Because of the extensive damage caused by the Mapunapuna fire Oct. 27, fire investigators could not determine the exact origin of the fire or the manner in which it began, fire officials said. 

Honolulu Fire Department investigators concluded their investigation of the large-scale fire at ABC Supply Co., and announced Tuesday that the cause was classified as “undetermined.” 

The three-alarm fire caused an estimated $5.45 million in damage to ABC’s warehouses filled with building materials, eight forklifts and three boom trucks, and $50,000 to neighboring structures. 

The fire investigator reported the blaze began in or near one of two warehouses, said fire Capt. David Jenkins, in an email. But the “undetermined” classification indicates there is insufficient information to identify any one cause. 

HFD investigators have closed the case, which can be reopened if new information is introduced or uncovered. 

Nineteen fire companies with 70 personnel responded to the three-alarm fire at 749 Mapunapuna St. The first HFD unit found the large warehouse and lumber yard heavily involved in fire. 

Firefighters used used multiple master-stream and ladder-pipe operations to douse the flames with large volumes of water. 

The fire reported at 6:15 p.m. was brought under control at 9:14 p.m. and was extinguished 3:07 p.m. Oct. 28. 

Two of the three warehouses on the property were heavily damaged and posed a collapse hazard, which hampered efforts to fully extinguish the smoldering debris in the two buildings, Jenkins said.