[JURIST] The US Supreme Court [official website] heard oral arguments [transcript, PDF] Wednesday in three consolidated cases regarding the consideration of the cost of regulating hazardous air pollutants by the Environmental Protection Agency (EPA) [official website]. The question before the court was “whether the Environmental Protection Agency unreasonably refused to consider costs in determining whether it is appropriate to regulate hazardous air pollutants emitted by electric utilities.” The three cases, Michigan v. EPA, Utility Air Regulatory Group v. EPA, and National Mining Association v. EPA [SCOTUSblog materials] were consolidated into a single 90-minute argument. They present a challenge to the EPA’s rules on toxic emissions, arguing that the EPA did not sufficiently consider the cost of reducing the emission of hazardous substances from power plants when drafting the Mercury and Air Toxics Standard [materials]. The court also considered whether Congress really wanted power plants to be treated differently from all other sources of hazardous air pollutants.

The Supreme Court granted certiorari [JURIST report] in the three cases in November, limiting the grant to the main question currently before the court, and consolidated them. A petition for a writ of certiorari was filed in each case in July. All three cases address the statutory interpretation of “appropriate” in regards to determining costs addressing regulations of hazardous pollution under the hazardous air pollutants statute [42 USC § 7412(n)(1)(A)].