Three engine companies, an aerial ladder truck and three rescue trucks called to a house fire in the Mayfair area at 9:33 p.m. Saturday.
When crews arrived at 1829 Avenue E North they found smoke and flames coming from the back of the building.
Within 15 minutes firefighters had the blaze under control and a large propane tank that was leaking near the fire was moved.
In a media release sent late Saturday, the fire investigator says the cause of the blaze was determined to be incendiary.
Damage is estimated at $3,000 and there were no injuries.