LOS ANGELES (AP) — The Los Angeles Fire Department says a spark from a welder’s torch caused a smoky fire at a Port of Los Angeles wharf that forced about 850 workers to evacuate the area Monday night.

Los Angeles Fire Department Chief Ralph Terrazas says that while the bulk of the fire is under control, it could take until Tuesday afternoon or evening for crews to fully extinguish the blaze.

The fire was smoldering in wooden timber piers, which are coated with water-resistant, highly flammable creosote.

Thick smoke from the fire prompted the Los Angeles fire and police officials to issue advisories to residents in Wilmington, San Pedro and Long Beach to remain indoors and keep windows closed.

Nearby schools remained open with all outdoor activities suspended.

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