A three-alarm fire broke out Wednesday night at a roofing supply warehouse in West Oakland, and the fire appeared to have started outside the building, possibly in a debris pile.

The fire was first reported around 10:15 pm Wednesday, on the 1700 block of 24th Street, at Wood Street. The building on fire belongs to Pacific Supply, a roofing supply company, and it sits across the street from what was, until last spring, the sprawling Wood Street homeless encampment near I-880.

Images of the fire from the Oakland Fire Department show a small group of tents up against the Pacific Supply Building, suggesting that some unhoused individuals have repopulated the area since the clearing of the 300-person encampment occurred. The Chronicle confirms that the building "is near a large homeless encampment alongside Interstate 880."

The fire department says it was able to contain the fire by around midnight, and prevent it from spreading to an interior supply yard. No one was injured in the fire, and it did not spread to any other buildings.

Pacific Supply sells a number of flammable materials, as KTVU reports, "like insulation, drywall and stucco."

The fire burned hot within the building, and ultimately a metal roof collapsed onto the flames.

"It's burning debris under the roof, because we had a full roof collapse," said Oakland Fire Battalion Chief Lionel Jarreau, speaking to KTVU.

Jarreau said that firefighters would likely be on the scene most of today, using excavating equipment to access the smoldering fire.

In its heyday, the Wood Street encampment was the site of frequent fires, which was one of the reasons it was ultimately cleared out of public health and safety concerns.

The cause of this fire is not known as is under investigation.