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Michael Brandy, Deseret News
Firefighters douse flames from a crash on I-80 Saturday near the Salt Lake-Tooele border. A westbound FedEx semitruck collided with a Dodge Dakota, killing the driver of the Dodge and injuring the FedEx driver. Traffic on I-80 was shut down for about four hours.

One person is dead following a fiery crash Saturday morning that closed I-80 for about four hours near the Salt Lake-Tooele county line.

Mark Neilson of Magna was killed instantly.

About 11 a.m., a FedEx semitrailer pulling three trailers was traveling west and collided head-on with an eastbound sports-utility vehicle driven by Neilson.

The crash caused both vehicles to catch fire and halted both directions of traffic, Utah Highway Patrol spokesman Cameron Roden said.

The FedEx truck was transporting an unknown amount of ammunition, some of which discharged.

Police are looking for a "dirty white pickup" that witnesses say may have been a contributing factor in the crash, Roden said. Witnesses to the accident said the white pickup cut off the SUV and did not stop at the scene.

The driver of the semitrailer was transported by medical helicopter to University Hospital in serious condition, he said.

One lane in each direction was open by 3 p.m.

— Clayton Norlen