Court Vacates Over-The-Top Dicamba Registration; EPA Issues Existing Stocks Order

In a situation reminiscent of 2020, an Arizona federal court has vacated the registration of three over-the-top dicamba products, XtendiMax, Enginia, and Tavium (the Products).  See Center for Biological Diversity v. U.S. Envt’l Agency, No. 4:20-cv-00555 (D. Ariz. Feb. 6, 2024).   The Environmental Protection Agency (EPA) has issued an existing stocks order allowing for some limited uses in specific circumstances for the 2024 growing season.


Dicamba is a herbicide used to kill broadleaf plants that has been on the market for over 50 years.  Dicamba is toxic to certain problematic weeds like palmer amaranth, but also to a number of desirable plants, bushes, and trees.  Dicamba is also known to be highly volatile, meaning that it can evaporate and travel to off-target locations.

Initial Registration

In 2015 Monsanto developed dicamba-tolerant versions of cotton and soybean seeds.  This opened the door for over-the-top spraying of dicamba products on these growing crops.  Companies developed over-the-top dicamba herbicides to be used in connection with these newly released seeds.   In 2016, the EPA granted two-year conditional registrations to Monsanto (now Bayer) for Xtendimax, DuPont (now Corteva) for FeXapan, and BASF for Enginia.  In 2019, the EPA issued a “me too” conditional two-year registration for Tavium, (meaning the Tavium registration was based upon the same information as the other then-registered products).

After a number of complaints of offsite damage due to dicamba drift in the 2017 growing season, the EPA adopted an amended, more restrictive label.  Then, in 2018 the EPA granted requests for extensions and issued another conditional two-year registration for Xtendimax, FeXapan, and Enginia.  These new registrations came with further restrictions on when and how Xtendimax, FeXapan, and Enginia could be used.

Ninth Circuit Lawsuit

At that point, the Center for Biological Diversity (the same plaintiffs involved in this current lawsuit) sued the EPA claiming the 2018 registration of Xtendimax, FeXapan, and Enginia violated the Federal Insecticide, Fungicide, Rodenticide Act (FIFRA).  Tavium was not involved in this litigation. The Plaintiffs prevailed in that suit and in June 2020, the US Court of Appeals for the Ninth Circuit vacated the registration for the three over-the-top products at issue. Specifically, the court held that the EPA “failed to perform a proper analysis of the risks and the resulting costs” of registering the products. A few days later, the EPA issued a cancellation order but allowed for already purchased products to be used during the 2020 growing season.

2020 Registration

Four months later, the EPA issued new registrations for the Products that the EPA believed addressed the issues noted by the Ninth Circuit decision.  For XtendiMax and Engenia, each registration was unconditional for five years and included more restrictions to mitigate offsite damage.  For Tavium, the EPA extended its automatic expiration date of December 2020 to December 2025 and amended the registration to be unconditional.  Each of the registrations were issued without notice and comment from the public.

In March 2022, the EPA  granted voluntary registrant-proposed amendments to the registrations for use in Iowa and Minnesota.  In February 2023,  the EPA approved proposed amendments for use in Illinois, Indiana, Iowa and South Dakota.


The Center for Biological Diversity filed suit to challenge the 2020 registrations for the Products and the 2022 and 2023 amendments made by the EPA.  Specifically, they alleged violations of FIFRA, the Endangered Species Act (ESA), and the Administrative Procedures Act (APA).

Both parties filed cross-motions for summary judgment.

Overview of Applicable Laws

FIFRA prohibits the distribution or sale of any pesticide that is not registered by the EPA.  In registering pesticides, the EPA applies the standard of “unreasonable adverse effects.”  This means the EPA conducts a cost-benefit analysis “to ensure that there is no unreasonable risk created for people or the environment from a pesticide.”  In making this analysis, the EPA is to consider every relevant factor into account including economic, social, and environmental costs and benefits.  Under FIFRA, the EPA must publish a notice of each application for registration that contains any new active ingredient or if it would entail a changed use pattern and provide a 30-day comment period.

The APA requires agencies to take certain actions in their rulemaking processes.  A court presumes an agency’s action to be valid unless it can be shown to be “arbitrary and capricious.”  An action is considered arbitrary and capricious if the agency relied on factors for which Congress did not intend it to consider, entirely failed to consider an important aspect of the issue, offered an explanation for its decision that is counter to the evidence before the agency, or is so implausible that it could not be due to a difference in view or the product of agency expertise.

Court’s Opinion

The court sided with the Plaintiffs.  [Read Order here.]

Did EPA violate FIFRA’s public hearing requirements for new use and cancelled registrations?

The court first addressed the issue of whether the EPA violated public hearing requirements.

New Use

The Plaintiffs argued that the 2020 registration for the Products was a “new use” for which notice and comment rulemaking was required because at the time it was issued, the prior registration had been cancelled. The EPA claimed the 2020 dicamba registrations did not fall under the FIFRA “new use” requirements because there was no different active ingredient and there was not a new or additional use pattern.  They based this on the then-existing registration of Tavium, which was still in place and was not vacated by the Ninth Circuit.

The court said this reliance was misplaced.  Tavium was registered as a so called “me too” product based upon the 2018 registrations of XtendiMax and Enginia.  For “me too” registrations, no notice and comment is required by FIFRA.  In registering Tavium, there was no additional data or notice and comment needed because it was not a new use, it had the same ingredients and use patterns as the then-registered XtendiMax and Enginia and was registered as such.  Similarly, the EPA argued, when it registered XtendiMax and Enginia in 2020, those were registered as “me too” products to Tavium.

The court rejected the EPA’s argument.  The registrations upon which Tavium was based were vacated and cancelled.  Thus, the EPA could not rely upon the Tavium registration, which was based on the then-vacated and cancelled XtendiMax and Enginia registrations, to claim an existing active ingredient and use pattern.  Because the over-the-top dicamba application was a new use in 2016, when that use was vacated and cancelled, it was again a new use which required notice and comment under FIFRA.  The fact that Tavium was registered as a “me too” product based upon those vacated registrations did not change this fact.

Cancelled Registrations

The Plaintiffs also argued that when the EPA issued its cancellation order in June 2020, it triggered notice-and-comment provisions before it was able to re-register a cancelled pesticide.  The court found that regardless of whether such notice and comment was required for a re-registration, it was required because the 2020 registration was “new use.”

The court held that the “EPA sidestepped the statutory mandate under FIFRA that notice and comment be afforded all stake holders for new use registrations.”  This violated the APA.  It was prejudicial and impinged on the fundamental right of interested parties, particularly those not using the Products, to be heard.

What is the proper remedy?

Next, the court considered whether it should vacate the registrations or remand the case without vacatur.  The presumptive remedy when an agency violates the law is vacatur of the rule at issue.  Courts should remand without vacatur “only in limited circumstances…when equity demands” it.   The court considered the two relevant factors in selecting the proper remedy.

Seriousness of procedural error

“The procedural error at issue in this case, lack of notice and hearing, upsets the delicate balance created by Congress and between Agency determinations and judicial view.  Therefore, the court finds the procedural error is very serious.”  Further, the court noted that the last time the public was given the opportunity to comment on the registration of the Products was in 2016.

The court provided an overview of the EPA’s actions and evidence it considered when issuing the 2020 registration, calling the agency’s logic “circular.”  The court faulted the EPA for failing to assess costs from offsite movement for non-dicamba users.  Despite knowing that damage reports increased between 2018 and 2020, the EPA still issued unconditional registrations in 2020 without the need for additional data.

In light of this, the court found “the EPA is unlikely to issue the same registrations on remand if it follows FIFRA procedures for notice and comment and hears from all stakeholders, especially those who have from the inception of OTT dicamba use been subjected to the risks of OTT dicamba offsite movement.”

Disruptive consequences of vacatur

Next, the court considered the disruptive nature of vacating the registrations.

Both the EPA and Bayer requested the court to remand without vacatur.  They stressed the economic importance of using the Products to control weeds, and claim this outweighs any risk to the environment, endangered species, or critical habitat. The court recognized the substantial benefits from the Products for weed control and their popularity.  By 2020, the court said, about 2/3 of soybean acres and 3/4 of cotton acres planted used dicamba-tolerant seed.

The court noted that these same facts were true in 2020 when the Ninth Circuit vacated the labels.  “There is no evidence before the court that the ramifications of vacatur of these registrations on growers or the environment is more dire now than it was in 2020” when the Ninth Circuit issued vacated the registrations.

The EPA also raised concerns that growers will use more dangerous dicamba products not labeled for over the top use if they are unable to use the Products.  This, the court wrote, was weakened by evidence that such non-compliant uses already occur.

Although the court said it understood that “growers, through no fault of their own, will be placed in the difficult position of finding effective and legal herbicides to protect their dicamba tolerant crops if the registrations are vacated,” it nevertheless found vacatur appropriate given the seriousness of the EPA’s procedural error in failing to afford notice and comment on the 2020 registration.


Thus, the court found that the EPA violated FIFRA by failing to allow notice and comment and vacated the 2020 registrations for XtendiMax, Enginia, and Tavium.  In light of this decision, there are currently no over-the-top dicamba products approved in the United States.

Existing Stocks Order

On February 14, 2024, the EPA issued an existing stocks order. [View order here.]  Based upon this order, as of February 6, 2024 (the date of the Arizona court’s decision), the Products are no longer registered under FIFRA and it is illegal to sell or distribute them except for those “existing stocks” discussed in the order.

The EPA will allow the use during portions of the 2024 growing season of “existing stocks” of the formerly-registered Products.  It defines “existing stocks” as those stocks of previously registered pesticide products “that are currently in the United States and were packaged, labeled, and released for shipment prior to February 6, 2024.  A product is considered “released for shipment ‘when the producer has packaged and labeled it in the manner in which it will be distributed or sold, or has stored it in an area where finished products are ordinarily held for shipment.  Thus, this order does allow the limited sale and distribution of existing stocks already in possession of persons other than the registrant.  The use of the products must comply with the previously approved labeling.  There are also date restrictions depending on the states in which the products will be used.  In Texas, existing stocks may be sold and distributed for soybeans through May 31, 2024 and must be used on soybeans by June 30, 2024.  For cotton in Texas, existing stocks may be sold and distributed through June 30, 2024 and must be used by July 30, 2024.  Dates for other states may be found in the order.

What Happens Next?

Although we now know the status of the Products for the 2024 growing season as things currently sit, a number of questions still remain going forward.  First, keep in mind that the EPA and/or Bayer could appeal the Arizona decision to the United States Court of Appeals for the Ninth Circuit.  Note that would be returning to the court that previously sided with these same plaintiffs and vacated the 2018 registration of the over-the-top dicamba products.  Second, it is possible that the Plaintiffs could challenge the Existing Stocks Order and seek some sort of injunctive relief to prevent the use of the Products pursuant to that order.  Third, we do not know whether the manufacturers may seek to re-register the Products by offering additional evidence for the EPA to consider.  If that were to happen, it seems necessary for the EPA to hold notice and comment rulemaking and to consider the comments offered by stakeholders and the pubic before coming to a decision.

To listen to my discussion of this issue and a number of other environmental law issues around the country, click here for a podcast episode I did with Brigit Rollins from the National Agricultural Law Center.

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