By Stephen W. Wiegand

On August 21, 2012, the United States Court of Appeals for the District of Columbia Circuit vacated EPA’s Cross-State Air Pollution Rule (CSAPR). EPA issued CSAPR in August 2011 pursuant to Sec. 110(a)(2)(D)(i)(I) of the Clean Air Act (the “good neighbor” provision) which requires that State Implementation Plans contain adequate provisions to prevent a state’s emissions from affecting another state’s air quality. The CSAPR rule was promulgated in response to the D.C. Circuit’s remand in 2008 of EPA’s Clean Air Interstate Rule (CAIR), which was EPA’s prior attempt at implementing the good neighbor provision.

Under the rule, certain “upwind” states were required to reduce emissions of sulfur dioxide (SO2) and nitrogen oxides (NOx), based on those states’ contributions to downwind states’ air quality problems. Industry strongly criticized CSAPR for its draconian reductions in allowable power plant emissions. CSAPR would have required many states, including Louisiana and Texas, to reduce power plant emissions of SO2 and NOx, particularly during the summer ozone season. Industry challenged EPA’s data and methodology in formulating the CSAPR.

In a 2-1 decision, the Court vacated CSAPR on two main grounds. First, CSAPR required that upwind states reduce emissions by more than their own significant contributions to the downwind states’ nonattainment. Specifically, only states that contributed a threshold amount to the air pollution in a downwind state were subject to the provision. The restrictions placed on those states, however, were based on region-wide air quality monitoring projections. Thus, the rule could require states to reduce emissions by more than the amount of their actual contribution. Second, after quantifying the states’ obligations under the rule, EPA set forth those obligations in Federal Implementation Plans rather than giving the states the initial opportunity to implement the required reductions.

In vacating CSAPR, the Court ordered EPA to continue to administer CAIR pending the promulgation of a valid replacement.

The full opinion can be viewed here (pdf).