WEST ORANGE — It's not clear why a dump truck plowed into several vehicles at a crash scene on Route 280 on Tuesday, injuring three State Police troopers and five firefighters.

The incident partially closed the eastbound side of the highway for 11 hours.

State Police said the troopers were with several people involved in a crash scene near Exit 9 about 10:20 a.m. when the dump truck driven by Edgar Penafiel, 54, of Newark, hit a Honda Accord and Ford Econoline van that had pulled over.

The van was pushed into a Honda CR-V and then into a State Police vehicle with a trooper inside. The State Police car was then pushed into a Ford E-450 and an unoccupied State Police vehicle.

The dump truck continued onto the right shoulder and struck the rear of a West Orange Fire Department ambulance, which was pushed into the rear of a West Orange Fire Department truck before partially overturning.

A firefighter assisting someone in the ambulance was seriously injured.

The trooper in the vehicle suffered moderate injuries while another trooper suffered a severe cut on one of his hands when he jumped over a guardrail to avoid being struck by one of the vehicles.

State Police Sgt. Lawrence Peele said Wednesday that it had not been determined why Penafiel lost control of the truck. No charges have been filed in the crash.

Two West Orange police officers and five firefighters who had responded to the first crash were injured in the second crash, according to a statement from the township.

"Our last member in University Hospital actually spoke a little today. Great sign! He has a long road of recovery ahead of him," New Jersey Firefighters Mutual Benevolent Association PresidentEd Donnelly told New Jersey 101.5.

Donnelly also took the opportunity to ask drivers to slow down when they see emergency situation on the highway.

"People think the fighting fires is the most dangerous part of the job. Being out on the highways of New Jersey is never routine. We ask all drivers to slow down and move over if they encounter an accident scene," Donnelly said.

West Orange emergency medical technician Tyler Treible who was at the Route 208 crash had the same message.

"I beg you, even if this just reaches one person. PLEASE slow down and move over if safe if you see emergency lights, or even just a car pulled over on the side of the road. Today was a huge wake up call for me and my partner, it shows how quickly life can change."

Contact reporter Dan Alexander at Dan.Alexander@townsquaremedia.com or via Twitter @DanAlexanderNJ

Sign up for the NJ1015.com Newsletter

Get the best of NJ1015.com delivered to your inbox every day.