After years of debate in the lower courts, the Environmental Protection Agency (EPA) Cross-State Air Pollution Rule (CSAPR) gained Supreme Court approval on April 29, 2014 to further regulate power plant emissions across 27 central and eastern states.

States Impacted by CSAPR (EPA)

Overview
CSAPR was finalized in July 2011 to replace the 2005 Clean Air Interstate Rule (CAIR) to further reduce Sulfur Dioxide (SO2) and Nitrogen Oxide (NOx) emissions across 27 central and eastern states and the District of Columbia. Under CSAPR, states were originally required to comply by January 1, 2012. However, due to significant state and industry litigation, the D.C. Circuit Court ordered a stay on December 30, 2011, leaving CAIR in place until the courts and EPA re-examined implementation plans. Although upheld by the Supreme Court, the case will now return to the D.C. Circuit Court to revisit intricacies of CSAPR implementation, and EPA has stated that despite the positive Supreme Court ruling, “no immediate action from States or affected sources is expected.”