JEFFERSON CITY, Mo. (AP) — 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 weedkiller could cause cancer.

Bayer, which disputes the cancer claims, has been hit with about 170,000 lawsuits involving its Roundup weedkiller 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.