NORTH BRUNSWICK, N.J. (CBSNewYork) — A small explosion sparked a large investigation Friday in Middlesex County, N.J.

As CSB 2’s Andrea Grymes reported, the blast happened around 4 a.m. outside a building in the area of busy Livingston Avenue in North Brunswick.

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One person suffered serious burns, and was taken to Robert Wood Johnson University Hospital in New Brunswick. But on Friday evening, many unanswered questions remained.

“It sounded like a really big firecracker; like an M-80,” said Marie Huftel of North Brunswick. “But it was an explosion, without a doubt.”

The sound woke up many neighbors who had been fast asleep.

“I heard a loud explosion and I didn’t know what it was,” said Michael Giannetti Sr. of North Brunswick. “I jumped up. The dog got up.”

The neighbors were even more shocked to find the neighborhood swarming with law enforcement officers in hazmat suits – including police officers, the FBI, and the U.S. Bureau of Alcohol, Tobacco, Firearms, and Explosives.

“It’s supposed to be a nice town, and you know, you have this happen,” said Richard Altman of North Brunswick. “It’s very unnerving.”

But what exactly sparked the blast, and who was responsible? The authorities would not provide any information Friday afternoon.

The FBI only said a “small explosion” happened, and there is no threat to public safety – a response that left many questions and no answers.

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The FBI said the blast occurred in the vicinity of a locksmith’s shop. The owner told CBS 2’s Grymes she had no idea what happened – only that the explosion left the glass in her door cracked.

“I don’t know anything,” said locksmith owner Lexine Skinner. “I just walked through the door, and I feel like I’m blind.”

Skinner was not even able to get into her shop until 1:30 p.m. Friday, when the street finally reopened. She said driving up Friday morning to see the massive law enforcement response was chilling.

“I panicked right away – like, what happened?” Skinner said.

Still others took it in stride.

“Just a little inconvenience, you know, going around this street,” said Dianne Romer of North Brunswick.

But everyone in the area wanted the peace of mind to know exactly what happened.

The North Brunswick Schools superintendent said the district sent out a communications blast to parents Friday morning, warning them of the outside investigation and the extra police presence they would likely see in the area.

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