Issue Brief by Senior Policy Analyst, Tom Opdyke | topdyke@csg.org

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In recent years, numerous lawsuits have been filed alleging that glyphosate used in certain herbicides caused plaintiffs to develop non-Hodgkin lymphoma. Many of these lawsuits claim that, under state laws, the manufacturer failed to warn of the health risks associated with using the product. However, there is much debate around whether the presence of glyphosate causes cancer in humans. In addition, the manufacturers of these products claim that federal labeling requirements that do not require such warnings should preempt failure-to-warn state laws.

As a result, legislation has been introduced in at least 11 states in the last two years that limits such manufacturers’ liability. These bills aim to codify that federal labeling requirements are sufficient to comply with state requirements. To date, only Georgia and North Dakota have successfully enacted such laws.

Glyphosate-based Herbicides

Glyphosate is an organic compound containing phosphorus. It works by hindering the 5-enolpyruvylshikimate-3-phosphate (EPSP) enzyme, which in turn blocks a plant’s growth (animals do not have the EPSP enzyme). Glyphosate-based herbicides (GBHs) are often used on crops that have been genetically modified to be resistant to their effects.

Developed by Monsanto in the 1970s, Roundup was the first GBH. In 1996, the first glyphosate-resistant crop (GRC), a soybean variant, was developed, followed by cotton and maize GRCs. This led to the wider adoption of GBHs as a weed management source,¹ and today, GBHs are the most widely used herbicides in the world.² In addition, GBHs are now used for agricultural, residential, and commercial purposes with a wide range of application methods.³ Due to the widespread use of GBHs throughout the world, traces of glyphosate are now found in soil, water, air, food products, and even human fluids.⁴

The Debate on Cancer Risk

In 2015, a working group of the World Health Organization’s International Agency for Research on Cancer (IARC) examined possible links between glyphosate and cancer in humans. The group concluded that there was “limited evidence in humans for the carcinogenicity of glyphosate. A positive association has been observed for non-Hodgkin lymphoma,” and that “glyphosate is probably carcinogenic to humans”⁵ (note that a “carcinogen” is a substance that causes cancer,⁶ and “carcinogenic” is used to describe something that may cause cancer).

Later in 2015, the European Food Safety Authority (EFSA) reached the opposite conclusion, that glyphosate is “unlikely to pose a carcinogenic hazard to humans.”⁷ The U.S. Environmental Protection Agency (EPA) released its own study in 2016 with the same conclusion. The EPA’s report stated that, “the available data at this time do not support a carcinogenic process for glyphosate.”⁸ In 2017, Reuters reported that the IARC “dismissed and edited findings from a draft of its review of the weedkiller glyphosate that were at odds with its final conclusion that the chemical probably causes cancer.”⁹

Nevertheless, the IARC’s conclusion created a stir among researchers, and many launched their own studies. In 2017, one paper showed that, in short periods of exposure, glyphosate was less toxic than 94 percent of other herbicides,¹⁰ as well as common household goods like vinegar and table salt.¹¹ However, over longer periods of exposure, it was found to be less toxic than 90 percent of herbicides.¹² Additional research examined how the IARC and EPA could have come to difficult determinations, concluding that the IARC’s assessment scenarios involved people with heightened exposure to the chemical. This assessment also concluded that more research was needed on real-world exposures to GBHs.¹³

Bans and Restrictions

Policymakers around the world also took note of the IARC’s findings.¹⁴ Today, approximately 30 countries, along with parts of Australia, Canada, and the United Kingdom, have banned or restricted the use of glyphosate.¹⁵ In 2015, Sri Lanka became the first country to ban the chemical outright. However, the decision was partially reversed in 2018, then revoked entirely in 2022. Researchers have concluded that the reason for this reversal was a mix of Sri Lanka’s political system shifting regulatory decisions from agencies to the political executive, a lack of cost-effective alternatives, and a failure to link glyphosate to adverse human health issues.¹⁶

In the U.S., New York State passed a law in 2020 banning the use of glyphosate on state property except in specific situations.¹⁷ Arkansas does not ban the use of glyphosate, but since 2021, state law does not allow glyphosate products to be released above certain wind speeds.¹⁸ From California to Connecticut, several counties and cities have enacted restrictions or bans on glyphosate.¹⁹

Lawsuits

Since the release of the IARC findings in 2015, thousands of lawsuits have been filed in federal courts claiming injuries due to the use of glyphosate-based herbicides (GBHs). The majority of these cases were filed under state law and alleged that the plaintiffs developed non-Hodgkin lymphoma (NHL) as a result of long-term exposure to glyphosate in the herbicides.²⁰ NHL is a type of cancer that starts in white blood cells called lymphocytes, which are part of the body’s immune system.²¹

In the majority of these tort cases, the state laws cited related to failure-to-warn claims, specifically that the GBH product label did not contain any type of cancer warning.²² Monsanto (and later Bayer, which bought Monsanto in 2018) has argued that claims related to state law should be preempted by labeling requirements set by the U.S. Environmental Protection Agency (EPA)’s Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA).²³

In August 2018, a jury reached a verdict in the first trial on allegations of GBHs’ cancer-causing effects. Dewayne Johnson, a groundskeeper from California, claimed that he developed NHL after using GBHs. The case, heard by the Superior Court of California in San Francisco, alleged that Monsanto failed to warn consumers of the cancer risks posed by its GBH products. The jury awarded Johnson $39 million in compensatory damages and $250 million in punitive damages.²⁴ The amount was later reduced to $20.5 million on appeal.²⁵

In March 2019, a federal court jury in California awarded Edwin Hardeman $80.3 million in a case that alleged that Hardeman’s use of Roundup on his 56-acre property over two decades had caused his NHL.²⁶ A U.S. District Court later reduced the amount to $20 million.²⁷

Two months later, in May 2019, an Alameda County, California, Superior Court jury awarded more than $2 billion in a case against Monsanto. The couple, Alva and Alberta Pilliod, used Roundup for residential landscaping over nearly 30 years, which they claimed was a major factor in both of their NHL diagnoses. Lawyers for the defense filed a motion to disregard the judgement, but then agreed not to pursue a new trial if the Pilliods accepted a reduced award of $86.7 million, which they did.²⁸

In June 2020, Bayer, the owner of Monsanto, announced that it would pay up to $10.9 billion to settle the approximately 95,000 to 125,000 pending lawsuits alleging the product’s links to cancer. The amount also included $1.25 billion for potential future claims.

Despite the settlement, Bayer continues to sell the commercial version of the product without cancer risk warnings. The company phased out glyphosate in residential products starting in 2023.²⁹

Between 2021 and 2024, Bayer won several trials in Arkansas, California, Missouri, and Pennsylvania. Many of these ended with juries reaching verdicts that upheld Bayer’s defense of its product labels.³⁰ In 2021, Bayer announced that it would replace residential products with “new formulations that rely on alternative active ingredients.”³¹

As of June 2025, the latest high-profile case occurred in Georgia, where a jury awarded more than $2 billion to John Barnes for allegations that GBHs caused his NHL.³²

Bayer has stated that a favorable ruling by the U.S. Supreme Court on whether the FIFRA’s federal label requirements preempt state-based failure-to-warn claims could bring an end to future litigation.³³ A decision in August 2024 from the U.S. Court of Appeals for the Third Circuit, based in Philadelphia, may give Bayer the springboard it is looking for. In Schaffner v. Monsanto, the Third Circuit disagreed with rulings from the Ninth and Eleventh Circuits and sided with Bayer (in 2024, in Carson v. Monsanto, the Eleventh Circuit concluded that the failure-to-warn claims were not preempted, and failure-to-warn claims ran parallel to FIFRA’s prohibition on misbranding³⁴).

The opinion released from the Third Circuit after Schaffner seemed to invite the Supreme Court to review the decision and answer the question once and for all, stating that “the issue presented by this case, which is clearly of general interest, has yet to be decided by the highest court capable of resolving it.”³⁵ As of June 2025, the Supreme Court is considering taking up a similar case, Durnell v. Monsanto, in the wake of the Third Circuit’s ruling.³⁶

In May 2025, it was reported that Bayer is considering another round of settlements, in addition to its 2020 settlements. Should the settlement fail, Bayer may consider placing its Monsanto agriculture business in bankruptcy.³⁷

State Actions

In light of the ongoing lawsuits alleging connections between cancer and glyphosate-based herbicides (GBHs), Bayer began lobbying policymakers at the state and federal levels on label requirements, specifically laws that would codify that FIFRA’s label requirements preempt any state failure-to-notify laws.³⁸ According to state lobbying records, Bayer lobbied state lawmakers in at least three states — Idaho, Iowa, and Missouri — in 2024.³⁹

In 2024 and 2025, at least eleven states saw legislation introduced that aimed to codify language stating that FIFRA’s pesticide* labeling requirements (or wider EPA language) shall be sufficient for any state law labeling requirements.

For example, Idaho’s S.B. 1245 (2024)⁴⁰ contained the following (the bill did not pass):

“Any pesticide registered by the United States environmental protection agency under the federal insecticide, fungicide and rodenticide act (FIFRA), the label approved by the United States environmental protection agency in registering the pesticide or a label consistent with the most recent human health assessment performed under FIFRA or consistent with United States environmental protection agency carcinogenicity classification for the pesticide under FIFRA shall be sufficient to satisfy any requirements for a warning regarding health or safety or any other provision or doctrine of state law, including without limitation state tort law or relevant common law.”

Georgia’s S.B. 144 (2025)⁴¹ contained slightly different language, but with similar intent (the bill was enacted):

“Any pesticide registered with the Commissioner, pursuant to Code Section 2-7-55, or the Environmental Protection Agency, pursuant to FIFRA, which displays a label that has been approved by the Environmental Protection Agency in registering the pesticide or is consistent with the most recent human health risk assessment performed under FIFRA shall be deemed a sufficient warning label for the purposes of an action commenced under any provision of state law concerning the duty to warn or label, or any other common law duty to warn.”

Similar bills were introduced in Iowa, Mississippi, Missouri, North Carolina, North Dakota, Oklahoma, Tennessee, and Wyoming during their respective 2024 and 2025 legislative sessions.

In addition, Florida saw legislation filed on the issue that potentially contained the most unique language. Senate Bill 1252 (2024)⁴² specifically stated that failure-to-warn liability cases may not be brought except in four specific instances:

1. the distributor, dealer, or applicator exercised substantial control over the aspect of the design, testing, manufacture, or labeling of the pesticide product;
2. the distributor, dealer, or applicator altered or modified the product, and that modification was a substantial factor in causing the alleged harm;
3. the distributor, dealer, or applicator handled, used, or applied the product in a manner inconsistent with the product label, and that such action caused the alleged harm; and
4. the manufacturer or the pesticide product is not subject to Florida’s jurisdiction

As of June 2025, only Georgia⁴³ and North Dakota⁴⁴ have enacted laws related to pesticide labeling and liability. Georgia’s law took effect in July 2025, and North Dakota’s law is expected to take effect in August 2025.

Conclusion

The debate over whether glyphosate-based herbicides (GBHs) cause cancer in humans is still ongoing. The EPA is expected to complete its next review of GBHs in 2026.⁴⁵ The federal government’s position will remain unchanged until then, and the 2026 review still may not shift that stance.

What may change is how the courts view the issue. Should the Supreme Court agree to rule on whether state failure-to-warn laws are enough for lawsuits against GBHs, it could stop the wave of lawsuits GBH manufacturers have faced for nearly ten years. Alternatively, a ruling that allows such lawsuits could push manufacturers to stop using glyphosate in herbicides altogether.

In the interim, state legislatures across the country are looking at laws to settle the matter within their borders. Following Georgia and North Dakota’s lead, more states may block future lawsuits against GBH manufacturers.

End Notes

1. Stephen Duke, “The History and Current Status of Glyphosate,” Publications from USDA-ARS / UNL Faculty, Vol. 1766, 2017.
2. “Glyphosate & Glyphosate Formulations,” National Toxicology Program, U.S. Department of Health and Human Services, accessed June 9, 2025; H. Metcalfe et al, “Trade-offs Constrain the Success of Glyphosate-Free Farming,” Scientific Reports, Vol. 14, 2024; Athanasios Valavanidis, “Glyphosate, the Most Widely Used Herbicide. Health and safety issues. Why Scientists Differ in Their Evaluation of Its Adverse Health Effects,” National and Kapodistrian University of Athens, March 2018.
3. “Glyphosate,” U.S. Environmental Protection Agency, accessed June 9, 2025.
4. Juliana Maria Bitencourt de Morais Valentim et al, “Glyphosate as a Food Contaminant: Main Sources, Detection Levels, and Implications for Human and Public Health,” Foods, Vol. 28, No. 13, May 28, 2024; Kavita Gandhi et al, “Exposure Risk and Environmental Impacts of Glyphosate: Highlights on the Toxicity of Herbicide Co-formulants,” Environmental Challenges, Vol. 4, August 2021; U.S. Environmental Protection Agency, accessed June 9, 2025.
5. International Agency for Research on Cancer Working Group on the Evaluation of Carcinogenic Risks to Humans, “Some Organophosphate Insecticides and Herbicides,” International Agency for Research on Cancer, World Health Organization, No. 112, 2017.
6. “Carcinogen,” National Cancer Institute, accessed June 10, 2025.
7. “Glyphosate: EFSA Updates Toxicological Profile,” European Food Safety Authority, November 12, 2015.
8. “Glyphosate Issue Paper: Evaluation of Carcinogenic Potential,” U.S. Environmental Protection Agency’s Office of Pesticide Programs, September 12, 2016.
9. Kate Kelland, “In Glyphosate Review, WHO Cancer Agency Edited Out ‘Non-carcinogenic’ Findings,” Reuters, October 19, 2017.
10. Andrew Kniss, “Long-term Trends in the Intensity and Relative Toxicity of Herbicide Use,” Nature Communications, Vol. 8, 2017.
11. John Wallace, Dwight Lingenfelter, and Art Grover, “Glyphosate (Roundup): Understanding Risks to Human Health,” Penn State Extension, January 5, 2023.
12. Kniss, 2017.
13. Charles Benbrook, “How Did the US EPA and IARC Reach Diametrically Opposed Conclusions on the Genotoxicity of Glyphosate-Based Herbicides?,” Environmental Sciences Europe, Vol. 31, 2019.
14. Tim Dorlach and Sandya Gunasekara, “The Politics of Glyphosate Regulation: Lessons from Sri Lanka’s Short-Lived Ban,” Global Health, Vol. 19, No. 84, November 13, 2023.
15. Mark Howell, “Is Roundup Banned?,” Consumer Notice, August 25, 2023.
16. Dorlach and Gunasekara, 2023.
17. NY Env Conserv L § 33-1301.
18. AR Admin Rules 209.02.03-002.
19. Al Rabine and Scott Faber, “Trump EPA May Threaten State and Local Bans of Toxic Weedkiller Glyphosate,” Environmental Working Group, February 12, 2025.
20. Daniel Zayas, “The Glyphosate Debate: Challenging Federal Preemption of State Failure-to-Warn Claims,” The Princeton Legal Journal, Vol. 3, No. 2, 2024; “Plaintiffs & Pesticides: Intro to Pesticide Injury Litigation,” The National Agricultural Law Center, March 31, 2022.
21. “What Is Non-Hodgkin Lymphoma?,” American Cancer Society, accessed June 11, 2025.
22. Hannah Frater, “Preempting Toxic Torts: Third Circuit Opens Split on Cancer Warnings in Schaffner v. Monsanto,” Harvard Law Review, November 18, 2024.
23. “Bayer’s High Court Filing Says State-Level Roundup Suits Conflict with Federal Law,” Ag Daily, April 8, 2025; Mark Elliott and Christopher Smith, “The Evolving Argument Surrounding Federal Preemption of Proposition 65,” Pillsbury Winthrop Shaw Pittman LLP, June 11, 2020.
24. Tina Bellon, “Monsanto Ordered to Pay $289 Million in World’s First Roundup Cancer Trial,” Reuters, August 10, 2018.
25. Brendan Pierson, “Bayer Will Not Appeal $20.5 Mln Roundup Judgment to Supreme Court,” Reuters, March 19, 2021.
26. Richard Gonzales, “Jury Awards $80 Million In Damages In Roundup Weed Killer Cancer Trial,” NPR, March 27, 2019; Andrew Wolfson, “Louisville Lawyer Wins $80M Verdict Against Monsanto Over Weedkiller Roundup,” Courier Journal, March 28, 2019.
27. Chloe Marie, “Review of Litigation Against Monsanto Regarding the Safety of Glyphosate,” Penn State Center for Agricultural and Shale Law, August 14, 2020.
28. Marie, 2020; April Siese, “Jury awards couple $2 Billion in Monsanto Roundup Cancer Lawsuit Trial,” CBS News, May 13, 2019.
29. “Bayer Announces Agreements to Resolve Major Legacy Monsanto Litigation,” Bayer, June 24, 2020; Patricia Cohen, “Roundup Maker to Pay $10 Billion to Settle Cancer Suits,” The New York Times, June 24, 2020; Ludwig Burger and Patricia Weiss, “Bayer CEO: We Will Have to Stop U.S. Glyphosate Production If Nothing Changes,” Reuters, August 6, 2025.
30. “Managing the Roundup Litigation,” Bayer, accessed June 11, 2025.
31. “Bayer Provides Update on Path to Closure of Roundup™ Litigation,” Bayer, July 29, 2021.
32. Wyatte Grantham-Philips, “Georgia jury orders Monsanto parent to pay nearly $2.1 billion in Roundup weedkiller lawsuit,” AP, March 24, 2025.
33. Bayer, accessed June 11, 2025.
34. Brigit Rollins, “Eleventh & Ninth Circuits Issue Decisions in Glyphosate Lawsuits,” The National Agriculture Law Center, June 18, 2024.
35. Schaffner v. Monsanto, 113 F.4th 364 (3d Cir. 2024); Frater, 2024
36. “Monsanto Company v. Durnell,” SCOTUSblog, accessed June 11, 2025.
37. Andrew Scurria, Akiko Matsuda, Patrick Thomas, and Alexander Gladstone, “Bayer Seeks New Roundup Settlement While Exploring Monsanto Bankruptcy,” The Wall Street Journal, May 15, 2025.
38. Bayer, accessed June 11, 2025; Tony Romm, “Bayer Lobbies Congress to Help Fight Lawsuits Tying Roundup to Cancer,” The Washington Post, June 20, 2024.
39. Romm, 2024.
40. An Act Relating to Pesticides, S.B. 1245, Second Regular Session of the Sixty-seventh Idaho State Legislature, Idaho, 2024.
41. An Act to Amend Article 6 of Chapter 7 of Title 2 of the Official Code of Georgia Annotated, S.B. 144, First Regular Session of the 158th Georgia General Assembly, Georgia, 2025.
42. An Act Relating to Exemptions from Products Liability Actions, S.B. 1252, Regular Session of the 2024 Florida Legislature, Florida, 2024.
43. Georgia, 2025.
44. Act to Create and Enact a New Section to Chapter 28-01.3 of the North Dakota Century Code, Relating to Pesticide Labeling, H.B. 1318, Regular Session of the Sixty-ninth Legislative Assembly of North Dakota, North Dakota, 2025.
45. Jim Wiesemeyer, “EPA: Glyphosate Can Still be Used Through 2026,” Ag Web, September 26, 2022.