St. Patrick High School in Thunder Bay was placed under a brief hold and secure on Tuesday.
The Thunder Bay Catholic District School board says it was done as a precaution.
The hold lasted roughly an hour and a half and city police determined the school was safe around 2:20 p.m.
No information was provided as to why the safety measure was triggered.
All activities at the school have resumed as usual.
Hold and secures typically occur when there is a perceived threat in or near a school.
