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.
Bayer also had warned that allowing these sorts of claims will damage innovation in agriculture, health and other industries.
Bayer, which is based in Leverkusen, Germany, inherited Roundup and the litigation when it acquired Monsanto in 2018.
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.
The Justice Department, which had sided with Bayer in the lower courts during the Trump administration, recommended that the high court not get involved.
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.