DINWIDDIE, Va. (AP) — Three students and a teacher were taken to hospitals Wednesday after a fire broke out during a demonstration in a Virginia high school chemistry classroom, officials said.

When the fire broke out in the classroom at Dinwiddie High School, the fire alarm was pulled and all students were evacuated from the building, Dinwiddie County Public Schools officials said in a statement.

A teacher was taken to a local hospital and three students were taken to VCU Medical Center, officials said. Officials didn’t release details of their conditions. One student was treated at the scene and released.

The cause of the fire is under investigation, officials said.

Students were dismissed early and Thursday will be an asynchronous learning day, officials said.