The first multi-plaintiff Roundup trial opened Wednesday in Monsanto's backyard of St. Louis, Missouri.

The case involves a woman from the Seattle area, and two men living in Florida, who got various forms of non-Hodgkin lymphoma after spraying their yards with Roundup, a pesticide. On Wednesday, plaintiffs attorney Gibbs Henderson, a partner at Nachawati Law Firm in Dallas, told jurors in his opening statement that Monsanto didn't prioritize safety, even as Roundup sales surged.

"This case is both simple and important," said Henderson, according to Courtroom View Network's livestream of opening statements Wednesday. "And, at the end of the day, I think the evidence is going to show that what brought us to this St. Louis County courthouse are a few basic safety rules—safety rules that protect people from hazardous chemicals in pesticides, and that must be in force to protect us."