Companies 1 and 5 responded mutual aid to the city of Derby at around 8:45am for a working structure fire. First in units arrived with heavy fire showing from the 2nd floor and in the attic of a 2.5 story dwelling. There were initial reports of 2 occupants trapped. An aggressive attack on the fire resulted in a quick knock down. No injuries reported. Engine 2 cleared an hour later and provided coverage for additional Shelton and Derby calls.