The U.S. Supreme Court on Thursday blocked a $6 billion bankruptcy plan for Purdue Pharma, the maker of OxyContin, over its inclusion of controversial legal protections for members of the Sackler family who as the company’s owner allegedly helped fuel the opioid crisis.

Justice Neil Gorsuch announced the court’s 5-4 ruling in Harrington v. Purdue Pharma, holding that the drugmaker’s Chapter 11 plan illegally included liability releases from future lawsuits from opioid victims. Justice Brett Kavanaugh wrote a dissent joined by Chief Justice John Roberts Jr. and Justices Sonia Sotomayor and Elena Kagan.