ANDERSON, Ind. — A central Indiana police department is back in operation after being evacuated when three officers became lightheaded after being exposed to a substance.

The Anderson Police Department was cleared for about three hours Wednesday night amid fears the officers were exposed to fentanyl, an extremely dangerous opioid.

Deputy Fire Chief Todd Cawthorn tells The Herald Bulletin that tests by the state fire marshal revealed the substance was instead a bulking agent used to cut drugs.

Anderson police spokesman Maj. Joel Sandefur says the officers were tagging evidence in an evidence locker room when a bag opened and the officers reported feeling "extremely lightheaded."

The building was immediately evacuated, and the air circulation system was shut down.

Sandefur says the officers went to a hospital for evaluation but didn't require treatment.