Venerable DuPont is one of the United States' oldest and most successful corporations. Founded in 1802 as a gunpowder and explosives maker, it became a household name by giving the world nylon, Lycra, Teflon, Kevlar and other materials, many of them based on revolutionary breakthroughs in polymer chemistry.

Indeed, for much of the 20th century, DuPont-and its fabled central R&D lab-has been viewed as ground zero of innovation in the chemical and materials industries: it currently spends nearly $2 billion a year on research and development. But some of these innovations have come at a cost. DuPont pioneered chlorofluorocarbons, which were phased out in the mid-1990s due to their role in the destruction of the atmosphere's ozone layer. And the company's various manufacturing processes, though perfectly legal, have made it one of the world's largest industrial polluters.