A Case Study:

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A Case Study

• THE WALKERTON TRAGEDY

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You SnoozeYou Lose!!
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Walkerton Public Water System

• Operated by the Walkerton, Ontario, CA PUC
• Stan Koebel-general manager, brother Frank was
  the foreman
• 3 groundwater sources with chlorine treatment

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Events..May 8-15, 2000

• Heavy rains, totaling more than 5 inches
• Heaviest almost 3 inches
• Well 5 was the primary source of water
• May 13,14,15 - Frank Koebel performed daily
  rounds
• Standard practice of not checking chlorine
• Fictitious log entries

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Events.. May 15

• Stan Koebel returns after one week away
• turns Well 7 on without chlorination
• a new chlorinator had been installed
• 3 bact samples taken by PUC employee
• labels did not show sample location
• from PUC workshop?

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Events..May 15 - 17

• May 15 - 4 samples taken
• one from the distribution system
• 3 from a water main construction site
• May 16- all samples are received by the lab
• May 17- lab advises Stan Koebel
• 3 samples from the construction site are positive
  for total and fecal coliforms (E. coli)
• other sample suspect
• 6 days to notify health authorities

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Events..May 18 - 19

• First indications of widespread illness
• members of the public contact the PUC
• Stan Koebel assures them the water is safe to
  drink
• More illness, bloody diarrhea, vomiting
• Doctor contacts Health Unit suspecting E. coli.
• Health authorities begin an investigation

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Events..May 19

• Stan informs the Health Unit that he thinks the
  water is OK
• does not mention positive samples or that Well 7
  had been operating without chlorination
• If health authorities were aware of test results
  and Well 7.with no chlorination..
• Boil Water Notice!!!!

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Events..May 19 20

• Stan begins flushing and super chlorinating
• the residual is elevated in the system and at the
  wellheads a few days later
• Stool sample from a child tests E.coli positive
• outbreak is expanding rapidly
• Stan informs health authorities of the system
  residuals
• false impression created

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Events..May 21

• E.coli is confirmed
• Health authorities issue boil order over AM/FM
  radio
• Doctor contacts Mayor requesting further public
  notification-no further steps taken

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Events..May 21 22

• Walkerton experiences its first death
• Health authorities take 20 water samples
• Hospital receives 270 calls for serious abdominal
  pain diarrhea
• Child is airlifted to London, Ontario for
  emergency treatment.
• Stan provides for the first time the May 17 test
  results
• Directs Frank to change the Well 7 log to imply
  that it had operated with a chlorinator, and
  provides altered logs to health authorities

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The Fallout..

• 7 people die
• 2,300 people became ill
• Many suffer permanent organ damage
• It was all preventable!

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A Community Devastated Loss of Confidence in
Services

• Suffering friends and family of lost ones
• Uncertainty about the future will it happen
  again?

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What Went Wrong?? What Could Have Been Done To
Address This?
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What Went Wrong?? What Could Have Been Done To
Address This?

• Chlorine residual turbidity monitoring daily at
  Well 5.
• Operator training
• Inadequate chlorine dosages
• Inadequate monitoring
• False chlorine residual log entries
• Poorly documented bacti sampling locations
• Intentional violation of regulations
• PUC Board members not well informed and may have
  delegated their responsibilities

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What Went Wrong?? What Could Have Been Done To
Prevent This??

• Health authorities needed to be more aggressive
• Lab should notify health authorities of lab
  results directly
• Boil Water Notice should have been more broadly
  disseminated
• Stan misrepresented and concealed information
• Test results
• Chlorinator not operating

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Anatomy of the Physical Causes

• The Well
• Shallow
• Casing extended 15 feet
• Water table 8 40 feet
• Nearby surface water influence
• Fractured rock
• Pathogenic bacteria quickly moved from the land
  surface to the ground water supply

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Anatomy of the Physical Causes

• The Farm
• Manure spreading, farm owner not faulted
• The owner of the farm was using best management
  and widely accepted practices

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Lessons Learned

• Who is ultimately responsible for the health of
  your customers?
• What are the weak links in your operations?
• Does anyone in your utility approach their job
  like the Koebels?
• In the event of an emergency do you have a plan
  (ERP) in place? Do you know what to do?
• Could this happen in your community?

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Stan The Man
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Walkerton Not An Isolated Case

• Milwaukee, Wisconsin
• Cabool, Missouri
• New York State Fairgrounds
• Centers For Disease Control Reporting Waterborne
  Disease Incidents and Investigations