A Vermont state trooper collapsed after being exposed to an unknown substance during a traffic stop and was revived by colleagues who administered several doses of Narcan, a drug used to reverse opioid overdoses.

News sources say Sgt. Brett Flansburg stopped a driver for a moving violation Friday night in Leicester, about 40 miles south of Burlington. The driver, 25-year-old Taylor Woodward, then reportedly swallowed a baggie that he later said contained cocaine.

Flansburg searched the car and allegedly found a baggie containing heroin as well as an empty baggie and a syringe. Woodward was taken into custody by other troopers. After arriving back at the State Police barracks in New Haven, Flansburg was found lying in the parking lot, unresponsive. Fellow troopers administered two doses of Narcan; a third was administered while Flansburg was being taken to UVM Medical Center in Burlington. He was released from the hospital after being treated.

Woodward, who was evaluated at UVMMC, did not require treatment. He is scheduled to be arraigned May 6 on a misdemeanor charge of heroin possession.

An investigation is underway to determine the nature of the substance which made Flansburg ill.