Photo Credit: Colin Opseth

HESPERIA, Calif. (AP) — Interstate 15 is expected to remain closed northeast of Los Angeles for up to two days after a fire erupted where a bridge is being constructed.

The freeway — Southern California's main connector to Las Vegas — was closed around 1:30 p.m. Monday after a construction worker's blowtorch accidentally ignited the bridge's wooden supports.

Caltrans spokeswoman Terri Kasinga says workers are demolishing remnants of the wooden skeleton of the Ranchero Road overpass, which had been under construction since early 2013.

She says firefighters will be there throughout the night, but while some areas are still smoldering, most of the flames were out.

The closure is just north of the CajonPass, and Kasinga says traffic has backed up 6 miles to the south and up to 20 miles to the north.

All three lanes of Interstate 15 in Hesperia were closed in both directions Monday after a construction worker's blowtorch accidentally ignited the wooden supports of an overpass that was under construction.

The freeway — Southern California's main connector to Las Vegas — has been closed since 1:30 p.m. because of falling debris, said California Highway Patrol supervisor Carlos Juarez.

Officials said drivers should stay away from the CajonPass, which is just south of the area of Interstate 15 closed by the fire.

Dozens of firefighters were battling the blaze in windy conditions, with limited access to water, and high danger that the wooden skeleton of the football-field-sized bridge would collapse, said San Bernardino County Fire Capt. Josh Wilkins.

Caltrans contractors were still working on top of the bridge after it caught fire and were unaware of the blaze until being evacuated by firefighters because the flames were being pushed away by the wind. One worker suffered from smoke inhalation, Wilkins said.

So far, Wilkins estimated, a third of the bridge has burned and he said Caltrans engineers are monitoring the flames to alert firefighters of a possible collapse. There were 55 firefighters battling the flames in winds that gusted to 35 mph.

"Right now the wind is helping and hurting us," Wilkins said. "If it were going the opposite direction, that whole bridge would be gone right now."

But, he added the wind also was pushing water away from the blaze as firefighters fought the flames that were ignited when the worker used his blowtorch on rebar.

Firefighters also have limited access to water because the area is newly constructed, and the nearest hydrant is half a mile away, Wilkins said. The department can't use water-dropping helicopters because the weight of the falling water would likely lead to a collapse of a wooden structure that would have served as a frame when concrete was poured.

"The CajonPass is going to be a nightmare for the next 24 to 48 hours at least," Wilkins said. "So if at all possible, avoid it altogether, because there is just no way they're going to open it any time soon."