OAKLAND (CBS SF) — An Alameda County Superior Court jury will begin deliberating Thursday in the case of a Livermore husband and wife who claim that Monsanto Co.’s Roundup herbicide caused both of them to develop cancer.

Alva Pilliod, 76, and Alberta Pilliod, 74, were diagnosed with non-Hodgkin’s lymphoma in 2011 and 2015. They allege that exposure from more than three decades of spraying Roundup on weeds in several properties was a substantial factor in causing their illness.

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Monsanto, now owned by Bayer AG of Germany, contends studies have shown Roundup is safe. Roundup is the world’s most popular weedkiller.

The U.S. Environmental Protection Agency has stated that Roundup’s principal ingredient, glyphosate, is not likely to cause cancer, while an agency of the World Health Organization has concluded the chemical is probably carcinogenic.

The jurors in the court of Judge Winifred Smith will begin deliberating Thursday after having heard about six weeks of testimony followed by closing arguments on Wednesday.

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The couple claims Monsanto sold a defective product, failed to warn consumers of the dangers and was negligent. Their lawyer asked the jury Wednesday to award the couple about $55 million in compensation plus $1 billion in punitive damages.

The Pilliods’ case is the third to go to trial among more than 13,000 lawsuits filed against Monsanto nationwide in state and federal courts.

In the first lawsuit to go to trial, a San Francisco Superior Court jury last year awarded former school groundskeeper Dewayne Johnson of Vallejo $289 million, later reduced by the trial judge to $78 million.

In the second case, a federal jury in San Francisco in March granted $80 million to Edwin Hardeman of Santa Rosa. Monsanto is appealing both verdicts.

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