By Jody MacPherson
Originally appeared in C3 Views (Climate Change Central Newsletter) in September, 2003

It had been “raining cats and dogs” for two days straight, so when April 22, 2000 dawned sunny and clear in Bruce County, Ontario, Dr. David Biesenthal welcomed the break in the weather. He decided to move 70 tons of manure stored on a concrete pad in the paddock area of his farm to be spread on the east front field.

Biesenthal, a veterinarian, and his wife, Carolyn, had a breeding herd of about 40 Limousin cows and heifers. In the spring, the couple brought cattle from other operations to be sold in the fall. There were up to 95 animals during peak times and this naturally meant there was manure to consider.

Never in his worst nightmare could Biesenthal have imagined his actions on that day would set the wheels in motion for “the most serious case of water contamination in Canadian history.”[1] The Biesenthal farm, located just outside Walkerton, a community of 5,000 people in southern Ontario, has been identified as the source of the deadly Escherichia coli (E. coli) 0157:H7 and Campylobacter jejuni bacteria that entered the municipal water system, killing seven people and sickening more than 2,000.

Heavy rainfall (134 mm) between May 8-12 that year, combined with a shallow, highly fractured rock zone around a nearby municipal well, allowed the bacteria in the manure to seep directly into the water source.

In a 700-page report following an Inquiry into the tragedy by the government of Ontario, Justice Dennis O’Connor exonerated Biesenthal from any blame. According to Part One of the Report, “the contamination entered the system through Well 5 from May 12 (or shortly afterward) until that well was shut off at about 1:15 p.m. on May 15. If the required chlorine residual of 0.5 mg/L had been maintained at Well 5 in May 2000, when the contaminants entered the system, substantially more than 99 percent of bacteria, such as E.coli and Campylobacter would have been killed. For practical purposes, this would have prevented the outbreak.”

Those responsible for monitoring the chlorine levels, Stanley Koebel, manager of the Walkerton Public Utilities Commission and his brother, Frank, were charged with multiple criminal offences carrying maximum sentences of between two and 10 years.[2]

By all accounts, the Biesenthal’s farming practices were above reproach. On that fateful spring day, Biesenthal’s equipment spread the manure further from the well than regulations required. In the days following the tragedy, the Ontario Cattlemen’s Association confirmed Biesenthal was among the first in Ontario to complete an Environmental Farm Plan, evidence of agricultural best practices.

Local activists pointed out the county, with a population of only 60,000 people, but home to 163,000 beef cattle and 100,000 hogs, had always been a high risk for E. coli contamination. They laid the blame on the shoulders of all levels of government.[3]

Still, this didn’t prevent angry victims from launching a $350 million lawsuit (later dropped) and didn’t stop the media from making accusations.[4] When O’Connor put the matter to rest in his final report by stating, “the owner of this farm followed proper practices and should not be faulted,” the Biesenthal’s gave a sigh of relief and tried to move on.

According to one estimate, the total cost of the tragedy was $155 million.[5] Biesenthal says he lost $20,000 in income from his clinic and farm and about “10 years off my life.” But Biesenthal says a surprise visit from the father of one of the victims is what he’ll remember most.[6]

“His eyes welled up…he was the father of the first girl who passed away…and he just came to say we, you know, don’t hold you people in any way responsible for what happened to our child,” Biesenthal told a CBC reporter. “I’ll always think of that poor man.”[7]

Sources: Part One Report of the Walkerton Commission of Inquiry, Ministry of the Attorney General, Government of Ontario (

FSNet, Food Safety Network, University of Guelph


Ontario Cattlemen’s Association, Communications


Concerned Walkerton Citizens (


[1] Walkerton Report Highlights, CBC News Online, January, 2002

[2] “Walkerton criminal charges met with anger,” by John Miner, Sun Media, April 24, 2003

[3] “Contamination: The poisonous legacy of Ontario’s environmental cutbacks,” by Ulli Diemer, Canadian Dimension, July-August 2000

[4] “Walkerton Experience Sends Message to Farmers,” Yorkton This Week & Enterprise, June 11, 2003, P. A1

[5] “Walkerton residents finally get their answers,” by Andrea Baillie, Canadian Press

[6] Transcript of interview with CBC News and Current Affairs, November 22, 2001

[7] Ibid

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