The U.S. Justice Department has begun a review of whether the use of electric shock therapy by a Massachusetts special needs school violates the Americans with Disabilities Act.

It describes its review of the Judge Rotenberg Educational Center in Canton, about 20 miles southwest of Boston, as a "routine investigation." A consortium of advocacy groups for people with developmental disabilities called for the review.

Center attorney Michael Flammia said the school is not violating the federal law. He says the pain created by the shock devices is far less than the severe injury, sometimes permanent, that residents do to themselves.

The treatment is known as aversive therapy. The school administers the shocks in 2 second intervals.

The school is residential and privately operated but receives public funds for some students.