A two-alarm fire at the Crosspointe complex in Halawa on Wednesday morning was caused by a faulty gas water heater.
More than 30 firefighters responded to the blaze that broke out just before 7:15 a.m.
Crews managed to extinguish the flames by 7:50 a.m. HFD said no one was in the unit at the time of the fire.
Several units were evacuated, according to Honolulu police.
HFD said the building suffered extensive damage, so the American Red Cross will be assisting those affected by the fire.
HFD estimated the damage to the building and its contents at $463,000.
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