JASON SCHREIBER/UNION LEADER CORRESPONDENTMultiple ambulances responded to Exeter Hospital Friday during a 'mass casualty incident'.
"We are working with the local fire and police departments and we're now transferring patients", she said shortly before 12:30 p.m.
Town Manager Russell Dean said possible sources of the leak are being investigated, CBS reported.
Carbon Monoxide is made when a fossil fuel is burned in a vehicle, generator, grill, furnace or elsewhere and can cause illness or death in minutes.
New Hampshire hospital evacuated due to 'chemical release': Reports
Exeter fire officials said they initially received a call for 20 ambulances, but not all of them were ultimately needed. Twelve of those who felt ill were sent to other facilities and seven were released, Vasapolli said.
A statement from the hospital said all other hospital wings were unaffected by the problem and running as usual.
Authorities also closed the emergency and operating rooms "out of an abundance of caution".
Their statement said most people affected by the problem are now feeling better. More and more patients began having similar symptoms, she said.