Stung by paying billions of dollars for settlements and trials, chemical giant Bayer has been lobbying lawmakers in three states to pass bills providing it a legal shield from lawsuits that claim its popular weedkiller Roundup causes cancer.

Nearly identical bills introduced in Iowa, Missouri and Idaho this year — with wording supplied by Bayer — would protect pesticide companies from claims they failed to warn that their product causes cancer, if their labels otherwise complied with the U.S. Environmental Protection Agency’s regulations.

But legal experts warn the legislation could have broader consequences — extending to any product liability claim or, in Iowa’s case, providing immunity from lawsuits of any kind. Critics say it could spread nationwide.