Associate Justice Antonin Scalia eked out a victory against the Environmental Protection Agency in a 5-4 opinion today limiting the EPA’s ability to regulate greenhouse gases. However, the decision however does not prevent the EPA from using other means to regulate the pollutants linked to global warming. Specifically the vote means that the Clean Air Act does not allow for the EPA require a point source to obtain a PSD or Title 5 permit. The vote was a straight ideological division with Justice Anthony Kennedy joining his conservative colleagues in the majority. The majority held that “A brief review of the relevant statutory provisions leaves no doubt that the PSD program and Title V are designed to apply to, and cannot rationally be extended beyond, a relative handful of large sources capable of shouldering heavy substantive and procedural burdens.” Utility Air Regulatory Group v. Environmental Protection Agency is the lead case of six cases on the regulation of greenhouse gases.

The decision reverses part of the 2012 opinion supporting the authority of the EPA on requiring permits for some industries. However, the difference may be quite small. The EPA interpretation allows the agency to reach some eighty-six percent of the targeted industrial sources while other means would still allow it to reach eighty-three percent.

As we discussed earlier, the Supreme Court ruled previously that EPA has the authority to regulate greenhouse gases as a threat to human health and to the environment. The EPA proceeded in June 2010 to deal with pollution from cars and trucks (“mobile sources”) and then larger, stationary sources of greenhouse gas emissions. That latter move prompted a determined challenge from the all-powerful utility and energy industries both in Congress and the courts. The case saw a division of states, with California and New York supporting the administration. Scalia held that the D.C. Circuit failed to make a finer distinction between pollutants:

The Court of Appeals reasoned by way of a flawed syllogism: Under Massachusetts, the general, Act-wide definition of “air pollutant” includes greenhouse gases; the Act requires permits for major emitters of “any air pollutant”;therefore, the Act requires permits for major emitters of greenhouse gases. The conclusion follows from the premises only if the air pollutants referred to in the permit requiring provisions (the minor premise) are the same air pollutants encompassed by the Act-wide definition as interpreted in Massachusetts (the major premise). Yet no one—least of all EPA—endorses that proposition, and it is obviously untenable.

The Act-wide definition says that an air pollutant is“any air pollution agent or combination of such agents, including any physical, chemical, biological, [or] radioactive . . . substance or matter which is emitted into or otherwise enters the ambient air.” §7602(g). In Massachusetts, the Court held that the Act-wide definition includes greenhouse gases because it is all-encompassing; it “embraces all airborne compounds of whatever stripe.” 549 U. S., at 529. But where the term “air pollutant” appearsin the Act’s operative provisions, EPA has routinely given it a narrower, context-appropriate meaning.

Recall that in April, the Court handed a big victory to the Administration in another case in upholding the regulation over 28 states in the Midwest and South to reduce ozone and fine particle emissions that flow north and east into other states.

The Court closed the door on PSD and Title V but left another open:

To sum up: We hold that EPA exceeded its statutory authority when it interpreted the Clean Air Act to require PSD and Title V permitting for stationary sources based on their greenhouse-gas emissions. Specifically, the Agency may not treat greenhouse gases as a pollutant for purposes of defining a “major emitting facility” (or a “modification” thereof) in the PSD context or a “major source” inthe Title V context. To the extent its regulations purport to do so, they are invalid. EPA may, however, continue to treat greenhouse gases as a “pollutant subject to regulation under this chapter” for purposes of requiring BACT for “anyway” sources. The judgment of the Court of Appeals is affirmed in part and reversed in part.

Here is the opinion.