Justice Ginsburg also expresses support for the EPA’s position, and questions Keisler about whether his view is in line with the dissent from the D.C. Circuit, namely that the EPA only has the authority to regulate certain pollutants from stationary sources that do not include greenhouse gases.  Keisler argues that greenhouse gases should not be included in the PSD program—which originally was designed to be applied to traditional pollutants that can be measured at a local level—because greenhouse gases do not have such “area-specific air quality impacts.”  Justice Ginsburg pushes Keisler on this point, and asks him about the “endangerment finding” that found greenhouse gases to have “severe effects” at the local level.  At the end of the clip, Justice Scalia jumps in briefly to defend the private party petitioners’ position by asserting that air quality impact is not measureable.

Note:  In this exchange, Justice Ginsburg refers to BACT, which is the Best Available Air Control Technology.  New and modified stationary sources (such as new or modified power plants) subject to the EPA’s Prevention of Significant Deterioration (PSD) program must install BACT to limit greenhouse gases.