The Maine Fire Marshal's Office said carbon monoxide that prompted the evacuation of a Kittery day care and led to nearly a dozen people being treated at an area hospital came from a gas-powered saw that was being used elsewhere in the building.

Authorities say a concrete saw used during an unpermitted construction project next to a Maine daycare caused a carbon monoxide leak that hospitalized several children and staff members on Wednesday.

Twenty-seven children and 10 staff members were at Building Blocks daycare on Route 236 when firefighters, police, and ambulances arrived at the scene, according to a statement issued by the Kittery Fire Department.

The Building Blocks Learning Center daycare in Kittery, Maine, remains closed 24 hours after a carbon monoxide incident sent several people to the hospital Wednesday<a class="excerpt-read-more" href="