The Supreme Court has refused to block a Biden administration rule aimed at preventing legacy toxic waste from closed coal plants from seeping into and contaminating nearby groundwater.

In a brief order, the court denied an emergency request from the East Kentucky Power Cooperative to temporarily halt the rule while ongoing litigation challenging it is resolved, The Hill reported.

The Supreme Court did not provide an explanation for its decision to reject the power cooperative’s petition, and no dissents were noted, the outlet said.

The ruling does not necessarily indicate that the justices believe the rule is lawful; it simply means they are not prepared to block it before lower courts have ruled on the challenges.

The rule in question targets “coal ash,” a byproduct of coal plants containing hazardous substances such as mercury and arsenic. It mandates that coal plants closed before October 19, 2015, take measures to prevent coal ash from leaking out of storage ponds.

The East Kentucky co-op asked the court to halt the rule, arguing that it would suffer from “unrecoverable compliance costs” if it did not.

Earlier this week, the nation’s highest court passed up an opportunity to correct a ruling by Hawaii’s Supreme Court that appears to violate Second Amendment interpretations.

In a February ruling, the Hawaii court openly rejected landmark Second Amendment cases that have been decided by the highest court in the country, finding the “spirit of Aloha clashes with a federally mandated lifestyle that lets citizens walk around with deadly weapons during day-to-day activities.”

“In Hawaii, there is no state constitutional right to carry a firearm in public,” the super-blue state court wrote.

Justice Clarence Thomas explained in a statement joined by Justice Samuel Alito that fixing the state court’s error “must await another day.”

Thomas, Alito, and Neil Gorsuch criticized the Hawaii court’s decision but stated they could not take up the case at this time. They further explained that the defendant, Christopher Wilson, has yet to stand trial on other charges. Wilson was arrested in 2017 for trespassing on private property while carrying an unlicensed pistol.

“Wilson moved to dismiss only some of his charges, most notably leaving for trial a trespassing charge on which his Second Amendment defense has no bearing,” Thomas wrote in a statement joined by Justice Samuel Alito. “He thus seeks review of an interlocutory order over which we may not have jurisdiction.”