A fire investigator has determined that a fire to a warehouse in Campbell Industrial Park Nov. 29 was caused unintentionally when workers taking apart components off a car produced some sparks that ignited gasoline vapor from an open container.

The 11:16 a.m. fire then spread to a pile of tires and the warehouse on 91-080 Hanua Street, Honolulu fire Capt. Terry Seelig said.

The damage to the structure and contents of the warehouse belonging to Tows R Us, an auto recycling and salvage company, was estimated earlier to be $800,000.

About 20 percent of the 20.800-square-foot warehouse was damaged. Five other businesses in the warehouse had little or no damage.

Firefighters on the scene said it was fortunate in that the fire came close to, but did not reach several fuel tanker trucks filled with flammable vapors. If the tankers had caught fire, there could have a major explosion, Seelig said.