Incident/Accident They Both
Need to Be Investigated at Work
An incident refers to any event or chain of events with the
potential to lead to injury to humans, or damage or loss of
There is a need to investigate an incident to find out what is
behind the incident.
Incident or accident
• Though the terms “incident” and “accident” are often
used interchangeably in referring to reporting
procedures, a distinction should be made between the
two words. An accident is an unplanned event that
results in injury, harm or damage. An incident is an
event that had the potential to cause injury, harm or
damage. Incidents include accidents, as well as near
misses and dangerous occurrences. In this program,
the term “incident” refers to all possible occurrences,
including accidents, near miss incidents, environmental
releases . All incidents, even when seemingly minor,
should set in motion the facility’s reporting and
Prevention is the purpose of an
An incident investigation should:
• determine what actually happened,
• determine the cause or causes of the incident,
• identify any unsafe conditions, acts or procedures,
• help management to identify practical corrective
• determines whether due diligence was observed,
• show the commitment of management that an
adequate investigation system is in place.
Near Miss / Hit
• The term near miss - which may better be called near hit - describes an
incident that did not result in an actual loss but that had the potential to
do so. For example if an object is dropped from a crane but no one is hurt
then the incident is a near miss. Near misses, particularly those that could
have had high consequences, should be investigated thoroughly because
they are strong indicator of system failures. They are a free lesson learned.
In terms of fault tree analysis a near miss is an event in which one or more
of the inputs to an end was negative.
• The following are examples of near misses: Process conditions go outside
safe operating limits, and are then returned to normal with no
• An emergency shut down system is unnecessarily activated;
• A safeguard such as a relief valve or fire suppression system is called upon
• A hazardous chemical is released but does not affect workers in the area.
How do you define a serious incident?
Workplace Safety and Health considers an incident to be serious if it results in:
• death, or serious injury (as defined below),
• collapse or structural failure of a building, tower, crane, hoist, temporary
construction support system or excavation,
• an uncontrolled spill or escape of a toxic, corrosive or explosive substance
• explosion, fire or flooding.
Serious injuries are defined as:
• fracture of a major bone
• loss of sight
• internal hemorrhage
• third degree burns
• unconsciousness resulting from concussion, electrical contact, asphyxiation
• cuts requiring hospitalization or time off work
• any injury resulting in paralysis
• any other injury likely to endanger life or cause permanent disability.
A potential incident creates the possibility of an event, but nothing
actually happens. The key difference between a near miss and a
potential incident is that, with a near miss, an event did take place
but the consequences were minor. With a potential incident
nothing happened at all. For example, if a worker drops a wrench
from an upper deck and it hits the floor three stories below but no
one is hurt then a near miss has taken place. If the same worker
holds the same wrench such that, were he to drop it, it would fall
to a lower deck, then he has created a potential incident.
Potential incidents can be classified as either unsafe acts or unsafe
conditions. The worker who holds the wrench such that it may fall
has committed an unsafe act. If he fails to secure the area
immediately below him with barricade tape then an unsafe
condition has been created.
It is very necessary
Incident investigation is necessary to
determine why an incident took place, if it
was an isolated event, and what can be done
to prevent similar incidents in the future, as
well as to determine the root cause(s) .
Incident investigation is crucial, as it provides
a feedback mechanism to assist in improving
existing incident mitigation systems.
• Incidents don’t just happened. They are
• Incidents can be prevented if causes are
• Causes can be eliminated if all incidents are
• Unless the causes are eliminated, the same
situation will reoccur.
The 5 fingers of an incident
• The Task: The actual work procedure being used at the time of the
• The Material/Equipment: Review the design of machinery, tools and
equipment and how they are used by the workers in terms of machine
guarding, emergency stop devices, lock-out, pinch points, design of
equipment for use by workers, body positions to work and demands such
as repetitive work.
• The Worker(s):Consider the factors that affect the worker(s) when
performing the task
• The Management: Management is legally responsible for the safety and
health of workers and therefore the role of management must always be
considered in an incident investigation.
• The Environment: The physical workplace environment as well as sudden
change to that environment are factors that need to be identified. Keep in
mind to assess the environmental factors at the time of the incident.
Do we really need to talk about this
Have you ever heard someone in your organization say:
"We have had exactly the same type of incident in
another part of our business…we are just not learning
from our mistakes"?
Analyzing Barrier Failure
• There are certain defense mechanisms managers set
up to prevent incidents from occurring. In the case of
the chemical plant, there are adequate safety
procedures in place to prevent chemical leaks, for
instance. The barrier analysis approach to incident
investigation goes into the reasons behind what went
wrong with the defense mechanisms in place.
• Interviews of personnel working in the
operations involved in the incident is another
way to investigate. These people have firsthand
knowledge of the operations and can provide
input based on their perspective. Interviewers
have to be careful in interpreting the data they
obtain though. It could be subjective, rather than
objective. Also, personnel should not feel there
will be any retaliation in case they provide any
input critical of management.
Bring out the Key Factors Analysis
The investigation looks into all the key factors associated with an
incident. The investigation determines whether people, processes,
systems and equipment were in any way responsible for the
incident. Once the investigation establishes, for instance, a key
safety system was not functioning right, the investigation
determines what went wrong.
• Root Cause Analysis: In the root cause analysis approach to
incident investigation, the investigator charts the incident and
charts the immediate factors just behind the incident that
contributed to it. For example, in the chemical plant, it could be
some particular safety procedure was omitted and this was the
immediate cause of the leak. There are also reasons behind why
the safety procedure was omitted. The investigator outlines the
other contributing factors in this way, until the chart arrives at the
root cause of the incident.
Yes I see tell me more
• Such analyses are, of necessity, theoretical and speculative; there can be no
assurance that all plausible events have actually been identified. Indeed, it is more
than likely that some important failure mechanisms will be overlooked.
• It is difficult to predict the true level of risk associated with each identified event
because estimated values of both consequence and likelihood are usually very
approximate. In particular, predictions as to what might happen are invariably
colored by the personal experiences of the persons carrying out the analysis. If a
person has witnessed a particular type of incident he or she is likely to assign it a
high value of happening again, and vice versa.
• Most serious events have multiple causes, some of which appear to be totally
implausible or even weird ahead of time (which is why serious accidents so often
seem to come out of the blue). Even the best qualified hazards analysis team will
have trouble identifying such multiple-contingency events, and then persuading
others of the plausibility of such events.
• It is very difficult to predict and quantify human error - yet most events involve
Some times you really have to listen
Pick a technique
There are four types of root cause analysis.
Argument by analogy (story-telling);
• Each of these approaches can be of value -
to purposely exclude any of them,
particularly for commercial reasons, is short-
An effective incident investigation and analysis program generally contains two
major components: technical and human. The technical side of the investigation is
what most publications in this area focus on, particularly with regard to root cause
analysis. However, what does not always receive the same degree of attention is
the human aspect of incident investigation work.
Most incidents involve front-line technicians (operators and maintenance workers),
some of whom may have been injured or emotionally shaken. Technicians often
may not understand what caused the incident, but they worry that they will be
blamed anyway. An effective investigator encourages these front-line technicians
to be open and candid - primarily by simply shutting up and letting then them talk.
• Mid-Level Managers
Most investigations find that changes are needed at the facility's mid-level
management systems. Examples of such changes include an increased emphasis
on equipment inspection, upgraded operating procedures and more training for
the technicians. Mid-level managers, and will understand the demands that are
being placed on the organization by the investigation and its follow-up.
• Senior Managers
Many investigators find that technicians are candid and open, and mid-level
managers are generally willing to honestly address the need for improvements to
the facility's systems. What these investigators sometimes find, however, is that
senior managers can be more resistant to the findings and implications of an
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