The case centers around the regulation of glyphosate, the world’s most commonly used herbicide, which researchers have linked to health problems in both animals and people.By Lee HedgepethJohn Durnell just wanted to make things around his St. Louis neighborhood look a little nicer. So, on occasion, he’d spray a bit of Roundup in the obvious places—along weedy sidewalks and in public spaces he thought needed a little extra attention.