On April 2, 2014, a chemical explosion at the Greenbrook water treatment plant in Kitchener, Ontario, shook the neighbourhood. A chlorine tank exploded when it was filled with ammonia, leaving a strong chemical smell in the air. Officials said no one was injured in the explosion. Thomas Schmidt, the region's transportation and environmental services commissioner, said there is no risk to the water supply or to people who were outdoors in the vicinity of the plant.
This is a great opportunity to discuss safety as well as having your students propose what happened and write out the chemical equations.