A discarded cigarette appears to have caused a fire on the back porch of a multi-family home in Janesville early Tuesday morning, according to fire officials. Janesville fire says around 4:40 a.m., they resp onded to a fire at a home on the 800 block of McKinley Street. When firefighters arrived they found the back porch of the home and exterior wall had been partially extinguished by the residents. Still, it was smoldering and actively burning in some areas. Firefighters quickly extinguished the fire. They say the fire was contained to the porch and exterior wall of the home. All residents inside the multi-family home were able to safely escape and no one has been displaced.