U.S. public schools routinely isolate and physically restrain disabled students deemed to have misbehaved or become uncooperative, according to a new report released on Thursday.

Analysis of Department of Education data by NPR and news website ProPublica found that public schools restrained or secluded students more than 267,000 times in the 2012 school year. Figures also indicate that around 75 percent of the students who were restrained had physical, emotional or intellectual disabilities.

Practices include pinning students face down on the floor, locking them in dark rooms and “tying them up with straps, handcuffs, bungee cords or even duct tape,” according to the report.

The data showed 163,000 instances of physical restraint, with mechanical restraints used 7,600 times, and 104,000 times when children were placed in secluded “scream rooms,” ProPublica reported.

“For more than a decade, mental-health facilities and other institutions have worked to curtail the practice of physically restraining children or isolating them in rooms against their will,” wrote ProPublica’s Heather Vogell. “Indeed, federal rules restrict those practices in nearly all institutions that receive money from Washington to help the young — including hospitals, nursing homes and psychiatric centers. But such limits don't apply to public schools.”

The investigation described incidents of injuries resulting from such restraints, such as those of Carson Luke, a 10-year-old autistic boy, at a public school in Chesapeake, Virginia. He was regularly locked in a dark, separate “quiet room” after any behavioral outbursts. One day he became so upset and agitated when a teacher suggested he’d be sent there that he had to be physically taken there by multiple staff members at once — and badly injured his hand when it was accidentally slammed in the room’s metal door.

“A surgeon later needed to operate to close the bleeding half-moon a bolt had punched into his left palm. The wound was so deep it exposed bone,” Vogell reported. No one at the school had sought medical treatment for his injury, and only after his mother was called to the school and took him to the emergency room did doctors discover he’d also broken his foot.

ProPublica said that at least 20 children have died while being restrained or isolated within the last two decades, citing the Government Accountability Office. Among those deaths was that of a 13-year-old boy in Georgia who hanged himself after school officials gave him a rope to hold his pants up before they locked him in a room alone.

"It's hard to believe this kind of treatment is going on in America," parent and advocate Phyllis Musumeci told ProPublica. She said her autistic son was restrained 89 times over 14 months at his school in Florida a decade ago. "It's a disgrace."

Schools that defend the practice of restraint or isolation say it’s necessary to protect teachers and children if a student becomes so agitated that he or she might endanger others, and would otherwise have to be sent to an institution.

But parents are often unaware that their children have been restrained or isolated because many states don’t have to notify them that it’s happened, according to the National Autism Committee (PDF).

Musumeci learned that her son had been restrained, and she discovered he’d often been forced to lie face down on the floor, which restricts breathing. She told ProPublica that “if you did this at home, you'd be arrested."

Lawmakers have introduced legislation to limit the use of restraints and seclusion, and in a February 2014 Senate report concluded (PDF) that “there is no evidence that physically restraining or putting children in unsupervised seclusion in the K-12 school system provides any educational or therapeutic benefit to a child. In fact, use of either seclusion or restraints in non-emergency situations poses significant physical and psychological danger to students.”

Al Jazeera