A fire broke out at an Appleton duplex last night. The call came in at around 7:30 PM to report the fire in the duplex on West Washington Street. Upon arrival, crews found the building engulfed by heavy smoke, but were able to control the blaze. No one was home at the time of the incident, and the residents were not allowed back in just yet. The cause remains under investigation, and the Red Cross is assisting the residents affected.