Pottsgrove School District now says 22 middle school students were transported to area hospitals after a few fainted and others felt light-headed. The school was also evacuated.
However, the district says "there is no physical cause for the vast majority of the students who were transported based on their reported symptoms."
"We believe that students who witnessed the first three children faint became anxious and panic ensued. We ask that you reassure your children this evening that this was an isolated incident and that they are safe when they return to the middle school tomorrow," a district statement says.
It was around 10 a.m. when three students at Pottsgrove Middle School participating in a choral practice became light-headed and fainted.
Emergency medical personnel were contacted immediately, the school says. Additional students then reported similar symptoms, and prompting the evacuation.
Due to the chilly temperatures, the remaining student body and staff were taken by bus to the high school, where they were provided lunch.
"The hazmat team as well as the fire department were not able to identify any environmentally related cause and have determined that it is SAFE for students to return to the middle school," a district news release said. "However, due to the bussing schedule, it will be necessary to release the students from the HS at their regularly scheduled dismissal time."
The district says students will not be able to return to the building to retrieve personal belongings Thursday afternoon.
School is expected to resume as regularly scheduled on Thursday.
The cause of their illness is unknown at this time. The school has been evacuated.
According to a series of tweets sent out by Pottsgrove SD, all middle school children are being transported to Pottsgrove High School.
We'll continue to bring you the latest information as soon as it becomes available.