Although an investigation was continuing, a welder's torch appear responsible for igniting the fire in an unfinished area of the Terhune Avenue building's enormous basement shortly after 9 a.m. March 9, Passaic Fire Chief Patrick Trentacost said.
Firefighters quickly gained control of the blaze, which extended to a loading dock, but had to keep searching for the source while contending with 60,000 feet of basement smoke, the chief said.
It was a labor-intensive job, he said, adding that crews rotated in and out.
A firefighter and a civilian had to be taken to St. Mary's Hospital for treatment, although Trentacost didn't know what for.
Police evacuated the occupied stores, shops and offices in the mall, Mayor Hector Carlos Lora said.
Streets were temporarily closed around what had been the old Passaic Metal Ware Company while firefighters completed their work, he said.
They had help from their colleagues from Clifton, East Rutherford, Paterson and Wallington as the fire went to four alarms for coverage, the mayor said.
Commercial areas of the complex were reopened around 1:30 p.m., about 4½ hours after the fire began.
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