Clearing The Air

EPA may require businesses to install modern air pollution control equipment if renovations to a facility cause its emissions to rise on an annual basis, the U.S. Supreme Court ruled unanimously on April 2.

The decision is expected to influence whether companies, including electric utilities and chemical manufacturing plants, have to install expensive emission controls on older facilities.

The case involves part of the Clean Air Act called new source review. This provision requires industry to put in up-to-date air pollution controls when modifications to a facility cause emissions to rise. The suit revolved around just what constitutes an increase in emissions.

The Clinton Administration initially brought the suit against Duke Energy after the power company made modifications did not boost hourly emissions of its units but extended the number of hours they could operate. The Bush Administration continued the case but abandoned it in 2005 after the U.S. Court of Appeals for the 4th Circuit decided in favor of Duke.

Environmental Defense and two North Carolina environmental groups brought the case to the Supreme Court.

In an opinion written by Justice David Souter, the high court rejected the 4th Circuit's reasoning that EPA should determine pollution increases by examining a plant's hourly emissions before and after a modification.