THOMASVILLE, Pa. -- An explosion at a facility that refurbishes propane tanks for gas grills shredded a tractor-trailer and injured two workers Thursday. Investigators were trying to determine whether a ringing cell phone could have ignited propane from a leaking canister, a fire official said. A workers' cell phones rang at the time of the blast, which was heard more than 12 miles away. The Aero Energy Inc. employees were securing a truckload of 1,152 propane tanks for delivery to Maryland at 4:25 a.m. when the explosion occurred, said plant manager William Wagner. The employees, who were not identified, called...