SUMMIT TWP — A school bus with at least four students from the Indiana Area School District in Indiana County collided with a tanker truck Wednesday afternoon on Route 422.

The school bus driver was seriously injured. The truck driver had unknown injuries.

The students were taken to a hospital as a precaution.

The bus driver was taken by medical helicopter after his bus collided into the back of a tanker truck. The incident occurred about 12:45 p.m. at the intersection of Route 422 and Bonniebrook Road.

It took rescue crews about an hour to extricate the bus driver before he was taken by the helicopter. Authorities believe the 67-year-old Sharon man did not have life-threatening injuries.

Authorities at the scene said the bus was on its way to a band event at the Hermitage School District in Mercer County.

The students were taken to Butler Memorial Hospital for precautionary reasons by a teacher who was following the bus in a private vehicle.

The truck driver also taken to Butler Memorial with unknown injuries.

State police still are investigating the accident and are not sure if charges will be filed.