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Accident InvestigationAccident Investigation
Learning from mistakesLearning from mistakes
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Accidents
It may be that up to
95% of accidents arecaused by people
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Incident Investigation
90% of all accidents andincidents are attributable
to a companys
management. Demming.
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Definitions
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Definitions
Accident: An undesired event that
results in harm to people, damage
to property or the environment or
loss to process
Incident: An undesired event
which under differentcircumstances could have
become an accident.
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What causes an accident
or incident?
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What causes an accident
or incident?
Someone commits anunsafe act
Something is in an unsafe
condition
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What causes an accident
or incident?
Someone commits anunsafe act
Something is in an unsafe
condition
An Immediate Cause
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What causes an accident
or incident?
An Immediate Cause
Conditions exist which
allow the Immediate Cause
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What causes an accident
or incident?
An Immediate Cause
Conditions exist which
allow the Immediate Cause
A Basic Cause
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What causes an accident
or incident?
An Immediate Cause or
Causes
A Basic Cause or Causes
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What causes an accident
or incident?
An Immediate Cause or
Causes
A Basic Cause or Causes
Underlying Management
Failures
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The Accident Sequence
Basic Cause
Immediate Cause
Basic Cause
Basic Cause
Immediate Cause
Immediate Cause
An Accident Happens
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Immediate Cause
The circumstances which immediatelyprecede the accident
Can usually be seen or sensedOften described as Unsafe Acts or Unsafe
Conditions
They are substandard practices or
conditions
Addressing these may not preventrecurrence
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Basic Cause
The factors which allowed the ImmediateCause to exist
Not always obvious, require probingSometimes called Root, Real, Underlying
or Contributing Cause
Explain why we have substandard
performance or conditions
Must be addressed to prevent recurrence
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Immediate Causes 1
Inadequate Guards or barriers
Failure in Communication
Failure to follow rules or procedures
Inadequate warning or safety deviceFailure to observe
Failure to use warning device
Improper manual handling
Inadequate personal protective equipment
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Immediate Causes 2
Influence of alcohol or drugs
Inadequate tools or equipment
Misuse of tools or equipment
Work environmentPoor housekeeping
Inadequate access or egress
Lack of training
Lack of attention
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Basic Causes 1
External factors
Personal factors
Inadequate knowledge or skill
Inadequate physical abilityExcessive stress
Improper motivation
Inadequate supervision
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Basic Causes 2
Inadequate policy or plan
Inadequate planning or organisation
Inadequate standards or procedures
Inadequate engineering or designInadequate maintenance
Inadequate inspection
Inadequate training
Many of these are Management System Failures
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Investigation
Count Morozzo and the bakery.
Milan 1785.
First account of a flour explosion.
It is therefore of great importance thatthese facts should be universally known,
that public utility may reap from them
every advantage
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Investigation
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Investigation
3 Main Questions:
What happened?Why did it happen?
How do we stop it
happening again?
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Investigation
Keep asking the question Why?
Note all the answers.
Put the answers into a logical
sequence.
Test the theory against theevidence.
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Why did the sub drop?
The chain came unhooked.
Why was that? The hook has a safety catch.
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The catch failed.
Why?
The hook was upside down.
Why was that?
Because the hook was looped through the
lifting eye and hooked back round itself.
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Why did he do it l ike that?
The hook was not big enough to go over the lifting eye on the
sub.
Why?
The chain hoist was designed for a smaller lifting eye.
Why did he use it then?
It was left there from a previous job with a smaller sub. Itwould have meant getting a larger hoist from the rigging loft
and he was only going to be a few minutes inspecting the
sub
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Steps in Investigation
Respond to the incident promptly
Gather all the pertinent information
Analyse the incident and determineimmediate and basic causes
Review the findings to ensure they fit theevidence
Prepare a report
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Steps in Investigation
Review the report with those involved
Assist in developing corrective actions
Ensure an action plan is drawn upMonitor the action plan to ensure
completion
As appropriate, share the experience and
lessons learned
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Investigation tools
Various proprietary packages are available:
TopSet
TapRoot
Tripod (Bow tie method)
Investigator
These guide you through a process, and ensureyou dont miss items. However you can do justas good a job with basic tools, by making sureyou are methodical and consistent.
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Bow tie diagram
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Communication after the
Investigation
Communicate to as wide an audience aspossible
Dont just think of your own operation, aslight variation in circumstances maymake the same incident possibleelsewhere
Learn from the incident
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B C Water jet accident