O’FALLON, Ill. — A school has been evacuated after 16 students became ill Thursday morning in the gym. This is at St. Clare Catholic Grade School on West Third Street.

The source of the sickness appears to be a natural gas leak. There is a triage area set up to treat other students who have been affected.

The gas leak was in a kitchen. Police tell FOX 2 that the source of the leak has been isolated and parents have been notified.

Students at the school have been sent to the old church across the street. Parents are showing up to pick up their kids. The school has canceled classes for the remainder of the day.

First responders are on the scene. In addition to O’Fallon fire, Saint Clair County special emergency services has also been dispatched to the scene. They handle hazmat and other emergency calls in Saint Clair County.

Sixteen children have been taken to the hospital to be evaluated. We’re told they have mild, non-life-threatening symptoms.

This is a developing story and more details will be posted here as they come into the FOX 2 Newsroom.