EHJ June 2004, pages 186-188
In May 2000, a contaminated water supply brought death to the beautiful Canadian town of Walkerton. David Clapham reports on the world's worst E.coli outbreak equating it to a Shakespearian tragedy

In May 2000, a contaminated water supply brought death to the beautiful Canadian town of Walkerton. David Clapham reports on the world's worst E.coli outbreak equating it to a Shakespearian tragedy With seven people dead, 27 with permanently damaged kidneys and over 2,300 people ill, the Walkerton E.coli O157 and campylobacter outbreak was a tragedy waiting to happen. The outbreak inquiry by the Honourable Dennis R O'Connor reads like a Shakespearian play with villains, a few fools, convoluted plots, political passions running out of control, some intrigue and an inevitable outcome that was signalled from the beginning.

THE PROLOGUE

"Accursed fatal hand that hath contriv'd this woeful tragedy" Henry IV part one

In 1978, on the outskirts of Walkerton, in this beautiful riverside town in southern Ontario, a new borehole is being drilled. It will become the infamous Well 5. It is a shallow borehole extending 5.5 metres into highly fractured soft brown limestone with a soil cover so shallow that a fence post knocked into it will compromise the safety of the aquifer beneath.

When the pump to the well is switched on, several surrounding springs dry up because of geological channels running from the surface to the well. These channels will carry contaminants and faecal matter into the water supply. Tests with tracers show that this takes less than an hour.

When the water is examined, both total and faecal coliforms are present - proof that the well is contaminated. The quality of the water fluctuates wildly and the turbidity levels, usually a sign of recent pollution, should have given serious cause for concern. Properly constructed boreholes often produce water of sufficient bacteriological quality that no treatment, other than disinfection, is considered necessary. Well 5 was seriously contaminated (with up to 230 faecal coliforms per 100 ml) but because it was a "borehole" no treatment, other than chlorination was applied.

The safety of water relies on a multiple-barrier approach. Well 5 should have had four barriers - being drilled deep enough to ensure a reasonably safe supply, protection from contamination, adequate treatment and chlorination. As the engineers walked away, chlorination was the only barrier left.

In 1994, legislation was changed to require continuous chlorine residual and turbidity monitoring to boreholes under the influence of surface water. But no one checked Well 5 and the monitors were never installed. If they had been, their alarms would have shut the pump down and prevented the outbreak.

ACT ONE

"And with his mad attendant and himself, each one with ireful passion, with drawn swords,
met us again and, madly bent on us, chas'd us away." Comedy of Errors

In June 1995 at Queen's Park Government Building, Ontario, Mike Harris, the new premier of Ontario, is a man with a mission. Inspired by the political ideology of the UK's Thatcher government, he begins a campaign to reduce the bureaucracy of government, to remove all unnecessary legislation that puts pressure on business and prevents the economic growth of his territory. This is a radical transformation where premier Harris has to make unpopular decisions to free the citizens from unnecessary red tape. Talking of a "common sense revolution", he and his colleagues continue to strip an already reduced Ministry of the Environment (MoE) of people, power and money. Its budget is cut by 42 per cent, and the ministry loses 37 per cent of its frontline staff, including those checking the town's water quality. Self-regulation is introduced and monitoring becomes little more than receiving reports and making recommendations.

Four years before the outbreak, the MoE stops water testing altogether handing responsibility to the municipalities and public utility commissions. They are given eight weeks to find a new private laboratory as the MoE's own laboratories are closed to save money. This change to privatised laboratories has unforeseen, but bitter results.

ACT TWO

"These eyes that see thee now well coloured, shall see thee withered, bloody, pale, and dead.
Hark! hark! The Dauphin's drum, a warning bell." Henry IV Part One

Scene one: Ontario, 1996. In the spring, a waterborne cryptosporidium outbreak within an hour's drive from Walkerton makes hundreds ill. A Japanese E.coli O157 outbreak kills 13 children who ate bean sprouts grown in water contaminated by cattle manure. The provincial auditor criticises the MoE for deficient monitoring of groundwater resources.

Scene two: the outbreak inquiry hears that by 1998 MoE staff "walked around like zombies" with morale at rock bottom due to the government's apparent lack of concern about the environment. Also that year, the MoE makes its final inspection of the Walkerton water supply system, concluding there is a high risk of contamination. But the ministry fails to check the report's recommendations are carried out.

In 1996 the Ontario environmental commissioner warns that the government is compromising environmental protection, especially drinking water quality. In 1997, MoE officials tell the government that closing the water-testing programme will endanger public health. The Premier dismisses the warnings as the "self-interested exaggeration of empire-building officials". The government's decision to switch to private laboratories raises concerns that medical officers of health no longer have to be notified when water sampling failures occur - an automatic process in government laboratories.

Early in 1997, government officials meet to decide upon a plan to protect themselves from civil liability, "if and when an environmental catastrophe occurs". The 1997 Environmental Approvals Improvement Act prohibites legal action against the government by anyone adversely affected by the environment minister's failure to apply environmental regulations. The lack of environmental regulation also encourages the growth of huge cattle farms with little control over the disposal of their manure. In 1999, Health Canada publishes a report that says the area where Walkerton is located is a high-risk area for E.coli because of this.

As their worries increase, MoE officials send a memo to the government in January 2000. This states that "not monitoring drinking-water quality is a serious concern for the MoE in view of its mandate to protect public health". It also notes that a number of smaller municipalities are not up to the job of monitoring the quality of their drinking water.

ACT THREE

"Here comes a pair of very strange beasts which in all tongues are call'd fools." As You Like It

It is January 2000 in Walkerton. Enter upon the stage Stan and Frank Koebel, employees of the Walkerton Public Utilities Commission (WPUC), the other major players in this piece. The WPUC is responsible for drinking water provision in Walkerton. Stan has been the general manager of the WPUC since 1988. His brother Frank has started in 1975 and has risen to be foreman, despite a serious drinking problem. Under Stan's leadership, the WPUC is a "cavalier and undisciplined place" that has engaged in a host of improper operating practices.

In his report, Mr O'Connor states that these include "mislabelling sample bottles for microbiological testing, failing to adequately chlorinate the water, failing to measure chlorine residuals daily, making false entries on daily operating sheet, submitting false annual reports to the MoE and operating wells without chlorination".

Mr O'Connor is clear that Stan Koebel did not set out to put his fellow residents at risk. These malpractices had in some cases been going on for years and Stan did not believe that the water needed any chlorination, often drinking it himself. With Frank, Stan has said that he was not clear what "turbidity" or "organic nitrogen" meant or the difference between total chlorine and free chlorine. Even more importantly he did not know what E.coli was, what its implications for human health were or that its presence indicated faecal contamination. It could legitimately be asked however, how anybody in his position could manage to be so uninformed on these basics of water safety.

What were the malpractices referred to in the report? Remember multiple-barrier number four - chlorination. The brothers only mixed in half the amount of sodium hypochlorite necessary when disinfecting Well 5. Instead of checking the free chlorine levels daily, they merely filled the sheet in with an appropriate figure.

The level should be at least 0.5 mg/l of free chlorine after 15 minutes of being mixed with the raw water. Both the amount and time are important. The 15 minutes allows the chlorine to do its work and the amount of free chlorine ensures there is enough left to carry on disinfecting throughout the system. Prior to the events of this tragedy, 0.75 mg/l had been entered on the form for nine days straight. Not only was this made up, but it was also highly unlikely, as the water quality would have fluctuated wildly during that time.

Other malpractice included not taking a sufficient number of samples and not bothering to sample the water at various properties around the distribution network. It was a lot easier to take a sample from the hut next door to the office. Well 5 samples labelled "raw" and "treated" were routinely collected from there. They were then mislabelled to cover this up.

INTERLUDE

"It is not madness that I have utt'red. Bring me to the test, and I the matter will reword."
Hamlet, Prince of Denmark

April and early May 2000,Walkerton. Drinking-water samples are taken and results come back. They are bad and getting worse, they contain coliforms both total and faecal. Well 7, a larger, safer source of water was not operating because its chlorinator needed replacing. On May 5, Stan decides to go to a water conference.

Frank is left in charge with an order to replace the chlorinator - a new one arrived months before. Well 5 is now the main provider of drinking water to the unsuspecting people of Walkerton.

ACT FOUR

"Such groans of roaring wind and rain, I never remember to have heard. Man's nature cannot
carry th' affliction nor the fear" King Lear

It is 13 May, Walkerton. During the last four days, 134mm of rain has fallen on Walkerton. Most of it on the evening of the 12 May. This amount of rainwater would be expected only once every 60 years. Waterborne outbreaks of disease are habitually associated with periods of heavy rain. It is not known whether Well 5 became flooded, it may have been. What is known is that on 22 April, 22 days earlier, 70 tonnes of cow manure were spread on land adjacent to Well 5 and incorporated into the soil at a depth of about 7cm. The nearest point that the manure was applied was 81 metres from the well. E.coli O157:H7 survives for up to six months in soil and is common in cattle. The cattle on the farm and the people who became ill had the same strains of E.coli O157:H7 and campylobacter jejuni.

On 13 and 14 May, as the deadly bacteria were entering and moving around the water system of Walkerton, Frank Koebel was entering fictitious data about chlorine residuals on his form. If he had checked them properly he would have been able to reduce the scope of this tragedy quite considerably. If he had replaced the chlorinator for Well 7 when he was supposed to, he may have averted it completely.

At 6am on 15 May, Stan Koebel returns from his conference. He finds that his brother has not replaced the chlorinator at Well 7, but he switches its pump on anyway. Unchlorinated, untreated water begins to be pumped into the system. An untrained operative is sent out to sample the water system - he goes to the hut next door.

ACT FIVE

Uncertain life and sure death. Alls Well That Ends Well

It is now 18 May, Walkerton. People start to become very ill. Stan Koebel knows about poor results from recent water tests, but probably suspects this is due to the unchlorinated supply from Well 7. He doesn't know the real culprit is the contamination of Well 5.

The local medical unit fears a food poisoning outbreak. E.coli is known as the "hamburger disease". Ill people begin to telephone Stan and ask about the water supply. He assures them it is fine but begins to get a bit worried and tells his brother to get on with replacing the chlorinator to Well 7.

On Friday, 19 May, more people are ill. This time someone from the local health unit rings to ask Stan about the drinking water. He reassures the caller. If the laboratory had not been a private one, the medical officer of health would have known that E.coli was in the water. This would have stopped 400 to 500 people getting ill.

But the laboratory manager, where the adverse results of 15 May were analysed, considered them to be confidential to his client, the WPUC, and could not be shared with the medical or MoE authorities.

On Saturday, 20 May the disease was spreading and people were being taken to hospital. The first test results for patients were coming back as presumptive E.coli O157:H7. The health unit then heard that the local radio station was warning people not to drink the water. At 3pm the unit asked Stan to ring the radio station to reassure them that the water was safe. The inquiry heard he was reluctant to do so.

More people became ill throughout the weekend. On the Sunday residents were advised to boil water as a precautionary measure. But the advice had come too late. Another two barriers; boil water advice and medical authorities knowing about failures in the water supply, had fallen.

Frank and Stan Koebel had been chlorinating and flushing the tanks during the outbreak and were hoping the problem would start to go away. On 22 May, the records for Well 7 were altered to disguise the fact it had not had a working chlorinator. By 24 May, four people, including a two-year-old child, had died. Another three were to follow them. The multiple-barrier approach that should have protected them had been totally dismantled by the players in this drama. In the view of the report, the people of Walkerton were entitled to expect more.

EPILOGUE

"Then all too late I bring this fatal writ, the complot of this timeless tragedy; and wonder greatly that man's face can fold in pleasing smiles such murderous tyranny." Titus Andronicus