Only two months after issuing a memorandum interpreting which pollutants are covered (or not covered) by the federal Prevention of Significant Deterioration (PSD) Perrmit Program, EPA is reconsidering its approach.

On December 18, 2008, Ste ve Johnson, the EPA Administrator under the previous administration, issued a memorandum that guided regulators on how to consider carbon dioxide emissions under the Prevention of Significant Deterioration (PSD) permitting program. The memo stated that EPA does not consider a pollutant (including carbon dioxide) to be "subject to regulation" until EPA has promulgated a regulation that requires emission controls. As a result, carbon dioxide would not be subject to emission limitations before a PSD permit was issued.

In a February 17, 2009 letter to the Sierra Club, Lisa Jackson, EPA's new administrator, announced the Agency was opening up the memorandum for reconsideration and public comment. EPA specifically noted that the memo did not bind States issuing permits under their own authority, and that it should not be considered "the final word on the appropriate interpretation of Clean Air Act requirements". The letter added that the Agency will publish a notice of a proposed rulemaking on the matter in the near future.

Click here for the orignial memo and Sierra Club letter.