The fire happened around 10:30 a.m. in the 600 block of North Main Street in Ithaca, which is located in southern Darke County.

Firefighters from about a half-dozen departments were called to the scene.

Arcanum Assistant Fire Chief Kurt Troutwine said the cause of the fire is unknown, but the investigation is centered near the furnace.

Authorities said family of six includes a mother, father and four children. They said only the mother and two younger children were home at the time of the fire.

The three managed to escape the fire without injury.

The owner of the home, Neal Fourman, said he and his wife bought the house in May 2007 and were in the process of fixing it up.

The fire remains under investigation.