A tractor-trailer rolled onto its top and became engulfed in flames Thursday night near the base of Coal Bank Pass on U.S. Highway 550.

The crash was reported about 8:54 p.m. near mile marker 53, close to the hairpin turn at Cascade Creek, said Capt. Adrian Driscoll with the Colorado State Patrol.

The driver was taken to Mercy Regional Medical Center; his condition was not immediately known Thursday night.

The highway reopened to one lane of traffic at 10:45 p.m. and was expected to be fully reopened shortly after midnight. The truck will likely remain on scene until Friday morning when it can be removed. A hazmat team was dispatched for a diesel fuel spill, Driscoll said.

The truck was transporting gilsonite, which is used for as a road base for asphalt, he said. The substance was not considered an environmental hazard, he said. The Colorado Department of Transportation has created a berm in the area that preventing anything from going into the Animas River.

Tim Rose of Canton, Texas, said the truck was traveling southbound, down Coal Bank Pass and toward Durango, when it ended up in a ditch, upside down. The truck was fully engulfed in flames, he said.

The driver was out of the vehicle standing and walking, Rose said. He had a gash on his right knee, knots on his head and many scratches.

Rose and his wife were the second witnesses to arrive on scene.

“When you came around the corner, you could see the fire and pretty much tell it was an 18-wheeler because it was upside down,” Rose said. “... The tires were exploding on it, so there were a lot of explosions.”

Firefighters arrived within 10 to 15 minutes, he said.

shane@ durangoherald.com