Supreme Court Tells EPA To Regulate Carbon Dioxide

The Supreme Court in a 5-4 decision ruled on April 2 that the U.S. EPA erred in rejecting the state of Massachusetts petition and others. Now EPA will grant the petition or deny it again. The Supreme Court decision said EPA had the express authority to regulate carbon dioxide emissions from vehicle tailpipes as an air pollutant. The ruling came after the state of Massachusetts, joined by 11 other states, New York City, the District of Columbia and Baltimore, filed suit to reverse EPA's 2003 decision not to regulate tailpipe emissions.

EPA's argument that the Department of Transportation sets fuel economy requirements was a non-starter. "That DOT sets mileage standards in no way licenses EPA to shirk its environmental responsibilities," the court wrote. The state of California has sought a waiver under the Clean Air Act to dramatically reduce tailpipe emissions in the coming decade -- a move that could require automakers to have fleetwide averages of more than 40 miles per gallon.