Firefighters responded at 1:38 a.m. to a call of at least one loud "boom" and flames shooting 40 feet high from the roof of Ocean Fresh Seafood and The Hawaiian Chef, both businesses located at the 'ewa end of the strip mall.

Approximately 20 patrons and workers at Zippy's, which fronts the center, were forced to evacuate. Police also went to nearby neighborhoods, waking residents and initially asking them to evacuate.

"They were knocking on doors, basically," said Gerald Lau, who lives in the neighborhood behind the center, about 500 yards away. "They said they thought there was a chance there was chlorine or some sort of chemical at first, but then they came back and said we could stay. They were worried about the propane tanks nearby."

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Ten engines and two ladders, encompassing 40 firefighters, responded to the call, said Capt. Terry Seelig of the Honolulu Fire Department. The fire was deemed under control at 3:15 a.m., but firefighters continued to look for pockets where the fire could flare up until 4 a.m.

Because of the severe damage to the roof of the building and fears that it could collapse, firefighters were going to wait until first light to resume working on the center.

"We had reports of an explosion inside and we had propane tanks outside," Seelig said. "We had to use defensive tactics to fight this one — rather than go inside we had to shoot water from the outside so it took longer to get under control.

"It looks like three businesses were affected by the fire, but there may be smoke damage to others."

Cause of the fire is under investigation and there is no estimate on damage yet.