Residents of an apartment building in Gardner, Massachusetts, were forced out in the cold Monday morning after elevated levels of carbon monoxide were detected.
Firefighters were called to the multi-unit building on Elm Street at about 9 a.m. after a carbon monoxide detector was activated inside the building.
Residents were evaculated while crews measured what fire officials said was a dangerous level of CO.
"At that time, they found nearly 2,000 parts per million which is extremely high," said Gardner Fire Captain Gregory Lagoy.
A malfunctioning heating unit in the basement was determined to be the cause of the high CO levels. Fire officials shut off the heating until and began ventilating the building.
Residents were evaluated outside by a number of first responders. No one had to be taken to the hospital.
Lagoy said once the building is ventilated, the building manager will begin working on having the heating unit fixed. Until then, residents cannot be let back inside. Medstar Ambulance provided a shuttle to keep residents warm.