19, Koebel was aware that the May 15 testing of water in the Walkerton system had returned results that indicated contamination, and his action to flush the system with heavily chlorinated water from Well 7 on May 19 was taken in the hopes of eradicating the contamination before further tests could be conducted. Significantly, Koebel did not disclose to the health inspectors to whom he spoke on May 19 or May 20 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. At the same time, however, Koebel continued to consume PUC-served water and allow his family to do the same with no apparent concern about its safety; O'Connor concluded that while Koebel knew the system was contaminated, he did not understand that the E. coli bacteria causing the contamination were potentially deadly. 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. McKay also reported to the SAC that Walkerton water had failed "lab tests", but he was unable to provide detail about what aspect of the water quality had caused the failure. Later in the day on May 20, McKay attempted to contact the Ministry of Health directly about his suspicions, but was unable to get in contact with anyone empowered to handle issues in Walkerton; hoping to speed up government response time, he phoned the SAC again to report his knowledge that the Walkerton PUC was using an "unlicensed operator". SAC employees, in response to this information, contacted the Walkerton PUC the same day for information on possible adverse water testing results. Stan Koebel acknowledged to the Ministry of the Environment (MOE) that "we've had the odd [adverse sample]" due to previous construction work but that the system flushing was occurring only as