Fire crews were forced to evacuate Western University's Spencer Engineering Building after a small fire broke out in a laboratory classroom.
The London Fire Department says firefighters were called to the building just before 3pm on Tuesday, after the fire started in a ventilation hood.
The fire was put out quickly, but around 25 people had to evacuate the building as a precaution due to the chemicals present in the lab. The fire department's hazardous materials unit also attended the scene to ensure the building was safe to re-enter.
Damage to the classroom was minimal, fire officials say, adding that the all clear was given at around 5pm.