An Armstrong Elementary student brought a BB gun to school on Tuesday, according to a letter sent home to parents by new principal Roger LeBlanc.
LeBlanc said the gun was never used in a threatening manner.
Other students found out about the gun and immediately reported it.
The student who brought the BB gun to school is being disciplined according to the Hazelwood School District's Behavior Guide, Leblanc said.
"We work very hard to create a culture in which students, staff members and parents feel comfortable alerting the principal or other school officials when they see or hear anything that causes concern," LeBlanc said. "I am very proud of the students who reported the incident."
Parents can help keep schools safer by encouraging kids to share this kind of information with them or with an adult at school, he added.
"It is very important for all of us to keep an open line of communication and share critical inforamtion," he said.