What was something tragically that happened in the year 2000?

In May of 2000, more than 2500 hundred people became ill with symptoms of E. coli infection, and 7 people died, in Walkerton, Ontario, Canada.

Although the water sample taken during this time proved the contamination of E. coli bacteria, the Public Utilities commission denied any danger. As such, the resulting illness and deaths could have been avoided.