The concrete saw was being used in a nearby suite that was under construction, and smoke detectors near the saw were covered up, authorities said.

Twenty-seven children and approximately 10 employees were evacuated from the Building Blocks daycare center in Kittery due to CO scare.

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.