Utility Air Regulatory Group v. Environmental Protection Agency

Utility Air Regulatory Group v. Environmental Protection Agency, 573 U.S. 302 (2014), was a United States Supreme Court case regarding the Environmental Protection Agency's regulation of air pollution under the Clean Air Act.
In a fractured decision, the Court largely upheld the ability of the EPA to regulate greenhouse emissions.
Background.
In 2007, the U.S. Supreme Court ruled in "Massachusetts v. EPA" that the Environmental Protection Agency has the authority to regulate greenhouse gas emissions, if it determined that these emissions endangered public health. Following that, in 2010, the EPA introduced a new set of regulations designed to control carbon dioxide emissions from light and heavy vehicles as well as generators and industrial and utility sources. A coalition of power companies challenged the legality of the regulations, arguing that the science used by the EPA in deciding the regulations was inaccurate.
In 2012, a three-judge panel of the D.C. Circuit court unanimously rejected the challenges. In 2013, the case was accepted for review by the United States Supreme Court.
Opinion of the Court.
Justice Scalia authored the majority opinion, which Justices Roberts and Kennedy joined in full. The Court ruled that the EPA can regulate greenhouse emissions on power plants and other large stationary sources of pollution, but the agency overstepped its authority when it started to use those same regulations on smaller stationary sources like shopping centers, apartment buildings and schools.
In his opinion, Scalia noted that the Clean Air Act imposes specific requirements on stationary sources of pollution that have the potential to emit 250 tons per year of "any air pollutant", or 100 tons per year for certain types of sources. Furthermore, the "any air pollutant" language in that section of the law specifically refers to regulated air pollutants, not greenhouse emissions. When the EPA attempted to apply those same standards to "any" source of greenhouse emissions, it found it "would radically expand those programs, making them both unadministrable and unrecognizable to the Congress that designed them.". Instead, the EPA adopted a different threshold for sources of greenhouse emissions, 100,000 tons per year, which the Court also objected to. "An agency has no power to 'tailor' legislation to bureaucratic policy goals by rewriting unambiguous statutory terms", Scalia wrote.
On the other hand, the Court ruled that the EPA could regulate the large sources of greenhouse emissions as long as they were already being regulated for emitting conventional pollutants. Scalia wrote that the "EPA may ... continue to treat greenhouse gases as a 'pollutant subject to regulation'" under the provisions in the Act.
Justice Breyer wrote a concurring/dissenting opinion, joined by Ginsburg, Sotomayor, and Kagan. Breyer argued that the EPA should have been allowed to interpret the "any air pollutant" language broadly to also include greenhouse emissions: "I do not agree with the Court that the only way to avoid an absurd or otherwise impermissible result in these cases is to create an atextual greenhouse gas exception to the phrase 'any air pollutant'."
Alito, joined by Thomas, wrote a second concurring/dissenting opinion, arguing that the EPA should not be able to regulate the larger sources of greenhouse emissions either using those regulations: "The Clean Air Act was developed for use in regulating the emission of conventional pollutants and is simply not suited for use with respect to greenhouse gases." He cited two scenarios of incompatibility between greenhouses gases and normal pollutants, which caused the EPA to eventually either declare that officials may disregard some provisions in the Act, or give authorities "a great deal of discretion".