Seven children were rushed to the hospital after a carbon monoxide emergency inside a Kittery, Maine day care.

KITTERY, Maine (WGME) -- Investigators say they have determined the source of the carbon monoxide leak at a Kittery day care center that resulted in multiple children and adults being rushed to the hospital.

The fire marshal’s office said it operated the building’s heating system in coordination with Maine Fuel Board inspectors and found no concerns related to the emission of carbon monoxide.