North Hastings High School was locked down just after noon Thursday.
A loud bang was heard outside the school and was originally thought to be a gunshot. It was determined after an OPP investigation to have been firecrackers that had been lit and put inside a metal garbage can on school property.
After the lockdown ended, the remaining classes continued on as usual.
Anyone with information on what happened is being asked to call the Bancroft OPP at 1-888-310-1122 or call Crime Stoppers at 1-800-222-8477Â to report it anonymously.