(Reuters) - A trial in which a school groundskeeper alleged that his use of Monsanto’s Roundup weed killer caused his terminal cancer will go to a California jury after lawyers for both sides delivered their closing arguments on Tuesday.

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Groundskeeper Dewayne Johnson is one of more than 5,000 plaintiffs across the United States who claim Monsanto’s glyphosate-containing herbicides, including the widely-used Roundup, cause cancer. His case, the first to go to trial, began in San Francisco’s Superior Court of California four weeks ago.

Johnson’s lawyer Brent Wisner on Tuesday urged jurors to hold Monsanto liable and punish them with a verdict he said would “actually change the world.” Wisner claimed Monsanto knew about glyphosate’s cancer risk, but decided to bury the information.

Monsanto, a unit of Bayer AG BAYGn.DE following a $62.5 billion acquisition by the German conglomerate, denies the allegations and says expert testimony on which Johnson and others rely does not satisfy any scientific or legal requirements.

“The message of 40 years of scientific studies is clear: this cancer is not caused by glyphosate,” Monsanto’s lawyer George Lombardi said, according to an online broadcast of the trial by Courtroom View Network.

The U.S. Environmental Protection Agency in September 2017 concluded a decades-long assessment of glyphosate risks and found the chemical not likely carcinogenic to humans. The World Health Organization’s cancer arm in 2015 classified glyphosate as “probably carcinogenic to humans.”

If it finds Monsanto liable, the jury can decide to award punitive damages on top of the more than $39 million in compensatory damages Johnson demanded. The jury is expected to start deliberating on Wednesday.

Johnson’s case, filed in 2016, was fast-tracked for trial due to the severe state of his non-Hodgkin’s lymphoma, a cancer of the lymph system that he alleges was caused by Roundup and Ranger Pro, another Monsanto glyphosate herbicide. Johnson’s doctors said he is unlikely to live past 2020.

A former pest control manager for a California county school system, Johnson, 46, applied the weed killer up to 30 times per year.

His case is not part of proceedings consolidated in Missouri, Delaware or California state court, where most of the Monsanto cases are pending. It is also separate from consolidated federal multidistrict litigation pending before U.S. District Judge Vince Chhabria in San Francisco.

Chhabria in July allowed hundreds of Roundup lawsuits to proceed to trial, finding there was sufficient evidence for a jury to hear the cases despite calling plaintiff’s expert opinions “shaky.”