The Bush Administration's EPA has had a hard time defending its air pollution regulatory reforms in federal court (as I've noted before). Today, yet another regulation went down in (another case styled) Sierra Club v. EPA. The majority opinion by Judge Rogers, joined by Judge Tatel, begins:

Petitioners challenge the final rules promulgated by the Environmental Protection Agency exempting major sources of air pollution from normal emission standards during periods of startups, shutdowns, and malfunctions ("SSM") and imposing alternative, and arguably less onerous requirements in their place. Because the general duty that applies during SSM events is inconsistent with the plain text of section 112 of the Clean Air Act ("CAA"), even accepting that "continuous" for purposes of the definition of "emission standards" under CAA section 302(k) does not mean unchanging, the SSM exemption violates the CAA's requirement that some section 112 standard apply continuously. Accordingly, we grant the petitions and vacate the SSM exemption.

Senior circuit Judge Randolph dissented. I hope to have more to say about the opinion later.

Meanwhile, the EPA ruled yesterday that power plant carbon dioxide emissions should not be considered in the air pollution permit approval process. I expect this decision will be the subject of litigation or a notice-and-comment rulemaking in 2009, if not both.