2016 registration allowed for fewer uses of sulfoxaflor than the 2013 registration, and provided additional requirements for the protection of bees. Those protections included limiting use of sulfoxaflor to crops that are not attractive to pollinators, and only allowing application of sulfoxaflor post bloom on crops that could attract pollinators. However, in 2019, EPA expanded sulfoxaflor’s registration to allow use of the pesticide on a variety of crops that attract pollinators, including citrus, soybeans, strawberries, and pineapples. EPA also removed the restriction that sulfoxaflor could only be applied after the target crop had bloomed.

Following the 2019 decision to expand the use of sulfoxaflor, several environmental groups and beekeeper’s associations filed suit. The parties who had filed the lawsuit challenging the 2013 registration of sulfoxaflor came together to challenge the 2019 registration of sulfoxaflor. To read more about that lawsuit, click HERE. However, those parties were not the only ones to challenge the decision. The Center for Food Safety and the Center for Biological Diversity filed their own lawsuit in the Ninth Circuit alleging that the 2019 registration decision violated both FIFRA and the Endangered Species Act (“ESA”). According to the plaintiffs in that lawsuit, not only had EPA violated FIFRA by failing to present substantial evidence showing that the 2019 registration would not adversely affect the environment, the agency had also failed to engage in mandatory ESA consultation on the impacts that registering sulfoxaflor may have on endangered species.

The 2019 Lawsuit & Recent Developments

In response to the plaintiffs’ allegations in Ctr. for Food Safety v. Wheeler, No. 19-72109 (9th Cir. 2019), EPA acknowledged that it had violated the ESA. Under the ESA, federal agencies have a duty to ensure, in consultation with Fish and Wildlife Service (“FWS”) or the National Marine Fisheries Service (“NMFS”) that “any action authorized, funded, or carried out by such agency […] is not likely to jeopardize the continued existence of any endangered species[.]” 16 U.S.C. § 1536(a)(2). Accordingly, if a federal agency determines that an action it is carrying out “may affect” a listed species, it is required to consult with FWS or NMFS on whether the proposed agency action is likely to jeopardize the existence of an endangered species. 50 C.F.R. § 402.14.

In a motion filed with the court, EPA acknowledged that it had failed to determine what effects the 2019 registration of sulfoxaflor would have on endangered species in violation of ESA requirements. EPA requested that the court remand the issue back to the agency so that it could come into compliance with the ESA. Additionally, EPA asked that the court not vacate the 2019 sulfoxaflor registration while EPA worked to satisfy its ESA obligations. In other words, EPA asked that the court to issue an order sending the registration back to EPA for ESA compliance, while allowing the registration to remain in place so that sulfoxaflor could continue to be used while EPA determines its effects on endangered species.

Several parties, including eleven states, have filed motions opposing EPA’s request to remand the issue while keeping the 2019 registration decision in place. The group of states, including California, Hawaii, Maryland, Massachusetts, Minnesota, New Jersey, New York, New Mexico, Oregon, Vermont, and Washington, argue that remanding the issue back to EPA would deprive the plaintiffs of the opportunity to have their FIFRA claims heard. According to the states, sending the registration decision back to EPA for ESA compliance would prevent the plaintiffs from presenting their arguments that EPA had violated FIFRA as well as the ESA to the court. Additionally, the states argue that resolving the matter in the court system would be more efficient than remanding it back to EPA because of EPA’s own acknowledgement that an agency backlog would prevent EPA from beginning work on ESA compliance until 2025. The states argue that in the meantime, sulfoxaflor will remain registered and legal to use despite its registration being in violation of the ESA. In their brief, the states urged the court to issue a ruling vacating the 2019 sulfoxaflor registration.

Going Forward

The brief filed by the group of states in Ctr. for Food Safety v. Wheeler is an amicus curiae brief. Such briefs are typically persuasive documents filed by nonparties to a case who nevertheless have an interest in the outcome. While the purpose of an amicus curiae brief is to help the court make a decision, it is up to the court whether to consider the brief or not. Therefore, it is up to the Ninth Circuit to decide how persuasive the argument presented by the states is. However, the plaintiffs in the case have also filed a motion requesting that the court not send the issue back to EPA. The plaintiffs make many of the same arguments as the states, claiming that sending the decision back to EPA would deprive the plaintiffs of their right to be heard in court.

At the moment, the court has yet to decide whether to send the 2019 sulfoxaflor registration back to EPA for review. If the court grants EPA’s request, then the litigation would be stopped while EPA brings the registration into ESA compliance. Should EPA’s full request be met, then sulfoxaflor would remain registered and legal to use during that time. However, if the court sides with the plaintiffs and the states then litigation of the issue would continue and could potentially result in the 2019 sulfoxaflor decision being vacated.


To read the brief filed by the states, click here.

To read the initial petition for review in Ctr. for Food Safety v. Wheeler, click here.

To read the 2019 sulfoxaflor registration decision, click here.

To read the court’s decision in Pollinator Stewardship Council v. U.S. Envtl. Prot. Agency, click here.

For additional National Agricultural Law Center resources on pesticides, click here.