PHILADELPHIA — A school bus here was hit with a deluge of debris after a nearby building under demolition collapsed at a construction site last week.

Bus driver Spencer Reynolds had just dropped off students at the nearby National Constitution Center for a field trip and was sitting in traffic when the debris began to hit the bus, NBC 10 reports. Reynolds told NBC 10 that there were stones flying onto the steering wheel and glass falling onto the seats while he was trying to drive away, and told WPVI that he heard rumbling, saw dust and “the rest was scrambling.” No one was injured in the incident.

A slab of concrete from the building had fallen onto a section of street that was blocked off by a fence and barriers, and the bus was next to the barrier when it was struck, according to NBC 10. The city Department of Licenses and Inspections said that a support column may have given way, WPVI reports. That allowed the 8-foot by 15-foot section of reinforced concrete floor to fall off and crash into a light pole and trees, in addition to the school bus.

Police told NBC 10 that the construction company had safety measures in place.