An early morning fire in Burlington appears to be caused by vapors from flammable liquids coming into contact with a pilot light on a water heater. That’s according to the Burlington Fire Department. Firefighters were called to a house on South Street around 6:41 Wednesday morning. When they arrived, they located a small fire in the basement of the home. The fire was put out a short time later, but not before causing about $6,000 in damage to the house and its contents. The homeowners have insurance. The occupants discovered the fire while investigating the source of a loud noise. The house did have working smoke alarms and the people inside were able to get out without injury. The fire is considered accidental.