Hundreds of people in this southern Ontario town have gotten sick in Canada's worst ever outbreak of the potentially deadly bacteria, CBS News Correspondent Cynthia Bowers reports.
So far, the dead include a baby and three elderly adults who died Wednesday and another elderly person who died Thursday, according to Dr. Murray McQuigge, health officer of the Grey-Bruce region west of Toronto.
People in Walkerton attended the second funeral in two days, gathering at Sacred Heart church to remember Edith Pearson, 83, a mother of five with 13 grandchildren who had been preparing to celebrate her 60th wedding anniversary.
Health officials say more people in Walkerton, still could fall ill with cramps, diarrhea, vomiting and fever symptomatic of the intestinal bacteria often spread through animal or human feces.
However, the number of people seeking treatment at the local health center has decreased, and a doctor at a hospital in London, Ontario, where the most critically ill children were taken, said he thought all 12 would recover.
Still, signs on government buildings warn the 5,000 residents of this town, set in farm country 90 miles west of Toronto, to boil their water. Cases of bottled water are being distributed for free at the community center. The contamination caused officials to close all five schools in the community, including the day care center.
And at least one class-action lawsuit has been filed on behalf of town residents, and three investigations were under way.
Ontario Provincial police were interviewing water utility workers and gathering documents, while environment and health officials worked to learn what caused the contamination.
"How did it happen? Why did it happen? Where was everybody? Why werent we notified?" asked Edith Grass, a resident.
"We wasted time looking for a food source of contamination when in fact they could have told us right away this was in the water," said McQuigge.
But Jim Kieffer, chairman of the utility commission, said utility workers may have been unaware of how dangerous E. coli could be. The utility's general manager, Stan Koebelm, could not be reached for comment.
Additionally, Thomson said the chlorinating unit on one of the two main wells pumping water had only been working sporadically. He said a new unit that officials had ordered weeks earlier finally arrived last week and was installed over the weekend.
Officials suspect recent flooding caused by heavy rain may have contaminated the town's water supply by washing animal waste into the system.
But on Friday, an official of a private laboratory that tests water said it detected traces of another bacteria in the Walkerton water as far back as January. Garry Palmateer of GAP EnviroMicrobial Services told the Canadian Broadcasting Corp. there were indications that surface water was entering the town wells.
"It was obvious that there was a contamination problem," as a result of malfunctioning wells, Palmateer said.
Freelton, a community about 60 miles from the small southern Ontario town of Walkerton, came under a boil order for its water Saturday after traces of E. coli turned up. No illness had been reported and officials described the move as precautionary, saying they have yet to determine the strain of E. coli detected.
CBS Worldwide Inc. All Rights Reserved. This material may not be published, broadcast, rewritten, or redistributed. The Associated Press contributed to this report