The hard-fought settlement of thousands of lawsuits against Purdue Pharma was close to capsizing on Thursday, after the Supreme Court rejected liability protections for the company’s owners. The ruling effectively prevents the release of billions of dollars that could help alleviate the ravages of opioid addiction.

The future of the cases, some of which are a decade old, is now in limbo, as states, local governments, tribes and more than 100,000 individuals who sued the company, best-known for its prescription painkiller OxyContin, figure out next moves.

The court effectively upended the settlement by striking down a provision that Purdue’s owners, members of the billionaire Sackler family, had insisted upon: immunity from all current and future opioid lawsuits in return for payments of up to $6 billion to plaintiffs.

In a statement, Purdue called the decision “heart-crushing,” because the settlement had been agreed to by an overwhelming majority of plaintiffs.

“We will immediately reach back out to the same creditors who have already proven they can unite to forge a settlement,” the company said, so that Purdue could emerge from bankruptcy and funds could begin to flow.

In statements, a number of states said they, too, were eager to resume talks.

“The court’s ruling means we now have to go back to the negotiating table. Purdue and the Sacklers must pay so we can save lives and help people live free of addiction.,” Josh Stein, the attorney general of North Carolina, said. “If they won’t pay up, I’ll see them in court.”