The Supreme Court will hear arguments Monday morning over the legality of an almost $6 billion bankruptcy settlement involving Purdue Pharma, the manufacturer of the medication OxyContin that has spurred the deadly opioid epidemic.

But the US Trustee petitioned the Supreme Court to review the deal, calling it an “abuse” of the bankruptcy system. Barring individual victims from pursuing their own lawsuits against the Sackler family “raises serious constitutional questions,” the department argued.