A California jury awarded has awarded $332 million to a man who said Monsanto weedkiller Roundup caused his cancer. 

In 2020, Carlsbad, California resident Mike Dennis, 57, was diagnosed with a rare form of non-Hodgkin's lymphoma, which he alleged in a lawsuit stemmed from decades of using Roundup weedkiller, made by Bayer-owned Monsanto. 

Dennis claimed Roundup's active ingredient, glyphosate, caused his cancer. 

"Glyphosate, the active ingredient for roundup, is genotoxic," Adam Peavy, an attorney for Dennis, told NBC 7. "It causes DNA damage once it's absorbed through the skin, and that's what ultimately causes non-Hodgkin's lymphoma."

Peavy also said Dennis has been in remission for nearly three years, while noting there is no cure for the disease.

"His doctors have told him it's going to come back and we're just waiting to see if that happens," Peavy said.

A San Diego Superior Court jury concluded that Monsanto failed to warn consumers of Roundup's risks. Dennis was awarded $7 million in compensatory damages and $325 million in punitive damages. The jury sided with Bayer in finding that the Roundup product design wasn't defective and the company wasn't negligent. 

Bayer, headquartered in Germany, is expected to appeal the verdict. 

"We respectfully disagree with the jury's adverse verdict, though it found in favor of the company on two of the four claims, and believe that we have strong arguments on appeal to get this unfounded verdict overturned and the unconstitutionally excessive damage award eliminated or reduced, given that there were significant and reversible legal and evidentiary errors made during this trial," Bayer said in a statement to CBS MoneyWatch. "We have a winning record in the Roundup litigation — having won nine of the last twelve cases at trial — and have resolved the majority of claims filed in this litigation."

Bayer acquired Monsanto in 2018 for $63 billion, creating the world's biggest seed and agrochemical company. Although Bayer moved quickly to retire the Monsanto brand, it was left to grapple with thousands lawsuits related to Roundup. In 2020, Bayer announced it would pay up to $10.9 billion to settle some 125,000 filed and unfiled claims.

The Supreme Court last year rejected a bid by Bayer to shut down thousands of suits claiming the weedkiller causes cancer. 

In 2022, a government study found glyphosate in more than 80% of urine samples from U.S. kids and adults. The National Health and Nutrition Examination Survey identified glyphosate in 1,885 of 2,310 urine samples representative of the population at large. 

— The Associated Press Contributed to this report