Chemical giant Monsanto has argued for years that if the U.S. Environmental Protection Agency approves a pesticide label without requiring a cancer warning, states cannot hold its manufacturer liable in court for failing to warn consumers about cancer risks. The U.S. Supreme Court has now taken up the question after hearing oral arguments for and against that position on April 27, 2026.
Between 2009 and 2019, the EPA repeatedly concluded there is no evidence that glyphosate causes cancer in humans. The agency has, therefore, allowed glyphosate-based weed killers, including Monsanto’s Roundup, to remain on the market without a cancer warning on its label. That’s despite a 2015 report from the International Agency for Research on Cancer, a branch of the World Health Organization, that classified glyphosate as “probably carcinogenic to humans” based on “limited” evidence of cancer in humans from real-world exposure and “sufficient” evidence of cancer in experimental animals. A 2025 study had similar findings in lab rats.
