UPDATE 2/21 4:25 p.m.

Honolulu firefighters have concluded their investigation and have determined that the fire was on Kumukoa Street was accidental. 

It was determined that the fire was accidentally caused by the spontaneous combustion of discarded sanding dust from a flammable finish in a plastic trash bag. 

Fire damages are estimated at $829,000 to the structure and $12,000 to its contents. The total property loss for this incident has been estimated to be $841,000.

It was reported that the second-story unit was under renovation at the time of the fire and both the upstairs and downstairs units were unoccupied. No injuries have been reported. 

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New video shows the aftermath of a massive house fire that broke out Wednesday night deep in Manoa Valley.

The clip captured the charred remains of a multi-family home.

Honolulu Fire officials say more than 50 firefighters worked to put out the fire on Kumukoa Street around 9:30 p.m. Wednesday.

"Most of the fire was on the second floor of the two-story structure. That's where we noticed most of the damage. I'm not sure if there were any electrical issues. I know the home was under renovation at the time, and that it was unoccupied," said Alan Carvalho, HFD Battalion Chief.

The blaze was put out just before 11 p.m. 

The cause and extent of the damage are still be investigated.