A Danbury family has been temporarily displaced by a fire at their Cottage Street home.  A Danbury Police officer on routine patrol in the area shortly before 6 o'clock last night saw heavy smoke coming from a 2-family home.  Firefighters were alerted that the officer made sure all occupants were out of the house and noted that there was a working fire in the kitchen.  Firefighters determined that the blaze was being fed by a broken gas line.  They quickly extinguished the fire with one hose line.  One unit in the two-family home was restored to be occupied, while the other occupants will stay with family. The Fire Marshal's Office is investigating. There were no injuries reported.  Residents are urged to make sure their smoke alarms are up to date and in working order.