HILLSBOROUGH, NJ – Thick plumes of black smoke are still pouring from filled warehouses at Veterans Industrial Park this morning as firefighters continue to work around the clock containing the blaze which spread to both buildings quickly after it began around 3 p.m. Thursday.

Officials say the fire – though it has been knocked down considerably – will continue into Saturday.

There are conflicting reports as to whether the smoke is toxic; the EPA claims there is no toxicity whereas a published report early this morning said Somerset County officials did characterize the smoke as toxic.

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“Air quality is being monitored by the New Jersey Department of Environmental Protection,” according to a press release from Hillsborough police, which advised people in the area to stay indoors. The police department is only providing emergency information at this time because of its high call volume.

Schools in Hillsborough are closed, extending the President’s Day holiday weekend for students. Route 206 was reopened around 5 a.m. Some homes in the area were without electricity; PSE&G cut power to the Veterans Industrial Park complex as a precaution.

Firefighters from Hillsborough, Manville, Bridgewater, Bound Brook, Franklin and Somerville were working in shifts hosing down the fire which engulfed approximately 300,000 square feet of the World War II era warehouses. The two buildings were separated by about 40 to 50 feet with a railroad line running in between.

Hunterdon County’s Department of Public Safety is reporting that its Office of Emergency Management is working with its Somerset County counterparts to fill requests for mutual aid assistance and that EMS and firefighters from throughout Hunterdon are working to provide that support.

Witnesses and residents reported a heavy odor that smelled like burning plastic or rubber. The plume of smoke can be seen for dozens of miles – as far away as the Jersey shore and New York City.

There is no known cause of the fire. An extensive investigation is expected to begin once the fire is extinguished, according to fire officials.

Several businesses in the complex were destroyed by the fire.

Tap into Flemington-Raritan editor Curtis Leeds contributed to this report.