Dec. 19, 2012  -- A Boston area school for severely disabled children has received a warning letter from the U.S. Food and Drug Administration over its use of devices that administer shocks to its students when they misbehave, a form of restraint that is at the extreme end of a practice that has lawmakers calling for nationwide reform.

The devices "violate the Federal Food, Drug, and Cosmetic Act because your facility has failed to obtain FDA clearance or approval," the Dec. 6 letter to the Judge Rotenberg Educational Center says. An earlier version had FDA approval.

Disturbing video showing staff at the school administering 31 shocks in 2002 to a teenager with autistic characteristics, Andre McCollins, was part of a recent ABC News report about children who have been injured or killed while being restrained in school. The school's use of what it called "skin shocks" represents an extreme example, but is not the only measure that has brought objections from critics. Other schools have faced criticism for using handcuffs, stuffing children into so-called therapy bags, or placing them in small padded chambers known as seclusion rooms.

READ the original ABC News report.

WATCH the original Nightline report.

Rep. George Miller, D.-California, said all of the methods disturbed him and would be prohibited under legislation he has proposed that would set national standards for the use of restraints in schools.

"There's thousands and thousands of children that have been traumatized, that have been injured at the hands of the caregivers and it's just unacceptable," Rep. Miller told ABC News.

The formal warning letter came after the FDA inspected the school in October and discovered it was using the skin shock machines despite their not have been approved by FDA for use.

The Rotenberg Center sent a statement to ABC News saying school officials will meet with the FDA in January to provide answers to the warning letter.

"The FDA's position is important to [the Judge Rotenberg Center]," said the statement. The school "continues to work closely with the FDA to address the issues identified in the Warning Letter; and [the center] will continue to address any and all of the agency's concerns."

The use of skin shocks was approved by the Massachusetts courts as part of behavioral treatment plans for people afflicted with disorders that pose physical danger to themselves and others, the school said, noting that "the treatment has been in use at JRC for over twenty years and has proven to be extremely beneficial and lifesaving for students with whom all other treatments have failed." School officials said they have reduced the number of shocks a student can receive in a given session and no longer apply the shocks while students are strapped to boards.

Some parents with children receiving skin-shock therapy at the Rotenberg Center have called the program miraculous. One mother, whose statement was provided to ABC News by the school, said that three years ago her daughter "attacked anyone who came near her, including infants and toddlers."

"Nearly 4 years ago when we brought her to [the Rotenberg Center], she spent about 10 months on a positive only program," the mother's statement said. After petitioning to have her daughter treated with the skin shock therapy, "the impact was almost immediate. She comes home for visits, has a roommate at school, goes out to dinner with staff and friends; she attends classes and enjoys learning and working in the dining hall."

No other school in the country uses this type of treatment. In 2007, ABC News Correspondent Cynthia McFadden visited the Judge Rotenberg Center where she spoke to Dr. Matthew Israel, the school's founder and developer of the controversial treatment. A staff member attached the device, known as the graduated electronic decelerator, to McFadden and administered the two-second skin shock therapy to the surface of her skin.

"It hurts a lot," said McFadden after being shocked. "I'm glad it's over."

"It's intended to hurt," said Dr. Israel at the time of McFadden's visit. "If it didn't hurt it wouldn't be effective. It has to hurt enough so that the student wants to avoid showing that behavior again."

The technique has come under fire from numerous human rights and disability groups, including the United Nations, which has called the school's practice "torture."

The mother of the boy who appears in the video is still angry 10 years after the incident during which he was shocked. The school had parental and court approval.

"I can't believe they call themselves human and do such a thing to someone who is so vulnerable and can't help themselves," said Cheryl McCollins. "I cannot believe that they actually got away with it."

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