Four students at Maple Grove Junior High were hospitalized Thursday morning after a failed science experiment involving flammable gas. The students suffered burns ranging from mild to severe.

KARE-11 says the Osseo School District has changed their science experiment policy a day after a chemical explosion during a class demonstration left four Maple Grove Middle School students with severe burns.

The alleged incident apparently happened during archery class. The district won’t go into detail, but high school principal Bob Dockendorf said, “the teacher was placed on paid administrative leave pending investigation.” Students told WCCO that they didn't think it was a big deal.

A 15-year-old student at Maple Grove Junior High School was taking notes while his science teacher conducted an experiment. The next thing he knew, he was burning. Fox 9 says the class was learning about methanol, a flammable substance, when a container exploded.

The Osseo School District is making changes to its teacher-led science demonstrations after four students were injured in a classroom accident at Maple Grove Junior High. In a 71-page report, the district says the methanol "flash bottle" demonstration will not be allowed pending further review. It also calls for a more stringent approval process for science demonstrations and a detailed list of approved demonstrations.

Minnesota has no state guidelines governing classroom science experiments. A teacher's association has issued recommendations, but following them is purely voluntary. This month's accident that burned four Maple Grove students may lead to more scrutiny.

WCCO reports parents of some black students say their children have suffered racial discrimination and prejudice from a teacher at Heights Community School. An attorney for the families said the teacher has called the students "fat, black and stupid" and said things such as "You only have one parent."