PHILADELPHIA (AP) — At least seven people were killed and 19 were injured when an air ambulance crashed to the ground on a busy Philadelphia street, creating what witnesses described as a massive fireball and a chaotic street scene. The dead from Friday’s accident include a child who was receiving treatment at a Philadelphia hospital. All six on board the medical transport jet were from Mexico. None survived, while one person in a car was killed. Hospitals say most of the injured have been released. NTSB chair Jennifer Homendy called it a “high-impact crash” that left the plane “highly fragmented.” Officials say the impact area is blocks-long, and it could take weeks to recover the debris.