SHREWSBURY, Pa. (WJZ) — State police in Pennsylvania are investigating the cause of a massive 10-car pileup on the busy interstate connecting Maryland and southern Pennsylvania.

Derek Valcourt has the unbelievable pictures of the crash.

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Only seven people had relatively minor injuries. When you see it for yourself, you’ll agree it’s a miracle no one died.

Sky Eye Chopper 13 was over the mangled mess of metal, with trucks on top of cars on top of trucks. It happened around 1:30 p.m. Thursday along northbound I-83, just north of the Maryland state line.

“For unknown reasons traffic began to slow down on the interstate. A tractor-trailer was unable to stop in time, ended up rear- ending another vehicle which led to a chain reaction and caused a 10-car pileup,” said Rob Hicks, Pennsylvania State Police.

The crash involved four tractor-trailers, five cars and one tow truck, which flipped on its side. The driver of that tow truck was Jordan Calabrese of Glen Burnie.

“All of a sudden,  I just felt a hard bang and was being pushed forward and the truck flipped over. I guess I got drug a little bit more and then it stopped,” he said. “I was just shocked and amazed that nobody got killed.”

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The pileup created major delays for thousands of commuters who use the highway every day to commute between Maryland and southern Pennsylvania.

The wreck shut down both northbound lanes.

“Crowded, bumped up. Absolute mess,” a driver said.

It took nearly seven hours to clear all the debris from the highway. State police investigators are now looking into what went wrong.

“Obviously, it was a tractor-trailer that rear-ended the vehicle. That was the initial cause of the crash. So at this point, you have to look at the tractor-trailer and the driver and see if it was vehicle failure or driver failure,” Hicks said.

Investigators have taken blood samples from some of the drivers to rule out whether drugs or alcohol were a factor in the crash.

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So far, no charges have been filed in the crash.