THOMASTON — A raised ranch house was heavily damaged by fire Saturday night.

The tenants in the two units in the house escaped unharmed. Firefighters also rescued one cat. Another cat is missing but is believed to have gotten out of the house.

The fire at 296 Beechwood St. was reported shortly before 7:30 p.m. by the woman who lived in the upstairs apartment, according to Thomaston Assistant Fire Chief Jamie Leo. The woman initially thought the ceiling fan in the bathroom was on fire but then noticed the back exterior wall of the house was on fire.

She called 911 and then went to alert the downstairs tenant, Leo said.

The assistant chief said the fire appears to be accidental and started outside. He said he believes he knows the cause but wanted to wait until he consulted with the state fire marshal Monday morning before releasing the origin.

The duplex is owned by Brian Barnes. The town’s tax records show that the building is assessed by the town for about $77,000. The owner was insured and one tenant was insured, according to Leo.

The fire damage was limited to the outside, a bathroom and the attic, but there was extensive water and smoke damage throughout the house which may make the home a total loss, he said.

Rockland, Owls Head, South Thomaston, Warren and Cushing fire crews also responded to assist in the firefighting effort.

The former tenants are staying with families and friends, the assistant chief said.