The U.S. Court of Appeals for the District of Columbia Circuit ruled today by a 2-1 margin that EPA’s Cross-State Air Pollution Rule (CSAPR) exceeded EPA’s statutory authority. CSAPR was to put a limit on sulfur dioxide emissions in 28 states, but the court issued a last minute stay at the end of 2011 before the rule went into effect.

The decision, written by Judge Brett Kavanaugh, states that EPA’s CSAPR “exceeds the agency’s statutory authority in two independent respects,” and therefore violates federal law. First, the rule requires that a state to reduce emissions by more than the amount that drifts into another state causing nonattainment, overreaching statutory authority. Secondly, the Clean Air Act gives states the initial right to develop their own plan to reduce emissions; however the rule would not afford the states that ability. Judge Griffith joined Judge Kavanaugh, while Judge Rogers filed the dissenting opinion.

Although the court threw out CSAPR, it left in place the Clean Air Interstate Rule (CAIR). The same court ruled in 2008 that CAIR did not do enough to protect public health, which prompted EPA to develop CSAPR.