Cardboard boxes left on top of a stove started a fire in a fifth floor Salt Lake apartment yesterday causing $20,000 worth of damage to the kitchen.

Honolulu Fire Department investigators have classified the 12:10 p.m. fire at 3020 Ala Napuua Place as accidental. The stovetop burners was accidentally turned on setting the cardboard boxes to ignited.

Two people, who live in the apartment, were not home at the time of the fire. There were no injuries.

Twenty firefighters responded to the fire in the nine-story building at 12:20 p.m. and was reported under control by 12:30 p.m. and extinguished at 12:35 p.m. First arriving firefighters found smoke coming from kitchen window and observed flames inside the kitchen. Firefighters forced entry through the apartment door and used hose lines to confine and extinguish the fire in the kitchen.