Fresno City Fire officials say they were called to the scene about 1:30 this afternoon.
The classroom, along with other classrooms in the same building was evacuated immediately. One student suffered minor burns in the fire, and another student's hair was singed.
The fire department went in and cleared the classroom so students could return later.
Kelly Avants of Clovis Unified School District said, "They created what's called a flash fire that caused disruption to the school day."
The teacher was checked out, but did not need to be treated. There is no word on the chemicals involved.
The classroom suffered smoke damage, and there is a plan to repair it but its unknown when it will be done.