UPDATE: All Passengers Out of Tour Bus Accident That Shut Down Soldiers Field Road

State Police shut down Soldiers Field Road for hours Saturday night after a tour bus accident that entrapped several passengers and left 34 injured. 

Boston firefighters spent more than an hour extricating passengers, using backboards, from the roof of the bus at 500 Soldiers Field Road, eastbound. The tour bus, which was going from Harvard University to Pennsylvania, hit an overpass at 7:34 p.m. Forty-two people were on board.

Sixty firefighters and "many, many EMS" responded to the scene, Boston Fire reported. The last victim was taken from the bus at 9 p.m. Four MBTA buses were on scene with those not injured, keeping them out of the cold. 

Boston EMS reported that 34 people were injured, including three with serious injuries and one with a life-threatening injury. 

The eastbound side of Soldiers Field Road remained closed as of 12:30 a.m. and the westbound side has been closed at the Bowker overpass, State Police report. Two heavy-duty tow trucks will lift the bus on to a flatbed truck.

Some of the passengers on the bus are high school students, a father of a victim told NBC10.com in Pennsylvania. 

The bus was operated by Calvary Coach out of Philadelphia and chartered by the local Destined for a Dream Foundation.

The group was in New England to explore Harvard University. The trip also included shopping and sightseeing, the nonprofit group posted on Facebook several days ago.

"Investigation ongoing as to whether charges warranted in bus crash," according to the Massachusetts State Police. Officials said the bus driver is believed to have missed sign prohibiting the bus traveling on the road.

State Police have begun an investigation into the accident.