NEW YORK (CBSNewYork) – Multiple police officers are among several people taken to a local hospital in the Bronx after a major drug bust.

All of those people, including the suspects in the drug bust and at least four members of the NYPD, are being treated for exposure to fentanyl.

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The NYPD tells CBS2’s Ali Bauman they were conducting a search in an apartment building on Willis Avenue by East 140th Street Thursday night.

Officers found what they believe to be fentanyl inside an apartment and – because it is such a highly dangerous substance – several people were taken to Lincoln Hospital for evaluation.

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Authorities say most were taken as a precaution. One officer reported feeling some sort of effects from what they were exposed to, but no one has been severely injured.

CBS2 spoke to one woman who lives across the hall from the apartment that was raided and watched the commotion through her peephole.

“You heard a big bang, police open up, they raided in, flash grenade, and boom next thing you know they’re taking out people,” the neighbor told Ali Bauman.

“It was just scary, it was a little scary, but it’s not normal in this neighborhood.”

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Residents were evacuated for some time but have since been allowed back in their homes. Officers are still guarding the front door and it’s still an active investigation.