An electrical failure or outlet malfunction caused an early morning residential fire in Kailua Thursday, the Honolulu Fire Department said.

Thirty-five firefighters responded to the fire on Hele Street at about 5:35 a.m. When they arrived, they saw a single-story structure fully engulfed in flames.

Fire crews brought the fire under control at about 6:05 a.m. and extinguished it at 7 a.m.

The fire department said the blaze was confined to the front unit, which was heavily damaged by the fire.

Smoke alarms were not present in the front unit, but were present in the rear unit, which sustained minor smoke and water damage.

Nine occupants safely escaped the fire. No injuries were reported. The American Red Cross was notified to assist displaced residents.

Fire investigators classified the cause of the fire as accidental due to an electrical failure or malfunction of an outlet along the front porch.

Damage to the structure and its contents were estimated at $440,000.