BENICIA (CBS SF) — A 2-alarm wildfire erupted near Highway 680 early Monday, igniting a pile of wood pulp, bark and mulch at a composting facility, sending a massive plume of smoke into the sky near Benicia.

The Solano County Sheriff said the fire was reported about 3:40 a.m. on Goodyear Road about five miles northeast of the Valero refinery.

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The fire was burning at CCL Organics, which handles wood chips, wood debris, wood scraps among other things.

Firefighters battled gusty winds, high temperatures and extremely dry conditions as they fought the blaze.

The California Highway Patrol said the blaze slowed traffic on 680.

Firefighters from surrounding communities including Benicia, Vallejo and Fairfield descended onto the scene to help the Cordelia fire department contain the blaze.

Crews used bulldozers to take apart the mulch and dumped thousands of gallons of water on the stump pile.

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The fire was likely started by spontaneous combustion.

“The mulch and the compost just sitting there in the heat. As it is slowly starting to decompose, it is putting off heat. Along with the hot temperatures that we had and it just started off,” Keith Martin, Fire Chief with the Cordelia Fire Protection District.

The fire happened at the same location as a mulch fire two years ago. That fire took eight hours to put out.

“It could take five or six hours working that stump fire to put it out. And the thing is, we have to make sure it is completely out, cold to the touch so we don’t get a rekindle and have to come out here later tonight,” explained Martin.

Fire crews were also concerned about the wind and the possibility of embers flying from the mulch crossing the street and going into the marsh, sparking fires there.

“If it starts over there, we are going to put guys on it,” said Martin. “But the goal is to keep it out of the marsh because then we are going to be chasing it for a lot longer.”

Goodyear Road remained closed as the firefighters continued their work containing the fire at the scene.

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