FIFRA Preempts Label-Based Failure-to-Warn Claims, Supreme Court Rules

On June 25, 2026, the Supreme Court held, 7-2, that the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) preempts a state-law failure-to-warn claim alleging that Monsanto failed to warn users that the weedkiller Roundup causes cancer.  The decision in Monsanto Co. v. Durnell concludes that EPA’s approval of a pesticide label without a cancer warning constitutes a federal labeling “requirement” that state tort law cannot override.

The ruling resolves a circuit split. The Third Circuit previously found preemption on these facts, while the Ninth and Eleventh Circuits and several state appellate courts had not.

What the Court Decided

Writing for the majority, Justice Kavanaugh identified two interlocking features of FIFRA’s registration regime that together produce the preemptive effect.  First, before registering any pesticide, EPA must determine that the proposed label contains all warnings “necessary and . . . adequate to protect health and the environment” and is not false or misleading.  That determination reflects the agency’s considered judgment about what a label must—and need not—say.  Second, EPA’s implementing regulations require manufacturers to use the EPA-approved label, subject to narrow exceptions not at issue in this case.  Changing the label without EPA approval, including by unilaterally adding a cancer warning, may expose the manufacturer to civil and criminal penalties under federal law.  Together, the majority reasoned, those features constitute a federal labeling “requirement” under FIFRA’s preemption clause that preempts state tort law claims imposing labeling requirements “in addition to or different from” those required under FIFRA.

The majority found support for that reasoning in Riegel v. Medtronic, Inc., which held that FDA premarket approval of medical devices preempts conflicting state-law device claims, emphasizing the similarities between that preemption clause and FIFRA’s.  It also distinguished Bates v. Dow Agrosciences LLC, which allowed state failure-to-warn claims equivalent to FIFRA’s misbranding standard, on the ground that Bates involved efficacy claims—statements EPA does not review at registration.  Safety determinations, which EPA does review, carry preemptive force that efficacy claims do not, the majority ruled.

Writing for the dissent, Justice Jackson argued FIFRA’s own misbranding prohibition is the relevant federal requirement, and a state claim that simply parallels that prohibition should not be preempted under Bates.  The majority and dissent also disagree over whether EPA’s precautionary-statement regulations reach chronic risks like cancer, as opposed to only acute hazards.  The majority concludes they do, while the dissent maintains the regulatory text addresses acute hazards only.  Because cancer is a chronic condition, the dissent argues pesticide manufacturers can add a cancer warning without EPA approval.

Justice Thomas joined the majority in full but wrote separately to question whether FIFRA’s registration scheme exceeds Congress’s Commerce Clause authority, whether FIFRA unlawfully delegates legislative power to EPA, and whether agency action can carry preemptive force under the Supremacy Clause at all.  No other Justice joined that view.

Who’s Affected

The decision most directly benefits pesticide and agrochemical manufacturers defending failure-to-warn claims premised on an EPA-approved label.  The Court’s reasoning, however, leans on a comparison to other federal statutes with similarly worded preemption clauses, which suggests the analysis may be cited in disputes involving other federally regulated, labeled products.  The opinion does not address other theories—such as design defect, manufacturing defect, or advertising-based claims—that were not before the Court in this case.

What to Watch

The Judicial Panel on Multidistrict Litigation’s pending-dockets report lists roughly 3,900 active cases in the Roundup MDL as of July 1, 2026, a population of claims against which Durnell‘s reasoning will likely be tested in dismissal motions.  EPA’s glyphosate registration posture also remains unsettled in part, since the Ninth Circuit vacated the agency’s most recent 2020 interim registration review decision in 2022.

In addition, federal lawmakers have introduced legislation to override the Court’s interpretation.  The People Over Poison Act, H.R.9528, would add language to FIFRA clarifying that the law’s preemption clause “shall not be construed to prohibit or otherwise limit a claim related to the labeling or packaging of pesticides or devices under the tort law of any State.”  The bill was introduced on June 29, 2026, by Reps. Chellie Pingree (D-ME) and Thomas Massie (R-KY) and has been referred to the House Committee on Agriculture.

The case is Monsanto Co. v. Durnell, No. 24-1068 (U.S.), petition for writ of certiorari granted January 16, 2026.  A previous post on the case, written after the Court granted certiorari, can be found here.

Texas AG Launches Glyphosate Investigation into Major Food Companies

Texas Attorney General Ken Paxton has initiated an investigation into glyphosate residue in foods, especially foods containing oats, his office announced June 2, 2026.

The investigation will examine whether major food companies are complying with Texas law and whether consumers have been misled by health claims on common food products.  The office has already issued civil investigative demands to pesticide and food manufacturers including Bayer and PepsiCo, the press release states.

According to the release, the percentage of Americans with detectable levels of the herbicide in their bodies has risen sharply in recent decades—from 12% in 1993 to over 70% today.  The office attributes this largely to the widespread use of glyphosate as a desiccant, or drying agent, applied to crops shortly before harvest, which it claims accounts for over 90% of glyphosate found in food.

Oats are a particular focus.  While the EPA prohibits using glyphosate as a desiccant on oats grown domestically, the office alleges that “major food companies source their oats from foreign countries where the practice is allowed,” leading to elevated exposures in children through foods such as cereals, breakfast bars, and cookies.

“In fact, studies show that certain food products marketed to children are some of the most glyphosate-contaminated food products in the United States,” the release states.  “Other products are marketed as ‘healthy’ when manufacturers know their products are contaminated with dangerously high levels of glyphosate.”

The glyphosate probe comes less than two months after Paxton’s office announced a similar investigation into activewear company Lululemon over alleged consumer deception related to PFAS in its products.

Glyphosate is one of the most widely used herbicides worldwide and the active ingredient in Roundup.  In 2015, the International Agency for Research on Cancer classified glyphosate as a probable human carcinogen, a designation that EPA has not adopted.  Under the Federal Insecticide, Fungicide and Rodenticide Act (FIFRA) and Federal Food, Drug, and Cosmetic Act (FFDCA), EPA sets pesticide food tolerances at levels at least 100 times below the dose that produced no adverse effects during animal testing.

EPA Avoids Court Order on Organophosphates, but Timeline Concerns Remain

The Ninth Circuit has declined to force EPA to act on a petition brought by nonprofits targeting organophosphate pesticides, calling the request “premature” despite noting concerns with the agency’s response timeline for certain pesticides.

The 2021 petition, brought by environmental and farmworker groups, asks EPA to revoke Federal Food, Drug, and Cosmetic Act (FFDCA) food tolerances and cancel Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) registrations for organophosphate pesticides due to health harms.

In a memo issued April 27, 2026, the court generally accepted EPA’s plan to address the disputed pesticides in three groups, finding the delay thus far “below the threshold of what we have generally found to be unreasonable.”

Under EPA’s proposed schedule, the agency plans to respond to the first group of pesticides in 2026.  For the second group, EPA plans to address the FFDCA issues in 2026 and the FIFRA issues during registration review.  EPA plans to address the third group entirely in conjunction with registration review.

Still, the court expressed concern about “the lack of a concrete timeline” for resolving some of the petitioners’ FIFRA claims, particularly those involving pesticides that may present higher risks.

“EPA admits that it will not complete its registration review for any of the thirteen pesticides by the October 2026 statutory deadline,” the memo states.  “If, by the expiration of that statutory deadline, EPA still ‘does not offer a timetable’ for resolving the FIFRA-related claims for those particular pesticides presenting higher levels of risk,” the outcome may be different, the court said.

“If EPA chooses not to address the chemicals posing the greatest risk by the 2026 deadline, Petitioners are free to file a second mandamus petition as to those chemicals,” the court added, using the legal term for a petition seeking to compel agency action.

Registration Review

The court was partly persuaded by the existence of the October 2026 registration review deadline itself, which Congress extended from October 2022 through the Pesticide Registration Improvement Act of 2022, commonly known as PRIA 5.

“Congress thus judged that EPA needs more time to complete the FIFRA registration review process for the types of pesticides at issue,” the memo states.  “This weighs heavily against granting relief with respect to Petitioners’ FIFRA-related claims until after the congressional deadline has passed.”

The October 2026 deadline for registration reviews applies to pesticides registered before October 1, 2007, when Congress formally required EPA to review each registered pesticide at least once every fifteen years to ensure that it can still be used without unreasonable adverse effect on human health or the environment.

Human Health Concerns    

The 2021 petition argues that organophosphate pesticides can cause a range of unreasonable adverse effects, including neurodevelopmental harm in children at exposures “far below” EPA’s current regulatory endpoint.  According to the petition, those harms include impaired motor and mental development, reduced IQ, attention disorders, and autism associated with low-level exposure.

These alleged harms were not sufficient for the court to force EPA’s hand, however.

“The breadth of [Petitioners’] request was perhaps reasonable in 2021 in light of what the EPA characterizes as its earlier conservative assumption ‘that all the [organophosphates] cause similar neurodevelopmental effects.’”  But “all parties now seem to agree that the degree of risk does not appear to be consistent for all thirteen pesticides still at issue.”

For example, the petitioners conceded that the pesticides chlorethoxyfos, tribufos, and terbufos are lower priority at oral argument, while emphasizing greater risk associated with bensulide, the court said.  “On this record, we cannot hold that human risks justify granting the petition as to all thirteen pesticides.”

The case is In re Pesticide Action Network North America, No. 25-3955 (9th Cir.), petition for a writ of mandamus filed 6/25/2025.  The memorandum disposition is unpublished.

California Bill Would Phase Out PFAS Pesticides, Require Label Disclosures

California is considering legislation to phase out use, require labeling, and prohibit registrations of pesticides containing PFAS, defined as a class of fluorinated organic chemicals containing at least one fully fluorinated carbon atom.

AB 1603 states that PFAS exposure “poses a significant threat to the environment and public health” and that their intentional use in pesticides is increasing.  The bill notes that EPA has approved 70 active ingredient PFAS pesticides, including 53 allowed for use in California by state regulators, and that a 2025 analysis found that approximately 2.5 million pounds of active ingredient PFAS pesticides are applied in California annually.

The bill would immediately prohibit the California Department of Pesticide Regulation (CDPR) from registering or re-registering pesticides with intentionally added PFAS as an active or inert ingredient, and would phase in the following additional requirements:

  • January 1, 2028: Prohibition on manufacturing, distribution, or sale unless labeled with the following statement: “This product contains perfluoroalkyl and polyfluoroalkyl substances, or PFAS, and can contaminate produce, groundwater, drinking water, soil, and the environment.”
  • January 1, 2030: Prohibition on using, manufacturing, selling, delivering, holding, or offering for sale pesticides with 23 specific intentionally added PFAS.
  • January 1, 2035: Blanket prohibition on using, manufacturing, selling, delivering, holding, or offering for sale pesticides with any intentionally added PFAS.

AB 1603 would also designate pesticides with intentionally added PFAS as a restricted material.  By January 1, 2028, CDPR would be required to prescribe the times and conditions under which such materials may be used or possessed across the state, with authority to prohibit use or possession in certain areas.  Use or possession would require a written permit from the county agricultural commissioner, and those permits and related public disclosures would be subject to the same label statement described above.

Any state labeling requirement must contend with the preemption provisions of the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA), which prohibit states from imposing labeling requirements “in addition to or different from those required under” the statute.  EPA does not currently require any label disclosure for pesticides containing PFAS.

AB 1603 was introduced on January 16, 2026.  The Assembly Committee on Environmental Safety and Toxic Materials will hold a hearing on the bill on April 14, 2026.

EPA: Single Fluorinated Compounds Aren’t PFAS

Late last year, EPA published a webpage pushing back on concerns about pesticides containing a single fluorinated carbon—the threshold for designation as PFAS under AB 1603.

“EPA-approved single fluorinated compounds are not forever chemicals, they are not PFAS, and do not pose any risks of concern when used as labeled,” the webpage states.

EPA emphasizes that, regardless of a pesticide’s contents, registration under FIFRA requires a determination that the product will not cause unreasonable adverse effects on human health or the environment.  The agency conducts “robust, chemical-specific” hazard and exposure assessments, “ensuring that every scientific aspect of these compounds is thoroughly evaluated before any registration decision is made.”  It conducts a similarly thorough evaluation when setting food tolerances under the Federal Food, Drug, and Cosmetic Act (FFDCA), which requires a “reasonable certainty of no harm,” EPA states.

EPA notes that pesticides containing a single fluorinated carbon can offer agronomic benefits and may replace more harmful alternatives, such as organochlorines.  The agency also points to the European Union, United Kingdom, Canada, and other jurisdictions that have registered or are considering registering pesticides containing a fluorinated carbon.

Supreme Court to Weigh FIFRA Preemption in Roundup Cancer Warning Case

The Supreme Court has agreed to hear Monsanto’s appeal of a $1.2 million jury verdict in favor of a plaintiff who claimed Roundup weedkiller caused his cancer, focusing on whether the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) preempts state failure-to-warn claims when EPA has not required the warning.

At the core of the dispute is FIFRA section 24(b), 7 U.S.C. 136v(b), which forbids states from imposing labeling requirements “in addition to or different from those required under” FIFRA.  Citing the Supreme Court’s 2005 decision in Bates v. Dow Agrisciences LLC, the Ninth and Eleventh Circuits have held that this language does not preempt state-law claims if the elements of the claim “parallel” FIFRA’s prohibition on misbranding.

However, more recently, in 2024, the Third Circuit created what many view as a circuit split, ruling that those courts erred by applying the “parallel requirements” test from Bates too generally.  According to the Third Circuit, EPA regulations implementing FIFRA prohibit manufacturers from adding precautionary statements to product labels without EPA approval, making such labels preempted.

Monsanto’s petition for certiorari, filed April 4, 2025, asks the Court to adopt the Third Circuit’s analysis.  “Because the jury verdict in this case requires Monsanto to include a cancer warning that EPA’s regulations did not require—and in fact affirmatively forbade it from adding—FIFRA preempts Respondent’s claim,” the petition argues.

Respondent John Durnell argues that the circuit split is both “irrelevant” and “illusory.”  In his June 9, 2025, brief, he argues that the jury verdict did not hinge on the labeling claims because Monsanto also advertised Roundup as safe in television advertisements.  He further maintains that there is no actual circuit split.

According to Durnell, there are two ways to update pesticide product labeling: by notification to EPA or by applying for amended registration.  Due to a “unique quirk” in the Third Circuit case, the court explicitly limited its analysis to the first option and “express[ed] no opinion” on whether Monsanto was required to pursue the latter, the brief states.

The Supreme Court’s decision is likely to have massive implications for numerous suits alleging that glyphosate, the active ingredient in Roundup, is carcinogenic.  EPA has repeatedly determined that glyphosate does not cause cancer, but the International Agency for Research on Cancer (IARC) has classified glyphosate as a probable human carcinogen.

The case is Monsanto Co. v. Durnell, No. 24-1068 (U.S.), petition for writ of certiorari granted January 16, 2026.

Court Reinstates Suit Alleging Roundup “Expiration” Due to Impurity

Allegations that Monsanto’s popular Roundup-brand weedkillers degrade into a carcinogenic impurity will proceed, after the Ninth Circuit reinstated a proposed class action a district court had dismissed for failure to state a claim.

Unlike the many personal injury suits over Roundup, the plaintiffs in this case assert purely economic harms.  They allege that consumers would have paid less for concentrated Roundup products had they known that glyphosate—the active ingredient—gradually degrades into harmful levels of N-Nitrosoglyphosate (NNG) over time from exposure to nitrites in “everyday air and water,” effectively causing the products to “expire.”

The District Court for the Northern District of California dismissed the case in December 2023, finding two key allegations implausible: that NNG is substantially certain to form at levels of 1 part per million (ppm), and that 1 ppm NNG is unsafe.

The Ninth Circuit disagreed, emphasizing that plausibility does not require probability.  While no regulation sets a specific 1 ppm limit for NNG, the panel found that an expert opinion combined with EPA statements sufficed to support a plausible claim regarding NNG’s hazard.

Similarly, although the complaint failed to allege that any products purchased by the plaintiffs or other consumers contained 1 ppm NNG, the court held that a variety of factual allegations—including that “Monsanto had discovered NNG at levels above 1 ppm in relevant products in its own possession”—were enough to make the plaintiffs’ claim about the occurrence of 1 ppm NNG plausible.

However, the Ninth Circuit affirmed the dismissal of claims against Roundup distributor The Scotts Co., finding that plaintiffs failed to allege that Scotts had “unbridled control” over the challenged conduct or knowledge of the alleged expiration.

The Ninth Circuit also criticized the lower court’s reliance on an incomplete version of a key study submitted by Monsanto, which likely presented findings in a more favorable light.  “The parties and the court should be concerned about submission of and reliance upon an incomplete document,” the opinion states.

The case is Koller v. Monsanto Co., No. 24-43, opinion filed March 27, 2025.

First Trials Scheduled in Long-Running Paraquat Litigation

The first three trials have been scheduled to begin in October 2025 in a multidistrict litigation with over 5,800 plaintiffs claiming that exposure to the pesticide paraquat dichloride caused them to develop Parkinson’s disease.  A second set of trials is scheduled to begin in April 2026.

The case was filed in June 2021.  A previous set of trial cases were tossed in April 2024 after the court ruled that expert testimony linking the herbicide to Parkinson’s disease relied on “methodological contortions and outright violations of…scientific standards.”

Defendants Syngenta and Chevron maintain that there is no causal link.  They also argue that the litigation is “burdened by cases alleging implausible theories of paraquat exposure,” despite court efforts to clean the docket of cases that “should never have been filed.”

EPA has not found a “clear link” between paraquat exposure from labeled uses and Parkinson’s disease or cancer.  However, on January 17, 2025, EPA asked the Ninth Circuit to allow the agency to withdraw a 2021 interim decision on paraquat to give the agency more time to consider its health risks.

According to EPA, paraquat is one of the most widely used pesticides in the US.  It often referred to as Gramoxone, the name of a popular end-use product manufactured by Syngenta.  Chevron stopped manufacturing and distributing paraquat in 1986.

The case is In Re: Paraquat Products Liability Litigation v. Syngenta Crop Protection, LLC, No. 3:21-md-03004 (S.D. Ill.).

EPA Issues Seldom-Used Emergency Order to Suspend Registrations of Pesticide DCPA

For the first time in almost 40 years, EPA has issued an emergency order under section 6(c)(3) of the Federal Insecticide, Fungicide, and Rodenticide Act to suspend the registrations of all pesticide products containing the active ingredient dimethyl tetrachloroterephthalate (DCPA).

The emergency measure is based on DCPA’s thyroid effects in fetuses, which EPA deemed so severe that continued use of DCPA during the time period required to cancel its registrations would pose an imminent hazard.  According to EPA, thyroid hormone perturbations linked to DCPA “can lead to downstream health problems such as low birth weight, impaired brain development, decreased IQ, impaired motor skills, and decreased bone deposition.”

Occupational exposures to DCPA can be over twice as high (as a factor of body weight) as the level at which the thyroid effects were observed in mouse fetuses, and the herbicide’s residues present risks of concern even 30 days after application to crops, EPA said.  DCPA is also registered for non-agricultural uses, including on golf courses and athletic fields.

American Vanguard Corporation (AMVAC), the sole registrant of DCPA, voluntarily canceled all but two of its DCPA products and their use on turf.  It also voluntarily ceased sale and distribution of the only remaining end-use product until EPA approved product labels that would address DCPA’s risks.  However, EPA “determined that there is no combination of practicable mitigations under which DCPA use can continue without presenting an imminent hazard.”

DCPA is currently undergoing registration review, which occurs every 15 years.  EPA assessed DCPA’s health risks in 2023 after AMVAC submitted a study on its thyroid effects and other information requested by the agency.

The agency intends to issue a notice of intent to cancel DCPA registrations within 90 days of the order, which was published on August 7, 2024.

Also known by its trade name Dacthal, DCPA is used on a variety of crops for weed control.  According to EPA, the emergency order will have a negligible impact on produce prices but may impact growers of crops including bok choy, collards, kale, green onions, and leeks.

Update:

On August 28, 2024, EPA announced that it is initiating a voluntary cancellation of DCPA after AMVAC notified the agency of its intent to cancel the remaining pesticide products.  According to EPA, AMVAC also intends to cancel its international registrations.

EPA Requests Comment on Petition Requiring Proof of Effectiveness for Systemic Insecticides

On November 24, 2023, EPA announced that the Agency is seeking public comment on a petition filed by environmental groups requesting that EPA consider efficacy data when evaluating the registration of neonicotinoids and other systemic insecticides under the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA).  Comments will be accepted through January 23, 2024.

In 1980, EPA waived (in most cases) the requirement that registrants provide efficacy data when registering a pesticide under FIFRA (see 40 CFR 158.400(e)(1)).  The petition, filed by the Public Employees for Environmental Responsibility and the American Bird Conservancy, argues that neonicotinoid use is largely ineffective and causes widespread environmental harm.  According to the petition, EPA’s failure to consider neonicotinoids’ lack of efficacy conflicts with the stated purposes of the Agency’s FIFRA registration data requirements to “make regulatory judgments…about the risks and benefits of pesticide products” (40 CFR 158.1(a)) and “ensure that pesticide products will perform as intended” (40 CFR 158.130(c)).

In addition to requiring efficacy data during systemic insecticide registration, the petition asks EPA to mandate that existing systemic insecticide registrants submit efficacy data to EPA within 180 days.  If a proposed or existing systemic insecticide registration “lacks a demonstration that its benefits exceed its environmental and overall costs,” EPA would be required to deny or revoke the registration accordingly.

Systemic insecticides are most commonly used prophylactically to treat plant seeds.  Treated seeds are currently exempted from FIFRA under the “treated articles and substances” exemption at 40 CFR 152.25(a) if their use is consistent with the treating pesticide’s label instructions.  However, EPA recently signaled that the Agency may revise this exemption.

Systemic insecticides are designed to be absorbed and transported through the target plant.  Neonicotinoids, a class of systemic insecticides that include the active ingredients imidacloprid, thiamethoxam, and clothianidin, are one of the most widely used types of insecticides in the world.

EPA Releases Strategic Plan for Endocrine Disruptor Screening Program

EPA has released a notice requesting comment on its strategic plan to meet its obligations under the Federal Food, Drug, and Cosmetic Act (FFDCA) to screen for and protect against endocrine-disrupting effects in humans. Endocrine disruptors are chemicals that mimic, block, or disrupt the normal function of endocrine system hormones and can negatively impact biological processes within the endocrine, immune, and nervous systems. Under the new program, the Agency will assess pesticides more quickly and effectively to evaluate their potential to cause endocrine effects in humans. These assessments will be incorporated into pesticide review efforts made under the Federal Insecticide, Fungicide, and Rodenticide Act (“FIFRA”).

In the Agency’s press release regarding the program, the Deputy Administrator for Pesticide Programs in the Office of Chemical Safety and Pollution, Jake Li, noted that the program is a major milestone. He also stated that “starting with our highest priority chemicals, EPA will communicate more transparently our endocrine findings for humans.”

EPA review of preliminary data has identified 30 high-priority pesticides that these chemicals affect the endocrine system. The Agency requests additional endocrine data for human health for these chemicals in its request for comment. The Agency intends to fill any remaining data gaps by issuing FIFRA human health data requests for these chemicals in early 2024. These chemicals are identified in EPA’s List of Conventional Registration Review Chemicals, for Which an FFDCA Section 408(p)(6) Determination is Needed, which is available in docket EPA–HQ–OPP–2023–0474 on regulations.gov. FFDCA section 408(p)(6) requires EPA to ‘‘as appropriate, take action under such statutory authority as is available to the Administrator, including consideration under other sections of this chapter, as is necessary to ensure the protection of public health’’ for ‘‘any substance that is found, as a result of testing and evaluation under this section, to have an endocrine effect on humans.’’ In addition, in the Federal Register notice, EPA requested that stakeholders submit data on the endocrine effects of these pesticides. Data are requested during the notice’s 60-day comment period. After the assessment of the high-priority pesticides is completed, the Agency will request data on a second group of 126 pesticides.

In the strategic plan, EPA explains that the program will pull from existing data when possible.   and request new data if needed. Existing data has been collected under FIFRA and the FFDCA. EPA has chosen 400 conventional pesticide active ingredients that are being registered for the first time or are undergoing registration review for which, through the implementation of its Strategic Plan, the Agency will assess for endocrine effects and determine if additional protections are needed.

The comment period for this notice began on October 27, 2023, and has been extended to February 26, 2024.