After failing in several U.S. states this year, global chemical manufacturer Bayer said Tuesday that it plans to amplify efforts to create a legal shield against a proliferation of lawsuits alleging it failed to warn that its popular weed killer could cause cancer.

Bayer, which disputes the cancer claims, has been hit with about 170,000 lawsuits involving its Roundup weed killer and has set aside $16 billion to settle cases. But the company contends the legal fight “is not sustainable” and is looking to state lawmakers for relief.

Bayer lobbied for legislation that could have blocked a central legal argument this year in Missouri, Iowa, and Idaho—home, respectively, to its North America crop science division, a Roundup manufacturing facility and the mines from which its key ingredient is derived. Though bills passed at least one chamber in Iowa and Missouri, they ultimately failed in all three states.

But Bayer plans a renewed push during next year’s legislative sessions and may expand efforts elsewhere.

“This is bigger than just those states, and it’s bigger than just Bayer,” said Jess Christiansen, head of Bayer’s crop science and sustainability communications. “This is really about the crop protection tools that farmers need to secure production.”

Many U.S. farmers rely on Roundup, which was introduced 50 years ago as a more efficient way to control weeds and reduce tilling and soil erosion. For crops including corn, soybeans, and cotton, it’s designed to work with genetically modified seeds that resist Roundup’s deadly effect.

The lawsuits allege Roundup’s key ingredient, glyphosate, causes a cancer called non-Hodgkin lymphoma. Though some studies associate glyphosate with cancer, the U.S. Environmental Protection Agency has said it is not likely to be carcinogenic to humans when used as directed.

The legislation backed by Bayer would protect pesticide companies from claims they failed to warn their products could cause cancer if their labels otherwise comply with EPA regulations.

Some lawmakers have raised concerns that if the lawsuits persist, Bayer could pull Roundup from the U.S. market, forcing famers to turn to alternatives from China.

Christiansen said Bayer has made no decisions about Roundup’s future but “will eventually have to do something different if we can’t get some consistency and some path forward around the litigation industry.”

Bayer’s most recent quarterly report shows that it shed more than 1,500 employees, reducing its worldwide employment to about 98,000. Bayer submitted a notice to Iowa that 28 people would be laid off starting Wednesday at its facility in Muscatine.

The Iowa layoffs are not a direct result of the failure of the protective legislation, Christiansen said, but are part of a global restructuring amid “multiple headwinds,” which include litigation.

Bayer has bankrolled a new coalition of agriculture groups that has run TV, radio, newspaper, and billboard ads backing protective legislation for pesticide producers. The campaign has especially targeted Missouri, where most of the roughly 57,000 still active legal claims are pending. Missouri was the headquarters of Roundup’s original manufacturer, Monsanto, which Bayer acquired in 2018.

Legal experts say protective legislation is unlikely to affect existing lawsuits. But it could limit future claims.

The annual deadline to pass legislation in Missouri expired last Friday. Though a Bayer-backed bill cleared the Republican-led House and a Senate committee, it never got debated by the full GOP-led Senate, which was mired in unrelated tensions.

If the legislation is revived next year, it could face resistance from senators concerned about limiting people’s constitutional right to a jury trial to resolve disputes.

“I support farmers, but I also think they need due process,” said Republican state Senator Jill Carter, who voted against the legislation this year in the Senate agriculture committee.

—By David A. Lieb, Associated Press