Hundreds if not thousands of federal prisoners are likely to have their sentences shortened – and in some cases get immediate release – due to one of the final opinions written by Justice Antonin Scalia.

Scalia’s little-noticed opinion focused on one phrase in federal law but has created uncertainty and upheaval for judges, prosecutors and defense attorneys facing a pile of prisoner requests to have their cases reviewed.

Federal inmates have until Sunday to try to challenge their prison terms after the Supreme Court labeled 12 words in the criminal code “unconstitutionally vague” in an opinion announced by Scalia last June, eight months before his death.

The ruling eliminated a section of law that prosecutors relied on to seek stiffer penalties for defendants they said were especially dangerous. Defense attorneys had decried the wording because it was used to brand too many defendants as violent.

Unlike the low-level, nonviolent inmates the Obama administration has targeted for clemency, prosecutors such as U.S. Attorney Rod J. Rosenstein in Maryland are concerned the new court ruling will lead to the early release of truly violent people. It also could be painful for victims’ families if sentences imposed years ago unravel.

“The finality for the families that we thought came with the appellate process is no more,” said assistant U.S. Attorney Debbie Dwyer, who is overseeing hundreds of sentencing petitions in Rosenstein’s office. “We don’t know when it will end. This makes the process seem endless.”

Rosenstein has hired two lawyers to help respond to requests to revisit more than 580 old cases, including one involving the kidnapping and murder of three women in Prince George’s County in 1996. He worries about the diversion of resources from prosecuting crime in Baltimore, which recorded nearly 350 homicides in 2015. For defense attorneys, the court’s decision provides a new avenue to challenge lengthy sentences for prisoners who received severe penalties for nonviolent offenses, such as resisting arrest.

“It was a dumping ground,” said Amy Baron-Evans of the Sentencing Resource Counsel Project of federal public defenders. “It ended up sweeping in crimes that no one would think of as being violent.”