Respondents Brief — Monsanto Company, Petitioner v. John L. Durnell

Supreme Court briefMar 25, 2026

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No. 24-1068

In the Supreme Court of the United States

_____________

MONSANTO COMPANY, PETITIONER

JOHN L. DURNELL, RESPONDENT

_____________

ON WRIT OF CERTIORARI

TO THE MISSOURI COURT OF APPEALS

_____________

BRIEF FOR THE RESPONDENT

_____________

JONATHAN F. MITCHELL

Mitchell Law PLLC

111 Congress Avenue

Suite 400

Austin, Texas 78701

(512) 686-3940

jonathan@mitchell.law

T. ROE FRAZER II

THOMAS ROE FRAZER III

JAMES GRANT LABAR

R. PRESCOTT SIFTON JR.

Frazer PLC

30 Burton Hills Boulevard

Suite 450

Nashville, Tennessee 37215

(615) 647-6464

ASHLEY C. KELLER

Counsel of Record

JOHN JAMES SNIDOW

Keller Postman LLC

1101 Connecticut Avenue NW

Suite 1100

Washington, D.C. 20036

(202) 918-1123

ack@kellerpostman.com

JAMES G. ONDER

W. WYLIE BLAIR

GREGORY J. PALS

MARK E. BERNS

OnderLaw LLC

110 East Lockwood Avenue

St. Louis, Missouri 63119

(314) 963-9000

Counsel for the Respondent

QUESTIONS PRESENTED

The Federal Insecticide, Fungicide, and Rodenticide

Act (FIFRA) prohibits the sale or distribution of a pesticide that is “not registered” with EPA. 7 U.S.C.

§ 136j(a)(1)(A). FIFRA delegates to EPA significant powers in the registration process. EPA is required to make

various determinations, including whether a pesticide’s

label complies with FIFRA. 7 U.S.C. § 136a(c)(5)(B).

Those determinations control only whether EPA “shall

requirements for labeling.

FIFRA imposes an independent prohibition on the

sale or distribution of any “misbranded” pesticide. 7

U.S.C. § 136j(a)(1)(E). A pesticide can be misbranded because its label is inadequate. 7 U.S.C. § 136(q)(1)(A), (G).

Unlike the registration requirement, the misbranding

prohibition does not vest EPA with any delegated authority to interpret or implement the statutory ban on selling

or distributing misbranded products. And FIFRA explicitly states that compliance with FIFRA’s registration requirements is no defense when a pesticide manufacturer

is sued for selling or distributing a misbranded product.

See 7 U.S.C. § 136a(f)(2) (“In no event shall registration of

an article be construed as a defense for the commission of

any offense under this subchapter.”).

Respondent John Durnell contracted cancer after using Roundup and sued Monsanto for failing to warn him

of the risks. Monsanto claims that Durnell’s failure-towarn claim is preempted under 7 U.S.C. § 136v(b), which

displaces state-law labeling requirements that are “in addition to or different from” those required by FIFRA.

Durnell claims that Missouri failure-to-warn law imposes

(i)

the same requirements as FIFRA’s textual prohibition on

selling a misbranded pesticide. Monsanto relies not on

FIFRA’s text, but EPA’s registration decision to argue a

difference between Missouri and federal law. So Monsanto

must believe that section 136a(c)(5) vests EPA with Chevron-like powers to interpret the ultimate meaning of the

statutory “misbranding” prohibition in a manner that

binds the judiciary. The questions presented are:

1. Is Durnell’s failure-to-warn claim expressly

preempted on the ground that Missouri law imposes labeling requirements that add to or differ from the misbranding provisions in FIFRA?

2. Is Durnell’s failure-to-warn claim impossibility preempted on the ground that federal law requires Monsanto to use the Roundup labeling

that Missouri law deems misleading or inadequate?

(ii)

PARTIES TO THE PROCEEDING

Petitioner Monsanto Company was the appellant in

the Missouri Court of Appeals. Respondent John L. Durnell was the appellee.

Monsanto’s stock-ticker symbol was MON, which

traded on the New York Stock Exchange (NYSE) until

June 7, 2018. On that date, Monsanto was acquired by

Bayer and subsequently delisted, and its operations were

integrated into Bayer’s Crop Science division. Bayer AG’s

primary stock-ticker symbol in the United States is

BAYRY, which represents its American Depositary Receipt (ADR) traded on the OTCQX market in USD. In its

home market (Germany), the stock trades on the XETRA

exchange under the ticker BAYN.

(iii)

TABLE OF CONTENTS

Questions presented ............................................................. i

Parties to the proceeding ................................................... iii

Table of contents ................................................................. iv

Table of authorities ............................................................ vii

Statutory provisions involved ..............................................7

Statement ...............................................................................7

I. Statutory and regulatory background ...................7

A. Federal law...........................................................7

1. Registration ................................................... 7

2. Misbranding................................................... 9

3. Post-registration changes to labels........... 11

4. Express preemption ................................... 11

B. Missouri law .......................................................12

II. Procedural history ..................................................14

A. History of Roundup litigation .........................14

B. History of this suit ............................................15

Summary of argument........................................................16

Argument .............................................................................19

I. Durnell’s failure-to-warn claim is not

expressly preempted ..............................................19

A. Missouri tort law does not add to or differ

from

FIFRA’s

adequate-warning

requirement .......................................................20

1. FIFRA delegates to the judiciary and

not EPA the power to determine

whether Roundup is misbranded .............. 21

2. FIFRA’s provisions show that EPA’s

decision to register a pesticide does

not preclude courts from finding that

pesticide misbranded .................................. 28

(iv)

3. Missouri’s warning requirements do

not add to or differ from FIFRA’s

misbranding provisions .............................. 33

B. Even if Monsanto could show that

Missouri tort law adds to or differs from

FIFRA,

Monsanto

forfeited

this

argument by failing to ask for a Bates

instruction at trial .............................................34

II. Durnell’s failure-to-warn claim is not

impliedly preempted ...............................................36

A. Neither FIFRA nor its implementing

regulations prevent Monsanto from

adding a cancer warning to Roundup’s

labeling ...............................................................37

1. 7 U.S.C. § 136j(a)(1)(B) prevents

manufacturers from altering the

statement of claims made for a

pesticide, not its labeling ............................ 38

2. EPA’s regulations do not and cannot

prevent Monsanto from adding a

cancer warning to Roundup’s labeling ..... 39

B. Durnell’s claim is not preempted even if

Monsanto could not change the label .............43

III.Monsanto’s preemption arguments find no

support in this court’s case law .............................46

A. Monsanto’s preemption arguments are

incompatible with Bates ...................................46

B. The Court’s decision in Riegel v.

Medtronic, Inc. is inapposite ...........................49

Conclusion ............................................................................52

Appendix ..................................................................................

7 U.S.C. § 136(q) .................................................................. 1a

(v)

7 U.S.C. § 136(bb) ................................................................ 4a

7 U.S.C. § 136a ..................................................................... 5a

7 U.S.C. § 136j(a)(1) .......................................................... 40a

7 U.S.C. § 136v(a)–(b) ....................................................... 44a

7 U.S.C. § 136w(a)–(c) ....................................................... 45a

40 C.F.R. § 152.44 .............................................................. 49a

40 C.F.R. § 152.46 .............................................................. 51a

Pesticide (PR) Notice 95-2 ............................................... 53a

Pesticide (PR) Notice 98-10 ............................................. 73a

Pesticide (PR) Notice 2000-15 ....................................... 103a

Letter from Larry R. Hodges, Bayer CropScience, to EPA, Office of Pesticide Programs

(Nov. 29, 2012) ............................................................ 113a

Letter from Jennifer Gaines, EPA, Office of

Pesticide Programs, to Larry Hodges, Bayer

CropScience (Dec. 17, 2012) ..................................... 115a

(vi)

TABLE OF AUTHORITIES

Cases

B&B Hardware, Inc. v. Hargis Industries, Inc.,

575 U.S. 138 (2015) ..........................................................29

Bates v. Dow Agrosciences LLC, 544 U.S. 431 (2005) .........

2, 3, 4, 10, 10–11, 12, 16, 18, 31, 33, 34, 44, 45, 46, 48, 49, 50

English v. General Electric Co., 496 U.S. 72 (1990) ........34

Epic Systems Corp. v. Lewis, 584 U.S. 497 (2018) ..........25

Haberly v. Reardon Co.,

319 S.W.2d 859 (Mo. 1958) ........................................12, 33

La Plant v. E.I. DuPont De Nemours & Co.,

346 S.W.2d 231 (Mo. Ct. App. 1961) ........................12, 33

Loper Bright Enterprises v. Raimondo,

603 U.S. 369 (2024) ..................5, 10, 11, 21, 22, 24, 25, 26

Marbury v. Madison, 1 Cranch 137 (1803) ......................24

Meeker v. Lehigh Valley R. Co., 236 U.S. 412 (1915) ......30

Merck Sharp & Dohme Corp. v. Albrecht,

587 U.S. 299 (2019) ..........................................3, 36, 42, 43

Moore v. Ford Motor Co.,

332 S.W.3d 749 (Mo. 2011) ....................................3, 12, 13

Mutual Pharmaceutical Co. v. Bartlett,

570 U.S. 472 (2013) ..............................................19, 37, 44

National Cable & Telecommunications

Association v. Brand X Internet Services,

545 U.S. 967 (2005) ..........................................................47

Nesselrode v. Executive Beechcraft, Inc.,

707 S.W.2d 371 (Mo. 1986) ..................................12, 13, 33

NRDC v. EPA, 38 F.4th 34 (9th Cir. 2022) ........................15

PLIVA, Inc. v. Mensing, 564 U.S. 604 (2011) ..................36

(vii)

Racer v. Utterman,

629 S.W.2d 387 (Mo. Ct. App. 1981) ..............3, 12, 13, 44

Riegel v. Medtronic, Inc., 552 U.S. 312 (2008)...........49, 50

Rodriguez v. Suzuki Motor Corp.,

996 S.W.2d 47 (Mo. 1999) ................................................13

SEC v. Jarkesy, 603 U.S. 109 (2024) .................................31

Theatre Enterprises, Inc. v. Paramount Film

Distributing Corp., 346 U.S. 537 (1954) .......................30

Trump v. CASA, Inc., 606 U.S. 831 (2025).......................45

United States v. Carolene Products Co.,

304 U.S. 144 (1938) ..........................................................27

United States v. Mead Corp., 533 U.S. 218 (2001) ....10, 26

Wisconsin Public Intervenor v. Mortier,

501 U.S. 597 (1991) ............................................................7

Wyeth v. Levine, 555 U.S. 555 (2009) ................................39

Statutes

7 U.S.C. § 136(q) ............................................................29, 51

7 U.S.C. § 136(q)(1)–(2).........................................................9

7 U.S.C. § 136(q)(1)(A) ...... 2, 4, 10, 13, 18, 19, 20, 33, 39, 40

7 U.S.C. § 136(q)(1)(G) ..............................2, 4, 10, 13, 18, 40

7 U.S.C. § 136a(a) ..................................................................8

7 U.S.C. § 136a(c)(1)(C) ......................................8, 11, 19, 38

7 U.S.C. § 136a(c)(1)(D) ........................................................8

7 U.S.C. § 136a(c)(3)(A) ........................................................8

7 U.S.C. § 136a(c)(5) ............................................................22

7 U.S.C. § 136a(c)(5)(A)–(D) ................................................2

7 U.S.C. § 136a(c)(5)(B) ........................................ i, 8, 10, 23

7 U.S.C. § 136a(c)(6) ..........................................................2, 9

7 U.S.C. § 136a(f)(2) ...................i, 6, 9, 10, 11, 17, 28, 30, 32

(viii)

7 U.S.C. § 136d.......................................................................2

7 U.S.C. § 136j .....................................................................33

7 U.S.C. § 136j(a)(1)(A) ............................................. i, 2, 7, 9

7 U.S.C. § 136j(a)(1)(A)–(E) .................................................1

7 U.S.C. § 136j(a)(1)(B)...............................11, 18, 29, 38, 39

7 U.S.C. § 136j(a)(1)(B)–(E) .................................................2

7 U.S.C. § 136j(a)(1)(C).......................................................30

7 U.S.C. § 136j(a)(1)(E) .....................i, 2, 8, 9, 19, 21, 29, 44

7 U.S.C. § 136k(c) ................................................................31

7 U.S.C. § 136l(a)(1) ............................................................31

7 U.S.C. § 136l(b) .................................................................31

7 U.S.C. § 136n(b) ..................................................................2

7 U.S.C. § 136v(b) ...........................i, 3, 12, 20, 21, 32, 36, 50

7 U.S.C. § 136v(b)(2) ...........................................................13

7 U.S.C. § 136d.......................................................................2

21 U.S.C. § 331 .....................................................................49

21 U.S.C. § 360k(a)(1) .........................................................50

28 U.S.C. § 453 .....................................................................27

Ga. Code Ann. § 2-7-171 .....................................................28

N.D. Cent. Code § 28-01.3-11 .............................................28

Constitutional Provisions

U.S. Const. amend. VI ........................................................31

U.S. Const. art. VI, cl. 2 ........................................................4

Rules

21 C.F.R. § 314.70(c)(1) .......................................................42

21 C.F.R. § 314.70(c)(6)–(7).................................................36

21 C.F.R. § 314.70(c)(7) .......................................................42

40 C.F.R. § 152.44 ................................................................39

(ix)

40 C.F.R. § 152.46 ................................................................39

40 C.F.R. § 152.46(a)(1) .......................................................40

40 C.F.R. § 156.10(a)(5)(vii) ................................................10

EPA, Pesticide Registration Notice 95-02 (May 31,

1995) ..................................................................................40

EPA, Pesticide Registration Notice 98-10 (Oct. 22,

1998) ..................................................................................40

EPA, Pesticides; Guidance for Pesticide

Registrants on Mandatory and Advisory

Labeling Statements, 65 Fed. Reg. 31,313 (May

17, 2000) ............................................................................41

Executive Order No. 14387, Promoting the

National Defense by Ensuring an Adequate

Supply of Elemental Phosphorus and

Glyphosate-Based Herbicides, 91 Fed. Reg. 8703

(Feb. 18, 2026) ..................................................................28

Other Authorities

Bayer, Managing the Roundup Litigation .....................15

Black’s Law Dictionary (12th ed. 2024) ............................30

3 W. Blackstone, Commentaries on the Laws of

England (Robert Bell ed., 1771–72) .............................26

Cal. Office of Env’t Health Hazard Assessment,

Initial Statement of Reasons: Glyphosate (Mar.

28, 2017) ............................................................................15

EPA, Consensus Review of Glyphosate (Mar. 4,

1985) ..................................................................................14

EPA, Memorandum re Second Peer Review of

Glyphosate (Oct. 30, 1991)..............................................14

EPA, Memorandum re: Glyphosate Mouse

Oncogenicity Study (Apr. 3, 1985) ................................14

(x)

Letter from Jennifer Gaines, EPA, Office of

Pesticide Programs, to Larry Hodges, Bayer

CropScience (Dec. 17, 2012)...........................................42

Letter from Larry R. Hodges, Bayer CropScience,

to EPA, Office of Pesticide Programs (Nov. 29,

2012) ..................................................................................41

IARC Monographs Volume 112 (Mar. 20, 2015) ..............14

John F. Manning, Textualism as a Nondelegation

Doctrine, 97 Colum. L. Rev. 673 (1997) ........................25

Hiroko Tabuchi, A Trump Order Protected a

Weedkiller. And Also a Weapon of War, New

York Times, March 6, 2026 .............................................27

(xi)

In the Supreme Court of the United States

_____________

No. 24-1068

MONSANTO COMPANY, PETITIONER

JOHN L. DURNELL, RESPONDENT

_____________

ON WRIT OF CERTIORARI

TO THE MISSOURI COURT OF APPEALS

_____________

BRIEF FOR THE RESPONDENT

_____________

In a typical civil case, judges announce the law and juries determine the facts. If Congress wants to adjust that

paradigm and empower a federal bureaucrat to act as

judge, jury, and executor, it must say so expressly. FIFRA

does not. To the contrary, it textually reinforces the traditional role of the judiciary. In this case, a properly empaneled jury made factual findings that Roundup caused Mr.

Durnell’s cancer and failed to warn him of that risk. On

those facts, it further concluded that Roundup was unlawful to sell under Missouri common law that tracks

FIFRA’s misbranding standards. Those straightforward

points resolve this appeal.

There is no affirmative right to sell pesticides. Instead,

FIFRA makes it “unlawful” to “distribute or sell” “any

pesticide” when one of five conditions is met. 7 U.S.C.

§ 136j(a)(1)(A)–(E) (emphasis added). Any one of those

(1)

conditions is sufficient to trigger a ban. The first prohibition forbids the distribution or sale of a pesticide that is

not registered by EPA. See 7 U.S.C. § 136j(a)(1)(A).

FIFRA delegates to the EPA Administrator significant

powers over registration, including the authority to evaluate evidence and make factual determinations about

safety. See 7 U.S.C. § 136a(c)(5)(A)–(D). Challenges to registration decisions are judicially reviewed deferentially

and must be affirmed when based on substantial evidence.

See 7 U.S.C. §§ 136a(c)(6), 136d, 136n(b).

Even if a pesticide is registered, however, a manufacturer still must not distribute or sell it for four independent reasons,1 including that it is “misbranded.” 7 U.S.C.

§ 136j(a)(1)(E); Bates v. Dow Agrosciences LLC, 544 U.S.

431, 438 (2005) (a pesticide can be “registered but nevertheless misbranded”). A pesticide is “misbranded,” in

turn, if it falls afoul of any of a dozen independent safeguards. At least two are implicated here. First, a pesticide

is misbranded if its label “bears any statement … which is

false or misleading in any particular.” 7 U.S.C.

§ 136(q)(1)(A). Second, a pesticide is misbranded if its label “does not contain a warning or caution statement

which may be necessary and if complied with … is adequate to protect health and the environment.”

§ 136(q)(1)(G).

This Court held over 20 years ago that state failure-towarn law that imposes civil liability for selling a misbranded pesticide is not preempted. Bates, 544 U.S. at 447

(“[A] state-law labeling requirement is not pre-empted by

[FIFRA’s express preemption provision] if it is equivalent

to, and fully consistent with, FIFRA’s misbranding pro1.

See 7 U.S.C. § 136j(a)(1)(B)–(E).

visions.”). And Bates holds that state law is “fully consistent” with FIFRA if it targets a label’s “false or misleading statements” or “inadequate instructions or warnings.” 544 U.S. at 447 (cleaned up).

The reasoning is straightforward: Federal law forbids

those things, too. And where both sovereigns forbid the

same conduct, state law is not “in addition to or different

from”2 federal law, and there is no “logical contradiction”

between the sovereign commands. Merck Sharp &

Dohme Corp. v. Albrecht, 587 U.S. 299, 319 (2019) (Thomas, J., concurring). Both laws must be obeyed.

That is the situation here. Missouri law has long imposed “a duty on the manufacturer not to introduce into

commerce an unreasonably dangerous product” because

of its “failure to warn of danger.” Racer v. Utterman, 629

S.W.2d 387, 395 (Mo. Ct. App. 1981). So state and federal

law lay down parallel rules. State law forbids the sale of a

pesticide without a truthful and “adequate warning.”

Moore v. Ford Motor Co., 332 S.W.3d 749, 756 (Mo. 2011).

Federal law prohibits selling a pesticide with a misleading

or “inadequate warning[].” Bates, 544 U.S. at 451. Barring an outright copy-and-paste, it would be hard to have

less daylight escape between the legal standards established by state and federal law.

The facts relevant to applying Bates in this case have

all been conclusively established by a jury. Durnell used

Monsanto’s flagship pesticide, Roundup, for decades.

Though Monsanto protests that its product is safe, the

jury found that Roundup increases the risk of cancer,

caused Durnell to develop cancer, and never warned Durnell of this risk. Monsanto was therefore liable on Dur2.

7 U.S.C. § 136v(b).

nell’s failure-to-warn claim. Monsanto does not contest

that the jury’s verdict rests on substantial evidence.

The jury’s findings conclusively establish for purposes

of this case that Roundup is misbranded under federal

law. A label that lists carcinogens without identifying

them as such is “misleading.” 7 U.S.C. § 136(q)(1)(A). A

cancer-causing pesticide that “does not contain” a cancer

warning omits information “necessary” to protect “health

and the environment.” 7 U.S.C. § 136(q)(1)(G). The jury’s

verdict accordingly enforces a state-law duty not to sell a

dangerous pesticide that “parallel[s]” the federal duty under FIFRA’s misbranding provisions. Bates, 544 U.S. at

447.

So how, then, does Monsanto gin up the putative conflict of law necessary to implicate the Supremacy Clause?

Monsanto rests its preemption defense on the EPA Administrator’s factual finding (during the registration process) that Roundup is safe — and argues that this registration decision decisively controls whether a pesticide is

“misbranded” under federal law. Pet. Br. 35.

Monsanto’s maneuver does not withstand scrutiny.

Whether Roundup is misbranded turns on both a question

of fact: does Roundup cause cancer?; and a question of

law: is a cancer-causing pesticide that fails to warn of this

risk “inadequate” or misleading? Bates, 544 U.S. at 451.

The question of fact is one over which reasonable people — such as the jurors and the EPA Administrator —

can disagree. But absent an express statutory delegation,

the Administrator’s factual findings are not “laws of the

United States” that Congress “made in pursuance” of the

Constitution. U.S. Const. art. VI, cl. 2. The Supremacy

Clause does not of its own force anoint Lee Zeldin the

supreme arbiter of scientific truth with a veto over a Missouri jury. The Administrator’s factual findings during the

registration process are good for registration only. They

do not create non-mutual collateral estoppel in Durnell’s

civil action.

On the question of law, Monsanto and the Solicitor

General cannot argue that if Roundup causes cancer, but

lacks a cancer warning, it is anything other than the textbook example of a misbranded pesticide. EPA has never

offered that interpretation of the relevant congressional

definitions. And even if EPA had adopted that interpretation, it would not bind the Missouri jury because not one

word of FIFRA’s text delegates power to the Administrator to “give meaning to” these statutory provisions. Loper

Bright Enterprises v. Raimondo, 603 U.S. 369, 394 (2024).

There is similarly no provision of FIFRA that requires

judges or juries to defer to the Administrator’s determination that a pesticide complies with (or violates) the misbranding prohibition.

Yet the only way that Monsanto can prevail is by showing that FIFRA delegates Chevron-like powers to EPA,

allowing the Administrator — not judges and juries — to

conclusively interpret the law and find the facts necessary

to ascertain whether a pesticide is “misbranded.” Monsanto has not even attempted to make this showing in its

opening brief. It simply assumes that the Administrator

has these sweeping powers, spending page after page

begging the relevant question. And Monsanto cannot

show that FIFRA delegates these powers to EPA because

it faces two insuperable obstacles.

The first is Loper Bright. Courts no longer assume

that agencies rather than courts hold delegated powers to

render binding interpretations of federal statutes. So

Monsanto must point to statutory text that vests EPA

with the authority to render universally binding interpretations of “misbranding,” as well as the power to bind juries to its factual conclusion that Roundup is not misbranded. There is nothing in FIFRA that remotely suggests EPA can bind the judiciary on these points.

The second insurmountable obstacle is that FIFRA

contains numerous provisions that expressly reconfirm

the default rule. Most notably, 7 U.S.C. § 136a(f)(2) makes

clear that EPA’s decision to register a pesticide is not a

“defense for the commission of any offense under this subchapter.” This proves that EPA’s decision to approve a label during the registration process does not definitively

answer any factual or legal questions in a civil action that

parallels the misbranding prohibition. A jury may consider the Administrator’s determinations only as “prima

facie evidence.” 7 U.S.C. § 136a(f)(2). It is not obliged to

treat them as pronouncements ex cathedra.

Monsanto’s implied-preemption claim is equally unavailing. Monsanto claims that “federal law” compels it to

continue using the labels that EPA approved during the

registration process. But that is patently false. FIFRA

imposes no such requirement, and EPA’s own regulations — even assuming they are valid — authorized unilateral label changes without agency preapproval. Monsanto

knows this well, as its own parent company unilaterally

added a cancer warning to a pesticide label in 2012.

In any event, Monsanto’s ability to unilaterally change

the label is not determinative. Though EPA purports to

arrogate lawmaking power to itself, exclaiming that “the

label is the law!”3 does not make it so. The actual law is

the written text of FIFRA, which flatly requires a manufacturer to stop selling a misbranded pesticide. That duty

is the same one imposed by Missouri law. It is not impossible to simultaneously obey identical commands.

STATUTORY PROVISIONS INVOLVED

The relevant statutory provisions are included in the

appendix.

STATEMENT

STATUTORY AND REGULATORY BACKGROUND

Neither Missouri nor federal law establishes “an affirmative permit scheme for the actual use of pesticides.”

Wisconsin Public Intervenor v. Mortier, 501 U.S. 597, 613

(1991). Instead, each of these independent sovereigns has

established a series of independent and overlapping rules

that forbid the sale or distribution of pesticides unless

stringent safety conditions are satisfied.

A. Federal Law

FIFRA establishes a series of independent prohibitions on selling and distributing pesticides. A pesticide

must successfully run the entire gauntlet before it can be

sold consistent with federal law.

1. Registration

Federal law forbids the distribution or sale of any pesticide unless it has first been registered with EPA. See 7

U.S.C. § 136j(a)(1)(A) (“[I]t shall be unlawful for any person in any State to distribute or sell … any pesticide that

Pet. Br. 8 (quoting EPA, Pesticide Registration Manual: Introduction (May 21, 2025), https://perma.cc/RRQ4-S928).

is not registered under section 136a of this title”); 7 U.S.C.

§ 136a(a). To register a pesticide, an applicant must submit to EPA “the complete formula of the pesticide,” along

with “a statement of all claims to be made for it,” “directions for use,” and “a complete copy of the labeling.” 7

U.S.C. § 136a(c)(1)(C), (D).

Upon receiving an application, the EPA Administrator

must promptly “review the data” and either “register the

pesticide” or else “notify the applicant” that the application “does not comply” with FIFRA’s requirements. 7

U.S.C. § 136a(c)(3)(A). FIFRA requires EPA to make several determinations before deciding to register a pesticide, including that “its labeling and other material required to be submitted comply with the requirements of

this subchapter.” 7 U.S.C. § 136a(c)(5)(B). So the Administrator, under the registration process, assesses whether

a pesticide “compl[ies] with the requirements of ” FIFRA,

including FIFRA’s (separate) statutory prohibition on the

sale or distribution of misbranded pesticides. See 7 U.S.C.

§ 136j(a)(1)(E).

But the EPA Administrator makes these determinations only for the purpose of deciding whether to register

the pesticide under section 136a. FIFRA does not vest

him with the power to issue authoritative and final pronouncements on whether a pesticide is misbranded. Section 136a(f)(2) proves as much, stating in no uncertain

terms that:

In no event shall registration of an article be

construed as a defense for the commission of

any offense under this subchapter.

Selling an unregistered pesticide is one offense, while selling a misbranded pesticide is a distinct one.

To be sure, EPA is entitled to deference when it determines whether a pesticide should or should not be registered . 7 U.S.C. § 136a(c)(6). And EPA’s decision to register a pesticide is conclusive for one statutory requirement — the prohibition on the sale or distribution of unregistered pesticides. 7 U.S.C. § 136j(a)(1)(A).4 But

FIFRA does not give conclusive effect to the subsidiary

assessments of fact that the Administrator makes when

deciding whether to register a pesticide under section

136a. See 7 U.S.C. § 136a(f)(2). Outside the registration

context, Congress has not delegated to EPA the authority

to interpret or apply FIFRA’s separate misbranding provisions. Nor has Congress empowered EPA to resolve disputed legal or factual questions in a manner that binds

judges and jurors. Any factual or legal determinations

that EPA makes during the registration process are relevant only to whether EPA must register the pesticide under section 136a.

2. Misbranding

FIFRA categorically forbids the distribution or sale of

a “misbranded” pesticide. See 7 U.S.C. § 136j(a)(1)(E). A

pesticide can be “misbranded” under FIFRA for any

number of reasons. See 7 U.S.C. § 136(q)(1)–(2) (defining

“misbranded” pesticides). Two definitions are relevant

If Mr. Durnell had sued Monsanto on a negligence per se theory

by claiming that EPA never should have registered Roundup —

and thus that Monsanto violated section 136j(a)(1)(A) by selling

an unregistered pesticide — EPA’s decision to register Roundup

would definitively foreclose this theory of liability. The only thing

that matters under section 136j(a)(1)(A) is whether EPA has in

fact registered the pesticide under section 136a, and no state or

federal jury is allowed to second-guess or collaterally attack

EPA’s registration decision.

here. First, a pesticide is misbranded if its label “does not

contain a warning or caution statement which may be necessary … to protect health and the environment.” 7 U.S.C.

§ 136(q)(1)(G). Second, a pesticide is misbranded if “its labeling bears any statement … which is false or misleading

in any particular.” 7 U.S.C. § 136(q)(1)(A). When EPA

makes its misbranding assessment at registration, it considers even “[a] true statement” misleading if “used in

such a way as to give a false or misleading impression to

the purchaser.” 40 C.F.R. § 156.10(a)(5)(vii).5

The text makes clear what this Court has confirmed:

the “unlawful act” of selling a misbranded pesticide is separate and distinct from the unlawful act of selling an unregistered pesticide. See Bates, 544 U.S. at 438 (“Because

it is unlawful under the statute to sell a pesticide that is

registered but nevertheless misbranded, manufacturers

have a continuing obligation to adhere to FIFRA’s labeling requirements.” (emphasis added)). So even if EPA determines during the registration process that a pesticide

is not misbranded — as it must as a condition for registration6— that determination is not conclusive on whether

the pesticide is actually misbranded. See 7 U.S.C.

§ 136a(f)(2) (“In no event shall registration of an article be

construed as a defense for the commission of any offense

under this subchapter.” (emphasis added)); Bates, 544

No provision of the statute delegates to EPA the authority to give

meaning to the words “false or misleading,” so this regulatory

gloss receives only Skidmore deference. See Loper Bright, 603

U.S. at 412–13; United States v. Mead Corp., 533 U.S. 218, 227–

28 (2001). But EPA is correct that a technically true statement

can nevertheless be “misleading” if it omits key information.

See 7 U.S.C. § 136a(c)(5)(B).

U.S. at 438 (“[R]egistration does not provide a defense to

the violation of the statute”).

That is because FIFRA delegates to the judiciary, not

to EPA, the ultimate power to determine whether a pesticide is misbranded within the meaning of the statute. See

Loper Bright, 603 U.S. at 412–13. EPA’s decision to register a pesticide, and EPA’s tentative assessments that a

pesticide and its label comply with the requirements of

FIFRA, serve only as “prima facie evidence” that the pesticide is not misbranded. 7 U.S.C. § 136a(f)(2).

3. Post-Registration Changes To Labels

After EPA registers a pesticide, a manufacturer may

change its label so long as the updated label complies with

FIFRA’s requirements. Monsanto claims that 7 U.S.C.

§ 136j(a)(1)(B) prohibits changes to an EPA-approved label,7 but that is demonstrably false. Section 136j(a)(1)(B)

prohibits the distribution or sale of a registered pesticide

only if the “claims made for it” substantially differ from

the “claims made for it” in the registration statement. The

“statement of all claims to be made for” a pesticide is distinct from its “labeling.” See 7 U.S.C. § 136a(c)(1)(C) (distinguishing “the labeling of the pesticide” from the “statement of all claims to be made for it”); see also pp. 37–39,

infra.8

4. Express Preemption

Section 136v provides:

Pet. Br. 8–9, 21, 25, 30, 45.

The Solicitor General refuses to endorse Monsanto’s characterization of section 136j(a)(1)(B). SG Br. 5, 20.

(a) A State may regulate the sale or use of any

federally registered pesticide or device in the

State, but only if and to the extent the regulation does not permit any sale or use prohibited

by this subchapter.

(b) Such State shall not impose or continue in effect any requirements for labeling or packaging

in addition to or different from those required

under this subchapter.

This means that “States may ban or restrict the uses of

pesticides that EPA has approved.” Bates, 544 U.S. at 450.

The only limitation is that a state may not enforce any “requirements for labeling or packaging” that are “in addition to or different from those required under this subchapter.” 7 U.S.C. § 136v(b).

B. Missouri Law

Missouri bars the sale of an unreasonably dangerous

pesticide that lacks an “adequate warning.” Moore, 332

S.W.3d at 756. And it defines inadequacy to include any

“warning that has been given [that] is informationally deficient.” Nesselrode v. Executive Beechcraft, Inc., 707

S.W.2d 371, 382 (Mo. 1986). A label with truthful information that nonetheless creates a “misleading effect” supports a jury verdict for failure to warn. Haberly v. Reardon Co., 319 S.W.2d 859, 867 (Mo. 1958); La Plant v. E.I.

DuPont De Nemours & Co., 346 S.W.2d 231, 245 (Mo. Ct.

App. 1961) (similar).

Missouri law does not impose a duty to change a pesticide label. It establishes only a duty “not to introduce

into commerce” a product whose label “fail[s] to warn of

danger.” Racer, 629 S.W.2d at 395 (emphasis added); see

also id. (“The breach of that duty occurs by the act of introducing such product into commerce.”); Nesselrode, 707

S.W.2d at 382 (similar).9 So Missouri law tracks 7 U.S.C.

§ 136(q)(1)(A) and (G) by forbidding the sale of pesticides

that lack “adequate” warnings, and leaves it to the judiciary — judges and juries — to determine whether a particular warning is “adequate.” The only differences between

Missouri law and the requirements of 7 U.S.C.

§ 136(q)(1)(A) and (G) are the remedies. Missouri requires

compensation to tort victims, while federal law authorizes

condemnation proceedings, civil penalties, and jail time.

Whether a manufacturer has violated its duty, i.e., sold

an “unreasonably dangerous” pesticide for lack of an adequate warning, is “an ultimate issue” for the jury, i.e., a

classic fact question. Moore, 332 S.W.3d at 756 (“The concept of unreasonable danger … is presented to the jury as

an ultimate issue without further definition.” (cleaned

up)). The jurors “give[] th[e] concept [of unreasonable

danger] content by applying their collective intelligence

and experience to the broad evidentiary spectrum of facts

and circumstances presented by the parties.” Nesselrode,

707 S.W.2d at 378. A product can be unreasonably dangerous both because of a true “absence of a warning” or because “the warning that has been given is informationally

deficient.” Id. at 382. In arguing about whether the pesticide was in fact unreasonably dangerous, the defendant is

permitted “to argue that the utility of a design outweighs

its risks.” Rodriguez v. Suzuki Motor Corp., 996 S.W.2d

47, 65 (Mo. 1999) (cleaned up). So a defendant is free to

These duties imposed by Missouri law still qualify as “requirements for labeling” under 7 U.S.C. § 136v(b)(2).

argue that the benefits of the product as sold outweigh any

costs.10

II. PROCEDURAL HISTORY

A. History Of Roundup Litigation

Roundup is a weedkiller developed by Monsanto. Its

active ingredient is glyphosate, which kills plants at their

roots. In 1985, EPA reviewed a rodent-model study showing that “glyphosate was oncogenic” and caused “rare tumor[s].”11 Based on that review, EPA classified glyphosate

as a possible human carcinogen.12 It later reclassified

glyphosate as a chemical for which there exists “evidence

of non-carcinogenicity for humans.”13 Over the next decade, studies showed that glyphosate was possibly genotoxic, i.e., capable of causing mutations in genes that lead

to cancer. Court of Appeals Respondent’s Appendix 41, 73.

In 2015, the International Agency for Research on

Cancer (IARC) concluded that glyphosate is probably

carcinogenic to humans.14 Two years later, California cate10. Monsanto repeatedly made those arguments to the jury here.

See, e.g., JA 135–136 (describing how Roundup is “a big deal to

farmers” because it kills weeds, which “actually make it impossible for [farmers] to grow food because it blocks the sun”); JA 136

(describing Roundup as “an advance” from other pesticides that

were “toxic” and created “environmental issues like sticking

around for a long time in the soil and groundwater”).

11. EPA, Memorandum re: Glyphosate Mouse Oncogenicity Study

(Apr. 3, 1985), https://perma.cc/T6FJ-VAL9.

12. See EPA, Consensus Review of Glyphosate (Mar. 4, 1985),

https://perma.cc/Z4ZZ-PE8Z.

13. EPA, Memorandum re Second Peer Review of Glyphosate (Oct.

30, 1991), https://perma.cc/5GEG-RFH3.

14. IARC Monographs Volume 112 (Mar. 20, 2015), https://perma.cc/

L79E-6LEF.

gorized glyphosate as a carcinogen under Proposition

65.15 In 2020, EPA issued an “interim decision” stating

EPA’s own view that “glyphosate is not likely to be carcinogenic to humans.” NRDC v. EPA, 38 F.4th 34, 43 (9th

Cir. 2022). The Ninth Circuit then vacated EPA’s factual

findings after holding them unsupported by substantial

evidence and inconsistent with the views of EPA’s own epidemiologists. Id. at 51. EPA never sought review in this

Court, so the vacatur is final. 16

In 2021, Monsanto’s parent company, Bayer, announced that it would discontinue its glyphosate-based

products sold in the residential market. Although farmers

continue to use glyphosate-containing Roundup, Monsanto says that it has been using other ingredients in

Roundup for the lawn-and-garden market since 2023.17

B. History Of This Suit

John L. Durnell began using Roundup in 1996. For

more than 20 years, he sprayed Roundup without wearing

protective equipment. Based on Monsanto’s label and

marketing, Durnell believed that Roundup was safe. In

2018, Durnell was diagnosed with mantle cell lymphoma,

a rare and aggressive form of non-Hodgkin lymphoma.

Durnell sued Monsanto in Missouri state court, bringing design-defect and failure-to-warn claims. He present15. Cal. Office of Env’t Health Hazard Assessment, Initial Statement of Reasons: Glyphosate (Mar. 28, 2017), https://perma.cc/

N4DK-FWEG.

16. Monsanto’s unbalanced and tendentious presentation of the scientific evidence does not reflect reality. See Brief of Amici Curiae

Roundup and Paraquat MDL Leadership.

17. Bayer, Managing the Roundup Litigation, https://perma.cc/

UGV5-Y8MV.

ed expert testimony that Roundup caused his cancer and

that Monsanto had failed to warn about it. Monsanto

never requested a Bates instruction to ensure that the

jury would interpret and apply Missouri law in a manner

consistent with FIFRA’s misbranding requirements.18

The jury awarded Durnell $1.25 million on his failure-towarn claim. To reach this verdict, the jury necessarily had

to find that Roundup lacked an adequate warning and

caused Durnell’s cancer. The jury found for Monsanto on

the remaining claims.

Monsanto appealed to the Missouri Court of Appeals.

Monsanto did not contest that the jury’s verdict rests on

substantial evidence, but argued only that Durnell’s failure-to-warn claim was preempted. The Missouri Court of

Appeals affirmed, holding that Missouri law does not impose any requirement “in addition to or different from”

those imposed by FIFRA. Pet. App. 7. The Missouri Supreme Court declined further review, and this Court

granted certiorari.

SUMMARY OF ARGUMENT

The Court should reject Monsanto’s preemption arguments and affirm.

Monsanto and the Solicitor General are making two

separate arguments for express preemption. Their first

18. Bates holds that juries considering failure-to-warn claims must

be instructed to apply state law in a manner that tracks the misbranding requirements of FIFRA, but it places the onus on the

defendant to request such a jury instruction if it believes that

state law could extend beyond federal labeling requirements. See

Bates, 544 U.S. at 454 (“If a defendant so requests, a court should

instruct the jury on the relevant FIFRA misbranding standards.”); see also pp. 34–35, infra.

argument is that EPA has authoritatively pronounced

that Roundup’s labeling does not violate FIFRA’s misbranding provisions. On this view, EPA’s approval of the

label represents a binding agency determination that the

label comports with federal law, so any state-law failureto-warn claim over an EPA-approved label will add to the

federal labeling requirements under section 136v(b).

This argument fails because EPA has no delegated authority to interpret or apply FIFRA’s misbranding provisions in a manner that binds the judiciary. Under Loper

Bright, it is for courts to determine the meaning of

FIFRA’s provisions absent an express delegation of interpretive authority to the agency. Monsanto does not even

attempt to identify any language in FIFRA that departs

from Loper Bright’s default rule. Instead, Monsanto begs

the question by assuming that EPA’s beliefs on the legality of Roundup’s labeling must somehow bind the courts,

and that EPA’s factual assertions that glyphosate is noncarcinogenic must somehow bind juries under a doctrine

akin to nonmutual collateral estoppel. But there is no statutory language in FIFRA that purports to give EPA these

powers, and there are numerous provisions throughout

FIFRA that explicitly refute the notion that EPA’s registration decision has binding effect in subsequent court

proceedings. Foremost among them is 7 U.S.C.

§ 136a(f)(2), which explicitly prohibits EPA’s registration

decisions from being invoked as a “defense” to a misbranding charge.

Monsanto and the Solicitor General’s second argument for express preemption is equally unavailing. They

contend that Missouri’s failure-to-warn law differs from

the requirements of FIFRA because federal law compels

courts to consider both costs and benefits when deciding

whether a pesticide warning is “adequate” under 7 U.S.C.

§ 136(q)(1)(G), while Missouri merely allows the factfinder to conduct a cost-benefit analysis. Pet. Br. 43; SG

Br. 24–25. But FIFRA requires consideration of both

costs and benefits when the only basis for declaring a pesticide “misbranded” is failure to include an “adequate”

warning under 7 U.S.C. § 136(q)(1)(G). FIFRA does not

require (or even allow) consideration of costs and benefits

when a pesticide is misbranded because its label is “misleading” under 7 U.S.C. § 136(q)(1)(A), and a label that

lists carcinogens as ingredients without mentioning the

risk of cancer is “misleading” (and thus misbranded) under FIFRA. Monsanto also forfeited this argument by

failing to request a Bates instruction that would have told

the jury to apply Missouri law in a manner that tracks

FIFRA’s misbranding requirements. See Bates, 544 U.S.

at 454. And any forfeited error in the jury instructions

would be harmless, as it is inconceivable that a jury instructed to apply cost-benefit analysis would conclude

that (1) Roundup in fact caused Durnell’s cancer but (2)

the supposed financial benefits of the weedkiller somehow

outweigh the minimal costs of including a life-saving cancer warning.

Finally, the Court should reject Monsanto’s impliedpreemption argument. If Missouri and federal law impose

the same duty — as required to avoid express preemption — it is logically impossible for Monsanto to show impossibility. Monsanto claims that “federal law” prohibits

it from adding a cancer warning to its Roundup labels, but

nothing in FIFRA or EPA’s regulations says that. Monsanto repeatedly cites 7 U.S.C. § 136j(a)(1)(B), but that

provision does not mention labels, and prohibits manufacturers from altering only the “claims made for” the pesticide in the registration statement. See 7 U.S.C.

§ 136a(c)(1)(C). Monsanto also asserts that adding a cancer warning on its Roundup labels would render those labels “false” under 7 U.S.C. § 136(q)(1)(A), but Monsanto

could add tomorrow an indisputably truthful and appropriately hedged warning such as: “The International

Agency for Research on Cancer considers glyphosate

probably carcinogenic to humans.” Monsanto also mischaracterizes EPA’s regulations, which allow these sorts

of label changes without EPA’s preapproval.

Even if FIFRA or EPA’s regulations somehow barred

Monsanto from adding a cancer warning, that still would

not establish impossibility. That is because FIFRA requires Monsanto to comply with the statutory misbranding provisions, regardless of whether EPA regulations allow Monsanto to alter a label. 7 U.S.C. § 136j(a)(1)(E). If

Roundup’s labels are misleading or inadequate, then

Monsanto must either stop selling Roundup, as it has in

the residential market, or pay the damages that result

from its decision to distribute or sell a pesticide that Durnell’s jury found was misbranded. When both state and

federal law require cessation, stopping is both possible

and required. See Mutual Pharmaceutical Co. v. Bartlett,

570 U.S. 472, 487 n.4 (2013).

ARGUMENT

DURNELL’S FAILURE-TO-WARN CLAIM IS NOT

EXPRESSLY PREEMPTED

FIFRA preempts state laws only when they impose

labeling requirements “in addition to or different from

those required under” FIFRA. 7 U.S.C. § 136v(b). Monsanto cannot establish a preemption defense under this

section for two reasons.

First, Missouri tort law does not impose any labeling

requirements that add to or differ from FIFRA’s requirements. That is because: (1) Missouri law tracks the language of 7 U.S.C. § 136(q)(1)(A), (G) by requiring “adequate” warnings on pesticide labels that are not “false or

misleading”; and (2) Both Missouri law and FIFRA delegate to the judiciary the power to fill the interstices of

their adequate-warning requirement. So both state and

federal law establish identical legal standards, and each of

them empowers the same actors — judges and jurors — to

decide whether a particular pesticide label actually contains lawful warnings. Monsanto’s argument to the contrary presumes that FIFRA has delegated to EPA the

power to interpret the misbranding prohibition in a manner that binds state and federal judiciaries. But Monsanto

never even attempts to explain how FIFRA delegates

these powers to EPA given the holding of Loper Bright.

Second, even if Monsanto could show some difference

between Missouri law and FIFRA, it still cannot prevail

on its express-preemption defense. As an initial matter,

Monsanto forfeited its affirmative defense by failing to

ask for a Bates instruction at trial. Regardless, any error

was harmless, as no jury that necessarily found that

Roundup causes cancer would conclude that the benefits

of ignorance outweigh the costs of the truth.

A. Missouri Tort Law Does Not Add To Or Differ From

FIFRA’s Adequate-Warning Requirement

Monsanto’s and the Solicitor General’s more ambitious express-preemption argument depicts EPA’s deci-

sion to register a pesticide as the final and authoritative

pronouncement that the pesticide complies with the misbranding prohibition. On this theory, any failure-to-warn

claim against an EPA-approved label is automatically

preempted by 7 U.S.C. § 136v(b). Pet. Br. at 23–26. Because registration is simply EPA’s application of the

FIFRA requirements, not a binding determination that

changes their legal content, the argument fails.

1. FIFRA Delegates To The Judiciary And Not EPA

The Power To Determine Whether Roundup Is

Misbranded

If FIFRA authorizes the judiciary to decide whether

Roundup is misbranded under 7 U.S.C. § 136j(a)(1)(E),

then the jury verdict and the Missouri Court of Appeals’

ruling do not “add” anything to FIFRA’s labeling requirements. They represent nothing more than a judicial interpretation and application of the adequate-and-non-misleading-warning standard, which is established in FIFRA

and mirrored in Missouri law. A court does not “add” to or

“differ” from existing law by applying an established legal

standard to a particular set of facts. And a state does not

“add” to the labeling requirements of FIFRA by authorizing judges and jurors to enforce parallel state law.

EPA’s determinations that a label complies with

FIFRA’s misbranding provisions are nothing more than

EPA’s opinion on the matter, and they do not bind the

courts unless Congress has delegated interpretative authority to the Administrator. See Loper Bright, 603 U.S.

at 413 (“[W]hen a particular statute delegates authority to

an agency consistent with constitutional limits, courts

must respect the delegation, while ensuring that the

agency acts within it.”).

Monsanto’s brief assumes that FIFRA vests EPA

with powers to bind the judiciary to its interpretations

and applications of the statutory misbranding provisions.

But Monsanto never attempts to explain how the statutory text could be read to provide such a delegation given

Loper Bright, which holds that the default regime empowers courts to interpret and apply the law. Id. at 394–96,

412–13. That default applies because FIFRA’s registration provision delegates only narrow and carefully defined

powers to EPA. Consider the text of 7 U.S.C. § 136a(c)(5):

The Administrator shall register a pesticide if

the Administrator determines that, when considered with any restrictions imposed under

subsection (d) —

(A) its composition is such as to warrant the proposed claims for it;

(B) its labeling and other material required to

be submitted comply with the requirements of

this subchapter;

unreasonable adverse effects on the environment; and

(D) when used in accordance with widespread

and commonly recognized practice it will not

generally cause unreasonable adverse effects on

the environment.

All of the Administrator’s factfinding authority is textually linked to his power to “register a pesticide.” That

includes determining whether a pesticide’s proposed la-

beling “compl[ies] with the requirements”19 of FIFRA.

The statute requires EPA to register a pesticide if it concludes that its labeling complies with FIFRA and that the

remaining requirements of section 136a(c)(5) have been

met.

But this provision does not vest EPA with authority to

conclusively and definitively resolve whether a pesticide’s

label complies with FIFRA in an adversarial judicial proceeding. It merely instructs EPA to make a one-time, limited-purpose determination whether the label (in EPA’s

opinion) comports with FIFRA’s registration requirements. The powers conferred by section 136a(c)(5) cannot

be construed to give EPA authority to render binding pronouncements on whether a pesticide actually violates

FIFRA’s misbranding provisions. This is so for at least

three reasons.

First, EPA’s findings during the registration process

are based on the limited information submitted at that

time, and subsequent discoveries could show that an EPAregistered pesticide is in fact misbranded. It is untenable

to think that section 136a(c)(5) would make EPA’s approval of a label during the registration process the authoritative and conclusive determination of whether a label actually and always complies with FIFRA’s misbranding provisions.

Second, the statute provides that the only legal consequence of EPA’s decision to approve a label during the

registration process is that EPA “shall register” the pesticide, so long as the remaining criteria listed in section

136a(c)(5) are also met. Neither section 136a nor any other

provision of FIFRA purports to attach additional legal

19. 7 U.S.C. § 136a(c)(5)(B).

significance to EPA’s determination that a proposed label

complies with the statutory misbranding provisions.

Third, there is no language in section 136a(c)(5) or

elsewhere in FIFRA that purports to delegate such

sweeping interpretive powers to EPA.20 After Loper

Bright, Monsanto must point to text that expressly vests

EPA with authority to render conclusive pronouncements

on the meaning of FIFRA’s misbranding provisions and

their application to particular pesticides. Monsanto has

not even attempted to carry its burden,21 content to assume that FIFRA departs from Loper Bright’s rule without presenting an argument to that effect.

20. Does Monsanto truly believe that section 136v’s reference to requirements “under” FIFRA — as opposed to “by” FIFRA —

shows that Congress delegated to EPA the authority to definitively pronounce that a pesticide’s label is not misbranded? Pet.

Br. 26–27. That “is too extravagant to be maintained.” Marbury

v. Madison, 1 Cranch 137, 179 (1803). Congress’s choice of preposition comes nowhere close to a legislative decision to “expressly

delegate” binding interpretative authority to EPA or to empower

the Administrator to “fill up the details” of the misbranding prohibition. Loper Bright, 603 U.S. at 394–95 (cleaned up). Whether

requirements are created “under,” “by”, or “in” FIFRA, Monsanto must show on the face of the statute that Congress intended

to give controlling legal effect to EPA pronouncements “that do

not appear on the face of the statute.” Pet. Br. 26. Apart from

EPA’s decision to register a pesticide, Monsanto has not and will

not make that showing.

21. Neither has the Solicitor General, who baldly asserts that EPA’s

determinations under section 136a(c)(5) have binding legal force

without ever bothering to address the delegation issue. See SG

Br. 27 (“[W]hen EPA carries out its duties under FIFRA by making a statutorily required determination — here, whether a pesticide contains all warnings necessary and adequate to protect human health — that determination preempts different state-law

requirements on the topic.”).

To the extent one can cobble together a delegation argument from Monsanto’s brief, it rests on nothing more

than snippets of legislative history22 and handwringing

over the policy implications of a non-preemption holding.23

As Monsanto would have it, EPA must be vested with delegated authority to construe FIFRA’s misbranding provisions and render binding factual determinations on whether glyphosate causes cancer — even though Monsanto

cannot identify any statutory language empowering EPA

to displace the judiciary’s law-interpretation and factfinding functions — because congressional committee reports

discuss the need for “balance” and “uniformity,”24 and because agency diktats are needed to prevent a “crazyquilt”25 of conflicting state regulations. That won’t cut it

under the Loper Bright regime. Agencies must identify

textual delegations of authority before their pronouncements can bind the judiciary, and delegations to agencies

cannot be effectuated through congressional committee

reports. See Epic Systems Corp. v. Lewis, 584 U.S. 497,

523 (2018) (“[L]egislative history is not the law.”); John F.

Manning, Textualism as a Nondelegation Doctrine, 97

Colum. L. Rev. 673 (1997).

Monsanto’s policy concerns are likewise irrelevant to

the delegation issue. A desire to promote “uniformity” is

no reason to construe federal statutes as vesting agencies

with the power to bind courts to their interpretations and

applications of the law. See Loper Bright, 603 U.S. at 403.

If Monsanto wants to wage a rearguard action against this

22. Pet. Br. 5–6.

23. Pet. Br. 36–37, 50–53.

24. Pet. Br. 6 (quoting H.R. Rep. No. 104-669(II), at 29-30 (1996)).

25. Pet. Br. 2, 6.

holding, it should say so candidly. A mere two years after

Loper Bright, the Court should not begin creating one-off

exceptions of the sort that eventually doomed Chevron’s

presumed-delegation regime. See id. at 404–06.

Monsanto’s concerns about balkanized and conflicting

state regulatory regimes are also overblown. Section 136v(b) prohibits state legislatures from enacting labeling requirements that cannot be found in FIFRA. So

there is no possibility of conflicting state legislation over

whether pesticide warnings must appear in red or yellow

letters or whether ignitable pesticides will be described as

“flammable” or “inflammable.” Pet. Br. 5. There is also no

judge or jury that will find a pesticide insufficiently labeled under state common law over issues of coloring or

nomenclature, and any manufacturer sued on such a theory would be entitled to a directed verdict. And EPA’s labeling regulations are still entitled to Skidmore deference

from the judiciary, even though EPA lacks delegated interpretive authority over FIFRA’s misbranding provisions. See Mead, 533 U.S. at 227–28.

Courts and juries may well diverge in applying the

standards in FIFRA, but that is always the consequence

of allowing citizen fact-finders — not government technocrats — to safeguard the people’s cherished rights. Where

Monsanto and the Solicitor General see a “patchwork”26

or hear a “cacophony,”27 Madison and Blackstone saw “the

glory of the English law.” 3 W. Blackstone, Commentaries

on the Laws of England 379 (Robert Bell ed., 1771–72).

Monsanto cannot deny the power of the jury to determine

26. Pet. Br. 5, 50–51; SG Br. 13.

27. Pet. Br. 5; SG Br. 4.

the ultimate facts when applying the standards from state

tort law that parallel FIFRA’s requirements.

Monsanto also worries that preemption is needed to

protect American “agriculture and innovation.” Pet. Br.

50. That cannot serve as a reason to construe FIFRA as

giving EPA powers to bind the judiciary. Courts do not

have the capacity to assess the policy consequences of

their rulings, and judges are bound by oath to administer

justice without regard to persons or pesticides. See 28

U.S.C. § 453. Whatever preemptive force FIFRA might

have over state law is entirely unaffected by the importance of the pesticide or the effects that liability might

have on the overall economy. If a non-preemption holding

would produce the dire results Monsanto fears, then it

must ask Congress and not the courts to change the law.

Monsanto and its parent company Bayer have more than

enough clout with state and federal officials,28 and they are

about as far as one can get from the “discrete and insular

minorities”29 that can rely only on courts to protect their

interests.

Indeed, after a decade of litigation and billions of dollars of settlement payments, Monsanto has been vigorously lobbying Congress and state legislatures to secure

the immunity from suit that the company is telling this

Court has been hidden in a law of the United States since

1974. In 2023 and 2024, Monsanto tried to insert a provision into FIFRA that bars state-law liability “for failing

28. See, e.g., Hiroko Tabuchi, A Trump Order Protected a Weedkiller. And Also a Weapon of War, New York Times, March 6, 2026,

http://bit.ly/40wpdac (visited March 25, 2026)

29. United States v. Carolene Products Co., 304 U.S. 144, 152 n.4

(1938).

to comply with requirements with respect to labeling or

packaging that is in addition to or different from the labeling or packaging approved by the Administrator.”30

The difference between the law Monsanto wishes Congress would enact and the one that has already navigated

the bicameralism and presentment process is obvious.

Perhaps the political branches will be swayed by Monsanto’s policy arguments and enact the express preemption clause the company so desperately seeks. The executive branch, at least, seems receptive to Monsanto’s entreaties. See Executive Order No. 14387, Promoting the

National Defense by Ensuring an Adequate Supply of

Elemental Phosphorus and Glyphosate-Based Herbicides, 91 Fed. Reg. 8703 (Feb. 18, 2026). But this Court is

confined to reviewing the enacted law, not the rewrite a

massive corporation might one day shepherd through the

halls of Congress.

2. FIFRA’s Provisions Show That EPA’s Decision To

From Finding That Pesticide Misbranded

FIFRA explicitly negates the idea that EPA’s approval of a label during the registration process somehow

insulates that label from subsequent judicial attack.

Start with 7 U.S.C. § 136a(f)(2), which says:

In no event shall registration of an article be

construed as a defense for the commission of

any offense under this subchapter. As long as no

30. H.R. Rep. No. 188-4288, at 2 (2023). Monsanto has also persuaded

lawmakers in Georgia and North Dakota to enact immunity legislation under state tort law. Ga. Code Ann. § 2-7-171; N.D. Cent.

Code § 28-01.3-11.

cancellation proceedings are in effect registration of a pesticide shall be prima facie evidence

that the pesticide, its labeling and packaging

comply with the registration provisions of the

subchapter.

This means that there will be EPA-approved labels that

courts may find “inadequate” or “misleading” under 7

U.S.C. § 136(q). That cannot be squared with Monsanto’s

claim that the use of an EPA-approved label prevents

courts from finding that label “inadequate” or “misleading” under FIFRA or a state law that tracks the federal

misbranding standards.

The statute also says that EPA’s decision to register a

pesticide — and the concomitant determinations that EPA

makes during the registration process — serve as nothing

more than “prima facie evidence” that the label complies

with FIFRA’s registration provisions. Monsanto, by contrast, is insisting that EPA’s determinations have res judicata effect. Cf. B&B Hardware, Inc. v. Hargis Industries, Inc., 575 U.S. 138, 148 (2015) (allowing agency findings to bind a court only when the agency was “acting in a

judicial capacity” and all the issue-preclusion factors are

met, including an issue actually litigated between the

same parties (cleaned up)).

Monsanto and the Solicitor General try to get around

section 136a(f)(2) by suggesting it applies only when

someone sells a pesticide without the EPA-approved label

or in violation of its terms of registration. Pet. Br. 38–39;

SG Br. 26. But according to Monsanto, that conduct is

prohibited by 7 U.S.C. § 136j(a)(1)(B), not the misbranding provision of (a)(1)(E). Pet. Br. 8–9, 21, 25, 30. The separate prohibition on selling a misbranded pesticide —

which surely counts as “any offense” under FIFRA —

does not do any work on Monsanto’s view. Superfluity is

not Monsanto’s only problem. The text of section

136j(a)(1)(B) forbids selling a “registered pesticide” with

claims that differ from “the statement required in connection with its registration.” The very next section uses

identical language, forbidding the sale of a “registered

pesticide” if the composition differs from the registration

statement. 7 U.S.C. § 136j(a)(1)(C). If the misbranding

prohibition were only meant to cover a registered pesticide that departed from the label contained in the registration statement, surely Congress would have used a

parallel formulation.

One needs only to read section 136a(f)(2) to see that it

applies without regard to the type of FIFRA violation that

a plaintiff or prosecutor alleges. See 7 U.S.C. § 136a(f)(2)

(“In no event shall registration of an article be construed

as a defense for the commission of any offense under this

subchapter.” (emphases added)). And Monsanto does not

engage with the second sentence of 7 U.S.C. § 136a(f)(2),

which makes EPA’s label-approval decisions “prima facie

evidence” of statutory compliance. Prima facie evidence,

by its very nature, is evidence that can be rebutted in

court. See Black’s Law Dictionary (12th ed. 2024). Indeed,

the reason this Court long ago construed an almost identical provision in the Interstate Commerce Act not to violate the Seventh Amendment is because making an

agency finding “prima facie evidence” “takes no question

of fact from either court or jury.” Meeker v. Lehigh Valley

R. Co., 236 U.S. 412, 430 (1915) (emphasis added); see also

Theatre Enterprises, Inc. v. Paramount Film Distributing Corp., 346 U.S. 537, 541 (1954) (Prima facie evidence

was not enough, even in conjunction with other evidence,

to form the basis for a directed verdict). Without even

grappling with the text, Monsanto wants to convert

“prima facie evidence” into an irrebuttable presumption.31

If EPA’s determinations about misbranding were conclusive, they would apply with as much force whenever the

Administrator believes that a pesticide is misbranded as

when he thinks, as here, that one is not misbranded. After

all, a textual delegation to definitively announce misbranding vel non does not turn on the answer the Administrator gives for a particular pesticide. But FIFRA unambiguously rejects that approach. Section 136k, for example, allows the United States to bring condemnation actions against misbranded pesticides, but it guarantees the

right to a jury trial in those proceedings. See 7 U.S.C.

§ 136k(c) (“[E]ither party may demand trial by jury of any

issue of fact joined in any case”). FIFRA also empowers

the Administrator to seek civil penalties against those

who distribute or sell misbranded pesticides,32 where the

accused would be constitutionally entitled to a jury trial

under the Seventh Amendment. See SEC v. Jarkesy, 603

U.S. 109 (2024). And FIFRA authorizes criminal prosecutions of those who knowingly violate the statute’s misbranding provision,33 where the defendant likewise enjoys

a constitutional right to a jury trial. See U.S. Const.

amend. VI; Bates, 544 U.S. at 452 (“In criminal prosecu31. It is astounding that Monsanto would deny that juries may “second-guess” the findings and determinations that EPA makes

during the registration process when section 136a(f)(2) not only

allows but explicitly invites courts and juries to second-guess

those findings and determinations. Pet. Br. 2, 22, 50.

32. 7 U.S.C. § 136l(a)(1).

33. See 7 U.S.C. § 136l(b).

tions for violation of FIFRA’s provisions … juries necessarily pass on allegations of misbranding.”).

In all of these judicial proceedings, there would be

nothing for a jury to do if jurors must simply accept the

Administrator’s factual determinations and legal conclusions as binding “laws of the United States.” Yet Congress

expressly contemplated that a jury will decide for itself

whether a pesticide is misbranded under FIFRA, performing its traditional role of resolving any disputed questions of fact relevant to the inquiry. The jury can consider

EPA’s views as “prima facie evidence,” 7 U.S.C.

§ 136a(f)(2), which is the opposite of a legal conclusion that

cannot be second guessed absent jury nullification.

Congress’s decision to reaffirm the right to trial by

jury hammers home that FIFRA does not delegate to

EPA the prerogative to decree as a matter of law whether

a pesticide is misbranded as a matter of fact. No different

result can obtain when a litigant such as Durnell is contesting EPA’s belief that a pesticide is not misbranded.

FIFRA delegates these decisions to judges and juries regardless of whether EPA takes the side of the injured tort

victim or the manufacturer.

Monsanto’s next move, echoed by the Solicitor General, is to claim that the Court can ignore section

136a(f)(2) because it “is not a preemption provision at all,”

Pet. Br. 38–39; SG Br. 25–27. So what? By negating registration as a defense to any federal offense, section

136a(f)(2) confirms beyond doubt that the separate prohibition on selling a misbranded pesticide remains a federal “requirement.” Missouri failure-to-warn law is thus

free to operate so long as it parallels that federal obligation. 7 U.S.C. § 136v(b). Indeed, the key federal require-

ments themselves are not contained in “a preemption provision,” see 7 U.S.C. § 136j, but that hardly makes them

irrelevant to an express-preemption clause that turns entirely on whether state law dictates what federal law also

compels.

3. Missouri’s Warning Requirements Do Not Add To

Or Differ From FIFRA’s Misbranding Provisions

Monsanto and the Solicitor General have a more modest express-preemption theory. They try to concoct a “difference” between Missouri and federal warning regimes

by claiming that FIFRA requires consideration of costs

and benefits when assessing the “adequacy” of a warning,

while Missouri merely allows that analysis. Pet. Br. 40–43;

SG Br. 24–25. But this argument pretends that the statutory definition of “misbranding” encompasses only the adequate-warning requirement in 7 U.S.C. § 136(q)(1)(G).

Monsanto and the Solicitor General completely ignore the

definition that forbids the sale of pesticides with a “false

or misleading” label. See 7 U.S.C. § 136(q)(1)(A); cf. Bates,

544 U.S. at 438 (citing that provision). That definition of

“misbranding” does not require or even allow cost-benefit

analysis.

Missouri law similarly allows a jury to determine

whether Roundup’s label is “informationally deficient” by

listing glyphosate without disclosing its risks.34 This does

not reach beyond the requirements of FIFRA, which categorically prohibits “misleading” labeling without regard

to costs or benefits, and it vests the judiciary with auth34. See Nesselrode, 707 S.W.2d at 382; La Plant, 346 S.W.2d at 245;

Haberly, 319 S.W.2d at 867 (similar holding regarding a label

with “misleading effect”).

ority to determine whether a particular pesticide label is

“misleading” (and therefore misbranded). So Missouri’s

failure-to-warn law does not add to or differ from

FIFRA’s misbranding requirements, regardless of the extent to which Missouri law merely allows or requires consideration of cost-benefit analysis.

B. Even If Monsanto Could Show That Missouri Tort

Law Adds To Or Differs From FIFRA, Monsanto

Forfeited This Argument By Failing To Ask For A

Bates Instruction At Trial

Even if Monsanto could show some difference between

Missouri law and FIFRA, it still cannot prevail because

Monsanto forfeited this affirmative defense by failing to

ask for a Bates instruction at trial. To ensure that Monsanto was found liable only for a “genuinely equivalent”

Missouri labeling requirement, the burden was on the

company to “request[]” an instruction “on the relevant

FIFRA misbranding standards.” Bates, 544 U.S. at 454.

Monsanto, however, agreed with the jury instructions in

the trial court and never challenged them on appeal.

Bates was right to require defendants to seek corrective jury instructions where state common law could extend beyond the requirements of FIFRA. Federal preemption operates as applied, displacing only the applications of state law that conflict with federal law. English v.

General Electric Co., 496 U.S. 72, 79 (1990) (“[S]tate law

is pre-empted to the extent that it actually conflicts with

federal law”); Bates, 544 U.S. at 453 (If state law imposed

a “broader obligation” than FIFRA, plaintiff ’s claim

would be preempted only “to the extent of that difference.”). If Missouri law permitted Durnell to recover on

one theory of liability that entirely tracks FIFRA, i.e., one

where a necessary cost-benefit analysis cuts in plaintiff ’s

favor, and another theory that is slightly easier for plaintiff to satisfy, i.e., one where a cost-benefit analysis is

merely a consideration, the burden was on Monsanto to

seek the appropriate limiting instruction so the jury could

only return a plaintiff ’s verdict on the parallel theory.

Monsanto cannot convert section 136v(b) into a categorical immunity from suit by lying behind the log and refusing to request a jury instruction that would have obviated

its grievances with the scope of Missouri law.

Even if this Court were to assume that Monsanto had

preserved its objections to the jury instructions, any failure to make the jury conduct a cost-benefit analysis was

harmless. There is no conceivable scenario in which a jury

would conclude: “Roundup causes cancer, but it was acceptable not to warn Durnell of this deadly risk because

the benefits of ignorance induced him and others to keep

using the product, leaving gardens beautiful and farm

yields abundant. You cannot have manicured lawns and

cheap groceries without some people getting cancer, so

omitting the warnings was worth it.” That kind of callous

disregard for human agency and informed consent would

be dead on arrival even at a University of Chicago lawand-economics seminar. There is no chance it would have

persuaded Durnell’s jury — which even Monsanto agrees

was permitted to consider costs and benefits — to reach a

different verdict.35

35. If the Court holds that Missouri’s state-law labeling requirements reach beyond the commands of FIFRA and further rejects

Durnell’s forfeiture and harmless-error defenses, it should remand for a new trial with proper jury instructions under Bates.

II. DURNELL’S FAILURE-TO-WARN CLAIM IS NOT

IMPLIEDLY PREEMPTED

Durnell’s claim is not expressly preempted because it

is not “in addition to or different from” federal law. 7

U.S.C. § 136v(b). That means Missouri law imposes the

same requirements that appear in the federal misbranding provisions: do not sell a pesticide the label of which is

misleading or inadequate.

That dooms Monsanto’s impossibility-preemption argument as a matter of basic logic. Two equivalent commands cannot logically contradict each other, so no court

would view federal law as displacing state law under the

traditional doctrine of implied repeals. PLIVA, Inc. v.

Mensing, 564 U.S. 604, 622 (2011) (plurality op.) (“[F]ederal law should be understood to impliedly repeal conflicting state law.”) (citing Caleb Nelson, Preemption, 86 Va.

L. Rev. 225 (2000)). Nor is it “impossible” to do what both

state and federal law require. Albrecht, 587 U.S. at 313.

Refusing to accept state and federal duties on their

own terms, Monsanto repackages its obligation under

Missouri law as a duty to change the label. Even with this

framing, Monsanto has come nowhere close to establishing the “demanding defense” of impossibility. Id. Nothing

in FIFRA prevents unilateral label changes to cure a misbranded label. See pp. 38–39, infra. EPA’s regulations,

even if they carried the force of law, permitted such

changes. See pp. 39–42, infra. And there is no EPA rule

akin to the pharmaceutical Changes Being Effected regulation that would allow the Administrator to order Monsanto to walk back a unilateral change. 21 C.F.R.

§ 314.70(c)(6)–(7).

Though Monsanto could have (and should have)

changed Roundup’s label, it was duty bound not to sell a

misbranded pesticide under state and federal law. And although this Court has rejected a “stop-selling” response

when only state law imposes a labeling requirement,36 the

analysis is entirely different when federal law also compels an actor to stop selling the product that is mislabeled

under state law. Bartlett, 570 U.S. at 487 n.4. If state and

federal law both require an actor to stop selling, it is not

impossible to obey both commands.

In short, there is no impossibility because: (1) Nothing

in FIFRA or EPA's regulations prevented Monsanto from

adding a cancer warning; and (2) Even if federal law prevented Monsanto from changing Roundup’s labeling, it

was obligated by FIFRA’s misbranding requirements to

either stop selling Roundup or willingly pay the damages

and penalties that attach to selling a pesticide that Durnell’s jury determined to be misbranded.

A. Neither FIFRA Nor Its Implementing Regulations

Prevent Monsanto From Adding A Cancer Warning To

Roundup’s Labeling

Monsanto’s impossibility-preemption argument hinges on its assertion that “federal law” requires it to use

labels identical to those EPA approved during the registration process.37 Pet. Br. 35. But nothing in FIFRA or

36. Bartlett, 570 U.S. at 488.

37. Pet. Br. 2 (“Monsanto could not provide the warnings Missouri

law requires without rendering Roundup misbranded under federal law.”); id. at 30 (“FIFRA makes it illegal to distribute a pesticide with health warnings other than those approved by EPA.”);

see also id. at 8–9, 21–22, 25–26, 33, 35, 44–45.

EPA regulations prevents Monsanto from unilaterally

adding cancer warnings to Roundup’s labeling.

1. 7 U.S.C. § 136j(a)(1)(B) Prevents Manufacturers

From Altering The Statement Of Claims Made For

A Pesticide, Not Its Labeling

Monsanto falsely asserts that 7 U.S.C. § 136j(a)(1)(B)

prohibits post-registration label changes. Pet. Br. 25

(“FIFRA makes it illegal to distribute a pesticide with labeling substantially different from the EPA-approved label. 7 U.S.C. § 136j(a)(1)(B).”). What the provision actually prohibits is the distribution or sale of:

any registered pesticide if any claims made for

it as a part of its distribution or sale substantially differ from any claims made for it as a

part of the statement required in connection

with its registration under section 136a of this

title;

7 U.S.C. § 136j(a)(1)(B) (emphases added). The “claims

made” in the registration statement are distinct from the

label:

Each applicant for registration of a pesticide

shall file with the Administrator a statement

which includes — …

and any directions for its use;

7 U.S.C. § 136a(c)(1)(C) (emphases added). So the “labeling,” the “statement of all claims to be made for” the pesticide, and the “directions for its use” are different pieces

of information that an applicant submits during the regis-

tration process. Yet section 136j(a)(1)(B) locks into place

only the statement of claims made for the pesticide, leaving manufacturers free to change the “labeling” and the

“directions for its use.” Equating the statement of claims

with the label is nothing short of misdirection.

Monsanto also claims that including a cancer warning

on Roundup labels would violate FIFRA’s misbranding

provisions by making those labels “false or misleading”

under 7 U.S.C. § 136(q)(1)(A). Pet. Br. 2. That defense was

available to Monsanto, but the jury disagreed. It is for jurors and judges, not Monsanto, to resolve the factual

question of whether a cancer warning would violate

FIFRA’s misbranding provisions. And in all events, Monsanto can easily provide an adequate cancer warning that

is irrefutably truthful and not misleading, such as: “The

International Agency for Research on Cancer considers

glyphosate probably carcinogenic to humans.” Nothing in

FIFRA prohibits such a warning, and nothing in state law

required a particularly worded warning so long as it was

adequate. See Wyeth v. Levine, 555 U.S. 555, 565 (2009).

2. EPA’s Regulations Do Not And Cannot Prevent

Monsanto From Adding A Cancer Warning To

Roundup’s Labeling

Monsanto also cites EPA regulations that purport to

prohibit unilateral modifications to the label of a registered pesticide. See 40 C.F.R. §§ 152.44, 152.46. But regulations cannot prohibit what the statute allows under

Loper Bright, and EPA cannot concoct a prohibition on

label modifications when 7 U.S.C. § 136j(a)(1)(B) bars

manufacturers from altering only the claims made for the

pesticide. Nothing else in FIFRA prevents a manufacturer from unilaterally changing the registered label. In

fact, complying with the misbranding provision will often

require that the manufacturer either amend the label or

cease selling the pesticide altogether. EPA lacks statutory

authority to impose a preclearance requirement for label

modifications, especially when a manufacturer is seeking

to add warnings or caution statements that are “necessary … to protect health and the environment” or to avoid

rendering the label “false or misleading.” 7 U.S.C.

§ 136(q)(1)(G), (A).

Even assuming the regulations are valid, these EPA

rules are no help to Monsanto because they allow Monsanto to unilaterally add cancer warnings so long as it

avoids placing the warning in certain sections of the label.

And the versions of these rules in effect when Durnell

first started using Roundup were even clearer in permitting unilateral changes.

Under 40 C.F.R. § 152.46(a)(1), EPA may permit “minor” label modifications to proceed through notification

without the need for EPA approval. EPA lists the permissible unilateral changes in its “Pesticide Registration Notices” or “PRNs.” In 1995, EPA issued PRN 95-02, which

provides that “advisory statements,” including “those related to precautions,” “may be added or revised via notification.”38 In 1998, EPA issued PRN 98-10, which reaffirmed that PRN 95-02’s rule on “advisory statements …

related to precautions” remains the PRN that manufacturers should “continue to follow.”39 This PRN also made

clear that “other revisions” to the label were permissible

38. EPA, Pesticide Registration Notice 95-02, 3 (May 31, 1995),

https://perma.cc/C8XM-7NAZ.

39. EPA, Pesticide Registration Notice 98-10, 3 (Oct. 22, 1998),

https://perma.cc/ZK8Z-2NNM.

if they are “consistent with 40 CFR Part 156” and “involve

no change” to certain sections of the label, e.g., the “ingredients statement,” “First Aid statement,” or “precautionary statements.”40

It was not until 2000 — four years after Durnell began

using Roundup — that EPA issued PRN 2000-5, which

states that “registrants may no longer add or change advisory labeling statements to existing products by notification as previously permitted by PR Notices 95-2 and 9810.”41 But PRN 2000-5 made no adjustment to a manufacturer’s ability to change other sections of the Roundup label unilaterally. Id.

Durnell used Roundup for more than 20 years. For the

first four years of that use — 1996 to 2000 — Monsanto

could have unilaterally added a cancer warning in the “advisory statements” section of the Roundup label. And for

the remaining years of use, unilateral warnings could still

be added so long as the manufacturer placed them in the

proper section of the label.

Monsanto knows full well that this sort of label change

was permissible. Its parent company Bayer notified EPA

in 2012 that it had unilaterally added a cancer warning to

the very end of one of its pesticide labels.42 And EPA con40. Id. at 8.

41. EPA, Pesticides; Guidance for Pesticide Registrants on Mandatory and Advisory Labeling Statements, 65 Fed. Reg. 31,313,

31,314 (May 17, 2000).

42. See Letter from Larry R. Hodges, Bayer CropScience, to EPA,

Office of Pesticide Programs 4 (Nov. 29, 2012), https://perma.cc/

X64N-WX5F (“As allowed by PR Notice 98-10, we are notifying

the Agency of a minor labeling amendment for LARVIN Technical (EPA Reg. No. 264-343). As required by California Proposition 65, the following statement was added to label, ‘This pro(continued…)

firmed that Bayer was allowed to make this unilateral

change.43 It cannot be impossible to do what has already

been done.

Monsanto’s fallback argument is to assert that EPA

would have vetoed the change, and it claims to have produced “clear evidence” that this would have happened.

Pet. Br. 48 (citing Albrecht, 587 U.S. at 314). But this

“clear evidence” defense comes from cases interpreting

the Food Drug and Cosmetic Act (FDCA), which requires

manufacturers to submit unilateral label changes to FDA

and gives the agency authority to reject them even after

the manufacturer has made the changes. 21 C.F.R.

§ 314.70(c)(1), (c)(7). With the agency empowered to veto

a label change, this Court held that a manufacturer can

establish preemption if it proves by “clear evidence” that

FDA would have walked back a stronger warning. Albrecht, 587 U.S. at 315; but see id. at 321 (Thomas, J., concurring) (“[N]either agency musings nor hypothetical future rejections constitute pre-emptive ‘Laws’ under the

Supremacy Clause.”).

That rationale does not apply here. FIFRA freely allows manufacturers to make unilateral changes to their

labels. See pp. 38–39, supra. So do EPA’s regulations. And

neither FIFRA nor EPA’s regulations establish any mechanism for EPA to force a manufacturer to undo a uniduct contains a chemical known to the state of California to cause

cancer.’ ”)

43. See Letter from Jennifer Gaines, EPA, Office of Pesticide Programs, to Larry Hodges, Bayer CropScience 2 (Dec. 17, 2012),

https://perma.cc/X64N-WX5F (“The Registration Division (RD)

has conducted a review of this request for its applicability under

PRN 98-10 and finds that the action(s) requested fall within the

scope of PRN 98-10.”).

lateral change. That Monsanto thinks it has adduced

“clear evidence” that EPA dislikes a hypothetical cancer

warning that the company never added to its label says

nothing about whether it was impossible to provide this

warning to Durnell.

And even if this Court were to import the clear-evidence regime into FIFRA, Monsanto has not satisfied it.

Monsanto never once asked EPA to approve a Roundup

label that warns about the risk of cancer. But to establish

clear evidence, Monsanto must “show that it fully informed the [agency] of the justifications for the warning

required by state law and that the [agency], in turn, informed the … manufacturer that the [agency] would not

approve changing the [product’s] label to include that

warning.” Albrecht, 587 U.S. at 314. Monsanto claims that

EPA sent letters to other manufacturers suggesting that

it no longer agreed with their cancer warnings,44 but none

of that matters under Albrecht. Perhaps Monsanto could

have made a more persuasive case. It cannot throw up its

hands and declare “impossibility” when it did not deign to

try. Albrecht, 587 U.S. at 314.

B. Durnell’s Claim Is Not Preempted Even If Monsanto

Could Not Change The Label

Even accepting the (false) premise that Monsanto was

forbidden to change the EPA-approved label, that still

does not establish an implied-preemption defense. Monsanto is arguing impossibility, and the only way that Missouri law can be “impossible” for Monsanto to comply with

is by characterizing the relevant state-law duty as a duty

to change the label.

44. Pet. Br. 48.

But that is simply not the relevant duty under state or

federal law. The duty under federal law is to not sell a misbranded pesticide. See 7 U.S.C. § 136j(a)(1)(E). The duty

under state law is to not sell a pesticide that has an inadequate or misleading label. Racer, 629 S.W.2d at 395.

There cannot be an “impossibility” conflict between those

two duties.

It is true enough that this Court has held that a party

cannot be required to cease activity altogether as an alternative to complying with a state duty that contradicts

federal law. If federal law commands “drive on the right”

and Missouri law proclaims “drive on the left,” a plaintiff

cannot avoid preemption by asserting that the defendant

should have ceased driving altogether. See Transcript of

Oral Argument at 46–47, Bartlett, 570 U.S. 472. Neither

sovereign was attempting to force drivers off the road.

Each simply selected incompatible modes of driving.

While not driving at all is both possible and a way to avoid

liability, “physical impossibility” is not always the test for

preemption. See Bartlett, 570 U.S. at 488.

None of that applies when federal and state law both

require a party to cease acting. In that circumstance, cessation is not some pettifogger’s excuse to leave in place

conflicting legal commands. It is instead the only way to

ensure that both commands are obeyed. That is why Bartlett made clear that it was not addressing claims “that parallel the federal misbranding statute” under the FDCA,

which, like FIFRA, compels drugmakers to stop selling

misbranded pharmaceuticals. Id. at 487 n.4 (citing Bates,

544 U.S. at 447). The Court cited Bates because that case

already applied the same logic under FIFRA. Bates affirmed that states have the complete prerogative to re-

quire a manufacturer to stop selling a pesticide for any

reason, to say nothing of reasons that parallel federal law.

Bates, 544 U.S. at 450 (“States may ban or restrict the

uses of pesticides that EPA has approved.”).

Settled or not, the question is straightforward.

FIFRA unambiguously requires Monsanto to stop selling

a misbranded pesticide. Missouri law requires the exact

same thing. Where complying with “the supreme law of

the land” requires cessation, Monsanto must comply with

both state and federal law by either withdrawing Roundup from the market or willingly accepting the risk that it

must pay individual tort victims the damages that juries

award them.45

Monsanto, of course, remains free to argue in future

cases by future plaintiffs that Roundup is not misbranded

and can continue to be sold. By its nature, the judicial power binds only the parties to the case, so the jury verdict

and judicial decisions below (and here) bind Monsanto

only vis-à-vis Durnell. They do not have universal effect.

Cf. Trump v. CASA, Inc., 606 U.S. 831 (2025). State and

federal legal duties — stop selling if the pesticide is inadequately or misleadingly labeled — will remain completely

parallel in those future actions. But future juries may accept Monsanto’s presentation of the facts and conclude

that selling Roundup did not breach any state and federal

obligations.

45. Monsanto never deals with this fact because its entire argument

is premised on the idea that Roundup cannot possibly be “misbranded” under FIFRA because EPA approved its label during

the registration process. See pp. 21–33, supra.

III. MONSANTO’S PREEMPTION ARGUMENTS FIND

NO SUPPORT IN THIS COURT’S CASE LAW

Monsanto’s preemption arguments are incompatible

with this Court’s precedents.

A. Monsanto’s Preemption Arguments Are Incompatible

With Bates

Monsanto’s preemption arguments would have required a finding of preemption in Bates. The Strongarm

label, which failed to warn Texas peanut farmers that it

would destroy their crops, had been approved by EPA

during the registration process. Bates, 544 U.S. at 434–35.

So if “the label is the law!,” as Monsanto insists throughout its brief,46 then any failure-to-warn claim predicated

on an EPA-approved label is preempted. The Court obviously did not take that view in Bates; it allowed the failureto-warn claim to proceed.

Monsanto and the Solicitor General attempt to circumvent Bates by observing that EPA never actually weighed

in on the efficacy of Strongarm or the accuracy of the labeling statements that recommended its use for peanut

crops. Pet. Br. 32, SG Br. 27. But the outcome in Bates did

not in any way depend on that fact. 544 U.S. at 438 (“Because it is unlawful under the statute to sell a pesticide

that is registered but nevertheless misbranded, manufacturers have a continuing obligation to adhere to FIFRA’s

labeling requirements.”). That is because nothing in

FIFRA’s text turns on whether the Administrator ignored

46. Pet. Br. 8, 26, 45.

or thoughtfully weighed a scientific question.47 Id. at 448

(“[A]lthough FIFRA does not provide a federal remedy to

farmers and others who are injured as a result of a manufacturer’s violation of FIFRA’s labeling requirements,

nothing in § 136v(b) precludes States from providing such

a remedy.” (emphasis added)).

Monsanto’s effort to distinguish Bates is also incompatible with its sweeping statements on the supposed

sanctity of the EPA-approved label that appear throughout its brief. Instead of proclaiming that “the label is the

law!”, Monsanto should appropriately hedge this slogan

given its desire to accommodate Bates. Perhaps it could

try: “The label is the law, but only if EPA actually considered and affirmatively agrees with the particular statements that appear on the label!” But then Monsanto

would have to explain what would happen if a future Administrator determines that glyphosate does indeed cause

cancer. Could Durnell then reopen his case under the

state-law equivalent of Rule 60(b)? And would EPA’s new

factual determination entitle Durnell (and similarly situated plaintiffs) to a directed verdict? Cf. National Cable &

Telecommunications Association v. Brand X Internet

Services, 545 U.S. 967 (2005). Modified once again, Monsanto’s mantra must really be: “The label is the law, so

long as EPA has actually considered and blessed its contents, but only for so long as EPA has not changed its

47. The argument fails on its own terms. EPA has never considered

whether all of the ingredients in Roundup — including surfactants, ethylene oxide, and 1, 4-Dioxane — combined with glyphosate can cause cancer. And it has never considered Durnell’s experts’ interpretations and analysis of the scientific evidence.

mind!” That catchphrase has little to recommend it. And

it is inconsistent with Bates, to say nothing of FIFRA.

Bates also shuts down Monsanto’s fears that civil-jury

enforcement of FIFRA’s labeling standards will produce

a “crazy quilt”48 of conflicting obligations. Bates considered and rejected this idea both as an empirical matter

and as a reason to find preemption. Bates, 544 U.S. at 451–

52 (“Dow and the United States exaggerate the disruptive

effects of using common-law suits to enforce the prohibition on misbranding.”) And although Bates acknowledges

that “properly instructed juries might on occasion reach

contrary conclusions on a similar issue of misbranding,” it

specifically holds that the prospect of divergent verdicts

is no reason to prevent state juries from enforcing “state

rules that are fully consistent with federal requirements.”

Id. at 452. Yesterday’s “crazy quilts” are today’s “patchworks” and “cacophonies,”49 but changing the nomenclature does not change Bates’s holding. Whatever discordant noises Monsanto fears will emanate from jury boxes,

Bates does not permit the company to take the interpretation and application of the misbranding standard from

the judiciary.

Bates poses an even bigger problem for Monsanto’s

implied-preemption argument. If Monsanto is right to

claim that “federal law” prohibits manufacturers from

changing EPA-approved labels without permission, then

Dow would have been forbidden to change its Strongarm

labels absent prior EPA approval. So Dow would have

been in the same position that Monsanto claims to be in.

And although Dow eventually obtained EPA approval to

48. Bates, 544 U.S. at 448, 451.

49. Pet. Br. at 5, 50, 51.

include the desired warning,50 Monsanto insists that is irrelevant. Pet Br. 44 (“The question for ‘impossibility’ is

whether the private party could independently do under

federal law what state law requires of it.” (cleaned up)).

Bates would have to come out the other way if this Court

accepts Monsanto’s impossibility-preemption argument.

B. The Court’s Decision In Riegel v. Medtronic, Inc. Is

Inapposite

Monsanto and the Solicitor General try to analogize

this case to Riegel v. Medtronic, Inc., 552 U.S. 312 (2008),

which held that a similarly worded express-preemption

provision blocked a state-law failure-to-warn claim over a

medical device that had received premarket approval

from FDA. But Riegel is inapposite for two reasons. First,

the Court in Riegel held that the Medical Device Amendments banned manufacturers from altering an FDAapproved device or its labeling absent FDA permission.

See id. at 319 (citing 21 U.S.C. § 360e(d)(5)(A)(i)). Nothing

in FIFRA or its implementing regulations prohibits Monsanto from adding a cancer warning to its Roundup labels;

indeed, the EPA regulations explicitly allow Monsanto to

add this warning without seeking EPA approval. See pp.

39–42, supra.

Second, no one in Riegel even attempted to argue that

the FDA-approved medical device violated the separate

statutory misbranding prohibitions in the FDCA. See 21

U.S.C. § 331 (“The following acts and the causing thereof

are prohibited: (a) The introduction or delivery for introduction into interstate commerce of any … device … that

is adulterated or misbranded.”). The plaintiff in Riegel

50. Bates, 544 U.S. at 435.

hinged her entire case on the contentions that: (1) FDA’s

premarket approval of a medical device failed to impose

“requirements” within the meaning of the statute’s express-preemption provision, 21 U.S.C. § 360k(a)(1); and

(2) state common-law duties fail to qualify as “requirements.” See Riegel, 552 U.S. at 322–25.

Durnell concedes51 that Missouri’s failure-to-warn law

imposes some “requirements for labeling” within the

meaning of 7 U.S.C. § 136v(b). And Durnell — unlike Riegel — is arguing that Missouri may impose failure-towarn liability on Monsanto because the jury could reasonably conclude that Roundup’s labeling violates FIFRA’s

prohibition on selling misbranded pesticides. Riegel is no

help at all to Monsanto because it expressly refused to address a situation in which a plaintiff claims that a statelaw failure to warn also violates the misbranding prohibitions enshrined in federal law.

***

Monsanto’s brief is a 53-page non sequitur. EPA’s belief that Roundup’s labels comply with FIFRA’s misbranding provisions means nothing when Loper Bright

gives courts rather than agencies the authority to interpret and apply those provisions. EPA’s repeated pronouncements that glyphosate is noncarcinogenic are likewise irrelevant unless this Court is prepared to extend the

doctrine of nonmutual collateral estoppel to an agency’s

factual assertions. And Monsanto’s policy arguments for

why EPA should be given delegated power belong in its

lobbying materials for congressmen and senators, not in

a Supreme Court brief. Monsanto has forfeited any claim

51. See Bates, 544 U.S. at 443, 446; Riegel, 552 U.S. at 323–25.

that Missouri tort law adds to or differs from FIFRA’s requirements by failing to request a Bates instruction at

trial, and there is no reason to believe that a cost-benefit

analysis instruction would have affected the jury’s verdict

in any way.

Monsanto’s claims that FIFRA and EPA’s regulations

prohibit it from adding a cancer warning to Roundup’s labels are untrue. And even if federal law prevented Monsanto from adding a cancer warning to Roundup’s EPAapproved labels, FIFRA would still prohibit Monsanto

from distributing or selling Roundup if the judiciary finds

its labels misleading or inadequate under 7 U.S.C.

§ 136(q) or state tort law. Monsanto cannot escape the fact

that Loper Bright empowers the judiciary and not EPA to

interpret and apply FIFRA’s misbranding prohibitions,

and it cannot establish express or implied preemption by

ignoring the statutory delegation issue and begging the

question throughout its brief.

CONCLUSION

The judgment of the Missouri Court of Appeals should

be affirmed.

Respectfully submitted.

JONATHAN F. MITCHELL

Mitchell Law PLLC

111 Congress Avenue

Suite 400

Austin, Texas 78701

(512) 686-3940

jonathan@mitchell.law

T. ROE FRAZER II

THOMAS ROE FRAZER III

JAMES GRANT LABAR

R. PRESCOTT SIFTON JR.

Frazer PLC

30 Burton Hills Boulevard

Suite 450

Nashville, Tennessee 37215

(615) 647-6464

March 25, 2026

ASHLEY C. KELLER

Counsel of Record

JOHN JAMES SNIDOW

Keller Postman LLC

1101 Connecticut Avenue NW

Suite 1100

Washington, D.C. 20036

(202) 918-1123

ack@kellerpostman.com

JAMES G. ONDER

W. WYLIE BLAIR

GREGORY J. PALS

MARK E. BERNS

OnderLaw LLC

110 East Lockwood Avenue

St. Louis, Missouri 63119

(314) 963-9000

APPENDIX