PHILADELPHIA – A propane tank on a food truck exploded in north Philadelphia Tuesday, sending a huge fireball into the sky and injuring at least 11 people, including two who suffered serious burns, police said. The explosion outside an auto body shop in the city's Feltonville neighborhood caused serious burns to a 27-year-old woman and teenage girl, said Philadelphia Police Chief Inspector Scott Small. He said that four others were listed in stable condition at area hospitals and at least five others were treated and released.