The attorneys general for 24 states and Washington D.C. say the proposed bankruptcy settlement involving the family that owns OxyContin maker Purdue Pharma is unjust, NPR reports.

Under the proposed settlement, members of the Sackler family have offered to forfeit control of their bankrupt company and pay $4.2 billion from their private fortunes. In exchange, the family and their assets would be protected from lawsuits linked to the opioid crisis.

The attorneys general filed a new brief describing the proposed settlement as “unprecedented,” “unjust” and “unconfirmable as a matter of law.” Massachusetts Attorney General Maura Healey told NPR, “The bankruptcy system should not be allowed to shield non-bankrupt billionaires. It would set a terrible precedent. If the Sacklers are allowed to use bankruptcy to escape the consequences of their actions, it would be a roadmap for other powerful bad actors.”

The attorneys general say that under the settlement, the bankruptcy court would be stopping private lawsuits against the Sacklers, as well as states’ efforts to investigate members of the family and hold them accountable.