Lessons from the Walkerton tragedy two decades later
With the news consumed by the COVID-19 pandemic, it’s important we don’t forget past public health tragedies to help prevent their reoccurrence.
This month marks the 20th anniversary of an outbreak of illness due to E. coli O157: H7 and Campylobacter bacteria in Walkerton, Ont.’s drinking water. The tragedy took the lives of seven people, including several young children. It sickened over half of the town’s 5,000 residents.
By the end of May 2000, the majority of Walkerton’s population became sick with stomach pains, diarrhea, and nausea. The outbreak was caused by contamination from cattle manure that contained the disease-causing and deadly bacteria.
It was swept into a nearby community well by heavy spring rains and the chlorination of the drinking water was found to be inadequate. Disinfection is one of the most critical barriers in drinking water treatment and chlorine, the most commonly used disinfectant, destroys pathogenic bacteria and viruses, like E. coli and coronaviruses.
The tragic situation in Walkerton reminds us that errors and misinformation costs lives. As illnesses spiked, the utility manager repeatedly stated that the water was safe to drink.
This continued for days, even after receiving test results on May 17 showing high levels of E. coli. It later came to light that the utility workers had not checked chlorine levels in decades. A “boil water notice” was not sent until May 21. The first death was on May 22.
As the crisis unfolded, officials first thought the outbreak was foodborne. It took several days to confirm that the cause of illnesses was contaminated drinking water. Walkerton holds the unenviable record for the largest and deadliest recorded waterborne disease outbreak in Canadian history.
In response, the Ontario government launched a public inquiry. It found the utility manager hindered the early investigation and outbreak response, but the utility was not solely to blame.
For example, the inquiry determined that serious problems, like low chlorine levels, were repeatedly identified during Walkerton inspections and that the Ontario Ministry for the Environment never ensured that these problems were fixed.
Waterborne disease outbreaks are thankfully rare in Canada, a fact that can make it easy to be complacent about the safety of our drinking water. Pathogens are released every day in human and animal wastes, meaning all sources of drinking water are potentially at some risk of contamination. Therefore, drinking and wastewater (sewage) disinfection should remain a public health priority.
As we emerge from this pandemic with a new appreciation for essential workers and disinfectants, remembering the Walkerton tragedy reminds us that water professionals and chlorine disinfection are essential to our health every day. Heather Murphy,