Bayer appeals to US Supreme Court over weedkiller cancer claims

German chemicals giant Bayer said on Friday that it had again asked the US Supreme Court to intervene in the dispute about its weedkiller Roundup, as it tries to draw a line under years of costly legal troubles.

It is the third time Bayer has appealed to the United States' top court to hear its case, and the first since Bill Anderson joined the group as CEO in 2023.

Bayer hopes for more success this time since federal appellate courts have issued contradictory rulings, which it says should increase the chances of a Supreme Court review.

The firm has been dogged by lawsuits linked to Roundup since it acquired its producer, the US agrochemical group Monsanto, in 2018.

Claimants have alleged that Roundup causes blood cancers but Bayer says scientific studies and regulatory approvals show that the weedkiller is safe.

In 2022, the Supreme Court rejected two previous attempts by Bayer to review rulings by Californian courts that went against the company.

The latest bid came days after the supreme court of the US state of Missouri refused to review a ruling against Bayer, opening the way to an appeal at the federal level, the group said.

Monsanto has lost claims in courts that have found it liable for failing to warn of a cancer risk, but Bayer argues federal law makes such warnings unnecessary.

The federal Environmental Protection Agency has said that glyphosate, the active ingredient in Roundup, is not carcinogenic, Bayer said.

It added that "tens of thousands" of claims were waiting in US courts and that a ruling in its favour could "largely curtail this litigation".

Bayer has spent more than $10 billion settling suits alleging that Bayer failed to disclose that Roundup causes cancer.

Anderson has said he hopes to have drawn a line under the legal troubles by the end of 2026.

Bayer shares plunged more than 10 percent in March after the group said it might have to raise billions of euros in extra funds to cover legal costs.