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DALLAS COUNTY (CBS11) – Investigators say five people are dead, including a pregnant woman and her unborn child, after a horrific highway crash and fire Monday morning.

The crash happened at 6:30 a.m. on the flyover ramp from I-20 to southbound I-35 in Dallas County, when a semi-tractor trailer hauling lumber collided with a passenger vehicle.

The fire and resulting investigation closed the ramp for nine hours Monday, and shut down part of I-35 during the morning commute.

While the official cause of the crash is under investigation, deputies are looking at the possibility that the passenger vehicle stalled on the flyover, and the semi struck it.

The vehicles burst into flames on impact, killing all inside the passenger vehicle.

“It sounded like it was next door, the explosion. The boom was really that close,” said Dolly Andre.

Andre lives on Bluecrest Drive, which faces the interchange.

She and several other neighbors were jolted out of bed by the impact, and the resulting fire that burned the semi’s load of wood. Bits of fiery debris floated down to the highway below.

Investigators with the Dallas County Sheriff’s Office spoke to the 58-year-old truck driver, but are not identifying him, citing an ongoing investigation.

The truck driver was not hurt in the crash.

The Dallas County Medical Examiner is working to identify the people who were riding in the second vehicle.

“The thought of a person being in there was just heartbreaking. It could have been a mom or her child, or a father. I mean, just anybody,” said Alma Jove.

Jove is a teacher’s assistant at a nearby elementary school. She was already awake when the explosion rang out this morning. Neighbors heard it several blocks away.

“The wood fire smell was so strong, that when I got to work I was still smelling like smoke,” she said.

TxDOT crews spent most of the day cleaning up the wreckage, and assessing any possible damage to the structure of the bridge.

Traffic on the flyover reopened just before 4 p.m., after TxDOT deemed it safe.

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Jennifer Lindgren