The American Farm Bureau and 11 other farm groups asked the U.S. Supreme Court to shield the Monsanto Company from lawsuits alleging glyphosate causes cancer.

Glyphosate, the active ingredient in Monsanto’s line of Roundup products, revolutionized the agricultural industry when it was introduced in 1974, the farm groups stated in a friend-of-the-court brief filed May 9.

“Glyphosate is the single most widely used herbicide for weed management in the United States and is essential to sustaining American farming in the 21st century,” the brief reads.

Monsanto, owned by Bayer AG, has been hit with thousands of claims that glyphosate causes cancer, even though the Environmental Protection Agency has determined the herbicide does not cause cancer and does not require warnings on labels.

Earlier this year, a jury in Missouri awarded $1.25 million to John L. Durnell, who claimed he got non-Hodgkin’s lymphoma from glyphosate. The jury ruled Monsanto failed to warn Durnell.

Monsanto argues the EPA’s determination under the Federal Insecticide, Fungicide and Rodenticide Act preempts state liability laws.

Federal courts have taken on the question and delivered conflicting decisions. Monsanto, facing some 30 trials this year and 50 more in 2026, has asked the Supreme Court to settle the issue.

In contrast to the EPA, the International Agency for Research on Cancer concluded in 2015 that glyphosate was probably carcinogenic to humans.

In a footnote to its petition to the Supreme Court, Monsanto said that by 2022 lawyers had spent an estimated $131 million on 625,000 television ads seeking litigants to sue the company.

In response, Monsanto took glyphosate out of its consumer version of Roundup, but the ongoing lawsuits threaten the company’s ability to supply glyphosate to farmers, according to the petition.

In the friend-of-the-cour brief, farm groups gave justices a tutorial on weed control. Prior to the 1940s, farmers typically tilled between rows to keep weeds from smothering crops. The Dust Bowl showed the dangers of overtilling, according to the farm groups.

“Gone are the days of repeatedly hoeing the rows throughout the growing season,” the brief states.

Farm groups said they were concerned state liability laws could take other EPA-approved pesticide products off the market. The brief, however, mostly dwelled on the importance of glyphosate.

Glyphosate-tolerant seeds make up more than 90% of corn, cotton, soybean and canola seeds, according to the farm groups. Alternatives to glyphosate don’t compare, they said.

“Glyphosate’s wide-ranging benefits cannot be overstated,” the brief reads. “All corners of America’s agricultural industry rely on, and benefit from, glyphosate.”

The other farm groups signing the brief were the American Soybean Association, American Sugarbeet Growers Association, Cherry Marketing Institute, Florida Fruit and Vegetable Association, International Fresh Produce Association;

National Association of Wheat Growers, National Corn Growers Association, National Cotton Council of America, National Sorghum Producers, North American Blueberry Council and Western Growers.