Norwalk Hospital is open and fully operational after an explosion closed an ambulance bay for about four hours Sunday night.
The Norwalk Fire Department says the explosion was caused by a faulty regulator on an oxygen tank from an out-of-town ambulance service.
Officials say an oxygen cylinder exploded on a transport gurney while a patient was brought into the emergency room around 7:30 p.m. A minor fire erupted, and was immediately put out.
Patients were moved to another pod and had to walk through the smoke wearing surgical masks.
Officials say the explosion caused burn marks on the walls and ceiling.
One of the EMTs was treated for minor injuries and released. They say the patient and another EMT involved were not hurt.
An ambulance bay was closed Sunday night for about four hours.
The Norwalk Fire Department is handling the investigation, and was unavailable for further details.