The ACLU of Indiana is suing the U.S. Bureau of Prisons over conditions on federal death row, which is housed in Terre Haute.

A lawsuit filed Thursday in federal court accuses the bureau of holding 38 men in isolated conditions that constitute cruel and unusual punishment.

“Long-term isolation costs too much, exacerbates mental illness, and is fundamentally inhumane,” ACLU legal director Ken Falk wrote in a statement.

The suit is seeking class action certification on behalf of everyone on federal death row, known officially as the “Special Confinement Unit”.

The SCU is inside a U.S. facility in Terre Haute, where all federal executions take place. The federal government has carried out 16 executions there since 2001, including 13 in the final months of the Trump administration.

The suit’s named plaintiff is Jurijus Kadamovas, a Soviet-born man who was sentenced to death along with a codefendant for murder and kidnapping in 2007.

“Mr. Kadamovas has suffered physical, mental, and emotional injuries and harm by the isolated, dangerous, and harmful conditions” on death row, the suit alleges.

The ACLU of Indiana and the law firm Faegre Drinker Biddle & Reath LLP filed the lawsuit jointly in U.S. District Court in the Southern District of Indiana. It names the current and most recent warden as well as the director of the prison bureau.

The plaintiffs are seeking an order declaring the conditions on death row unconstitutional and a preliminary injunction allowing people held there to leave their cells for multiple hours a day and to congregate with one another.

A spokesperson for the prison bureau declined to respond to the allegations, citing agency policy not to comment on pending litigation.

This story will be updated.