UPDATE at 2:24 p.m.:

Both drivers involved in the wreck have died, CHP said.

“It’s a double fatality,” Officer Chris Nave said. “Solo occupant per vehicle. It’s unknown if the injuries were due to the collision or the fire afterward.”

The bodies haven’t been recovered. Authorities still can’t approach the scene because of the flames, Nave said.

According to Nave, the fuel tanker was traveling southbound. The tow truck was going north.

“How the collision happened, that’s still under investigation,” he said.

UPDATE at 1:21 p.m.:

Kilroy’s Towing Service in Grass Valley said one of their trucks was involved in the wreck. The business had no further information.

UPDATE at 1:03 p.m.:

Mary Eldridge, public information officer with Cal Fire, said the fire from the wreck hasn’t reached nearby trees and vegetation.

CHP states that Highway 20 is closed from Uren Street in Nevada City to Interstate 80. There’s no estimate when the road might reopen.

UPDATE at 11:35 p.m.:

CHP Officer Chris Nave said authorities can’t yet reach the wreck scene because of the flames, which reach 40- to 50-feet high. The status of the occupants is unknown.

“We’re waiting for the scene to be safe before we can approach,” he said.

UPDATE at 11:06 a.m.:

The California Highway Patrol said Highway 20 is closed eastbound in Nevada City and westbound at its intersection with Interstate 80.

UPDATE at 10:42 a.m.:

Steve Corso said he was one of the first people on the scene of the wreck. He saw the tanker overturned and a large fire.

“I had to back off because stuff started exploding,” he said. “It looks like a lot of oil is burning.”

UPDATE at 10:30 a.m.: