Peoria Firefighters responded to a structure fire on Wiswall Street in Peoria early Tuesday morning.
As crews arrived, heavy smoke and flames were coming out of a second floor bedroom, but crews were able to put out the fire before it spread to the neighboring duplex.
Two adults and two children safely exited the structure while crews remained on scene extinguishing hot spots.
All occupents were provided assistance from ERS due to the building being unlivable.
Damage is estimated at $85,000, and the cause is unknown at this time.