Montgomery County Fire and Rescue evacuated an apartment building in Rockville, Md., Monday because of carbon monoxide.
People reported feeling sick at the building at 12510 Viers Mill Road about 6 p.m. In a first-floor apartment, the concentration of carbon monoxide reached 100 parts per million. Thirty-five parts per million or less is considered safe.
Fourteen people were evaluated. No life-threatening injuries were reported.
The issue was a faulty heating unit. The scene has since been cleared.
Residents were sheltered in a Ride On bus while authorities try to determine the source.