On May 24, 2021, the Environmental Protection Agency’s (“EPA”) Office of the Inspector General (“OIG”) issued a report addressing EPA’s 2018 decision to conditionally register three dicamba products under the Federal Insecticide, Fungicide, and Rodenticide Act (“FIFRA”). The 2018 registration decision allowed the three dicamba products to be applied directly onto dicamba-resistant soybean and cotton crops during the 2019 and 2020 growing seasons. Shortly after EPA approved the 2018 registration, a coalition of environmental interest groups filed a lawsuit with the Ninth Circuit Court of Appeals challenging the legality of the registration. Ultimately, the court agreed with the plaintiffs, concluding that the 2018 registration violated FIFRA for a variety of reasons, including EPA’s failure to adequately consider the risks of registering the products. To read more about that case and the Ninth Circuit’s decision, click here.

In the May 24 report, titled “EPA Deviated from Typical Procedures in Its 2018 Dicamba Pesticide Registration Decision” (“the Report”), the OIG found that EPA’s 2018 registration decision “varied from typical operating procedures.” According to the Report, EPA’s deviation from its normal procedures contributed to the Ninth Circuit’s decision to vacate the 2018 registration.


In the United States, FIFRA is the primary federal statute regulating pesticide distribution, sale, and use. All pesticides distributed or sold in the United States must be registered under FIFRA by EPA. Before EPA may register a pesticide, it must conclude that using the pesticide according to instructions on the label “will not generally cause unreasonable adverse effects on the environment.” 7 U.S.C. § 136a(c)(5)(C). FIFRA defines “unreasonable adverse effects on the environment” to include: “(1) any unreasonable risk to man or the environment, taking into account the economic, social, and environmental costs and benefits of the use of any pesticide, or (2) a human dietary risk from residues that result from a use of a pesticide in or on any food inconsistent with the standard under section 408 of the Federal Food, Drug, and Cosmetic Act.” 7 U.S.C. § 136(bb).

Within EPA, the agency’s Office of Chemical Safety and Pollution Prevention (“OCSPP”) oversees the pesticide registration process through its Office of Pesticide Programs (“OPP”). The Registration Division within the OPP is responsible for drafting the registration decision which serves as EPA’s determination of whether a pesticide registration should be confirmed or denied. When drafting the registration decision, Registration Division considers risk assessments conducted by other OPP divisions, and reviews materials from the party seeking to register the pesticide.

Prior to sending risk assessments to the Registration Division, the OPP uses a two-tiered approach to conduct peer reviews of those risk assessments. The branch of OPP that is responsible for completing the assessment conducts the first peer review, while a separate division of OPP conducts the second review. During the entire registration process, EPA relies on its Scientific Integrity Policy that was issued in 2012. All EPA employees are required to follow that policy when making EPA policy or management decisions, including decisions on whether to register a pesticide for use. The Scientific Integrity Policy encourages a culture of “scientific integrity” by mandating actions and ideals, including a prohibition against suppressing or altering scientific findings, and requiring the content of a scientific product to be based only on “scientific quality considerations.” When drafting the 2018 dicamba registration decision, EPA employees would have been required to follow this policy.

The OIG Report

According to the Report, the OIG began this evaluation for the purpose of determining “the effectiveness of [EPA] policies and procedures in addressing stakeholder risks in the 2016 and 2018 dicamba pesticide registration decisions.” The evaluation was conducted between April 2020 and March 2021. During that time, the OIG reviewed both the 2018 registration decision, and the initial decision to register dicamba for use directly onto crops which was made in 2016. Evaluators interviewed career scientists and other staff within the OCSPP and the OPP who would have been involved in both decisions. Ultimately, the Report focused on the 2018 registration decision and found that “EPA’s 2018 dicamba pesticide conditional registration decision varied from the OPP’s written standard operating procedures, namely because the EPA did not conduct the required internal peer review of scientific documents created to support the dicamba decision.”

According to staff scientists, senior members within the OCSPP were “more involved” in the 2018 registration decision than in other registration decisions. The Report notes that this involvement “led to senior-level changes to or omissions from scientific documents.” OIG found that some scientists did not sign off on final documents drafted for the registration decision due to revisions made by senior staff within OCSPP. Additionally, scientists interviewed by OIG “described feeling constrained or muted in sharing their scientific integrity concerns with senior management during the dicamba registration process.”

During interviews, staff scientists gave examples of where scientific analyses were change to support policy decisions from senior staff members. According to one staff scientist, senior staff at OCSPP decided to use plant height as the standard measure for the effect of dicamba on plants. This differed from EPA’s typical approach of using visual signs of plant injury to determine what effect dicamba was having on plants, an approach used in studies conducted not only by EPA but also by academics and the parties asking EPA to register the dicamba products. The Report states that the direction from senior staff to alter the standard measure changed EPA’s overall scientific conclusions. Ultimately, the Report concluded that this and other actions from senior staff contributed to the Ninth Circuit’s decision to vacate the 2018 registration in the middle of the 2020 growing season.

OIG Recommendations & Potential Impacts

Along with the findings made by OIG, the Report also contains recommended actions that the OCSPP can take in response to those findings. Those recommendations include: (1) implementing a procedure requiring senior managers or policy makers to document changes or alterations to scientific opinions, analyses, and conclusions in pesticide registration decisions and the basis for such changes or alterations; (2) requiring an assistant administrator-level verification statement that Scientific Integrity Policy requirements were reviewed and followed during pesticide registration decisions; and (3) annually conducting and documenting training for all staff to affirm the EPA’s commitment to the Scientific Integrity Policy.

EPA has indicated that it agrees with and intends to implement recommendations 1 and 3, but noted that requiring an assistant administrator-level verification statement for each pesticide registration decision as required in recommendation 2 would be difficult to achieve because only about five percent of pesticide registration decisions make it to the level of assistant administrator review each year. Recommendation 2 is currently unresolved as EPA and the OIG determine how best to address the OIG’s concerns. However, recommendations 1 and 3 will be implemented in pesticide registration decisions going forward.

It is currently unclear what effect the Report will have on the lawsuits that have been brought against the latest dicamba registration which was approved by EPA in 2020. In the Report, the OIG noted that it did not review the 2020 registration decision process, but did not indicate that it had any concerns about that decision.


To read the OIG Report, click here.

To read the text of FIFRA, click here.

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