VIDEO: Firefighters in New Jersey are still trying to determine what caused a massive fire in Passaic on Friday night. Hundreds of firefighters battled the 11-alarm blaze in an industrial complex where flames shot 70 feet into the air. The fire was just a few feet away from igniting the Qualco Chemical Plant which was filled with potentially hazardous materials such as chlorine. Officials say the heroic efforts by firefighters stopped the flames from hitting the chemical plant, which averted a disaster. The fire was finally put out on Saturday, but they had to come back to put out hot spots that flared up through the weekend. Fire officials are looking at the possibility that the fire might have begun in the back or upper floors of the location. They put in a heroic effort to prevent what could have been one of the worst disasters around.