[JURIST] The US Supreme Court [official website] ruled [opinion, PDF] 5-4 on Monday that the EPA [official website] could not make regulations regarding the toxic emissions of power plants without considering costs. In Michigan v. Environmental Protection Agency [SCOTUSBLOG materials], the court considered the question of whether the EPA could create regulations under theClean Air Act [42 USC §7412(n)(1)(A)] irrespective of costs that would be incurred. Justice Antonin Scalia wrote for the majority:

Our reasoning so far establishes that it was unreasonable for EPA to read §7412(n)(1)(A) to mean that cost is irrelevant to the initial decision to regulate power plants. The Agency must consider cost—including, most importantly, cost of compliance—before deciding whether regulation is appropriate and necessary… It will be up to the Agency to decide (as always, within the limits of reasonable interpretation) how to account for cost.

Justice Clarence Thomas wrote a concurring opinion while Justice Elena Kagan wrote a dissent with Justices Ginsburg, Sotomayor, and Breyer joining, “[T]he result is a decision that deprives the American public of the pollution control measures that the responsible Agency, acting well within its delegated authority, found would save many, many lives.” This decision reversed a ruling from the United States Court of Appeals for the DC Circut [official website] in favor of the EPA.

The Supreme Court granted certiorari in November and heard [JURIST reports] the case in March after the Court of Appeals upheld the regulations. This ruling comes amid other legal challenges to EPA regulations. In April, the US Court of Appeals for the DC circuit heard a case [JURIST report] concerning EPA regulations meant to slow climate change.