“We’re not suing them for the fact that their product causes cancer. We’re suing them because they didn’t tell people that it causes cancer.”

Annually, for weeks at a time over his more than 30 years of farming, John Barton would spray a thousand gallons of Roundup every day to kill the weeds springing up among his cotton crop outside Bakersfield, California.

Tugging a 200-foot hose when he couldn’t use his tractor or sometimes wielding a container of the herbicide strapped to his back, Barton or his three boys would walk and spray, sometimes in temperatures reaching 110 degrees. They would come home drenched in sweat and the weed-killing chemical, their clothes, boots and socks sopping wet and their toes pruned by the deep saturation.

“They said it was as safe as table salt. It’s so safe you can drink it. And it’s so effective now with GMOs,” he said, referring to crops genetically modified by Roundup’s parent company Monsanto to tolerate the herbicide, “that they can spray it over a multitude of crops and it gets into the root structure of just the weed and kills the plant totally.”