(CNN) A teacher and student on a field trip were killed Thursday when a school bus collided with a dump truck and flipped over in Mount Olive Township in New Jersey, Gov. Phil Murphy said.

More than 40 others were injured, some critically, and were taken to local hospitals, Murphy told reporters. The truck driver was also being treated at a hospital.

The names of the teacher and student killed in the Interstate 80 crash were not released.

"It's a tough day here in Paramus," Bergen County Executive Jim Tedesco told reporters. "Sixty-five years I've lived in this town and it's difficult to stand here today to talk about our education community suffering so deeply."

Mount Olive Mayor Rob Greenbaum, who saw the aftermath of the highway crash from an overpass, described the scene as "horrific." He told HLN on Thursday there were possible ejections from the bus during the crash.

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