On April 19, 2013, the state of Texas filed a Petition asking the U.S. Supreme Court to review the greenhouse gas (GHG) tailoring rule. The tailoring rule requires new sources that emit more than 100,000 tons per year of carbon dioxide-equivalent and modified sources that increase their emissions by more than 75,000 tons per year to satisfy prevention of significant deterioration (PSD) and Title V permitting requirements. Under the Clean Air Act, however, the emissions thresholds for the PSD and Title V permit programs are 250 tons per year and 100 tons per year, respectively.  The Petition asserts that U.S. EPA does not have the authority to regulate GHGs under the CAA and that the tailoring rule arbitrarily increases the permitting thresholds for GHG emissions.

Alabama, Florida, Georgia, Indiana, Louisiana, Michigan, Nebraska, North Dakota, Oklahoma, South Carolina and South Dakota are also listed as petitioners.