(Reuters) - Wisconsin was sued on Monday over conditions at two juvenile detention facilities in the state’s northeast, where teenagers claimed they are routinely subject to unlawful solitary confinement, shackling and pepper spray.

The American Civil Liberties Union and Juvenile Law Center filed the lawsuit against Wisconsin Department of Corrections officials on behalf of four unnamed youths at the Lincoln Hills School for Boys and the Copper Lake School for Girls in Irma, Wisconsin.

The civil rights class action lawsuit filed in the U.S. District Court for the Western District of Wisconsin named two department of corrections officials as defendants, as well as the supervisor of the facilities and the security director.

The Wisconsin Department of Corrections will review the suit, spokesman Tristan Cook said by email Monday evening.

Some 15 to 20 percent of detainees at the facilities are kept in solitary confinement for 22 or 23 hours a day, the complaint said.

“Many of these children are forced to spend their only free hour of time per day outside of a solitary confinement cell in handcuffs and chained to a table,” the complaint said.

“Officers also repeatedly and excessively use Bear Mace and other pepper sprays against the youth, causing them excruciating pain and impairing their breathing.”

The complaint added that, “these practices constitute serious violations of the children’s constitutional rights.”

The four plaintiffs are not named in the lawsuit because they are minors. They are represented by their parents.

Two are currently in custody at Lincoln Hills and one is in Copper Lake, the complaint said. The fourth was previously in custody at Lincoln Hills but is now at another facility.

Lincoln Hills and Copper Lake, which share a campus around 215 miles (346 km) north of Milwaukee, Wisconsin have been the subject of multiple complaints and investigations in recent years.

An investigation into allegations including child neglect and sexual assault at the facilities was launched by State Attorney General Brad Schimel in January 2015, according to local media. The FBI joined the investigation in December 2015.

A report by the Milwaukee Journal Sentinel published late last year detailed numerous issues at the facilities stemming from systemic breakdowns, lax management and staff shortages.

In one incident, a teenager’s toes were partially amputated after his foot was crushed in a cell door and authorities waited nearly two hours to transport him to the hospital, the newspaper reported.