Both brothers carried certification as class 3 water distribution system operators, licences obtained through a grandfathering program run by the Ministry of the Environment (MOE) and based on their work experience in their positions.
[23] The April incorporation of E. coli-contaminated manure into cool, wet soil near Well 5 meant that the bacteria were in an ideally suited environment for longevity.
[27] Attending physicians and health care workers, aware that the gastroenteritis symptoms they were seeing were consistent with possible E. coli infection, began collecting stool samples from affected patients.
[4] When public health officials put together common reports, they found that three area hospitals had recorded incidents of patients suffering from gastroenteritis symptoms.
[25] After speaking to public health officials that day, Stan Koebel (PUC manager) began the process of flushing the system and increasing chlorination levels, procedures he described to David Patterson as "precautionary".
Significantly, Koebel did not disclose to the health inspectors to whom he spoke on May 19[29] or May 20[27] any information about known adverse test results or the fact that he knew Well 7 had been providing unchlorinated water to the system from May 15 to May 19.
O'Connor's report interpreted this not as an act of accidental omission, but as a deliberate attempt by Koebel to conceal what he knew to be substandard and potentially unsafe practices in his department.
On May 20, Robert McKay, a PUC employee who was on medical leave at the time, anonymously contacted the Ministry of the Environment's Spills Action Centre (SAC) to report potential issues with the Walkerton water supply; after observing fire hydrants being used for system flushing, he had concluded that the flushing may have been related to the ongoing illness outbreak in the community and felt that he needed to report his conclusion.
Stan Koebel acknowledged to the Ministry of the Environment (MOE) that "we've had the odd [adverse sample]" due to previous construction work[27] but that the system flushing was occurring only as "a precaution".
[31] Shortly after the definitive laboratory results were received, McQuigge, representing BGOSHU, contacted David Thompson, the mayor of Brockton, Walkerton's parent municipality.
[30] Given that the outbreak was continuing and that no reliable information was yet available about the source of the contamination, the BGOSHU issued a cautionary Boil Water Advisory (BWA) to the community, to be distributed via local radio stations only.
Local radio station CKNX-FM, under the impression that the BWA was cautionary only, reported the advisory at roughly hourly intervals, beginning at 1:30 p.m., rather than more rapidly as they later stated they might have if the import of the announcement had been made clear to them at the time.
As a result of the limited distribution of information regarding the BWA, much of the community remained unaware of the Boil Water Advisory until days after its May 21 issuance.
[31] Around the time the BWA was first being broadcast, David Patterson (the Assistant Director of Health Protection at BGOSHU) contacted the MOE's Spills Action Centre (SAC) to officially report an E. coli outbreak in Walkerton.
Paul Webb, the SAC employee taking Patterson's phone call, mentioned that they had previously been contacted by an anonymous source (Robert McKay) about the quality of water coming out of the Walkerton PUC.
In later testimony, he acknowledged that this had been a deliberate omission; the O'Connor report concluded that Koebel had been hoping that when new samples were collected on May 23, they would test clean and lift the burden from his shoulders.
Bye, however, did not recognize the significance of E. coli being present in Walkerton water and, believing the measures public health officials had already taken to be sufficient to deal with the contamination, he did not pass the news on to the emergency response arm of the MOE that day.
[30] In the face of rising community casualties—by the evening of May 21, 270 people had contacted the Walkerton hospital after experiencing gastroenteritis symptoms, and one patient had had to be airlifted to London, Ontario, for treatment—the situation was being perceived as increasingly serious by most of those involved.
Mayor David Thompson, himself suffering from symptoms of gastroenteritis, which he assumed to be flu, took no investigatory or emergency-preparedness action on May 22, nor did James Kieffer, chair of the Walkerton Public Utilities Commission (PUC), who had been alerted to the outbreak the day before.
Ministry of the Environment (MOE) employee Philip Bye, who had been notified by Bruce-Grey-Owen-Sound Health Unit (BGOSHU) phone call the previous evening, did not understand that E. coli contamination was a life-threatening emergency; he took no action until he was contacted again later on May 22 by a concerned Dr. McQuigge.
Included in this documentation were records of the May 17 adverse testing results of May 15 samples from the "Highway 9" water main construction; excluded was pumping history for Well 7.
[32] By that evening, public health investigators had concluded based on patient interviews and demographic mapping that the water system was the most likely vehicle of infection, despite their not being aware of the corroborating documents that John Earl had collected.
[34] The Bruce-Grey-Owen-Sound Health Unit (BGOSHU)'s May 22 presumptive conclusion about Walkerton's water was confirmed at 8:45 the following morning, when the London Regional Public Health Laboratory reported testing results on the water Schmidt had collected on May 21 and 22: both E. coli and fecal coliform results had come back positive on the May 21 samples, and though testing was not complete on the May 22 samples, evidence of coliform growth was already apparent.
[33][35] John Earl (the Ministry of the Environment (MOE) environmental officer) returned to the Walkerton Public Utilities Commission (PUC) that morning to continue his investigation.
[33] At 9:45 on the morning of May 23, David Patterson (the Assistant Director of Health Protection at BGOSHU) contacted Stan Koebel at the Walkerton PUC and informed him of the May 21 test results.
[33][35] The Walkerton hospital hosted a roundtable at 1 p.m. the same day to inform local physicians of proper treatment for E. coli O157:H7-associated gastroenteritis, especially with regard to infected children, who were at increased risk for renal failure due to Hemolytic-Uremic Syndrome.
[33] Despite this declaration, publicizing of the epidemic, and the Boil Water Advisory, local hospitals continued to treat gastroenteritis patients during the last week of May at numbers more than double typical ER throughput.
[39] Authorities from the Ontario Clean Water Agency took over operations at the Walkerton Public Utilities Commission on May 25 at the request of Mayor Thomson.
[45] An inquiry, known as the Walkerton Commission led by Court of Appeal for Ontario Associate Chief Justice Dennis O'Connor, wrote a two-part report in 2002.
[58] On May 11, 2018, the Toronto Star reported that following 18 years of suffering Robbie Schnurr had doctors assist him in ending his life due to illness caused by the outbreak.