Standing by the side of Highway 63 with the Missouri state Capitol on the horizon, there’s a billboard that says, "Stand Up for Glyphosate."
Glyphosate is the key ingredient of Roundup, the flagship herbicide of Monsanto. Monsanto was based in St. Louis until it was purchased by German company Bayer in 2016. Monsanto and Bayer have been subject to tens of thousands of lawsuits alleging they didn’t warn customers that exposure to Roundup could cause cancer.
There’s no scientific consensus that Roundup is a carcinogen, but judgments and settlements have cost Bayer billions. Most recently, a Missouri appeals court upheld a $611 million judgment against the company.
A bill introduced by Rep. Dane Diehl, R-Butler, this year and supported by Bayer would have insulated Bayer and other chemical companies from those lawsuits. The bill would have prevented companies from being sued over the contents of pesticide labels if those labels have been approved by the EPA.
Since the EPA has not concluded that Roundup can cause cancer, litigants would no longer be able to claim in court that they weren’t properly warned about cancer risks.
“You know, when the amount of litigation out there starts almost hampering or changing a business model, you have to look from a business standpoint at what has to change,” Diehl said during floor debate on the legislation. This was Diehl’s second year sponsoring the bill.
Sen. Justin Brown, R-Rolla, introduced identical legislation in the Senate. The bill passed committee but made it no further. Both Brown and Diehl declined to be interviewed for this story.
Brenda Peculis, a retired University of Missouri professor of biochemistry, is opposed to the legislation.
Peculis said that since more independent studies have been done in the decades since Roundup received its initial EPA approval, the company should be required to attach more warnings. As a volunteer for the City of Columbia, she uses glyphosate to manage invasive plants.
“Every bottle I get says, ‘Caution, contains glyphosate.’ The city will do this for me. Why will the company not do it for my neighbor, who goes to the hardware store to buy it?” Peculis said.
The EPA is in the process of updating its glyphosate registration to incorporate more recent research.
“EPA is currently updating its evaluation of the carcinogenic potential of glyphosate to better explain its findings and include the current relevant scientific information,” an EPA spokesperson said in a statement. “EPA’s underlying scientific findings regarding glyphosate, including its finding that glyphosate is not likely to be carcinogenic to humans, remain the same.”
Glyphosate in farming
Glyphosate is important to what’s called no-till farming, in which weeds are controlled with methods like herbicides rather than through tillage. No-till farming is popular because it preserves soil and prevents erosion.
At a press conference after the session ended, Gov. Mike Kehoe said it was important to make sure glyphosate remains available as a tool for farmers.
“I was disappointed that bill didn’t get passed,” Kehoe said. “It’s very important to many of our ag producers across the state, as well as the actual manufacturers that make those products.”
Many supporters of the legislation, including Kehoe, say the lawsuits against Bayer are driven by lawyers seeking lucrative settlements.
Proponents worry that if Bayer continues losing money to lawsuits, it may deem Roundup too much of a financial liability and remove it from the market.
“If for some reason that particular product is not produced anymore in the United States, farmers are still going to need that type of product, that type of weed control,” Kehoe said. “(Glyphosate) will be produced somewhere, and if it is, it won’t be produced in this country, and farmers will not have the same protections or liability recourse.”
Jess Christiansen, Bayer’s head of crop science communication, says the bill wouldn’t represent blanket immunity for the company. Bayer could still be sued over charges like negligence, just not over failure to warn.
“Of course people should have their day in court,” Christiansen said. “This language is really specific to the labeling requirements that we as companies are held to by the EPA.”
Lobbying efforts
Rep. Adrian Plank, D-Columbia, opposed the bill, calling it “purchased policy.” Plank’s opposition is partly rooted in the fact that a friend and constituent died of lymphoma that he believed was caused by Roundup.
“He kept the jug that he thought gave him that cancer,” Plank said. “He didn’t make it to his third bone marrow transplant and died.”
Plank said Bayer’s push to block lawsuits is driven by greed.
“It’s an investment for them to buy politicians and policy, because it’ll save them money in the long run,” said Plank. “They lost the last four lawsuits to the tune of $11 billion and was able to pay it.”
The billboard on Highway 63 is just one element of a nationwide advertising campaign supporting the bill and parallel legislation in other states. The billboard is paid for by Modern Ag Alliance, a coalition of agricultural industry organizations founded by Bayer.
Modern Ag Alliance members include the Missouri Corn Growers Association and the Missouri Soybean Association. Diehl is a board member of the Missouri Soybean Association.
The bill dies
The bill passed the House by a vote of 85-72, just three votes over the threshold for passage. House Republicans were split on the bill, with 24 voting against.
But that momentum was halted in the Senate when mailers were sent to the districts of some of the most conservative Republican senators, urging them to support the bill. The nine senators targeted held a press conference saying they wouldn’t be pressured into supporting the legislation.
One of them, Sen. Nick Schroer, R-Defiance, said granting legal immunity to any corporation violates Missourians’ Seventh Amendment rights.
“I think as long as it’s going to provide some form of immunity or some form of legal protection for makers of products in the state of Missouri that could possibly injure our constituents it’s not going to be something we’re going to support,” Schroer said.
The Republican opposition in the Senate meant the bill never saw a vote and died with the end of the legislative session.
What comes next
The billboard next to Highway 63 has a link to a website where, through a form letter, visitors from any state can contact legislators to urge them to protect glyphosate manufacturers. In addition to advocating for state-level bills, Bayer has lobbied for similar protections on the federal level.
Similar legislation backed by Bayer passed in North Dakota and Georgia earlier this year.
“Those two have been signed into effect, and so that’s a big success story for the dialogue, and for the movement of really making sure we keep access to well-tested, safe and efficacious and affordable products for farmers to use,” Christiansen said.
Plank said he has no doubt the bill will come up again next year.
“I’m sure of it. You've got to remember that the bill sponsor is on the board of Missouri Soy, and that’s what they want,” Plank said. “They’re going to pander to the people who give them a bunch of money, and that’s Monsanto-Bayer.”
Christiansen said Bayer is keeping its options open regarding what legislation it will endorse in Missouri in the 2026 session.
The River City Journalism Fund supports St. Louis Public Radio's Statehouse internship. Evy Lewis is the 2025 reporting intern. See rcjf.org for more information about the fund, which seeks to advance journalism in St. Louis.
