Federal investigators say they still don't know for sure what caused this month's massive Hillsborough blaze at the Veterans Industrial Park — which burned for a day and a half, and sent thick black smoke through the area for at least 130 miles.

But a statement issued by the Bureau of Alcohol, Tobacco, Firearms said its Explosives National Response Team found no sign the fire was caused by an intentional act, according to multiple reports.

The ATF said that based on the scene examination and witness statements, it appears the fire originated in a high-rack storage area of building 14 in the west side of unit C of the park, the location of a paper storage records business.

An exact ignition source could not be determined and the fire was classified as undetermined.

The fire destroyed two large warehouses, together encompassing about 500,000 square feet. It took more than 90 fire companies with 200 emergency vehicles nearly two days to extinguish the blaze, the ATF said.

The fire shut down Route 206, a major commuter resource, for long periods during the battle.

Hillsborough officials have said that fire suppression systems in the buildings were inadequate, and that they'd voiced complaints about the systems in the past — but couldn't enforce stringent New Jersey fire codes because the buildings were on federal property.

Glenn Corbett, a former assistant fire chief for Waldwick Township and a current professor of fire science at John Jay College of Criminal Justice who currently serves on the Fire Code Advisory Council for New Jersey, told New Jersey 101.5 it's not uncommon for federally owned buildings to fall short of local fire codes.

“They can either accept or dismiss anything the local and state officials might bring to them, even though, ironically, if a fire does break out there, they’re going to rely on the local fire department to respond,” Corbett said.

YouTube video posted by user EFD205

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