Amicus Curiae Brief — Monsanto Company, Petitioner v. John L. Durnell

No. 24-1068

In the Supreme Court of the United States

MONSANTO COMPANY, PETITIONER

v.

JOHN L. DURNELL

ON PETITION FOR A WRIT OF CERTIORARI

TO THE MISSOURI COURT OF APPEALS

BRIEF FOR THE UNITED STATES

AS AMICUS CURIAE

D. JOHN SAUER

Solicitor General

Counsel of Record

MALCOLM L. STEWART

Deputy Solicitor General

ROBERT N. STANDER

Deputy Assistant

Attorney General

ASHLEY ROBERTSON

Assistant to the

Solicitor General

MATTHEW OAKES

CYNTHIA TAUB

Attorneys

Department of Justice

Washington, D.C. 20530-0001

SupremeCtBriefs@usdoj.gov

(202) 514-2217

QUESTION PRESENTED

Whether the Federal Insecticide, Fungicide, and Rodenticide Act, 7 U.S.C. 136 et seq., preempts a state-law

failure-to-warn claim concerning a pesticide registered

by the U.S. Environmental Protection Agency (EPA),

where EPA has determined that a particular warning is

not required and the warning cannot be added to a product label without EPA approval.

(I)

TABLE OF CONTENTS

Page

Interest of the United States ........................................................ 1

Introduction ..................................................................................... 1

Statement ......................................................................................... 3

Discussion ...................................................................................... 10

A. The decision below is incorrect ...................................... 11

B. The acknowledged circuit conflict warrants this

Court’s review .................................................................. 20

Conclusion ...................................................................................... 24

TABLE OF AUTHORITIES

Cases:

Bates v. Dow Agrosciences LLC,

544 U.S. 431 (2005) .................2, 3, 5, 7, 11, 13, 17, 18, 20, 23

Buckman Co. v. Plaintiffs’ Legal Comm.,

531 U.S. 341 (2001) ............................................................... 19

Caranci v. Monsanto Co.,

338 A.3d 151 (Pa. Super. Ct. 2025) ..................................... 21

Carson v. Monsanto Co.,

92 F.4th 980 (11th Cir. 2024) ........................................... 3, 21

Hardeman v. Monsanto Co., 997 F.3d 941

(9th Cir. 2021), cert. denied, 142 S. Ct. 2834 (2022) ..... 3, 21

Johnson v. Monsanto Co.,

554 P.3d 290 (Or. Ct. App. 2024), petition for

cert. pending, No. 24-1098 (filed Apr. 18, 2025) ............... 21

Medtronic, Inc. v. Lohr, 518 U.S. 470 (1996) ....................... 12

Monsanto Co. v. Hardeman:

142 S. Ct. 707 (2021) .......................................................... 10

142 S. Ct. 2834 (2022) ........................................................ 10

Moore v. Ford Motor Co., 332 S.W.3d 749 (Mo. 2011)........ 16

National Ass’n of Wheat Growers v. Bonta,

85 F.4th 1263 (9th Cir. 2023) ................................................. 8

(III)

IV

Cases—Continued:

Page

Natural Res. Def. Council v. EPA,

38 F.4th 34 (9th Cir. 2022) ..................................................... 7

Pilliod v. Monsanto Co.,

282 Cal. Rptr. 3d 679 (Cal. Ct. App. 2021),

cert. denied, 142 S. Ct. 2870 (2022) .................................... 21

Riegel v. Medtronic, Inc.,

552 U.S. 312 (2008) ................................................... 12-16, 18

Schaffner v. Monsanto Corp.,

113 F.4th 364 (3d Cir. 2024) ...... 3, 7, 9, 10, 12, 14, 15, 19-23

Statutes and regulations:

Federal Food, Drug, and Cosmetics Act,

ch. 675, 52 Stat. 1040 (21 U.S.C. 301 et seq.) ..................... 13

21 U.S.C. 360k(a)(1) .................................................... 13, 15

Federal Insecticide, Fungicide, and Rodenticide

Act, 7 U.S.C. 136 et seq. ......................................................... 1

7 U.S.C. 136(q)(1) ................................................................ 2

7 U.S.C. 136(q)(1)(A)........................................................... 6

7 U.S.C. 136(q)(1)(G)................................. 2, 4, 6, 11, 14-16

7 U.S.C. 136(x) ..................................................................... 6

7 U.S.C. 136(bb)............................................... 2, 4, 6, 11, 16

7 U.S.C. 136a(a) ............................................................... 1, 4

7 U.S.C. 136a(c)(1)(C) ......................................................... 4

7 U.S.C. 136a(c)(1)(D) ......................................................... 4

7 U.S.C. 136a(c)(1)(F) ......................................................... 4

7 U.S.C. 136a(c)(5)(B) ..................................................... 1, 4

7 U.S.C. 136a(c)(5)(C) ....................................................... 11

7 U.S.C. 136a(c)(5)(D) ............................................... 2, 4, 11

7 U.S.C. 136a(f )(2) ............................................................ 18

7 U.S.C. 136a(g)(1)(A)(iii)(II) ............................................ 5

7 U.S.C. 136a(g)(1)(A)(iv) ................................................... 5

7 U.S.C. 136d(a)(2) .................................................. 5, 12, 19

V

Statutes and regulations—Continued:

Page

7 U.S.C. 136d(b)................................................................... 5

7 U.S.C. 136j(a)(1)(E) ......................................................... 5

7 U.S.C. 136j(a)(2)(S) ........................................................ 19

7 U.S.C. 136k(a) ................................................................... 6

7 U.S.C. 136k(b)................................................................... 6

7 U.S.C. 136l ........................................................................ 6

7 U.S.C. 136v(a) ................................................................... 6

7 U.S.C. 136v(b) .......................... 2, 3, 6, 9, 11, 13-15, 18-23

7 U.S.C. 136v(c)(1)............................................................... 7

Medical Device Amendments of 1976,

Pub. L. No. 94-295, 90 Stat. 539.......................................... 13

40 C.F.R.:

Pt. 152 ................................................................................... 4

Subpt. C:

Section 152.42........................................................... 4

Section 152.44(a) ...................................... 2, 5, 12, 14

Section 152.46(a) ................................................ 5, 12

Section 152.50........................................................... 4

Section 152.50(f )(3)................................................ 19

Subpt. F:

Section 152.107......................................................... 4

Section 152.112(b) .................................................... 4

Section 152.112(c) .................................................... 4

Section 152.112(e) .................................................... 4

Section 152.112(f ) .................................................... 4

Pt. 155:

Section 155.40........................................................... 5

Section 155.53(a) ...................................................... 5

VI

Regulations—Continued:

Page

Pt. 156 ................................................................................... 4

Subpt. A:

Section 156.10(a)(1) ................................................. 5

Section 156.10(a)(1)(vii) .......................................... 4

Subpt. D:

Section 156.60........................................................... 4

Section 156.70(c) ............................................ 2, 5, 12

Pt. 158:

Subpt. A:

Section 158.34........................................................... 4

Subpt. E .......................................................................... 4

Subpt. F:

Section 158.500......................................................... 4

Miscellaneous:

EPA, Revised Glyphosate Issue Paper:

Evaluation of Carcinogenic Potential

(Dec. 12, 2017) ......................................................................... 7

Int’l Agency for Research on Cancer,

112 Some Organophosphate Insecticides

and Herbicides: Glyphosate (2015) ..................................... 8

Office of Pesticide Programs, EPA:

Pesticide Registration Notice 98-10

(Oct. 22, 1998), https://perma.cc/ZK8Z-2NNM ......... 5

Pesticide Registration Notice 2000-5

(May 10, 2000), https://perma.cc/ANB4-UGG9 ......... 5

In the Supreme Court of the United States

No. 24-1068

MONSANTO COMPANY, PETITIONER

v.

JOHN L. DURNELL

ON PETITION FOR A WRIT OF CERTIORARI

TO THE MISSOURI COURT OF APPEALS

BRIEF FOR THE UNITED STATES

AS AMICUS CURIAE

INTEREST OF THE UNITED STATES

This brief is submitted in response to the Court’s order inviting the Solicitor General to express the views

of the United States. In the view of the United States,

the petition for a writ of certiorari should be granted.

INTRODUCTION

The Federal Insecticide, Fungicide, and Rodenticide

Act (FIFRA), 7 U.S.C. 136 et seq., prohibits the distribution or sale of a pesticide “that is not registered” by the

U.S. Environmental Protection Agency (EPA). 7 U.S.C.

136a(a). To decide whether a pesticide should be registered, EPA must determine whether “its labeling * * *

compl[ies] with the requirements of ” FIFRA, 7 U.S.C.

136a(c)(5)(B); and whether, “when used in accordance with

widespread and commonly recognized practice,” the

(1)

2

pesticide “will not generally cause unreasonable adverse effects on the environment,” 7 U.S.C. 136a(c)(5)(D).

The term “unreasonable adverse effects on the environment” is defined to include “any unreasonable risk to

man or the environment, taking into account the economic, social, and environmental costs and benefits of

the use of any pesticide.” 7 U.S.C. 136(bb). If a pesticide’s label does not contain a warning “necessary and

* * * adequate to protect health and the environment,”

7 U.S.C. 136(q)(1)(G), the “pesticide is misbranded,”

7 U.S.C. 136(q)(1). Once EPA has approved a label, the

registrant may not add to or amend the label’s precautionary statements without review and approval by the

agency. See 40 C.F.R. 152.44(a); see also 40 C.F.R.

156.70(c).

In the interest of “[u]niformity,” FIFRA precludes

States from imposing any labeling requirements that

are “in addition to or different from those required under” FIFRA. 7 U.S.C. 136v(b). Section 136v(b) “pre-empts

any statutory or common-law rule that would impose a

labeling requirement that diverges from those set out

in FIFRA and its implementing regulations.” Bates v.

Dow Agrosciences LLC, 544 U.S. 431, 452 (2005). Thus,

although a State may enforce “rules that are fully consistent with federal requirements,” a “manufacturer

should not be held liable under a state labeling requirement subject to § 136v(b) unless the manufacturer is

also liable for misbranding as defined by FIFRA.” Id.

at 452, 454.

This case raises an important question about the

scope of FIFRA’s preemption provision. Since 1974, petitioner Monsanto Company has manufactured the pesticide Roundup with the active ingredient glyphosate.

3

For decades, EPA has classified glyphosate as a chemical that is not likely to be carcinogenic in humans, and

the agency has approved hundreds of labels for Roundup

and other glyphosate-based products without requiring

a cancer warning. Respondent alleges, however, that

petitioner is liable under state law for failure to include

such a warning. The court below affirmed a jury verdict

against petitioner in respondent’s suit, rejecting petitioner’s argument that Section 136v(b) preempted respondent’s state-law claims.

The decision below is incorrect and implicates a conflict of authorities on the question presented. The Ninth

and Eleventh Circuits have allowed similar state-law

claims to proceed against petitioner, holding that Section 136v(b) did not preempt state-law requirements to

warn of cancer risks purportedly associated with

Roundup. See Hardeman v. Monsanto Co., 997 F.3d

941, 955-958 (9th Cir. 2021), cert. denied, 142 S. Ct. 2834

(2022); Carson v. Monsanto Co., 92 F.4th 980, 989-996

(11th Cir. 2024). More recently, however, the Third Circuit correctly held that EPA’s approval of Roundup labels without a cancer warning, combined with regulations requiring the agency’s approval before such a

warning may be added, precludes imposition of statelaw tort liability based on petitioner’s failure to warn of

cancer risks. See Schaffner v. Monsanto Corp., 113

F.4th 364, 399 (2024). The Court should grant certiorari

to resolve that circuit conflict and clarify the scope of

FIFRA’s preemption provision.

STATEMENT

1. a. FIFRA is a “comprehensive regulatory statute” that governs the “use, as well as the sale and labeling, of pesticides.” Bates, 544 U.S. at 437 (citations omit-

4

ted). FIFRA prohibits the distribution or sale of a pesticide unless it has been registered by EPA. 7 U.S.C.

136a(a). To apply for registration, a manufacturer must

submit, among other things, the product’s “complete

formula,” “claims to be made for it,” proposed labeling,

and a “full description of the tests made and the results

thereof upon which the claims are based.” 7 U.S.C.

136a(c)(1)(C), (D), and (F). EPA’s implementing regulations impose additional requirements. See 40 C.F.R.

Pt. 152. The regulations require manufacturers to submit scientific and safety data, and to flag studies related

to potential adverse effects. See 40 C.F.R. Pt. 152,

152.50, Subpt. E, 158.34. The manufacturer must also

submit proposed labeling that includes any precautionary statements about potential effects on human health.

40 C.F.R. 156.10(a)(1)(vii), 156.60, 158.500.

EPA “shall register a pesticide” if the agency determines, inter alia, that “its labeling * * * compl[ies] with

the [statute’s] requirements,” and that “when used in accordance with widespread and commonly recognized

practice[,] it will not generally cause unreasonable adverse effects on the environment,” 7 U.S.C. 136a(c)(5)(B)

and (D), which the statute defines to include unreasonable

adverse effects on human health, 7 U.S.C. 136(bb). To

verify that the latter requirement is satisfied, EPA reviews scientific studies and safety data. 40 C.F.R.

152.107; 152.112(b),(c),(e), and (f ). EPA also reviews

the proposed label to ensure that it complies with

FIFRA’s requirements, including that it contains any

warnings necessary to protect human health. See

7 U.S.C. 136(q)(1)(G); see also 40 C.F.R. 152.42, 152.50,

Pt. 156.

Once EPA registers a pesticide, the registrant must

include all approved precautionary statements on its

5

product. 40 C.F.R. 156.10(a)(1). A registrant may not

alter the label, other than with “minor modifications,”

without first obtaining EPA’s approval. 40 C.F.R.

152.44(a), 152.46(a). As relevant here, registrants may

not alter “precautionary statements” without the

agency’s review and approval. 40 C.F.R. 156.70(c); see

Office of Pesticide Programs, EPA, Pesticide Registration Notice 2000-5 (May 10, 2000), https://perma.cc/ANB4UGG9; Office of Pesticide Programs, EPA, Pesticide Registration Notice 98-10 (Oct. 22, 1998), https://perma.cc/ZK8Z2NNM. A registrant, however, has a continuing obligation

to adhere to FIFRA’s requirements, including its labeling requirements. See Bates, 544 U.S. at 438-439. If a

registrant learns at any time of “additional factual information regarding unreasonable adverse effects,” it

must submit that information for EPA’s review. 7 U.S.C.

136d(a)(2).

EPA’s obligations also continue after a product’s initial review and registration. EPA may initiate the cancellation or modification of a registration if the agency

determines that the pesticide “causes unreasonable adverse effects on the environment” or is otherwise misbranded. See 7 U.S.C. 136d(b). EPA also formally reviews each pesticide registration every 15 years. 7 U.S.C.

136a(g)(1)(A)(iii)(II) and (iv). In that review, EPA assesses any new information about risks to human health

and the environment to verify that the pesticide continues to satisfy FIFRA’s safety standards. See, e.g., 40

C.F.R. 155.40, 155.53(a).

b. FIFRA prohibits the sale or distribution of a pesticide that is “misbranded.” 7 U.S.C. 136j(a)(1)(E). A

pesticide is misbranded if its labeling “bears any statement * * * which is false or misleading in any particu-

6

lar.” 7 U.S.C. 136(q)(1)(A). A pesticide is also misbranded if it “does not contain a warning or caution

statement which may be necessary and if complied with

* * * is adequate to protect health and the environment.” 7 U.S.C. 136(q)(1)(G). The statute defines “protect health and the environment” to mean “protection

against any unreasonable adverse effects on the environment,” 7 U.S.C. 136(x). which in turn includes protection against “any unreasonable risk to man or the environment,” 7 U.S.C. 136(bb). Taken together, those

provisions establish that a pesticide is misbranded under FIFRA if, among other things, its label fails to include information that is “necessary” to protect against

“any unreasonable risk to man or the environment, taking into account the economic, social, and environmental

costs and benefits of the use of any pesticide.” 7 U.S.C.

136(q)(1)(G) and (bb).

A breach of these requirements can expose registrants to significant sanctions. An EPA enforcement action premised on such violations may result in an order

that the registrant “stop [the] sale, use, or removal” of

the pesticide, 7 U.S.C. 136k(a); seizure of offending

products, 7 U.S.C. 136k(b); and civil and criminal penalties, 7 U.S.C. 136l.

c. FIFRA includes a preemption provision, which

bars a State from “impos[ing] or continu[ing] in effect

any requirements for labeling or packaging in addition

to or different from those required under” FIFRA. 7 U.S.C.

136v(b). A State may “regulate the sale or use of any

federally registered pesticide” within its borders, so

long as the State does not permit any sale or use prohibited

by FIFRA. 7 U.S.C. 136v(a). In certain circumstances, a

State may register a federally approved pesticide for additional uses in order “to meet special local needs” within

7

the State. 7 U.S.C. 136v(c)(1). But a State may not impose

“competing state labeling standards,” which “would create significant inefficiencies for manufacturers.” Bates,

544 U.S. at 452.

2. Petitioner is the manufacturer and registrant of

the pesticide Roundup with the active ingredient glyphosate. See Pet. App. 3. In 1985, EPA classified glyphosate

as a possible human carcinogen, but a scientific advisory

panel determined the following year that glyphosate’s

human carcinogenicity “could not yet be classified.”

Schaffner v. Monsanto Corp., 113 F.4th 364, 373 (3d Cir.

2024). Since 1991, and after reviewing additional data,

EPA has classified glyphosate as a chemical not likely

to be carcinogenic in humans. Ibid. In its 2020 interim

registration-review decision, EPA reaffirmed that assessment, after a decade-long review in which the

agency considered more than 238,000 public comments.

Pet App. 35; Natural Res. Def. Council v. EPA, 38 F.4th

34, 43 (9th Cir. 2022).1 EPA has consistently approved

Roundup labels without a cancer warning, see Pet. 7 n.1,

16, based on the agency’s conclusion that glyphosate is

not likely to be carcinogenic in humans, see EPA, Revised Glyphosate Issue Paper: Evaluation of Carcinogenic Potential 12-13 (Dec. 12, 2017).

In 2015, a working group at the International Agency

for Research on Cancer (IARC) classified glyphosate as a

The Ninth Circuit vacated the human-health portion of the 2020

interim registration-review decision and remanded to EPA for “further analysis and explanation.” Natural Res. Def. Council, 38 F.4th

at 52. In response, EPA withdrew the interim decision, while explaining that its withdrawal “does not automatically mean that

EPA’s underlying scientific findings, including its finding that

glyphosate is not likely to be carcinogenic to humans,” are incorrect.

Pet. App. 30-31.

1

8

possible human carcinogen. IARC, 112 Some Organophosphate Insecticides and Herbicides: Glyphosate at

398 (2015). EPA has since taken different positions as

to whether it would approve labels that reflected that

development. In 2019, the Director of the Registration

Division of EPA’s Office of Pesticide Programs issued a

letter to registrants of products that contain glyphosate. Pet. App. 38-40. The letter stated that, because

EPA had determined that glyphosate is “ ‘not likely to

be carcinogenic to humans,’ ” pesticide products that

contained a “warning statement due to the presence of

glyphosate are misbranded” under FIFRA. Id. at 39.

In 2022, in response to a request from California, EPA

stated that the agency would approve a warning label

that both (a) recited the IARC’s conclusion about

glyphosate’s probable carcinogenic effect and (b) explained that “EPA has determined that glyphosate is

not likely to be carcinogenic to humans.” Id. at 42; see

id. at 41-43. EPA noted at that time that the agency

“continue[d] to stand behind its robust scientific evaluation of the carcinogenic potential of glyphosate.” Id.

at 41.2

3. In 2019 respondent sued petitioner in Missouri Circuit Court, alleging that respondent’s use of Roundup until 2012 had caused him to develop non-Hodgkin’s lymphoma. Pet. App. 3. Respondent alleged, inter alia, that

petitioner had tortiously failed to warn of cancer risks

posed by Roundup. See ibid.

The trial court rejected petitioner’s argument that

FIFRA preempted respondent’s claims. Pet. App. 13EPA later withdrew the 2022 letter in light of a Ninth Circuit

decision that enjoined the enforcement of the California law that

had precipitated the request for the warning. See National Ass’n

of Wheat Growers v. Bonta, 85 F.4th 1263, 1266-1267 (2023).

2

9

16. The case proceeded to trial, where a jury awarded

respondent $1.25 million based on his failure-to-warn

claim. Id. at 20-21. Petitioner sought a judgment notwithstanding the verdict, which the court denied. Id. at 19.

4. The Missouri Court of Appeals affirmed. Pet. App.

2-12. The court held that FIFRA does not expressly

preempt respondent’s failure-to-warn claim. Id. at 5-7.

The court explained that “[t]he ‘practical effect’ of both

FIFRA’s prohibition on misbranding under [7 U.S.C.]

136(q)(1)(G) and a strict liability failure to warn claim in

Missouri are the same: both require a pesticide manufacturer to adequately warn users of the potential dangers of using its product.” Id. at 7. The court concluded

on that basis that, for purposes of Section 136v(b), Missouri law does not impose a requirement “in addition to

or different from” FIFRA’s misbranding prohibition.

Ibid.

The Missouri Court of Appeals acknowledged that

the Third Circuit had found similar state-law claims to

be preempted. Pet. App. 10 (citing Schaffner, 113 F.4th

at 370-399). The court did “not find Schaffner persuasive,” however, and it chose instead to follow decisions

in which the Ninth and Eleventh Circuits had rejected

petitioner’s express-preemption arguments. Id. at 1011. The court also held that respondent’s claims were

not impliedly preempted. Id. at 8-9. The court explained

that “[t]he record contains no evidence that [petitioner]

either informed the EPA of the justifications for a

change to its warning label or that the EPA has informed [petitioner] it would not approve such a warning.” Id. at 9.

The Missouri Supreme Court denied petitioner’s application for transfer. See Pet. App. 1.

10

DISCUSSION

In Monsanto Co. v. Hardeman, 142 S. Ct. 707 (2021),

this Court invited the Solicitor General to file a petitionstage brief addressing substantially the same preemption question as is presented here. The government’s

amicus brief argued that FIFRA did not preempt the

state-law failure-to-warn claim asserted in that case,

see U.S. Amicus Br. at 6-16, Monsanto, supra, No. 21241, and that the preemption question would not warrant review “unless and until a conflict in authority

emerge[d],” id. at 17-20. That amicus brief acknowledged that, in a prior court of appeals brief filed in the

same case, the government had argued that the failureto-warn claim was preempted. See id. at 6. This Court

denied certiorari. Monsanto Co. v. Hardeman, 142 S.

Ct. 2834 (2022).

Since that time, a conflict has developed among the

courts of appeals on the question whether FIFRA expressly preempts state-law tort claims premised on petitioner’s failure to warn its customers about potential

cancer risks created by use of Roundup. See Schaffner

v. Monsanto Corp., 113 F.4th 364, 382-385 (3d Cir. 2024).

In light of the Third Circuit’s intervening decision in

Schaffner and the change in Administration, the United

States has reexamined the arguments it pressed before

this Court in Hardeman and has returned to its previous position as to the scope of FIFRA preemption. Under that approach, EPA’s approval of Roundup labels

without a cancer warning, combined with an EPA regulation that prohibits petitioner from adding such a

warning without agency approval, preempts respondent’s failure-to-warn claim. The Missouri Court of Ap-

11

peals’ contrary holding is incorrect. Review is now warranted to resolve the conflict on an important question

of federal law.

A. The Decision Below Is Incorrect.

FIFRA “pre-empts any statutory or common-law rule

that would impose a labeling requirement that diverges

from those set out in FIFRA and its implementing regulations.” Bates v. Dow Agrosciences LLC, 544 U.S. 431,

452 (2005). Because Missouri’s failure-to-warn cause of

action imposes a “labeling or packaging requirement

that is ‘in addition to or different from those required

under [FIFRA],’ ” id. at 443-444 (quoting 7 U.S.C.

136v(b)) (emphasis omitted), the federal law preempts

respondent’s failure-to-warn claim to the extent of the

difference.

1. a. Under FIFRA, a pesticide is “misbranded” if,

among other things, its label omits “a warning or caution

statement which may be necessary and if complied with

* * * is adequate to protect health and the environment.” 7 U.S.C. 136(q)(1)(G). Through its registration

process, EPA “give[s] content to” FIFRA’s misbranding

standards as they apply to particular pesticides. Bates,

544 U.S. at 543. Before approving a registration request, EPA extensively reviews a manufacturer’s science and safety data, as well as publicly available science and data, to determine whether the pesticide will

pose any “unreasonable adverse effects on the environment,” 7 U.S.C. 136a(c)(5)(C), (D), with the term “unreasonable adverse effects on the environment” defined

to include any “unreasonable risk to man or the environment, taking into account the economic, social, and

environmental costs and benefits of the use of [the] pesticide,” 7 U.S.C. 136(bb); see p. 6, supra. The agency

approves the registration only if it concludes that the

12

label contains all warnings that are necessary to satisfy

that standard.

Once EPA has registered a pesticide, the agency’s

regulations limit a registrant’s ability to change its label

without EPA’s express approval. A registrant must apply for permission to make “any modification in the

composition, labeling, or packaging of a registered product,” 40 C.F.R. 152.44(a), including any “[s]pecific statements pertaining to the hazards of the product and its

uses,” 40 C.F.R. 156.70(c). The manufacturer may not

unilaterally alter a label that EPA has approved, even

if the registrant learns of “additional factual information

regarding unreasonable adverse effects.” 7 U.S.C.

136d(a)(2). Instead, the registrant must “submit such information to” EPA. See ibid.3

b. As applied to this case, the labeling requirements

imposed by Missouri’s failure-to-warn law are preempted

by FIFRA.

i. Although a State may permissibly impose “parallel” requirements on a manufacturer, preemption is appropriate where the “Federal Government has weighed

the competing interests relevant to the particular requirement in question, reached an unambiguous conclusion

about how those competing considerations should be resolved in a particular case or set of cases, and implemented that conclusion via a specific mandate on manufacturers or producers.” Medtronic, Inc. v. Lohr, 518 U.S.

470, 501 (1996). In Riegel v. Medtronic, Inc., 552 U.S. 312

EPA regulations allow registrants to make “certain minor modifications to registration” by notifying the agency, without waiting

for agency approval. 40 C.F.R. 152.46(a). A registrant could not

unilaterally amend its label, however, to include the type of precautionary statements about health risks that are at issue here. See 40

C.F.R. 156.70(c); Schaffner, 113 F.4th at 382-385.

3

13

(2008), this Court considered the preemption provision in

the Medical Device Amendments of 1976 (MDA), Pub. L.

No. 94-295, 90 Stat. 539, to the Federal Food, Drug, and

Cosmetics Act, ch. 675, 52 Stat. 1040 (21 U.S.C. 301 et

seq.). Similar to FIFRA’s express-preemption provision,

the MDA preempts state-law requirements that are

“different from, or in addition to, any requirement applicable under this chapter to the [medical] device.” 21

U.S.C. 360k(a)(1); see Riegel, 552 U.S. at 316; Bates, 544

U.S. at 447 (observing that the two statutes’ preemption

provisions are “similarly worded”).

The Court in Riegel held that the medical-device premarket-approval process conducted by the Food and

Drug Administration (FDA) created federal-law “requirement[s]” within the meaning of Section 360k(a)(1).

See 552 U.S. at 321-322. The Court explained that FDA

“premarket approval is specific to individual devices,”

id. at 323, and that “the FDA requires a device that has

received premarket approval to be made with almost no

deviations from the specifications in its approval application, for the reason that the FDA has determined that

the approved form provides a reasonable assurance of

safety and effectiveness,” ibid. The Court further held

that the federal-law requirements imposed on specific

devices by the FDA’s premarket-approval process

preempt any inconsistent duties imposed by state tort

law. See id. at 323-325, 330.

For substantially the same reasons, EPA’s pesticideregistration process produces “requirements for labeling” within the meaning of 7 U.S.C. 136v(b). Just as FDA

“premarket approval is specific to individual devices,”

Riegel, 552 U.S. at 323, EPA determines on an individualized basis what warnings are appropriate for particular pesticides. And once EPA has registered a particular

14

pesticide, the agency allows “almost no deviations from

the” approved labeling without express EPA approval.

Ibid.; see 40 C.F.R. 152.44(a). EPA determinations made

in the course of the registration process thus are binding and identify more specifically the “contents required

to be included on a pesticide label.” See Schaffner, 113

F.4th at 390.

ii. The Missouri Court of Appeals described “the dispositive question” before it as “whether [respondent’s]

failure to warn claim imposes a requirement that is ‘in

addition to or different from’ FIFRA’s labeling requirements.” Pet. App. 6. The court concluded that the relevant federal- and state-law requirements were equivalent because “[t]he practical effect of both FIFRA’s

prohibition on misbranding under section 136(q)(1)(G)

and a strict liability failure to warn claim in Missouri are

the same: both require a pesticide manufacturer to adequately warn users of the potential dangers of using its

product.” Id. at 7 (internal quotation marks omitted).

The court thus viewed the general rule set forth in

7 U.S.C. 136(q)(1)(G), which requires each pesticide label to contain whatever warnings are “necessary and

* * * adequate to protect health and the environment,”

as the only federal labeling “requirement[]” relevant to

the preemption inquiry. The court did not consider, as

potentially preemptive federal “requirements for labeling” within the meaning of Section 136v(b), the

Roundup-specific labeling requirements to which petitioner is subject as a result of the EPA registration process.

That approach reflects an unduly parsimonious reading of FIFRA’s preemption provision. Section 136v(b)

bars States from enforcing “any requirements for labeling or packaging in addition to or different from those

15

required under this subchapter [i.e., FIFRA].” 7 U.S.C.

136v(b) (emphasis added). The current federal-law requirements specifying what warnings must appear on

Roundup labels result in part from EPA’s approval (after a substantial scientific review) of a Roundup label

that contains certain warnings but not warnings about

cancer risk, and in part from EPA regulations that prohibit registrants from significantly changing their pesticide labels without the agency’s approval. See Schaffner,

113 F.4th at 393 (explaining that EPA’s regulations

“give[] content to the broad [FIFRA] misbranding standard by specifically requiring a pesticide’s label to bear

the particular precautionary statements on” the label

approved by EPA during the registration process); id.

at 390-393.

The specific labeling mandates that identify the prescribed contents of Roundup labels thus result from

EPA actions implementing FIFRA’s more general provisions. The mandates therefore are naturally characterized as being “required under” FIFRA, even though

they do not appear on the face of the statute. That reading is strongly supported by Riegel, in which the Court

held that FDA premarket approval of a specific medical

device “imposes ‘requirements’ under the MDA.” 552

U.S. at 322 (emphasis added); see 21 U.S.C. 360k(a)(1)

(giving preemptive effect to “any requirement applicable under this chapter to the device”) (emphasis added);

Schaffner, 113 F.4th at 388 (“The analysis of ‘requirements’ adopted in Riegel carries over to FIFRA.”); id.

at 388-389.

iii. The Missouri Court of Appeals also erred in treating FIFRA’s prohibition on misbranding under section

136(q)(1)(G) as substantively equivalent to a state

failure-to-warn claim. See Pet. App. 7. Under Missouri

16

law, a manufacturer is strictly liable for harms caused by

an “unreasonably dangerous” product if the manufacturer “did not give adequate warning of the danger.” Moore

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

banc); Pet. App. 6-7. In determining whether a particular product is unreasonably dangerous, a Missouri jury

need not consider the product’s economic and social benefits, as the “concept of unreasonable danger . . . is presented to the jury as an ultimate issue without further

definition.” Moore, 332 S.W.3d at 756 (citation omitted).

Under FIFRA, by contrast, a manufacturer is required

to add only such warnings as are “necessary and * * *

adequate to protect human health and the environment.”

7 U.S.C. 136(q)(1)(G). And in determining whether a particular pesticide will pose an “unreasonable risk to man

or the environment,” EPA “tak[es] into account the economic, social, and environmental costs and benefits of

the use of [the] pesticide.” 7 U.S.C. 136(bb) (emphasis

added). Because the jury below was not instructed to

account for such benefits, the jury did not apply the

same substantive standard that FIFRA instructs EPA

to apply in determining whether a pesticide is misbranded. Cf. Riegel, 552 U.S. at 325 (noting that, while

the FDA’s premarket-approval process involves a “costbenefit analysis,” the jury in a tort suit “sees only the

cost of a more dangerous design”).

2. Respondent’s contrary arguments are unavailing.

a. Respondent relies in part on this Court’s decision

in Bates. There, the Court considered whether FIFRA

preempted state-law fraud and failure-to-warn causes

of action that were premised on allegedly deceptive

statements on a pesticide’s label. The defendant manufacturer’s label stated that its pesticide (Strongarm)

was “recommended in all areas where peanuts are

17

grown.” Bates, 544 U.S. at 435 (citation omitted). The

plaintiffs alleged, however, that “[w]hen [they] applied

Strongarm on their farms—whose soils have pH levels

of 7.2 or higher, as is typical in western Texas—the pesticide severely damaged their peanut crops while failing

to control the growth of weeds.” Ibid. EPA subsequently

approved a “supplemental” label, authorized for use

only in New Mexico, Oklahoma, and Texas, that “contained the following warning: ‘Do not apply Strongarm

to soils with a pH of 7.2 or greater.’ ” Ibid. (citation

omitted).

The Bates Court explained that plaintiffs could pursue their claims if the state-law requirements were

“fully consistent with federal requirements,” but that

FIFRA would preempt “any statutory or common-law

rule that would impose a labeling requirement that diverges from those set out in FIFRA and its implementing regulations.” 544 U.S. at 452. The Court did not

decide whether the state-law requirements at issue in

Bates were “in fact * * * equivalent to a requirement

under FIFRA,” id. at 453, and it remanded with instructions that, if the case proceeded to trial, “the court’s

jury instructions must ensure that nominally equivalent

labeling requirements are genuinely equivalent,” id. at

454.

Respondent emphasizes (Br. in Opp. 26) that, in Bates,

the Court noted the possibility that a pesticide might be

“registered but nevertheless misbranded.” 544 U.S. at

438. In Bates, however, the plaintiffs did not allege that

the defendant had failed to warn about risks to human

health; they alleged that Strongarm had damaged their

crops and had not controlled the growth of weeds. Id.

at 435. The Court explained that, when EPA registered

the pesticide at issue, it was not required to confirm claims

18

on the proposed label about the product’s efficacy. See id.

at 440; id. at 450 (“Congress amended FIFRA to allow

EPA to waive efficacy review of newly registered pesticides.”). Because EPA had never “passed on the accuracy of the statements in Strongarm’s original label recommending the product’s use ‘in all areas where peanuts are grown,’ ” id. at 440, EPA’s registration of the

pesticide did not reflect any Strongarm-specific judgment that was inconsistent with the plaintiffs’ state-law

claims.

By contrast, EPA carefully evaluates the “particular

requirement in question” here, Riegel, 518 U.S. at 501—

i.e. that a pesticide’s label must contain warnings sufficient to prevent unreasonable risks to human health—

when it approves a pesticide label. See pp. 11-12, supra.

Through that process, EPA has identified more specifically the health-based warnings that a Roundup label

must include to avoid misbranding liability. With respect

to the ingredient (glyphosate) that respondent views as

hazardous, EPA has made specific and consistent factual findings, and the agency has repeatedly approved

Roundup labels that did not contain cancer warnings.

See p. 7, supra. By imposing liability for petitioner’s failure to include such a warning, the state-court judgment

subjected petitioner to a “requirement[] for labeling”

that is “in addition to or different from those required

under” FIFRA. 7 U.S.C. 136v(b).

b. Respondent’s reliance (Br. in Opp. 25-28) on

7 U.S.C. 136a(f )(2) is likewise misplaced. Section

136a(f )(2) states that registration is “prima facie evidence” that a pesticide complies with FIFRA’s requirements, but that registration is not “a defense for the

commission of any offense under” FIFRA, including

misbranding offenses. Ibid. Registration, for instance,

19

may not protect a registrant from federal liability if the

label that appears on a product in distribution differs materially from the label the agency approved. See Schaffner,

113 F.4th at 397 n.18. The registrant might also face liability under FIFRA if it fails to include in its registration application “factual information of which [it was]

aware regarding unreasonable adverse effects of the

pesticide,” 40 C.F.R. 152.50(f )(3), or fails to inform EPA

when the registrant learns of “additional factual information regarding unreasonable adverse effects,” 7 U.S.C.

136d(a)(2); see 7 U.S.C. 136j(a)(2)(S).

Even if a manufacturer’s failure to submit accurate

and timely information to EPA could subject it to liability under federal law (either for misbranding or other

offenses), it would not necessarily follow that state-law

failure-to-warn claims could go forward. The viability

of such claims would still depend on whether imposition

of state-law liability would impose labeling requirements “in addition to or different from those required

under” FIFRA. 7 U.S.C. 136v(b). And any private suit that

asked a court or jury to assess the adequacy of a manufacturer’s disclosures to EPA would raise distinct concerns. Cf. Buckman Co. v. Plaintiffs’ Legal Comm., 531

U.S. 341, 347-348 (2001) (holding that so-called “fraudon-the-FDA” claims are impliedly preempted because

the federal-law obligation to inform the FDA of any safety

concerns regarding a medical device is not privately enforceable).

In any event, respondent’s approach to FIFRA

preemption would allow state-law liability well beyond

the circumstances described above. Respondent suggests (Br. in Opp. 26) that pesticide manufacturers’ submissions to EPA may sometimes be “inaccurate, incomplete, or proven inadequate based on later research.” But

20

neither the Missouri Court of Appeals’ opinion nor the

jury instructions in this case required a finding to that

effect as a prerequisite to liability. Instead, the state

court’s approach would allow a jury to evaluate the same

information that EPA had evaluated and reach a determination that conflicts with the agency’s findings, thus

undermining the interest in “[u]niformity” that FIFRA’s

preemption provision is intended to protect. 7 U.S.C.

136v(b).4

B. The Acknowledged Circuit Conflict Warrants This

Court’s Review

1. The court below acknowledged that its decision

conflicts with the Third Circuit’s decision in Schaffner.

There, the Third Circuit held that FIFRA preempted

similar state-law claims based on respondent’s failure

to warn of cancer risks allegedly posed by Roundup.

Schaffner, 113 F.4th at 370-399. The Schaffner court

concluded that, because EPA had registered the pesticide and approved a label that omits a particular health

warning, FIFRA expressly preempted a state-law duty

to include that warning on the product’s label. Id. at

370-371. In particular, the Schaffner court explained

that EPA’s regulations require “pesticide labels to conform to the EPA’s opinion as to whether specific labels

would constitute misbranding, and thus each ‘give[s]

content to’ the broad requirement that such labels not

be misbranded.” Id. at 391 (quoting Bates, 544 U.S. at

453) (brackets in original). The court further held that,

Petitioner also contends that FIFRA impliedly preempts respondent’s failure-to-warn claim because it is “impossible” for petitioner to comply with both federal- and state-law requirements.

Pet. 28 (citation omitted). Because FIFRA expressly preempts the

claim at issue, this Court need not decide whether FIFRA impliedly

preempts respondent’s claims.

4

21

in determining whether enforcement of a state-law duty

to warn would impose labeling requirements “in addition to or different from those required under” FIFRA,

7 U.S.C. 136v(b), the court should take into account EPA’s

regulatory requirement that manufacturers adhere to

EPA-approved labels. Schaffner, 113 F.4th at 390-393.

Based on that comparison between state and relevant

federal requirements, the Third Circuit held that the

plaintiffs’ claims were preempted. Id. at 399.

The Ninth and Eleventh Circuits have reached a contrary conclusion. Those courts have allowed similar

state-law failure-to-warn claims against petitioner to

proceed, notwithstanding EPA’s registration of the pesticide and its approval of Roundup labels that do not

contain cancer warnings. See Hardeman v. Monsanto

Co., 997 F.3d 941, 955-958 (9th Cir. 2021); Carson v.

Monsanto, 92 F.4th 980, 989-996 (11th Cir. 2024). Several state courts have reached similar conclusions. See,

e.g., Johnson v. Monsanto Co., 554 P.3d 290, 306-307 (Or.

Ct. App. 2024), petition for cert. pending, No. 24-1098

(filed Apr. 18, 2025); Pilliod v. Monsanto Co., 282 Cal.

Rptr. 3d 679, 698 (Cal. Ct. App. 2021), cert. denied, 142

S. Ct. 2870 (2022); Caranci v. Monsanto Co., 338 A.3d

151, 167-170 (Pa. Super. Ct. 2025).

2. Respondent maintains (Br. in Opp. 22) that no

conflict is implicated here because the Third Circuit in

Schaffner relied on the assumption that “Monsanto had

no option to update Roundup’s labeling.” Respondent observes (ibid.) that EPA regulations did not prevent petitioner from seeking EPA approval to add a cancer warning to its label. In fact, the Schaffner court noted the possibility of a hypothetical state-law tort suit alleging that

FIFRA required petitioner to request EPA approval to

add a cancer warning to its label. 113 F.4th at 386 n.13.

22

The court “express[ed] no opinion” about such a claim’s

potential merits, however, because the plaintiffs in that

case had not advanced such a claim. Ibid.; but cf. p. 19,

supra (citing Buckman, supra).

Similarly here, the jury’s liability determination was

not premised on any finding that petitioner was remiss

in failing to request approval to add a cancer warning to

the Roundup label. Rather, the jury was instructed to find

petitioner liable so long as Roundup was sold without an

adequate cancer warning. See Cert. Reply Br., Supp. App.

4. That instruction left the jury no room to consider

whether petitioner could or should have provided updated information to the agency.

Respondent also contends (Br. in Opp. 16-20) that his

claims do not depend on Roundup’s labeling, which is

subject to Section 136v(b)’s preemption rule, but instead

turned on television advertisements, which are beyond

Section 136v(b)’s reach. The court below, however, characterized respondent’s failure-to-warn claim as a “common-law action which effectively imposes a state law requirement for labeling.” Pet. App. 5-6. Indeed, respondent’s failure-to-warn count alleged that “Monsanto had a duty to properly . . . label” Roundup products. Id. at 6 n.3. The decision below therefore turned

on whether respondent’s “failure to warn claim impose[d] a requirement that is ‘in addition to or different

from’ FIFRA’s labeling requirements”—the question

that has divided the federal courts of appeals. Id. at 6

(citation omitted).

3. The circuit conflict warrants this Court’s review.

FIFRA’s preemption provision is entitled “[u]niformity.” 7 U.S.C. 136v(b). The Third Circuit’s approach

correctly allows EPA to determine on a nationwide ba-

23

sis what warnings must appear on a particular pesticide’s label to avoid an unreasonable risk to human

health. Under the Ninth and Eleventh Circuits’ approach,

by contrast, “different factfinders deciding different individual cases” might reach conflicting determinations

as to “whether a particular warning was necessary to

protect health.” Schaffner, 113 F.4th at 393. That risk

goes beyond the concern that “properly instructed juries” will reach differing conclusions from each other.

Bates, 544 U.S. at 452. Rather, the approach that respondent advocates, and that the Ninth and Eleventh

Circuits have adopted, allows juries to reach different

determinations than EPA itself.

This is a case in point. After careful scientific review

and an assessment of hundreds of thousands of public

comments, EPA has repeatedly determined that glyphosate is not likely to be carcinogenic in humans, and the

agency has repeatedly approved Roundup labels that

did not contain cancer warnings. See p. 7, supra. Under

respondent’s approach, however, a jury may secondguess the agency’s science-based judgments and hold

petitioner liable for failing to provide warnings “in addition to or different from those required under”

FIFRA. 7 U.S.C. 136v(b).

Section 136v(b) was meant to prevent that sort of inconsistency and patchwork results. Where, as here, EPA

has specified the health warnings that should appear on

a particular pesticide’s label, a manufacturer should not

be left subject to “50 different labeling regimes prescribing” different requirements. Bates, 544 U.S. at 452.

This Court’s intervention is warranted to give FIFRA’s

preemption provision its proper force.

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CONCLUSION

The petition for a writ of certiorari should be granted.

Respectfully submitted.

D. JOHN SAUER

Solicitor General

MALCOLM L. STEWART

Deputy Solicitor General

ROBERT N. STANDER

Deputy Assistant

Attorney General

ASHLEY ROBERTSON

Assistant to the

Solicitor General

MATTHEW OAKES

CYNTHIA TAUB

Attorneys

DECEMBER 2025