Chemicals giant Bayer AG won’t appeal a $20.5 million jury verdict against it over Roundup, a weedkiller containing glyphosate whose use a California school groundskeeper said gave him cancer. Dewayne Anthony Lee Johnson, who worked for the Benicia Unified School District, sued Monsanto Co., claiming he developed non-Hodgkin lymphoma after being soaked in Roundup, which has been on the market since 1976 and contains glyphosate, the most popular herbicide in the United States. Bayer acquired Roundup with its 2018 purchase of Monsanto. The day of the accident, “the sprayer broke, and I got drenched in the [herbicide], I didn’t think that much about it,” Johnson told Time magazine in 2018. “I washed up in the sink as best I could and changed my clothes. Later, I went home and took a good long shower but I didn’t think, ‘Oh my god, I’m going to die from this stuff.’ Then I got …