Three students were injured after a teacher’s gun discharged in their classroom during a safety demonstration, BuzzFeed News reports.

Dennis Alexander, a reserve police officer, was showing students safe gun practices during his Administration of Justice class at a Seaside High School in Seaside, Ca. when the firearm went off, police told BuzzFeed.

Alexander was pointing the gun up when it went off, damaging pieces of the ceiling, which fell and injured the students, according to KSBW.

Seaside Police Department confirmed with the local TV station that there no serious injuries, but that a 17-year old boy was suffered from “moderate injuries when fragments from the bullet ricocheted off the ceiling and lodged into his neck.”

Fermin Gonzales, the father of the injured 17-year old, told KSBW the teacher was checking to make sure the gun was loaded when it went off.

“It’s the craziest thing. It could have been very bad,” Gonzales told the station. He’s shaken up, but he’s going to be OK.”

Alexander was placed on administrative leave from the high school and by the Seaside Police Department.