The most serious case of water contamination in Canadian history could have been prevented by proper chlorination of drinking water, according to a judicial inquiry report about Walkerton, Ontario's fatal E. coli outbreak.

Justice Dennis O'Connor's report also points to the region's public utilities managers and Ontario government cutbacks as contributors to the tragedy.

Seven people died and 2,300 became ill after Walkerton's water supply became contaminated with manure spread on a farm near the town, the report concludes.

The report, released in two parts over the winter and spring of 2002, contains hundreds of findings and recommendations.

From part one of the report
issued January, 2002:

• Up to 400 illnesses could have been prevented if water manager Stan Koebel had monitored the chlorine levels daily and had notified authorities right away that the water was contaminated.
• The Ontario government failed to make reporting of positive tests for contamination mandatory when water testing was privatized in 1996.
• Government cuts at the province's Environment Ministry made it less capable of identifying and dealing with problems at Walkerton's water utility.
• The local health unit was quick to respond to the crisis with a boil-water advisory, but it should have been more wide-spread. Many Walkerton residents were not aware of the warning.

• Seven people died, and more than 2,300 became ill. Some people, particularly children, may endure lasting effects.
• The contaminants, largely E. coli O157:H7 and Campylobacter jejuni, entered the Walkerton system through Well 5 on or shortly after May 12, 2000.
• The primary, if not the only, source of the contamination was manure that had been spread on a farm near Well 5. The owner of this farm followed proper practices and should not be faulted.
• The outbreak would have been prevented by the use of continuous chlorine residual and turbidity monitors at Well 5.
• The failure to use continuous monitors at Well 5 resulted from short-comings in the approvals and inspections programs of the Ministry of the Environment (MOE). The Walkerton Public Utilities Commission (PUC) operators lacked the training and expertise necessary to identify either the vulnerability of Well 5 to surface contamination or the resulting need for continuous chlorine residual and turbidity monitors.
• The scope of the outbreak would very likely have been substantially reduced if the Walkerton PUC operators had measured chlorine residuals at Well 5 daily, as they should have, during the critical period when contamination was entering the system.
• For years, the PUC operators engaged in a host of improper operating practices, including failing to use adequate doses of chlorine, failing to monitor chlorine residuals daily, making false entries about residuals in daily operating records, and misstating the locations at which microbiological samples were taken. The operators knew that these practices were unacceptable and contrary to MOE guidelines and directives.
• The MOE’s inspections program should have detected the Walkerton PUC’s improper treatment and monitoring practices and ensured that those practices were corrected.
• The PUC commissioners were not aware of the improper treatment and monitoring practices of the PUC operators. However, those who were commissioners in 1998 failed to properly respond to an MOE inspection report that set out significant concerns about water quality and that identified several operating deficiencies at the PUC.
• On Friday, May 19, 2000, and on the days following, the PUC’s general manager concealed from the Bruce-Grey-Owen Sound Health Unit and others the adverse test results from water samples taken on May 15 and the fact that Well 7 had operated without a chlorinator during that week and earlier that month. Had he disclosed either of these facts, the health unit would have issued a boil water advisory on May 19, and 300 to 400 illnesses would have been avoided.
• In responding to the outbreak, the health unit acted diligently and should not be faulted for failing to issue the boil water advisory before Sunday, May 21. However, some residents of Walkerton did not become aware of the boil water advisory on May 21. The advisory should have been more broadly disseminated.
• The provincial government’s budget reductions led to the discontinuation of government laboratory testing services for municipalities in 1996. In implementing this decision, the government should have enacted a regulation mandating that testing laboratories immediately and directly notify both the MOE and the Medical Officer of Health of adverse results. Had the government done this, the boil water advisory would have been issued by May 19 at the latest, thereby preventing hundreds of illnesses.
• The provincial government’s budget reductions made it less likely that the MOE would have identified both the need for continuous monitors at Well 5 and the improper operating practices of the Walkerton PUC.