No injuries were reported after a strong odour was detected at a high school in Guelph.
The Guelph Fire Department was called to Centennial Collegiate Vocational Institute around noon on Tuesday.
Students and staff were evacuated from the building.
Fire crews arrived and searched the building trying to track down the source of the smell.
An email from the Upper Grand District School Board to Global News said the initial investigation determined that the strong odour was likely from an irritant that was released in the building.
They say once fire officials gave the all-clear, students and staff were allowed back into the building at around 1:20 p.m.
The school board said it will be conducting its own investigation into the matter.