The US Supreme Court [official website] on Tuesday declined to hear an appeal of a 2017 environmental ruling [opinion, PDF] authored by the court’s newest member, Brett Kavanaugh.

The opinion, issued by a three-judge panel of Kavanaugh’s former court, the US Court of Appeals for the District of Columbia Circuit, struck down a regulation issued by the Obama administration’s Environmental Protection Agency (EPA). The rule restricted the use of hydrofluorocarbons (HFC), a chemical frequently found in aerosol products. HFCs, the EPA argued, contribute to global climate change, although they are not considered to be ozone-depleting substances.

In the decision, Kavanaugh concluded that the EPA lacked statutory authority under the Clean Air Act to replace chemicals such as HFCs in light of the EPA’s former conclusion that the chemicals were previously considered beyond the agency’s reach. In the opinion, Kavanaugh noted that the EPA itself took the position that the Clean Air Act does not grant them statutory authority to require the replacement of non-ozone-depleting substances like HFCs. The rule was ultimately found to be arbitrary and capricious because the rule and, by extension, the deviation from the agency’s prior precedent, was not “reasonable and reasonably explained.”