Atlanta, GA – Paramedics rushed 16 children and three adults to Atlanta hospitals Monday after a carbon monoxide leak made them sick.

Firefighters responded to G.A.T.E.S. Children & Adolescent Academy on Hapeville Road in southwest Atlanta at about 3:30 p.m. after getting a report that a child was having a seizure. When they arrived, they realized other children were experiencing headaches and vomiting, which are symptoms of carbon monoxide poisoning.

“Our units immediately evacuated everyone from the daycare, got them outside into fresh air which helps with the symptoms of being in that facility,” said Sgt. Cortez Stafford of the Atlanta Fire Department. “Once our squad four got on scene to identify and get measurements of the CO levels in the school, we identified that they were actually very high — very high for the children and very high for the adults.”

Firefighters believe a faulty furnace caused the carbon monoxide exposure. They do not know how long the children and staff members were exposed to the deadly gas.