Two adults including an elderly man were displaced by a residential fire in Petaluma on Sunday afternoon, Petaluma Fire Department Battalion Chief Mike Medeiros said.

The fire department received a report of a structure fire on the 1800 block of Fieldstone Lane at about 3:10 p.m. Sunday and dispatched the battalion chief, an engine, a ladder truck and an ambulance to the residence.

Upon arrival, firefighters saw that light smoke was coming from the front door of the home, Medeiros said. Firefighters quickly gained access, and they found a couch fire that had activated the overhead fire sprinkler and an elderly man who needed assistance to evacuate.

The man was evaluated for smoke inhalation and transported to Petaluma Valley Hospital for a further evaluation by a doctor, Medeiros said. A woman was outside when firefighters arrived on scene and was not injured.

An additional engine arrived to assist crews with salvage and overhaul to minimize further water damage from the sprinkler, Medeiros said.

The City of Petaluma Building Department and Fire Prevention responded to the scene. After an investigation, the residence was “red tagged,” due to the sprinkler system being activated, and the utilities shut off.

The preliminary fire investigation determined that the fire possibly started from an overloaded extension cord under the couch, but the exact cause of the fire is still under investigation, Medeiros said.

“Had it not been for the activation of the sprinkler system this fire would have grown to become much larger,” Medeiros said. Smoke detectors also alerted the residents to the fire.

The displaced adults have family who can care for them until their home is safe again, Medeiros said. Smoke and water damage is estimated at $25,000.

Rancho Adobe Fire and Cal Fire were also on the scene.