A move by the federal government to scrap a study about a controversial autism treatment is not being well received by some parents across the Island.

The National Institute of Mental Health said in a statement Wednesday that it was dropping plans to study the effects of the treatment, called chelation, on children with autism. The agency announced it decided funds for the study would be better used testing other potential therapies for autism and related disorders.

The treatment works by removing heavy metals from the body and is used to treat lead poisoning. Its use as an autism treatment is based on the disputed theory that mercury in vaccines triggers autism. Mercury hasn't been in childhood vaccines since 2001, except for certain flu shots.

Despite the study being dropped, some parents of autistic children on Long Island believe the therapy has changed their kids' lives.

Billy McKenna, 7, was diagnosed with autism when he was 2 years old. For the past several years, his parents have been taking him to the Autism Associates of New York in Woodbury, where he receives the treatment. His father, David McKenna, says he has seen a marked difference in his son's behavior.

"Years ago he would just zone out, now he knows what's going on, he knows what's around him," says David McKenna.