BUTLER — Butler police and firefighters responded to a small fire at 309 W. Cunningham St. at around 1:45 p.m. Thursday.

The cause of the fire is still under investigation, according to Butler Fire Lt. Scott Longdon, but investigators believe a bucket being used as an ashtray that was found at the site may be related.

The fire was mainly contained to a second floor walkway on the rear of the house and caused light to moderate damage, Longdon said.

No one was injured, and the house was already evacuated before authorities arrived.

Police arrived on the scene first and directed firefighters where to go, Longdon said, making for a quick extinguishing of the fire.

Firefighters extinguished the flames using compressed air foam.

The sudsy liquid was visible flowing from the walkway and into the alley after the incident.

The initial emergency report was for smoke seen at the residence. The building is directly next to a Salvation Army, whose workers also said they saw only smoke.

Longdon said the fire was “mainly contained to two stud cavities” on the rear of the house. The fire mostly affected the exterior of the building, but there was some damage inside.

He described damages as “light to moderate.”