The Honolulu Fire Department classified the cause of a fire that broke out at a two-story Kailua home Monday as accidental.

The fire was caused by a heat gun in the home that a robot vacuum cleaner knocked down to the floor, inadvertently turning it on, according to HFD’s investigator.

On Monday, 1:04 p.m., HFD responded to a 911 call for a fire at 16 N. Kalaheo Ave., about a half-mile from Kailua Beach Park. Ten units with about 38 personnel responded.

The first unit arrived on scene four minutes later to find smoke emanating from the home. Firefighters got the the fire was under control at 1:57 p.m. and fully extinguished it at 2:06 p.m.

No occupants were in the home at the time of the fire.

HFD estimated damages at $700,000 to the home and $60,000 to its contents.