Four people were killed and two people were injured Tuesday when a tractor-trailer crashed into vehicles stopped in an Interstate 30 construction zone near Texarkana and set off an explosion.

I-30 was closed in both directions after the fiery 2:30 a.m. accident, and the westbound lanes remained closed Tuesday afternoon.

State police said 43-year-old Vaughn Gentry of Dallas and 51-year-old Albert Pruitt of Addison, Texas, died in a rig that was hauling newspaper advertising inserts. Also killed were 77-year-old Walter Carpenter and 64-year-old Victory Barker of Hot Springs, who were in a passenger car.

Investigators said Carpenter and three other drivers were stopped in the work zone when a Freightliner that Gentry and Pruitt were in set off an explosion when they hit Carpenter's car. Police could not determine who was driving the truck.