Pottsgrove Middle School was evacuated Thursday morning because several students were hospitalized after passing out, but investigators found no environmental hazard in the building.
The Pottsgrove School District said three students fainted during a choral practice. As medical responders were treating those students, others reported that they felt light-headed or dizzy.
In total, 22 students were taken to Pottstown and Phoenixville hospitals for evaluation. But the school district said emergency crews found no apparent environmental hazard in the building and no cause for most of the students' symptoms.