A former Pennsylvania landscape contractor is suing the Monsanto Company, claiming that years of exposure to the company’s Roundup herbicide product has given him lymphoma.

Jeffrey B. Johnson of Schwenksville filed the complaint in U.S. District Court for the Eastern District of Pennsylvania, alleging negligence and other counts.

The court papers state that he was diagnosed with non-Hodgkins mantle cell lymphoma in September. He’d used Roundup from 1984 to 2016 during his career as a professional landscaper, and followed all safety and precautionary warnings.

Johnson is suing the giant agrichemical corporation for failing to warn him regarding the dangers of its popular herbicide’s main active ingredient, glyphosate. The state of California recently added glyphosate to a list of carcinogenic chemicals, based on a research agency’s conclusion. However, Monsanto has criticized the agency’s finding as being “fatally flawed.”

He’s seeking compensatory, economic, punitive and exemplary damages, plus interest, court costs and any further relief the court may grant. He’s requested a jury trial.