TOTOWA, N.J. (CBS) — Two workers were hurt after a powerful explosion rocked a North Jersey pharmaceutical lab late Saturday night in Totowa, New Jersey, just outside of Paterson. 

The blast blew the roof off part of the building of Pharmachem and shattered windows nearby.

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Eyewitnesses described the blast. “It shook the houses, shook us, and we all looked at each other and knew it was not fireworks,” said Kevin Frank. “Our first reaction was, propane tank, somebody’s grill went off, and then we realized it wasn’t that.”

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“Initially I had thought it was the movie we were watching because I had my surround sound on,” said Christopher Tencza, another eyewitness, “but then I felt my house actually shake.”

The cause of the explosion is under investigation.

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