Trump wants a world without the EPA. Here’s what that would actually look like

William Reilly, who served as the administrator of the Environmental Protection Agency under President George H. W. Bush, first moved to Washington D.C. in the late 1960s—before the EPA was established. He remembers a contest in which dogs were to retrieve items by swimming into the Potomac River. “After the first two dogs got out and vomited, it was closed down,” he says. At the time, the river was intensely polluted, full of raw sewage and industrial waste. 

Then came the EPA, which President Nixon established in 1970...