After months of investigation, the Honolulu Fire Department concluded no definite cause for the deadly Marco Polo high-rise fire.

(Download the full report here.)

"The HFD fire investigators have completed an extensive and scientifically based investigation in full collaboration with other agencies and have classified the fire cause as undetermined," Fire Chief Manuel Neves said at a news conference Oct. 16.

Three people died in the July 14 fire at the 36-floor condominium with another person dying later in a hospital. More than 130 firefighters responded to the fire, which caused an estimated $107 million in damage, destroying 30 units with another 180 dwellings sustaining fire, smoke and water damage.

The official incident report released did rule out arson, natural causes and rumored reasons, such as a drug lab accident. But the 85-page report left many questions unanswered, including chiefly what caused the fire.

Fire officials, however, did determine that the fire started in a living room on a unit on the 26^th floor in the building’s landward side.

The report quotes the apartment’s occupant as saying he saw a plume of smoke rising from the floor in the living room and shoot up to the ceiling followed by “what sounded like a whooshing sound, then fire appeared.”

Once started winds gusting toward the ocean spread the fire like “a blowtorch,” according to the report. All the fatalities were on the ocean side of the building across the hallway from where the fire originated.

Several items drew fire investigators’ attention as possible causes, including standard 110-volt wall outlets, a 220-volt air conditioner outlet, air conditioning, small gas fuel cylinders used for craft projects, a lighter, and a laptop and desktop computer. Another subject of concern is that at least one of the occupants of the unit on the 26^th floor was a smoker.

The Marco Polo apartment building has no fire sprinkler system. The tower overlooking Waikiki was constructed in 1971, before sprinklers were required for new construction in the city.

A new bill would require sprinklers in all high-rise buildings regardless of when they were constructed.

Meanwhile, an Associated Press investigation after the blaze revealed that the building also failed to update its fire alarms to meet safety standards despite an engineering firm recommending changes several years ago. The tower was not required, however, to meet the standards because they were not part of fire code at the time of original construction.

The Honolulu Fire Department may reopen the investigation pending any new information.

More details here.