The chemical pollution that irrevocably damages today's environment is, although many would like us to believe otherwise, the legacy of conscious choices made long ago. During the years before and just after World War II, discoveries like leaded gasoline and DDT came to market, creating new hazards even as the expansion and mechanization of industry exacerbated old ones. Dangers still felt today--smog, pesticides, lead, chromium, chlorinated solvents,...