On December 15, 2009, the EPA issued a final rule (the Endangerment Rule) in which it found that greenhouse gases (GHG), which include carbon dioxide, methane, nitrous oxide, hydroflurocarbons, perfluorocarbons, and sulfur hexafluoride, endanger the health and welfare of the American people under Section 202(a) of the Clean Air Act (CAA). The EPA's finding and rule, if permitted to stand, allow the EPA to use the CAA to regulate GHG. The EPA's new finding came following a 2007 U.S. Supreme Court decision that the EPA has authority to regulate GHG emissions using the CAA.
On December 23, 2009, and subsequently, several entities petitioned for review changing the Endangerment Rule. A host of state governments and environmental groups intervened as respondents, and numerous state governments, trade associations, and chambers of commerce intervened as petitioners. On February 17-18, 2010, the cases were consolidated. On February 22, 2010, MSLF sought to participate in the matter as an amicus curiae; that motion was granted on February 23, 2010.
Meanwhile, various entities petitioned the EPA to reconsider its Endangerment Rule given new evidence as to the validity of its findings. On August 13, 2010, the EPA denied those petitions. New petitions for review of the EPA's latest decision were filed and consolidated with the other petitions. On March 22, 2011, U.S. Court of Appeals for the D.C. Circuit set the briefing schedule for the case. On May 20, 2011, petitioners and their supporting intervenors filed their opening briefs. On May 20, 2011, MSLF and others filed a supporting amici curiae brief. On August 18, 2011, the EPA and its supporting intervenors filed their response briefs; amicus curiae briefs in support of the EPA were filed on August 25, 2011. On February 28 and 29, 2012, oral arguments were conducted by the D.C. Circuit.
On June 26, 2012, the D.C. Circuit issued a decision ruling that the petitioners failed to show injury and dismissed all challenges to the Endangerment Rule. On August 10, 2012, the petitioners filed petitions for rehearing/rehearing en banc. On October 12, 2012, the EPA filed oppositions. On December 20, 2012, the D.C. Circuit denied the petitions.
On April 19, 2013, the Chamber of Commerce of the United States filed a petition for writ of certiorari with the Supreme Court. Several other industry groups and states also filed petitions on the same day. On May 24, 2013, MSLF filed an amicus curiae brief in support of the Chamber of Commerce’s petition. On October 15, 2013, the Chamber of Commerce’s petition was granted and its case was consolidated with five other cases. On December 16, 2013, MSLF filed an amicus curiae brief on the limited question presented.Oral arguments were held on February 24, 2014.
On June 23, 2014, the Court held 9-0 that the CAA neither compels nor permits the EPA to interpret the CAA as requiring a stationary source of pollution to obtain a "Prevention of Significant Deterioration" permit on the sole basis of its potential greenhouse-gas emission.
On August 25, 2014, the Court of Appeals for the District of Columbia Circuit issued an order requiring the parties to file motions to govern future proceedings. On October 21, 2014, three motions to govern future proceedings were filed by the parties. On November 21, 2014, the parties responded to the motions to govern future proceedings.