St. Joseph Cathedral School in Jefferson City was evacuated after at least one student fainted and several others felt sick Wednesday morning.
Spencer Allen, the principal of the school, tells ABC 17 News that the students began feeling ill or lightheaded in the church during Mass.
The Jefferson City Fire Department says two students were taken to a local hospital while ten others were treated on the scene.
Around 12:15 p.m., school leaders announced students would be dismissed for the rest of the day. All school events and activities for Wednesday night were canceled.
The church and the school were then evacuated and tested for carbon monoxide, but tests came back negative.
Allen told ABC 17 News that the school has been cleared as of Wednesday afternoon, except for the water supply. The school will reopen on Thursday, however students and faculty will not be able to use water fountains and the cafeteria will not use water from within the building. Instead, Missouri American Water Company will bring 1,000 bottles of water to the school.
St. Joseph Cathedral School has about 500 students.
Stay with ABC 17 News and abc17news.com for the latest on this developing story.