Dunkirk firefighters early Thursday responded to a house blaze at 147 Franklin St. around 4:30 a.m. Upon arrival, crews found fire venting from the first-floor windows on the side of the house. Firefighters made an aggressive attack using multiple hose lines and tools to bring the fire under control. The exterior of the house at 149 Franklin Ave. suffered minor heat damage. The city of Dunkirk was assisted by the Fredonia Fire Department, East Dunkirk Fire Department, Chautauqua County Emergency Services, Alstar EMS, City of Dunkirk Police, City Code Enforcement, and National Grid. There were no occupants of the house. City and Chautauqua County Fire Investigators have ruled the cause of the fire as undetermined with probable human involvement.