By Greg Stohrm, Bloomberg News

The US Supreme Court gave Bayer AG a mixed reception on its bid to stop tens of thousands of lawsuits claiming its Roundup herbicide should have been labeled as a cancer risk.

Hearing arguments in Washington on Monday, the justices weighed a $1.25 million jury verdict won by a Missouri man who blamed Roundup for his non-Hodgkin lymphoma. The company contends that because US regulators didn’t require a cancer warning, federal law bars the Missouri suit and similar suits.

Bayer drew supportive comments from Justice Brett Kavanaugh, who questioned whether lawsuits alleging a failure to warn could be squared with a provision in federal law requiring “uniformity” in herbicide labels. But Chief Justice John Roberts suggested that states considering new evidence that a product is risky should be allowed to “call this danger to the attention of the people.”

Bayer shares slumped as much as 6.5% in early trading on Tuesday in Frankfurt. The stock had gained 67% over the past year through Monday’s close on optimism about containing the Roundup fallout and progress in its pharmaceutical pipeline.

Bank of America Corp. analysts, including Sachin Jain, said the hearing was less clear-cut in Bayer’s favor than expected. They cited feedback from a call with a legal expert, who still expects the ruling to favor Bayer with 70% probability.