The Osseo School District has placed a science teacher on paid administrative leave while it investigates an accident that injured four students last week.
Maple Grove Junior High School teacher Matthew Achor was conducting a demonstration on methanol on Thursday when a flash fire ignited in his classroom. One student was hospitalized for severe burns and other students suffered minor injuries.
District spokeswoman Barb Olson said it is unclear what caused the accident.
"The school district is conducting an investigation, and the state fire marshal is conducting an investigation," Olson said. "We are looking into what happened and why and what, if anything, action needs to be taken as a result of it."
Olson said the district has suspended all methanol demonstrations while it investigates. Achor has taught at the district since 1985.