A Roswell assisted living facility was evacuated overnight after an alarm warned of dangerous levels of carbon monoxide in the building.
The incident happened at the Elmcroft of Roswell facility on Marietta Highway.
Channel 2 Action News reported that fire officials determined that the fumes were caused by a cleaning crew using a propane-powered floor buffer.
Thirteen of the home's 66 residents were treated in the parking lot for minor exposure to the fumes.
Firefighters ventilated the building, and the residents had all returned to their rooms by 5 a.m.