A Mars School District bus with 43 students on board went over a Route 228 embankment Monday afternoon and rolled over onto its right side. At least seven students were taken to area hospitals by emergency services for evaluation, according to responders.

Mars School District confirmed that Bus No. 4 was involved in an accident reported at 2:42 p.m.

It is not known what happened to the bus driver — or what caused the accident.

Students and parents are being reunited at the CVS Pharmacy on Pittsburgh Street near the accident scene. Wesley Shipley, the district superintendent, was on scene to help, according the news release.

A second bus arrived on scene shortly after 4 p.m. to take children to UPMC Passavant for evaluation, but most are not electing to get on the second bus, according to reports from the scene.

Colleen Hannan opted to let her 13-year-old daughter be transported on the second bus for evaluation. She said her other child was at soccer practice and learned about the wreck via Snapchat.

“Her brother called me and said 'Did you hear about Emma?,” Hannan said. I said what about her? I was not expecting that phone call.”

She said her daughter didn't appear injured, but she wanted to have her evaluated just to be sure.

Parents are allowed to take their children home, although some parents are choosing to take the children to the hospital in their own cars.

This story will be updated when more information is available.