EPA has decided that greenhouse gas output cannot be considered by officials reviewing federal applications to build new coal-fired power plants, according to this article from the NYT. This is in response to a decision by EPA's Environmental Appeals Board last month, Deseret Power Electric Cooperative. A complete copy of the interpretive memorandum can be found here.
[Update: U.S. EPA published a notice of the interpretive memorandum in the Federal Register indicating that challenges to the interpretation must be brought in the U.S. Court of Appeals for the D.C. Circuit by March 2, 2009. (Moved up.)]
[Update: U.S. EPA reconsidering its interpretation: "EPA today granted a petition for reconsideration of a Bush Administration memo regarding the scope of the Clean Air Act. The interpretive memo, put forward by then-EPA Administrator Stephen Johnson in December 2008, addresses when the Prevention of Significant Deterioration program applies to carbon dioxide, a chief greenhouse gas." (Moved up).]