SECAUCUS, N.J. (CBSNewYork) —  A Kohl’s department store in Secaucus, New Jersey, was evacuated Sunday night after an unknown substance began to make shoppers sick.

The store was evacuated at around 9 p.m. after employees began telling customers to leave, CBS2’s Brian Webb reported.

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The substance seemed to be coming from the front of the store by the cash registers, Webb reported. Witnesses said some shoppers were coughing, choking and even vomiting.

Officials said at least a dozen people were affected. Firefighters and ambulances were still on scene treated sick store goers at around 11 p.m. Sunday night.

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“It was in the air and everybody had it all around the registers,” John Seboroski, a shopper, said. “When I got outside, my wife was in pretty bad shape.”

Officials said there is no indication of a gas leak at this point.

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The investigation is ongoing.