A divided Supreme Court appeared to search today for a middle ground in the challenge from industry and a dozen states to a U.S. EPA crackdown on heat-trapping greenhouse gas emissions.
A dozen states and industry groups including the U.S. Chamber of Commerce and American Chemistry Council want the court to overturn EPA's inclusion of greenhouse gases in an air permitting programs for emissions from power plants and other industrial sites.
During unusually long arguments, the justices frequently fractured along ideological lines, with the liberal wing asking pointed questions of the challengers and conservatives taking issue with EPA.
But two of the court's swing votes, Chief Justice John Roberts and Justice Anthony Kennedy, were troubled by EPA's decision to revise the statutory mandate that industrial sources must obtain a permit if their emissions exceed 100 tons per year of a pollutant.
EPA raised the minimum to between 75,000 and 100,000 tons per year for greenhouse gases because thousands of small emission sources -- such as hospitals and apartment buildings -- would need permits under the 100-ton standard. That, in turn, would overwhelm EPA's permitting ability.
Kennedy told Solicitor General Donald Verrilli that he "couldn't find a single precedent that seems to support your position."
The Prevention of Significant Deterioration, or PSD, program requires facilities to obtain permits before construction or modification. The permits require them to use the "best available" technology to control emissions of harmful pollutants.
After concluding greenhouse gases pose a threat to human health, EPA issued standards limiting emissions from motor vehicles. It then claimed, in 2010, that the tailpipe rules triggered regulation of greenhouse gases from other sectors through the Clean Air Act, including the PSD program. The agency then issued regulations.
Most of the arguments today centered on the definition of "any air pollutant" and whether it applied to greenhouse gases after the tailpipe rule.
Industry attorney Peter Keisler of Sidley Austin LLP argued "any air pollutant" can mean different things for different Clean Air Act programs. For the PSD program, he said, it should be defined as a pollutant that has an "area specific air quality impact."
But the court's liberal wing maintained the agency deserves deference.
"This is the apex of Chevron deference," said Justice Elena Kagan, referring to the Supreme Court's 1984 decision in Chevron v. Natural Resources Defense Council, which held courts must defer to agency interpretations when the law is ambiguous. . . .