An eighth-grade science project intended to make an explosion exploded at the wrong time at Wayside Middle School in Saginaw around 10 a.m. Thursday morning.
The class was mixing crushed chlorine and alcohol in bottles, then throwing them, with the expected reaction to be a explosion, but away from the students, said Kristin Courtney, Eagle Mountain-Saginaw Independent School District's director of communication.
When one of the bottles didn't explode, a student went up to it and opened the bottle, causing the explosion. That sent chemicals spraying onto about 30 students in the class.
The Saginaw Fire Department's HAZMAT team responded as a precaution, Courtney said.
MedStar said it assessed 20 patients on scene, with no transports to the hospital.
Some students went home after the incident. Classes have resumed.