The Honolulu Fire Department investigator has determined that the cause of a Kailua house fire on June 29 was accidental and involved a child playing with an open-flame ignition source.

HFD said the fire caused an estimated $525,000 in damage to the building at 461 Kawailoa Road and $25,000 damage to its contents.

The fire originated in the middle bedroom of a single-story structure attached to a two-story residential dwelling.

HFD said the child alerted the adults at home about the fire.

The department did not specify what the child was actually playing with — whether a lighter or matches.

When firefighters first arrived, they found heavy flames and smoke coming out of the two-story home.

Five adults and two children escaped the blaze without injury.

It took firefighters more than three hours to extinguish the blaze that began shortly after 5 p.m.