A stove left on started a house fire that displaced a family of three and killed a pet dog today in Waipahu, firefighters said.

The fire started at about 8:50 a.m. in the 94-200 block of Kihikihi Place while the family was away, said Honolulu Fire Capt. David Jenkins.

Two people at the scene were treated for smoke inhalation, Jenkins said. It was not clear how the people were involved in the incident, but they were not firefighters, Jenkins said. Paramedics said one of the two treated was a 42-year-old woman, who was taken to the hospital in serious condition.

The fire erupted after the kitchen stove was inadvertently turned on and ignited items left on the stove, Jenkins said. The flames then spread from the kitchen to other parts of the home.

About 25 firefighters responded and found light smoke coming from the attic of the two-story structure. Firefighters brought the fire under control within five minutes and extinguished it shortly afterwards.

The American Red Cross was assisting the displaced family.

A damage estimate was not immediately available.