PETALUMA (CBS SF) — The Tuesday afternoon fire that affected over a dozen homes in Petaluma and forced the closure of northbound Highway 101 caused an estimated $1,500,000 in damage, fire officials said.

The fire was first reported shortly after 3 p.m. as a vegetation fire on the northbound side of Highway 101 just north of the Lakeville onramp, but it quickly spread to nearby homes on Stuart Drive.

A second and third alarm were called soon after as the Petaluma Fire Department requested assistance from Cal Fire and neighboring agencies.

In the end, a total of 22 fire units – including 16 from agencies outside Petaluma – and a Cal Fire helicopter assisted in controlling the fire. It took approximately an hour for it to be brought under control and another three hours for the homes involved to be completely extinguished.

The fire caused damage to a total of 14 residences and destroyed four of them. No firefighters were injured in the incident. While many residents were home at the time of the fire, only two people suffered minor injuries that were treated at the scene.

One cat was killed when it became trapped in one of the houses that was destroyed.

The Red Cross provided services to the residents of the four homes that were destroyed. PG&E also responded and worked into the night to restore gas and electricity to homes that were still inhabitable.

The cause of the fire remains under investigation.