A 25-year-old mom and her two young children, ages 5 and 6, have been released from the hospital after suffering carbon monoxide poisoning in their apartment Wednesday evening.
The Red Cross is currently helping them.
A 35-year-old mom and her 9-year-old daughter remain at MetroHealth.
A man in a third apartment was advised by Cleveland firefighters to get checked out, but he refused to go.
Firefighters checked neighboring residents to make sure no one else was affected. Many left windows open to air out their apartments.
"We were very fortunate. Obviously, they had some exposure for some period of time and thankfully, they didn't go to sleep and the mother reacted appropriately," said assistant fire chief Tim O'Toole.
The gas has been shut off while repairs are made. Crews on the scene said the carbon monoxide detectors were malfunctioning and levels were so high that the victims could have died.
Fire officials say it's imperative to check heating equipment in your home annually.