In a 5-4 decision, the Supreme Court ruled Jan. 21 that EPA has authority to overrule a state construction permit that, as judged by the agency, violates air quality standards. In doing so, the court rejected the Alaska Department of Environmental Conservation’s claim that EPA lacked the authority to block construction of a power plant at Teck Cominco Alaska Inc.’s Red Dog Mine, the world’s largest zinc mine, located in northwest Alaska. (Cominco sought more generating capacity to expand zinc production by 40 percent.) The state of Alaska approved construction of the plant without insisting that Cominco install the most effective technology for controlling air emissions, as required by the Clean Air Act. EPA intervened at the urging of the National Park Service, which was concerned about air pollution in nearby Cape Krusenstern National Monument and Noatack National Preserve. “Only when a state agency’s [Best Available Control Technology] determination is ‘not based on a reasoned analysis’ … may EPA step in to ensure the statutory requirements are honored,” Ruth Bader Ginsburg wrote for the majority. “EPA adhered to that limited role here.” Ginsberg argued that without such federal oversight, states might be tempted to compete for business by undercutting federal environmental standards. The ruling upheld a 2002 decision by the U.S. Court of Appeals for the Ninth Circuit.