WASHINGTON, D.C. (AP) – The Supreme Court has rejected Bayer’s appeal to shut down thousands of lawsuits claiming that its Roundup weedkiller causes cancer.

The justices left in place a $25 million judgment in favor of Edwin Hardeman, a California man who said he developed cancer from using Roundup for decades to treat poison oak, overgrowth and weeds on his San Francisco Bay Area property. Hardeman’s lawsuit had served as a test case for thousands of similar lawsuits.

The high court’s action comes amid a series of court fights over Roundup.

A panel of the 9th U.S. Circuit Court of Appeals rejected a U.S. EPA finding from 2020 that glyphosate does not pose a serious health risk and is “not likely” to cause cancer in humans. The appellate court ordered the EPA to reexamine its finding.

At the same time, Bayer has won four consecutive trials in state court against people who claimed they got cancer from their use of Roundup. The latest verdict in favor of the pharmaceutical company came recently in Oregon.

Bayer had argued that federal regulators have repeatedly determined its products are safe and that lawsuits based on claims under state laws should be dismissed.

In a statement, Bayer said it disagreed with the Supreme Court’s decision not to take up its case. “The company believes that the decision undermines the ability of companies to rely on official actions taken by expert regulatory agencies, as it permits every U.S. state to require a different product label” in conflict with federal laws, Bayer said.

Last year, Bayer set aside $4.5 billion to deal with the claims that glyphosate, the weed-killing ingredient in Roundup, causes non-Hodgkin lymphoma, a type of cancer. The company had previously taken a charge of nearly $10 billion for earlier rounds of litigation.

The EPA says on its website that there is “no evidence that glyphosate causes cancer in humans.” But in 2015, the International Agency for Research on Cancer, part of the World Health Organization, classified glyphosate as “probably carcinogenic to humans.” The agency said it relied on “limited” evidence of cancer in people and “sufficient” evidence of cancer in study animals.

Bayer maintains the product is safe but said that it would replace glyphosate in Roundup for residential use beginning in 2023. Products containing glyphosate will still be available for professional and farm use.