Dunkirk city firefighters responded to a report of a structure fire late Sunday afternoon at 100 Willowbrook Avenue. Fire officials say crews found a small trash fire on the second floor of the abandoned office building around 5:30 pm. Firefighters used water cans to quickly extinguish the flames. Personnel remained on the scene for about an hour checking for extensions and ventilating the building. Damage was reported to be minimal and there were no injuries.