Crews battle five-alarm blaze on Mare Island

Firefighters were battling a five-alarm blaze Sunday morning that was tearing through an old naval warehouse on Mare Island, near Vallejo.

The blaze, which sent smoke hundreds of feet into the air and could be seen all over the Bay Area, was first reported just before 10 a.m. by multiple sources, according to Vallejo fire officials.

The warehouse was reportedly a U.S. Navy storage facility built back when the Mare Island Naval Shipyard was still in operation and much of the building was made out of wood, with the rafters reportedly soaked in creosote, an extremely combustible material. The building was abandoned after the shipyard's closure in the early 1990s.

The Vallejo Fire Department says homeless people sometimes stayed in the warehouse and a campfire may have started the blaze, though no cause had been determined as of Sunday afternoon.

The fire had consumed much of the building by late morning, but officials also said no other buildings were threatened.

As of 11 a.m., five alarms had been called by crews for assistance. At that time, no injuries were reported in the blaze at the condemned wooden structure at the north end of the island.

KTVU.com will provide more information when it becomes available.