Mystery odor forces south Charlotte building evacuation. Dozens of patients examined.

A mysterious odor forced the lunchtime evacuation of a south Charlotte professional building on Thursday, and Medic reported evaluating 46 patients. Their conditions were reported as “non-life threatening,” although Medic took five people to local hospitals.

The building is in the 200 block of Regency Executive Park Drive, off Nations Ford Road at Interstate 77.

Charlotte Fire Department officials said on Twitter that the source of the odor is unknown.

Medic initially reported on Twitter that people were believed to have inhaled carbon monoxide but has offered no updates on an official determination.

Charlotte Observer news partner WBTV reported that officials at the scene suspected tar from construction work on the building’s roof might have been the source. The building’s heating and air conditioning system might have dispersed the odor, according to the station.

Medic said on Twitter that it had two “mass casualty” buses at the scene.

This is a developing story.

Joe Marusak has been a reporter for The Charlotte Observer since 1989 covering the people, municipalities and major news events of the region, and was a news bureau editor for the paper. He currently reports on breaking news.