Five students passed out and 17 were injured after an earthquake drill in an elementary school in Lingao county, Hainan province, on Tuesday, local news portal Hinews.com reported.

The school wrapped up the drill at 5 pm, and students swarmed into the school building’s staircases, causing five students to faint due to lack of oxygen. The crowd then panicked and injured another 17 students in a stampede.

All the students are in stable condition after emergency treatment.

The county government is investigating the accident.