DANVILLE, Ill. (AP) — Authorities say two students at an eastern Illinois high school face criminal charges after a firework was set off inside the school, prompting a lockdown of all classrooms.

Police say the loud explosion happened Wednesday morning inside Danville High School.

Danville Public Safety Director Larry Thomason tells The News-Gazette that two male students were each charged with possession of an explosive and reckless conduct and were being detained at the county’s juvenile detention center.

Thomason says a third student was questioned but found to not be directly involved. He says no one was injured.