An arson investigation is underway following a fire at a derelict house in Crossland Street.
The incident at the end terraced property in Accrington occured shortly after 3pm on Wednesday.
The fire was put out quickly by two firefighters and they later used a portable fan to clear heavy smoke from the ground floor.
A spokesman for Lancashire Fire and Rescue Service said: "Two fire engines from Hyndburn were called out at 3.13pm. Two firefighters went into the property on Crossland Street with breathing apparatus and quickly extinguished the fire. The police have been informed and there is a suggestion it was started deliberately. It didn't filter through to next door and it took firefighters 30 minutes to deal with the incident."