More than half a dozen people were evacuated from a Knoxville apartment complex Tuesday night after a detector alerted rescues crews to a possible carbon monoxide leak.

Knoxville Fire & Rescue were called to 1105 Grant St. at 8:30pm for a medical call on a man who was unresponsive. Knoxville Fire Chief Jim Mitchell said while the crew was on scene, a CO detector on a medical bag started to alarm.

Rescue crews took the patient out of the building and transported him to Knoxville Hospital & Clinics, then evacuated the rest of occupants.

Firefighters and an Alliant Energy crewman then checked the air quality of the building. Families were allowed to return to their apartments after approximately 20 minutes when no further carbon monoxide was detected.

The status of the person transported has not been made available.