ALEXANDRIA, Va. (AP) – Ten students from a Boston-area private boys school were injured Sunday when the tour bus carrying them to George Washington’s Mount Vernon home failed to clear an arched bridge and had a large portion of its roof sheared off.

None of the injuries were considered life-threatening, U.S. Park Police Sgt. Scott Fear said.

The bus was carrying 25 students and two chaperones from the St. Sebastian’s School in Needham, Mass., according to Headmaster William L. Burke III. Fear said 29 people total were on the bus.

It was traveling with another bus on the George Washington Parkway, a scenic four-lane road which runs alongside the Potomac River in northern Virginia.

According to police, the bus was in the right lane and crashed into the arched bridge in Alexandria. Signs posted along the parkway warn buses to move into the left lane ahead of the bridge because of height restrictions, Fear said.

The injured were taken to three Washington-area hospitals, where nine were treated and released and the tenth was kept overnight for observation, Burke said. The rest of the group boarded other buses.

“The number of mothers I’ve talked to today who said there must be a guardian angel watching over St. Sebastian’s has been significant,” Burke said.

Federal inspectors are expected to look at the bridge and the bus on Monday.