Baltimore County fire crews and Baltimore County police fire investigators remain on the scene of yesterday's massive three-alarm fire at a Baltimore Highlands plastics warehouse.

Photo of fire at Adell Plastics Inc.The fire at Adell Plastics Inc., in the 4500 block of Annapolis Road, 21227, remains under investigation; a cause has not been determined at this time.

The fire continues to burn. As of 1 p.m. today, three fire trucks and four engines remain on scene. County building engineers have ruled the building unsafe, and demolition crews are dismantling the building so firefighters can get to the seat of the fire.

Firefighters will be on the scene throughout the day. Annapolis Road remains closed from Nursery Road to Virginia Avenue.

Fire crews responded to Adell Plastics at 1:07 p.m. Tuesday for a report of a building on fire. All occupants of the building evacuated before crews arrived, and no civilian injuries have been reported. One firefighter was treated for heat exhaustion.

Fire at Adell Plastics Inc.The warehouse was filled with cardboard boxes and other unknown material, and the fire quickly escalated. Commanders requested a second alarm at 1:11 p.m. and a third alarm at 1:15 p.m. Heavy black smoke was visible for miles.

The fire caused wall and roof collapses, and firefighters battled the blaze defensively; conditions made it unsafe for firefighters and, later, for investigators to go inside the building. Crews worked through the night, actively fighting the fire.

A focal point of the operation was preventing the fire from spreading to an area where hazardous materials were stored. A fire wall protecting this area proved helpful in in this regard.

About 55 pieces of fire equipment -- including support from Anne Arundel and Howard counties, Baltimore City and BWI -- fought this fire. At least 200 personnel were involved.