Three former residents of a state-run juvenile home for boys in Wyoming allege in a federal lawsuit that they were placed in solitary confinement for extended periods of time, in one case for 45 days, held in restraint chairs for hours and deprived of food.

They allege in the lawsuit filed Monday in Wyoming District Court that while they were teenagers in custody of the Wyoming Boys’ School, they suffered cruel and harsh punishments, including being strapped to a restraint chair for up to 12 hours at a time. The special high-backed chairs are equipped with straps to restrain combative or destructive detainees.

The lawsuit was filed against the Wyoming Department of Family Services, which oversees the school for “delinquent” boys, the school itself and several school employees.

Although the school has not said publicly why the teens were placed in solitary confinement or held in restraint chairs, they never exhibited behavior that warranted such harsh punishment, said Denver-based attorney Ciara Anderson, who is part of a team of lawyers representing the boys and their parents.

“It is astonishing that the abuses our clients suffered have been shielded from the public’s knowledge for so long,” Anderson said. “No human being should be subjected to solitary confinement.”

Males aged 12 to 21 are placed at the detention facility near Worland, Wyoming, after a court determines they “cannot be maintained safely in their homes/communities,” according to the department of family services website.

The school referred questions to the Department of Family Services, which disputed the accusations.

“The department refutes any allegations of wrongdoing,” said Clint Hanes, a spokesman for the Department of Family Services. “We look forward to formally responding to the complaint and having our day in court.”

One of the former residents who filed the lawsuit, Blaise Chivers-King, now 19, was ordered to the school two separate times from April 2020 to May 2022, according to the document.

During his two stays, he was placed in solitary confinement roughly 20 times, ranging from days to weeks, and endured psychological abuse at the hands of staff members who provoked him to act out, the lawsuit stated.

“I have insomnia and have a hard time communicating,” Chivers-King told NBC News in an interview, adding he was often placed in confinement for minor offenses such as “mouthing off.”

He has been back home with his mother in Wyoming for a year but has not fully adjusted to life outside the institution, he said. He is psychologically scarred by his experience at the school and has had difficulty holding down a job, he said.

His mother, Rose Chivers-King, said in an interview with NBC News that the school lied to her about her son’s well-being when she would call to check on him, informing her that he was fine when he was being confined and isolated from the general population.

“I want justice for my son,” she said, adding that he was placed at the facility after he destroyed property at a school when he was 15.

Human rights organizations, including the American Civil Liberties Union, say solitary confinement can cause extreme psychological, physical and developmental harm to juveniles and deprives them of the services they need for healthy growth and education.

Another plaintiff, Charles Rees Karn, 20, who first entered the Wyoming Boys’ School at age 13 and stayed two separate times from 2017 to 2021, said in the lawsuit that staff members put him in isolation on multiple occasions, including stints of 30 and 45 days each.

Staff members used excessive force against Karn when they broke his wrist while tackling him after he busted lightbulbs in a detention room while in solitary confinement, the lawsuit said, and staff members did not offer medical assistance.

“Rees was not seen by a doctor until a whistleblower raised concerns,” it said.

Over a two-week period, Rees was strapped to a restraint chair daily for up to 12 hours, the lawsuit said.

“During this time, Rees lost significant weight” and staff members “starved him,” it said.

Dylan Tolar, 20, who was sent to the school at 17, was diagnosed with a rare birth defect known as schizencephaly, which causes physical impairments to the right side of his body, and has used a leg brace to walk since age 2, according to the suit.

Tolar, who at times was locked in a room for hours, has several medical diagnoses, including cerebral palsy, epilepsy, bipolar disorder and ADHD, the lawsuit said.

While he was at the school from June 2020 to February 2021, he was mocked for his disabilities, and staff withheld his leg brace, causing long-term damage to his leg, the suit says.

As a child, Dylan experienced seizures but hadn’t had any for about 12 years until he was sent to the school, the lawsuit said. It did not say how many seizures he had while at the facility.

The lawsuit also said the number of boys held for more than 72 hours in solitary confinement rose from five in 2018 to 15 in 2021.

Restraint chair use also increased from once in 2018 to 13 in 2021, it said.