Columbia police, fire and EMS personnel responded about 8:40 a.m. Friday to the report of a carbon monoxide leak inside the new O’Reilly Auto Parts building under construction at 135 Admiral Trost Drive.

A fire official estimated that 10 to 12 construction employees inside the building complained of headaches and other symptoms consistent with carbon monoxide exposure. All of the subjects were treated by Columbia EMS at the scene and the construction site was closed down for the day.

None of the employees required medical transport from the scene.

Firefighters ventilated high levels of carbon monoxide from the building. The leak was caused by a commercial heater running on diesel fuel that was being used to cure drywall inside the building.