No students were sickened in the incident near N Chester Avenue and Coates Street around 2:45 p.m., district officials said.
Several students were evaluated but most did not leave the bus, per instruction from EMS.
One student complained of mild respiratory irritation, but refused medical treatment. The student's father signed off saying he did not want his son to be treated, officials said.
The bus was ventilated and students continued on their way home on that bus.
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