The D.C. Circuit heard oral argument in April in Murray Energy Corp. v. EPA and West Virginia v. EPA, challenging the proposed Clean Power Plan filed well in advance of the release of the final rule. The focus of these challenges were several often-cited potential vulnerabilities with EPA’s proposal. First, petitioners cited a language discrepancy in a 1990 amendment to the Clean Air Act that could affect EPA’s ability to regulate an emission source under Section 111(d) if that source is already regulated under Section 112. Second, petitioners claimed that the Clean Power Plan’s building blocks are largely aimed at activities outside the fence of power plants, and thus, the argument goes, outside of EPA’s 111(d) authority. Third, petitioners alleged that before EPA can regulate a category of sources under Section 111(d), EPA must regulate new sources in that category under Section 111(b). With the two rules moving forward almost in tandem—and the Section 111(b) rule likely to be subject to its own legal challenges—the ability to comply with this requirement is murky.
In June 2015, the court denied the petition on the grounds that the rule was not final. Murray Energy Corp. v. EPA, 788 F.3d 330 (D.C. Cir. 2015).
