PORT JEFFERSON, N.Y. (CBSNewYork) — Authorities are investigating if a rash of fires in a Long Island community Thursday could be connected.

The largest took place at a now-closed industrial site in Port Jefferson while nearby, a vacant home was also the subject of two separate fire calls hours apart.

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As red hot flames shot out from the vacant industrial building once home to Lawrence Aviation Industries, firefighters had to keep their distance. The structure, a Superfund site, has toxic waste and hazardous chemicals stored inside.

The aeronautics manufacturing site, discovered to be managing toxic chemicals illegally and irresponsibly more than two decades ago, was in danger of collapsing in on fire crews as they worked to put out the flames Thursday night.

It was the third time firefighters were called out for the day.

Twice firefighters fought flames at a vacant home on Willis Avenue, now gutted down to the frame, CBS2’s Magdalena Doris reported.

Once the fire was drowned out and crews cleared Thursday afternoon, they received another alarm eight hours later that the same house was once again on fire.

“When you come back several hours later and now the house is on fire again in a different location and it’s a bigger fire we have to look at it differently,” said Dennis Whittam of the Terryville Fire Department.

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“It’s weird, two times in one day,” a neighbor said.

As firefighters worked to drown the flames inside the home, where it appears squatters have been staying, they were alerted to another, much bigger problem nearby.

“Two citizens came up to us and informed us that there was flames coming from a building on Lawrence Aviation’s property,” Whittam said.

By early morning Friday, both fires were extinguished and the arson investigation began. The vacant home and defunct manufacturing building are only about 1,000 feet away from each other through the woods.

“The house is somewhere in here and if you continued walking up, you would come up to the Lawrence Aviation property,” Whittam explained.

Because of the timeline and close proximity of the fires, arson investigators have ruled this as criminal in nature. It’s not a matter of if someone intentionally set the fires, but who, Doris reported.

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Investigators are looking into the cause of all three fires.