PITTSBURGH —  Charges have been dropped against a doctor accused of causing the death of a 5-year-old autistic boy by incorrectly administering a controversial chemical treatment.

Dr. Roy Kerry was accused of using the wrong drug and administering it incorrectly while trying to use chelation therapy on Abubakar Tariq Nadama. He was charged with involuntary manslaughter, endangering the welfare of a child and reckless endangerment

The boy went into cardiac arrest in Kerry's office on Aug. 23, 2005, immediately after receiving the therapy.

Chelation removes heavy metals from the body. It is not approved by the federal government for treating autism, though the Food and Drug Administration has approved it for treating lead poisoning.