Aug 15 (Reuters) - Bayer won a legal victory

in its fight to limit liability from claims that its Roundup

weed killer causes cancer, as a U.S. appeals court on Thursday

said federal law shields the German company from a lawsuit by a

Pennsylvania landscaper.

The 3rd U.S. Circuit Court of Appeals in Philadelphia

rejected plaintiff David Schaffner's claim that Bayer's Monsanto

unit violated state law by failing to put a cancer warning on

the label for Roundup.

Schaffner was diagnosed in 2006 with a kind of cancer called

non-Hodgkins lymphoma, a common claim for Roundup plaintiffs.

He and his wife Theresa sued Bayer in 2019, in part over how

his illness affected their relationship.

Chief Judge Michael Chagares wrote for a unanimous

three-judge panel that the Federal Insecticide, Fungicide, and

Rodenticide Act requires nationwide uniformity in pesticide

labels, and prevented Pennsylvania from adding a cancer warning.

Bayer said the decision conflicts with rulings from federal

appeals courts in San Francisco and Atlanta in similar cases.

That may increase the prospect that the U.S. Supreme Court

could step in to resolve the split, and potentially reduce

Bayer's liabilities.

Lawyers for the Schaffners did not immediately respond to

requests for comment.

Bayer said it was pleased with the decision, and the Supreme

Court should "settle this important issue of law."

It has maintained that Roundup and its active ingredient

glyphosate are safe, and said it "continues to stand fully

behind" the brand.

Bayer has faced extensive litigation over Roundup, and has

seen its share price fall more than 73% since buying Monsanto

for $63 billion in June 2018.

The company settled much of the Roundup litigation for $10.9

billion in 2020, but still faces about 58,000 claims. Another

114,000 claims have been settled or deemed ineligible.

Though Bayer won 14 of 23 Roundup trials through July 23,

one victory was overturned on appeal, and the losses saddled it

with billions of dollars of damages awards.

The Schaffners settled with Bayer in September 2022,

conditioned on Bayer being unable to convince courts that

federal law preempted Pennsylvania from requiring a cancer

warning.

Chagares said it did, and that this approach "best achieves

Congress's stated aim of uniformity in pesticide labeling."

Roundup is among the most widely used weed killers in the

United States. Bayer phased out sales for home use last year.

The case is Schaffner et al v Monsanto Corp, 3rd U.S.

Circuit Court of Appeals, No. 22-3075.