The United States Court of Appeals for the District of Columbia recently issued an order vacating an action from Environmental Protection Agency (“EPA”) allowing the use of the pesticide aldicarb on orange and grapefruit trees in Florida. Although aldicarb has not been registered for use on citrus for nearly a decade, EPA approved its use earlier this year to help farmers in Florida combat citrus greening disease. The registration prompted a coalition of environmental and farm worker groups to file suit, arguing that the registration decision should be set aside because EPA had failed to comply with the Endangered Species Act (“ESA”). Ultimately, the court agreed and vacated the registration.

Background on Aldicarb

Aldicarb is a carbamate insecticide that was originally registered for use on food crops, including citrus, in 1970. It is effective against a variety of pests, including aphids and spider mites, and has also been used as a nematicide. However, aldicarb is also a known neurotoxin that can have negative impacts to humans at high enough doses. In 1981, EPA reclassified aldicarb as a restricted use pesticide, meaning that EPA found that it had the potential to cause unreasonable adverse effects to the environment and injury to applicators or bystanders without added use restrictions. Only certified pesticide applicators or persons supervised by certified pesticide applicators may use restricted use pesticides. In 1984, EPA put aldicarb under Special Review.

The Pesticide Special Review process is used by EPA when the agency believes that use of a registered pesticide may result in unreasonable adverse effects to people or the environment. Typically, the process will involve in-depth review of no more than a few potential risks. During the review, EPA will evaluate existing data, acquire new information, assess the identified risks, and develop suitable risk mitigation measures. When placing aldicarb under Special Review, EPA cited concerns regarding ground water contamination as the risk the agency had identified. The review process can take years. Aldicarb was still under Special Review in 2007 when EPA re-registered it for use. Under the Federal Insecticide, Fungicide, and Rodenticide Act (“FIFRA”), federally registered pesticides must go through a re-registration process every 15 years in order to ensure that continued use of the pesticide will not cause unreasonable adverse effects on the environment. In completing the 2007 re-registration decision, EPA identified both potential human health risks and potential environmental risks involving harm to wildlife that were associated with aldicarb use. However, EPA determined that aldicarb was eligible for re-registration provided additional risk mitigation measures were adopted. Those new measures included increased set-backs from drinking water wells, application rate reductions, and termination of certain uses.

In 2010, Bayer CropScience (“Bayer”), the then registrant of aldicarb, moved to voluntarily cancel aldicarb’s registration. In other words, Bayer asked EPA to de-register aldicarb under FIFRA meaning that use of the pesticide would no longer be legal. Bayer’s move to cancel the aldicarb registration came days after EPA had released a revised acute dietary exposure and risk assessment for aldicarb. In that assessment, EPA concluded that the current levels of exposure of aldicarb through food and drinking water exceeded the Agency’s level of concern for both infants and children ages 1-5. The assessment found that risk of exposure through citrus was particularly high. Because a pesticide registrant is not required to state why it is seeking voluntary cancellation of a pesticide, it is not clear whether the findings from EPA influenced Bayer’s decision to cancel aldicarb’s registration. Whatever the reason, EPA accepted Bayer’s voluntary cancellation of aldicarb for all uses, including use on citrus.

However, aldicarb was not unavailable for long. The year after Bayer moved to cancel its registration of aldicarb, another pesticide manufacturer, AgLogic, Inc. (“AgLogic”) applied to EPA to register uses of aldicarb under FIFRA. In 2011, EPA approved AgLogic’s application and registered aldicarb for a variety of uses, but not for use on citrus. AgLogic would not seek to register aldicarb for use on citrus until 2019.

Lead Up to Lawsuit

For over a decade, the state of Florida has been impacted by citrus green disease, a bacteria that affects a variety of citrus trees including oranges. The disease is spread by an insect known as the Asian citrus psyllid that has proven difficult to control with currently registered pesticides. On January 12, 2021, EPA approved aldicarb for use on citrus in Florida. In 2019, Ag Logic applied to register aldicarb for use on oranges and grapefruit in Florida for the purpose of fighting the Asian citrus psyllid in order to prevent citrus greening disease. EPA accepted the application, limiting the use of aldicarb to the orange growing season (November 15 – April 30), and adding application restrictions such as limiting the application area to 100,000 acres, and imposing setback requirements to protect drinking water wells.

The registration immediately drew criticism from both environmental and farm worker groups, and a lawsuit challenging the decision soon followed.

Plaintiffs’ Complaint & Court’s Decision

The plaintiffs in Farmworker Ass’n of FL v. Envtl. Protection Agency, No. 21-1079 (D.C. Cir. 2021) filed suit in March, 2021 to challenge EPA’s approval for use of aldicarb on citrus trees in Florida. Specifically, the plaintiffs asked the court to vacate the registration decision. Essentially, the plaintiffs asked the court to set aside EPA’s decision so that aldicarb would no longer be federally registered to use on citrus in Florida. According to the plaintiffs, vacatur was appropriate because EPA had violated both the ESA and FIFRA.

In their motion requesting vacatur of EPA’s registration decision, the plaintiffs argue that the Agency violated the ESA by failing to consult with the United States Fish and Wildlife Service (“FWS”) on the effects that registering aldicarb for use on citrus in Florida would have on endangered species. Under the ESA, all federal agencies are required to consult with FWS to ensure that “any action authorized, funded, or carried out by such agency […] is not likely to jeopardize the continued existence of any endangered species or threated species or result in the destruction or adverse modification of [critical] habitat[.]” 16 U.S.C. § 1536(a)(2). However, not every action authorized by a federal agency poses a threat to endangered species. The ESA’s regulations make it clear that need for an agency to consult with FWS is triggered only if the agency concludes that its action “may affect” an endangered or threatened species. 50 C.F.R. § 402.14.

Here, the plaintiffs argue that EPA had concluded that the 2021 registration decision “may cause acute and chronic risks for birds, reptiles, amphibians, birds, and mammals.” According to the plaintiffs, this finding was enough to trigger the ESA’s consultation requirement. Because EPA failed to carry out that requirement before finalizing its decision, the 2021 registration decision violates the ESA.

Next, the plaintiffs allege that the 2021 registration decision violates FIFRA. Under FIFRA, EPA may only register a pesticide for a specific use if it determines that the proposed use of the pesticide “will perform its intended function without unreasonable adverse effects on the environment.” 7 U.S.C. § 136a(c)(5). The term “unreasonable adverse effect” is defined to include “any unreasonable risk to man or the environment, taking into account the economic, social, environmental costs and benefits of the use of the pesticide.” 7 U.S.C. § 136(bb). Finally, FIFRA also states that if a registration decision is challenged in court, the decision may only be sustained if it is “supported by substantial evidence when considered on the record as a whole.” 7 U.S.C. § 136n(b).

In their request to vacate, the plaintiffs argue that EPA violated FIFRA by either understating or ignoring risks in its aldicarb 2021 registration decision. In doing so, the EPA failed to satisfy the “no unreasonable adverse effects on the environment standard,” and failed to support its registration decision with substantial evidence. According to the plaintiffs, EPA underestimated risks from consuming oranges, grapefruit, and orange juice. By underestimating risks, EPA is not able to fully ensure that the 2021 registration decision will not adversely affect the environment. Therefore, the decision should be vacated.

Ultimately, the court agreed with the plaintiffs that the 2021 registration decision should be vacated. In a short order issued on June 7, 2021, the court vacated the decision because EPA itself acknowledged that it had not conducted ESA consultation. EPA had also been explicit that if the court sent the 2021 registration decision back to the Agency for review without vacatur, it would not be able to complete consultation until 2024 at the earliest. Therefore, the court set aside the 2021 registration decision.

Going Forward

Following the order from the court, aldicarb is not currently available for use on citrus trees. EPA could choose to appeal the order to the United States Supreme Court, but it is currently unclear whether the Agency will pursue that option.

Although the immediate impact of this case is limited to aldicarb, it is possible that the court’s decision may ultimately end up influencing other pesticide-related lawsuits. Many recent legal challenges to pesticide registration decisions have included arguments that EPA violated the ESA by failing to consult with FWS, including a case currently before the D.C. Circuit Court of Appeals challenging EPA’s 2020 decision to register dicamba. It is possible that other courts may look at the decision to vacate the 2021 aldicarb decision based on EPA’s failure to initiate ESA consultation when determining how to settle similar issues in the future.


To read the plaintiff’s motion to vacate the 2021 aldicarb registration, click here.

To read the court’s order granting vacatur, click here.

To read the 2021 aldicarb registration decision, click here.

To read the cancellation MOU between EPA and Bayer, click here.

To read the 2007 aldicarb re-registration decision, click here.

To read the text of FIFRA, click here.

To read the text of the ESA, click here.

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

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