At around 1AM MHFD was called to a reported duplex on fire. Engine 1 and 2 arrived within 5 minutes of the call and found 1 side fully involved and also heavy fire traveling through-out the attic. Crews pulled a 2.5" attack line and quickly started knocking down the involved side while other crews took a hand line in the un burnt side and started pulling ceiling and knocking down the fire overhead. Crews had the fire under control in about 45 minutes but were on scene hitting hot spots for about 3 hours. All occupants managed to make it out of the units without any injuries. Crews on the assignment were Engines 1 and 2, Rescue 1, Unit 202, 203, and Chief 1.