Walkerton E. coli outbreak

The Walkerton E. coli outbreak was the result of a contamination of the drinking water supply of Walkerton, Ontario, Canada, with E. coli and Campylobacter jejuni bacteria. The water supply was contaminated as a result of improper water treatment following heavy rainfall in late April and early May 2000, that had drawn bacteria from the manure of nearby cattle used to fertilize crops into the shallow aquifer of a nearby well. The first reported case was on May 17. The contamination caused gastroenteritis and sickened more than 2,000 people and resulted in seven deaths, and left others with chronic illnesses.

Subsequently, Associate Chief Justice of Ontario, Dennis O'Connor led an inquiry into the outbreak, called the Walkerton Inquiry. Walkerton Public Utilities Commission operators Stan and Frank Koebel, neither of whom had any formal training, were sentenced on December 20, 2004, after pleading guilty to charges of common nuisance stemming from the contamination—Stan to one year in jail, and Frank to nine months house arrest. As a result, stricter water treatment guidelines were put in place by the government.