A water treatment plant in Georgia earlier this year. Officials have long warned that the nation’s roughly 150,000 water treatment systems are relatively easy targets for hackers.

Bryan Hubbell, former head of the air, climate and energy program at the Environmental Protection Agency’s research office. “I knew I wasn’t going to be able to keep doing the work.”

Bayer, the German conglomerate that acquired the maker of Roundup in 2018, argued that federal rules requiring herbicide safety labeling should bar people from filing state-level claims that accuse companies of failing to warn consumers of dangers.