John Sanders worked in the orange and grapefruit groves in Redlands, California, for more than 30 years. First as a ranch hand, then as a farm worker, he was responsible for keeping the weeds around the citrus trees in check. Roundup, the Monsanto weed killer, was his weapon of choice, and he sprayed it on the plants from a hand-held atomizer year-round.

Frank Tanner, who owned a landscaping business, is also a Californian and former Roundup user. Tanner relied on the herbicide starting in 1974, and between 2000 and 2006 sprayed between 50 and 70 gallons of it a year, sometimes from a backpack, other times from a 200-gallon drum that he rolled on a cart next to him. Continue reading »