There have been many cases worldwide where malfunctioning equipment in water treatment plants has resulted in overdosing water with toxic levels of Fluoride. In Brisbane, the latest accident occurred in August which resulted in the shut down of the facility for repairs. Citizens were not informed of this accident and what precautions to take till much later.
You read more about the Brisbane Fluoride overdose here
Worldwide overdosing accidents can be found here
Toxic Tap Brisbane 