At least two families were displaced by a residential structure fire in a duplex in Petaluma late Thursday afternoon, according to firefighters.
Crews were dispatched to a duplex in the 1800 block of Petaluma Boulevard North at 4:57 p.m.
On scene they found a fire burning in the living room of one unit and quickly extinguished it before the flames spread to the neighboring unit.
There was smoke and heat damage to the entire unit where the fire started, and firefighters said that families were displaced in both units, but no people or pets were injured.
Investigators said the fire may have started near a wall heater, but the cause is under investigation.
The duplex sustained roughly $60,000 in damage, firefighters said.