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Events and Causal Factors Chart Project

Read the U.S. Chemical Safety Board (CSB) investigation report of the 2007 propane explosion at the Little General Store in Ghent, WV. The final report can be read/downloaded at the following link: https://www.csb.gov/assets/1/20/csbfinalreportlittlegeneral ?13741

Additional information on the incident, including a video summary, can be found at the following link:

http://www.csb.gov/little-general-store-propane-explosion/

Complete the assignment as detailed below.

Part I: From the information in the report, create a chart listing events and causal factors for the incident in Microsoft Word, Open Office, or a similar word processing software. If you choose to use a program other than Microsoft Word, be sure to save and submit the document as a Microsoft Word document (i.e., , x). The objective of this project is to provide you with an opportunity to use this important and very practical analytical tool. The chart does not have to be infinitely detailed, but the key sequence of events should be charted as should the key conditions surrounding the events. Keep in mind that the purpose of an events and causal factors chart is to aid in identifying which conditions could be causal factors.

Use the charting procedures on pages 72–76 of your textbook to help you with this assignment. In addition, refer to the example events and causal factors (ECF) chart in the Unit IV Lesson for an example of this type of chart.

Part II: On a separate page, discuss the potential causal factors that are revealed in the analysis. How do these causal factors compare to the causal factors found in the CSB’s investigation report? Do you think more analysis is needed? This part of the assignment should be a minimum of one page in length.

Upload Parts I and II as a single document. For Part II of the assignment, you should use academic sources to support your thoughts. Any outside sources used, including the sources mentioned in the assignment, must be cited using APA format and must be included on a references page.

Useful hints: In Microsoft Word, you can use parentheses for events (events), square brackets for conditions [conditions], and brackets for the accident {accident}; you may also use a similar convention, such as color-coded text or the shapes that are available within Microsoft Word. Whatever convention you use, be sure you provide some kind of key.

Events and Causal Factor

Analysis

Technical Research and Analysis Center
SCIENTECH, Inc.

1690 International Way
Idaho Falls, Idaho 83402

August 1995

SCIE-DOE-01-TRAC-14-95

Events and Causal Factors
Analysis

Prepared by:
J.R. Buys, INEL
J.L. Clark, INEL

Revised by:
J. Kingston-Howlett, Aston University, Great Britian

H.K. Nelson, SCIENTECH, Inc.

Technical Research and Analysis Center
SCIENTECH, Inc.
1690 International Way
Idaho Falls, Idaho 83402
August 1995

SCIE-DOE-01-TRAC-14-95

August 1995 Events and Causal Factors Analysis i

Events and Causal Factors Analysis
Executive Summary

Events and Causal Factors Analysis (ECFA) is an important component in the accident
investigation repertoire of methods. It is designed as a stand alone technique but is most
powerful when applied with other techniques found in the Management Oversight and Risk
Tree (MORT) programme. ECFA serves three main purposes in investigations: (1) assists the
verification of causal chains and event sequences; (2) provides a structure for integrating
investigation findings; (3) assists communication both during and on completion of the
investigation. This document discusses the benefits of EFCA and provides a primer in the
application of the technique.

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August 1995 Events and Causal Factors Analysis iii

CONTENTS

Executive Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . i

1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2 Nature of Accident Investigation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

3 Description of Technique . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

4 Benefits of the Technique . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

5 Bibliography . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

Appendix: Events & Causal Factors Chart Example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

FIGURES

1. General Format for ECF Charts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

2. Events & Causal Factors Chart Example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

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August 1995 Events and Causal Factors Analysis 1

1 Introduction

Accidents are investigated to identify the causes of their occurrence and to determine the
actions that must be taken to prevent recurrence. It is essential that the accident investigators
probe deeply into both the events and the conditions that create accident situations, and also
the managerial control systems that let them develop so that the root accident causes can be
identified. Identification of these root causes necessitates understanding the interaction of
events and causal factors through a chronological chain of activity starting with an initiating
event through to the final loss producing occurrence. Vital factors in accident causation
emerge as sequentially or simultaneously occurring events that interact with existing
conditions. This pattern of events and conditions are traced out to reconstruct the
multifactorial path to unacceptable loss or loss-potential. A meticulous trace of unwant

energy transfers and their relationships to each other and to the people, plant, procedures, a

controls implicated in accident occurrence, further defines the sequence of accident
development.

The Events and Causal Factors (ECF) chart depicts the necessary and sufficient events and
causal factors for accident occurrence in a logical sequence. It can be used not only to analyse
the accident and evaluate the evidence during investigation, but also can help validate the
accuracy of pre-accident systems analyses.

Events & Causal Factors Analysis (ECFA) is an integral and important part of the
MORT-based accident investigation process. It is often used in conjunction with other key
MORT tools, such as MORT tree analysis, change analysis, and energy trace and barrier
analysis, to achieve optimum results in accident investigation. The fundamentals of this
valuable MORT tool are discussed in this paper.

2 Nature of Accident Investigation

Experience has shown that accidents are rarely simple and almost never result from a single
cause. Rather, they are usually multifactorial and develop from clearly defined sequences of
events which involve performance errors, changes, oversights, and omissions. Accident
investigators need to identify and document not only the events themselves, but also the
relevant conditions affecting each event in the accident sequence. To accomplish this, a
simple straight forward approach can be utilised that breaks down the entire sequence into a
logical flow of events from the beginning of accident development . It is important to realise
that the end point may be defined either as the loss event itself or as the end of the
amelioration and rehabilitation phase. This flow of events need not lie in a single event chain
but may involve confluent and branching chains. In fact, the analyst/investigator often has the
choice of expressing the accident sequence as a group of confluent event chains which merge
at a common key event, or as a primary chain of sequential events into which causative factors
feed as conditions that contribute to event occurrence, or as a combination of the two.

Events Conditions

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2 Events and Causal Factors Analysis August 1995

Construction of the ECF chart should begin as soon as the accident investigator begins to
gather factual evidence pertinent to the accident sequence and subsequent amelioration. The
events and causal factors will usually not be discovered in the sequential order in which they
occurred, so the initial ECF chart will be only a skeleton of the final product and will need to
be supplemented and upgraded as additional facts are gathered. Although the initial ECF
chart will be very incomplete and contain many information deficiencies, it should be started
very early in the accident investigation because of its innate value in helping to:

C organise the accident data;
C guide the investigation;
C validate and confirm the true accident sequence;
C identify and validate factual findings, probable causes, and contributing factors;
C simplify organisation of the investigation report;
C illustrate the accident sequence in the investigation report.

With all its virtues as an independent analytical technique, ECFA is most effective when used
with the other MORT tools (such as Fault Tree Analysis, MORT Chart Analysis, Change
Analysis) that provide supportive correlation. Furthermore, ECFA can perform as the
framework into which the results from other forms of analysis are integrated. An appropriate
combination of the major MORT analytic tools, including ECFA, provides the core for a good
investigation.

3 Description of Technique

A simple example of an ECF Chart is provided in Appendix 1.

Sections 3.1 and 3.2 provide a set of conventions and criteria to be used in ECFA. These
conventions are intended to improve comparability and consistency in accident reporting and
to assist the communication of investigation findings. In section 3.3, more general guidelines
are given for the administration of the ECFA method.

These conventions are intended to be as simple as possible whilst preserving the effectiveness
of ECFA. It is further intended that investigators be provided with helpful guidelines without
inhibiting their use of this tool by imposing an overly complex set of rules.

3.1 Conventions for Events and Causal Factors Charts

3.1.1 Events should be enclosed in rectangles, and conditions in ovals.

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It may be found helpful to draw up an evidence matrix to correlate the analysis with the1

evidence collected.

August 1995 Events and Causal Factors Analysis 3

3.1.2 Events should be connected by solid arrows.

3.1.3 Conditions should be connected to each other and to events by dashed arrows.

3.1.4 Each event and condition should either be based upon valid factual evidence or1

be clearly indicated as presumptive by dashed line rectangles and ovals.

3.1.5 The primary sequence of events should be depicted in a straight horizontal line
(or lines in confluent or branching primary chains) with events joined by bold printed
connecting arrows.

3.1.6 Secondary event sequences, contributing factors, and systemic factors should be
depicted on horizontal lines at different levels above or below the primary sequence
(see Figure 1 and Appendix 1).

S ys temic factors

Contributing factors

S econdary events

Primary events

S econdary events
Contributing factors
S ys temic factors

1 2 3

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4 Events and Causal Factors Analysis August 1995

Figure 1. General Format for ECF Charts

3.1.7 Events should be arranged chronologically from left to right.

3.1.8 Events should track in logical progression from the beginning to the end of the
initiation-pre-accident-accident-amelioration sequence and should include all pertinent
occurrences. This necessitates that the beginning and the end be defined for each
accident sequence. Analysts frequently use the accident as the key event and proceed
from it in both directions to reconstruct the pre-accident and post-accident ECF
sequences.

3.2 Suggested Criteria for Event Descriptions and Conditions

3.2.1 Each event should describe an occurrence or happening and not a condition,
state, circumstance, issue, conclusion, or result; i.e., “pipe wall ruptured”, not “the
pipe wall had a crack in it”.

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August 1995 Events and Causal Factors Analysis 5

3.2.2 Each event should be described by a short sentence with one subject and one
active verb; i.e., “mechanic checked front end alignment”, not “mechanic checked
front end alignment and adjusted camber on both front wheels”.

3.2.3 Each event should be precisely described; i.e., “operator pulled headlight switch
to ‘on’ position”, not “operator turned lights on”.

3.2.4 Each event should describe a single, discrete occurrence; i.e., “pipe wa

ruptured”, not “internal pressure rose and pipe wall ruptured”.

3.2.5 Each event should be quantified when possible; i.e., “plane descended 350 feet”,
not “plane lost altitude”.

3.2.6 Each event should be derived directly from the event (or events in the case of a
branched chain) and conditions preceding it; i.e., “mechanic adjusted camber on both
front wheels” is preceded by “mechanic found incorrect camber” which is preceded by
“mechanic checked front end alignment” – each event deriving logically from the one
preceding it. When this is not the case, it usually indicates that one or more steps in
the sequence have been left out.

3.2.7 Conditions differ from events insofar as they (a) describe states or circumstances
rather than happenings or occurrences and (b) are passive rather than active. As far as
practical, conditions should be precisely described, quantified when possible, posted
with time and date when possible, and be derived directly from the conditions
immediately preceding them.

3.3 Guidelines for Practical Application

The experience of many people participating in numerous accident investigations has led to
the identification of seven key elements in the practical application of ECFA to achieve high
quality accident investigations.

(1) Begin early. As soon as you start to accumulate factual information on events and
conditions related to the accident, begin construction of a “working chart” of events
and causal factors. It is often helpful also to rough out a fault tree of the occurrence
to establish how the accident could have happened. This can prevent false starts and
‘wild goose chases” but must be done with caution so that you don’t lock yourself into
a preconceived model of the accident occurrence.

(2) Use the guidelines suggested in sections 3.1 & 3.2 as these will assist you in getting
started and staying on track as you reconstruct the sequences of events and conditions
that influenced accident causation and amelioration. Remember to keep the proper
perspective in applying these guidelines; they are intended to guide you in simple
application of a valuable investigative tool. They are not hard and fast rules that must

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6 Events and Causal Factors Analysis August 1995

be applied without question or reason. They have grown out of experience and fit well
into most applications, but if you have a truly unique situation and feel that you must
deviate from the guidelines for clarity and simplicity, do it. Analytical techniques
should be servants not masters.

(3) Proceed logically with available data. Events and causal factors usually do not emerge
during the investigation in the sequential order in which they occurred. Initially, there
will be many holes and deficiencies in the chart. Efforts to fill these holes and get
accurate tracking of the event sequences and their derivation from contributing
conditions will lead to deeper probing by investigators that will uncover the true facts
involved. In proceeding logically, using available information to direct the search for
more, it is usually easiest to use the accident or loss event as the starting point and
reconstruct the pre-accident and post-accident sequences from that vantage point.

(4) Use an easily updated format. As additional facts are discovered and analysis of those
facts further identify causal factors, the working chart will need to be updated. Unless
a format is selected which displays the emerging information in an easily modified
form, construction of the chart can be very repetitious and time-consuming.
Successive redrafts of the ECF chart on large sheets of paper have been done;
magnetic display boards or chalkboards have been used; but the technique that has
consistently proven most effective and most easily updated is use of “post-it” notes on
which brief event or condition statements are written. A single event or condition is
written on each note. The notes are then stuck to a wall or a large roll of heavy paper
in the sequence of events as then understood. As more information is revealed, notes
can be rearranged, added, or deleted to produce a more complete and accurate version
of the working chart. Once the note-based working chart has been finalised, the ECF
chart can be drawn for inclusion in the investigation report. Several investigators have
testified of the value of this approach, commenting that it made their investigations
more expeditious and thorough. They further stated that use of the post-it notes for
the working chart not only was useful in establishing the accident sequence and
identifying key events and conditions, but it also illuminated deficiencies in knowledge,
pointed out areas for further inquiry, and finally made the report writing
straightforward.

(5) Correlate use of ECFA with that of other MORT investigative tools. The optimum
benefit from MORT-based investigations can be derived when such powerful tools as
ECFA, MORT chart based analysis, change analysis, and energy trace and barrier
analysis are used to provide supportive correlation.

(6) Select the appropriate level of detail and sequence length for the ECF chart. The
accident, itself, and the depth of investigation specified by the investigation
commissioning authority will often suggest the amount of detail desired. These, too,
may dictate whether ending the ECF chart at the accident or loss-producing event is
adequate, or whether the amelioration phase should be included. The way the
amelioration was conducted will also influence whether this should be included and in

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August 1995 Events and Causal Factors Analysis 7

how much depth it should be discussed. Certainly, if second accidents occurred during
rescue attempts or emergency action, or if there were other specific or systemic
problems revealed, the ECFA should cover this phase. However, the investigators and
the commissioning authority involved will have to decide, on a case-by-case basis,
what is appropriate depth and sequence length for each accident investigated.

(7) Make a short executive summary chart when necessary. The ECF working chart will
contain much detail so it can be of greatest value in shaping and directing the
investigation. In general, significantly less detail is required in the ECF chart presented
in the investigation report, because the primary purpose is to provide a concise and
easy-to-follow orientation to the accident sequence for the report reader. When a
detailed ECF chart is felt to be necessary to show appropriate relationships in the
analysis section of an appendix of the report, an executive summary chart of only one
or two pages should be prepared and included in the report to meet the above stated
purpose.

4 Benefits of the Technique

Use of the ECF charting technique by the accident investigator provides benefits in: (1)
meeting the general purposes of accident investigation and conducting the investigation, (2)
writing the investigation report.

4.1 Contribution of ECFA to Investigation Purposes and Condu

The primary purpose of accident investigation is to determine what happened and why it
happened in order to prevent similar occurrences and to improve the safety and efficiency of
future operations. When serious accidents occur, they are often symptomatic of systemic
deficiencies which also impair performance and production. When the accident is used as a
window through which to view the existing management system, these deficiencies are
revealed and benefits are derived which go far beyond correction of the immediate causes of
the accident. The emphasis, then, should be placed on discovering all cause-effect
relationships from which practical corrective actions can be derived to improve total
performance. The intent of the investigation, then, is not to place blame, but rather to
determine how responsibilities can be clarified and how loss-producing errors can be reduced
and controlled. Accurate ECF analysis can help satisfy these general purposes in the
following ways:

C provides a cause-oriented explanation of the accident;
C provides a basis for beneficial changes to prevent future accidents and operational

errors;
C helps delineate areas of responsibility;
C helps assure objectivity in the conduct of the investigation;
C organises quantitative data (e.,g., time, velocity, temperature, etc.) Related to loss-

producing events and conditions;

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8 Events and Causal Factors Analysis August 1995

C acts as an operational training tool;
C provides an effective aid to future systems design.

More specifically, ECFA:

C aids in developing evidence, in detecting all causal factors through sequence
development, and in determining the need for in-depth analysis;

C clarifies reasoning;
C illustrates multiple causes. As previously stated, accidents rarely have a single

“cause”. Charting helps illustrate the multiple causal factors involved in the accident
sequence, as well as the relationship of proximate, remote, direct, and contributory
causes;

C visually portrays the interactions and relationships of all involved organisations and
individuals;

C illustrates the chronology of events showing relative sequence in time;
C provides flexibility in interpretation and summarisation of collected data;
C conveniently communicates empirical and derived facts in a logical and orderly

manner;
C links specific accident factors to organisational and management control factors.

4.2 Use of the ECF Chart in Preparing the Report

The purpose of the investigation report is to convey the results of the investigation in clear
and concise language. The investigation report constitutes a record of the occurrence by
which the investigation is measured for thoroughness, accuracy, and objectivity. The report
should also fully explain the technical elements of the causal sequences of the occurrence and
describe the management systems which should have prevented the occurrence. Use of ECF

has been effective in satisfying these report objectives. Specific advantages provided are as
follows:

< provides a check for completion of investigative logic. Even the most elementary types of sequence charting can reveal gaps in logic and help prevent inaccurate conclusions;

< provides a method for identification of matters requiring further investigation or analysis. Significant event blocks with vague or non-existent causal factors can alert the investigator to the need for additional fact-finding and analysis;

< provides a logical display of facts from which valid conclusions can be drawn;

< provides appropriate and consistent subject titles for “discussion of facts” and “analysis” paragraphs;

< provides a method for determining if the general investigative purposes and

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August 1995 Events and Causal Factors Analysis 9

specific objectives have been adequately met in terms of the conclusions
reached;

< provides a method for differentiation between the analysis of the facts and the resultant conclusions.

< presents a simple method for clearly describing accident sequences and causes to a reading audience with divergent backgrounds. Without the use of sophisticated or exotic methodology, the accident causes can be easily communicated to readers with a wide variety of experience and technical expertise;

< provides a source for the identification of organisational needs and the formulation of recommendations to meet those needs. The charting technique provides the basis for a systematic trace of the logic from a statement of the facts through the analysis, conclusions, judgements of needs, and recommendations;

< provides a method for evaluating the factual basis of possible recommendations;

< finally, the technique has shown to be useful in solving various unanticipatad problems associated with preparing the final report for specific accident investigations. The clear and logical development of the accident events and causal factors facilitates agreement among report reviewers on accident causation and minimises negative reaction from those person and organisations whose performance deficiencies contributed to accident occurrence. They may not like what the report says, but they will agree that it is fair and accurate.

Finally, the use of ECFA has proven to be a valuable tool for accident investigators and a
clear and concise aid to understanding of accident causation for the report readers. Use it for
greater effectiveness in accident investigating and reporting.

5 Bibliography

L. Benner, Jr., “Accident Investigations: Multilinear Events Sequencing Methods”, Journal of
Safety Research, 7, 2 (1975).

W. G. Johnson, MORT – The Management Oversight and Risk Tree, SAN 821-2,
February 12, 1973.

W. G. Johnson, The Accident/Incident Investigation Manual, ERDA-76-20, Prepared for the
Division of Operational Safety, Energy Research and Development Administration, August 1,
1975.

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10 Events and Causal Factors Analysis August 1995

W. G. Johnson, “Sequence in Accident Causation”, Journal of Safety Research, 5, 2 (1973).

R. L. Kuhlman, Professional Accident Investigation – Investigative Methods and Techniques,
Institute Press, 1977.

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August 1995 Events and Causal Factors Analysis 11

Appendix: Events & Causal Factors Chart Example

Application of the suggested format and event description criteria for constructing a typical
ECF chart of a simple accident are illustrated in the following example.

Accident Description

The Ajax Construction Company was awarded a contract to build a block of flats on a hill
over-looking the city centre. Prior to initiation of the project, a comprehensive safety
programme was developed covering all aspects of the project. Construction activities began
on Monday, 7 October 1991, and proceeded without incident through to Friday, 11 October,
at which time the site was shut down for the weekend. At that time several company vehicles,
including a 2.5 tonne dump truck, were parked on the construction site. On Saturday, 12
October, a nine year-old boy, who lives some 400 yards from the site, climbed the hill and
began exploring the site. Upon finding the dump truck unlocked, he climbed into the cab and
began playing with the vehicle controls. He apparently released the handbrake and the tru

began to roll down the hill. The truck rapidly picked up speed. The boy was afraid to jump
out and didn’t know how to apply the brakes. The truck crashed into a parked car at the
bottom of the hill: it remained upright, but the boy suffered serious cuts and a broken leg.
The resultant accident investigation revealed that, although the safety programme specified
that unattended vehicles would be locked and the wheels chocked, there was no verification
that these rules had been communicated to the drivers.

Discussion

Figure 2 is the ECF chart of this accident. Note that the events are in chronological order,
that each follows logically from the one preceding and that the dates are indicated where
known. Events are enclosed in rectangles and the conditions in ovals. Event statements are
characterised by single subjects and active verbs. Primary events are connected by bold solid
lines, other events by solid lines, and conditions by dashed lines. Presumptive information
(i.e., the inference is clear but the evidence is lacking) is shown in ovals and rectangles drawn
in dashed lines. Please note that, in general, the primary event line should be extended
forward in time to include amelioration (in this instance, the first aid rendered to the injured
boy and subsequent attendance by the emergency services) because inadequate amelioration
can make matters considerably worse (and is therefore a contributor to the overall losses
incurred through an accident).

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12 Events and Causal Factors Analysis August 1995

References

Kletz, T. (2012). Missed opportunities in accident investigation. Loss Prevention Bulletin, 227, 6–9.

Timelineof

Event

1/2/16 – 5:33 am Mary leaves message for Tom (supervisor)

1/2/16 – 5:53am Bob found lying in pool of water

1/2/16 – 5:53 am Air horn sounds

1/2/16 – 5:34 am Sam notices leak and wet floor in valve dept.

1/2/16 – 5:41 am Sam leaves note for Mary to mop up wet floor

1/2/16 5:41 am

Sam goes home

1/2/16 – 5:33 am Tom leaves message for Mary

1/2/16 – 6:00 am Ambulance transports Bob to hospital

Key:

Event

Accident

8/19/2020 Accident Investigation

https://www.oshatrain.org/notes/2hnotes12.html 1/5

Resources – Accident Investigation and Root Cause
Analysis

Event and Causal Factor Charting

Event and causal factor charting is a written or graphical description for the time sequence of
contributing events associated with an accident. The charts produced in event charting consist
of the following elements:

Condition. A distinct state that facilitates the occurrence of an event. A condition may be
equipment status, weather, employee health, or anything that affects an event.

Event. A point in time defined by a specific action occurring.

Accident. Any action, state, or condition in which a system is not meeting one or more of its
design intents. Includes actual accidents and near misses. This event is the focus of the
analysis.

Primary event line. The key sequence of occurrences that led to the accident. The primary
event line provides the basic nature of the event in a logical progression, but it does not provide
all of the contributing causes. This line always contains the accident, but it does not necessarily
end with an accident event. The primary event line can contain both events and conditions.

Primary events and conditions. The events and conditions that make up the primary event
line.

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Secondary event lines. The sequences of occurrences that lead to primary events or primary
conditions. The secondary event lines expand the development of the primary event line to
show all of the contributing causes for an accident. Causal factors are almost always found in
secondary event lines, and most event and causal factor charts have more than one secondary
event line. Note that the secondary event lines can contain both events and conditions.

Secondary events and conditions. The events and conditions that make up a secondary
event line.

Causal factors. Key events or conditions that, if eliminated, would have prevented an accident
or reduced its effects. Causal factors are such things as human error or equipment failure, and
they commonly include the following:

The initiating event for an accident
Each failed safeguard
Each reasonable safeguard that was not provided

Items of note. Undesirable events or conditions identified during an analysis that must be
addressed or corrected but did not contribute to the accident of interest. These are shown as
separate boxes outside the event chain.

Limitations of Event and Causal Factor Charting

Although event charting is an effective tool for understanding the sequence of contributing
events that lead to an accident, it does have two primary limitations:

Will not necessarily yield root causes. Event charting is effective for identifying causal
factors. However, it does not necessarily ensure that the root causes have been
identified, unless the causal factor is the root cause.
Overkill for simple problems. Using event charting can overwork simple problems. A
two-event accident probably does not require an extensive investigation of secondary
events and conditions.

Procedure for Event and Causal Factor Charting

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1.0 Gather and organize data. Collect known data for actors associated with the accident. An
actor is a person, parameter, or object that has an action in the event chain. Organize the data
into a timeline. Review data for consistency and gaps. This step is not always necessary for
simple events.

2.0 Select the accident. Define the accident of interest. If there is more than one accident,
choose the last one to occur.

3.0 Define the primary sequence of events leading to the accident. Outline the thumbnail
sketch of the sequence of events leading to the accident. Work backward from the accident,
making certain that each subsequent event is the one that most directly leads to the previous
event.

Draw events using the guidance in the table and bullets below.

Draw events as rectangles
describe events specifically with one noun and one action verb
use quantitative descriptions when possible to characterize events
include the timing of the event when known
use solid lines for known events and dashed lines for assumed events

Draw conditions as ovals
describe conditions specifically using a form of the verb to be
use quantitative descriptions to characterize conditions

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include the timing and duration of the condition when known
use solid lines for known conditions and dashed lines for assumed conditions

4.0 Complete the model by adding secondary events and conditions. Add secondary
events and conditions as appropriate to ensure that all events and conditions leading to an
accident are sufficient and necessary to cause the accident. Add events as appropriate to
display the contributors to the secondary events and conditions.

5.0 Identify causal factors and items of note. Designate the underlying contributors to the
accident as causal factors. Document any items of note.

The following is an example accident scenario and the resulting event and causal factor chart.

Example

A barge carrying gasoline and diesel ran aground in an environmentally sensitive area. The
accident was a spill of 1,500 gallons of gasoline and 120 gallons of diesel fuel into a bay, which
is an especially sensitive environmental area. This accident was described as “gasoline and
diesel spill continued (1,500 gallons of gasoline and 120 gallons of diesel),” and it is shown on
the second page of the event and causal factor chart that follows. The chart traces the
sequence of events from the initiating event as the barge got under way through the grounding
event, which resulted in the gasoline and oil spill. The chart continues to trace the sequence of
events from the initial oil spill through spill identification, response, and control actions
implemented by both the Coast Guard and local authorities. The event chart identifies 10
causal factors judged to be significant contributors to the accident. The event and causal factor
chart also identifies one item of note revealed during the investigation.

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Copyright ©2000-2019 Geigle Safety Group, Inc. All rights reserved. Federal copyright prohibits unauthorized
reproduction by any means without permission. Disclaimer: This material is for training purposes only to inform
the reader of occupational safety and health best practices and general compliance requirement and is not a
substitute for provisions of the OSH Act of 1970 or any governmental regulatory agency. CertiSafety is a division
of Geigle Safety Group, Inc., and is not connected or affiliated with the U.S. Department of Labor (DOL), or the
Occupational Safety and Health Administration (OSHA).

Source: USCG Risk-based Decision-making (RBDM) Guidelines.

Certisafety Section Home Page (//www.certisafety.com/members/2hhome.html)

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Event

sand

Condition

No direct communication to anyone prior to leaving

No one to act on messages

Clean up of floor not done immediately

No “wet floor” signs placed

Leak not repaired for four months

1/2/16 – 5:33 am Mary leaves message for Tom (supervisor)

1/2/16 – 5:53am Bob found lying in pool of water

1/2/16 – 5:53 am Air horn sounds

1/2/16 – 5:34 am Sam notices leak and wet floor in valve dept.

1/2/16 – 5:41 am Sam leaves note for Mary to mop up wet floor

1/2/16 5:41 am

Sam goes home

1/2/16 – 5:33 am Tom leaves message for Mary

Emergency response was good

1/2/16 – 6:00 am Ambulance transports Bob to hospital

Key:

Condition
Event

Accident

Events

and Causal (Conditional+)

Factors Analysis

Mary Coffey

ECFA and ECFA+
�  ECFA – Buys and Clark 1995
◦  Assists in verifying the sequence of events

leading to the incident and the possible causal
factors for each event
◦  Provides a structure for integrating

investigation findings
◦  Assists communication during the procedure as

it must be a team approach
◦  Assists communication in reporting back the

findings
◦  Buys and Clark 1995

ECFA and ECFA+
�  ECFA+ – The Noordwijk Risk Initiative

Foundation
◦  Further refinement of the ECFA through

experiences gained over a decade

◦  The Noordwijk Risk Initiative Foundation

ECFA (Buys and Clark)

�  Incidents rarely simple and almost never

result from a single cause
◦  Multifactoral
�  Human factors
�  Environmental conditions
�  Omissions
�  Oversights
�  Performance related
◦  Different conditions may affect different

elements of the incident

�  The incident and its component elements
�  The conditions that created incident

situations
�  The managerial control systems that let

them develop
◦  To identify the root causes by understanding

the interaction of events and causal factors
through a chronological chain of activity
�  starting with an initiation event through to the final

event of the incident

ECFA (Buys and Clark)

�  Will help to
◦  Organise the data on the incident
◦  Guide the investigation
◦  Validate and confirm the true incident sequence
◦  Identify and validate factual findings, probable causes

and contributing factors
◦  Simplify organisation of the investigation report

�  Not used in isolation
◦  Most effective when used in conjunction with other

tools

ECFA (Buys and Clark)

�  Will help to clarify responsibilities and
reduce incidents by
◦  Providing a cause-oriented explanation
◦  Providing a basis for change
◦  Helping to delineate areas of responsibility
◦  Acting as an operational training tool
◦  Providing an effective aid to future systems design

ECFA (Buys and Clark)

�  Aids in developing evidence by
◦  Detecting all causal factors
◦  Illustrating multiple causes
◦  Providing a visual representation of interactions and

relationships
◦  Illustrating the chronology of events
◦  Providing a flexible interpretation
◦  Linking specific factors to organisation and

management control factors

ECFA (Buys and Clark)

Retrospective: Events and Causal
Factors Analysis

�  Representatives of all professionals involved
�  Presented with an incident
◦  Analysis in terms of
�  Clearly identifying and mapping the primary event
�  Considering possible

�  contributory factors
�  Systemic conditions
� 

Systemic factors

ECFA – Events and Causal Factors
Analysis

Typical ECFA work team using PostIt and a
White board

http://nri.eu.com/NRI4

Events What, When, Who

ECFA – Events

1.  Define what you consider to be the primary
incident – what actually happened- and enter
the individual events in sequence in the
central row

2.  Track in logical progression from beginning to
end (try to define the logical sequence)

Events What, When, Who
ECFA – Events

1.  Important that you describe an actual
occurrence and not a condition

2.  Events are active so use a verb for each event
and be precise

3.  Describe each event separately

Events What, When, Who
ECFA – Events

1.  If appropriate define what you consider to be
secondary events and place these in the rows
above or below the primary event

Primary Events

Secondary events

Plan modification
requested by
clinician

Final plan
calculated

Incomplete
saving of
plan

Error

message

displayed

MLC
points
moved to
holding
area

Appears
‘frozen’

Old
fluences
deleted

New
fluences
created

Plan save
attempted

Planner
responds
yes to
error
message

Second
save
attempted

Appears
‘frozen’

Primary and Secondary events

ECFA – Contributory factors

Influences Contributory
Factors

1.  Describe states or circumstances
2.  Passive and not active
3.  Conditions that could have influenced the

event or if they had been different might
have resulted in a different outcome

Primary Events

Contributing
Factors

Secondary events
Contributing
Factors
Plan modification
requested by
clinician
Final plan
calculated
Incomplete
saving of
plan
Error
message
displayed
MLC
points
moved to
holding
area
Appears
‘frozen’
Old
fluences
deleted
New
fluences
created
Plan save
attempted
Planner
responds
yes to
error
message
Second
save
attempted
Appears
‘frozen’

Plan

assessment
before fraction
one inadequate

Complex error

message

Complex data

storage

Request for

change during
treatment

The exercise – Events

1.  Read the incident carefully
2.  Transcribe all the actions onto individual

post-it notes
3.  Place on the chart in what you consider

the sequence to be
4.  Review

The exercise – Conditions/
Contributory factors

1.  Consider the conditions that existed when
the incident occurred

2.  Write all the conditions on post-it notes
3.  Match conditions with the different

elements of the incident
4.  Add conditions to the chart
5.  review

The exercise – Conditions/
Contributory factors

1.  Identify what you consider to be systemic
conditions or systemic factors

2.  Review and agree on your final
configuration

Retrospective: Events and Causal
Factors Analysis

Systemic condtions

Contributing factors

Primary events

Systemic condtions
Systemic factors

Treatment Unit
Service

Patient
changed

treatment unit

Patient
positioned on

couch
Beam selected

Beam
positioned
incorrectly

Treated wrong
target/isocenter

Too many
staffHeavy workload

Management
or supervisor

failure

Field names
confusing

Field/target
connection

missing

R/V design
flaw

Senile
Patient

Unclear
setup

instructions

Lack of
equipment

Beam
positioned
incorrectly

Lack of
communication

Staff not
familiar w

patient

Observation
failure

6 I Loss Prevention Bulletin 227 October 2012

or Kletz annivers

Missed opportunities in accident investigation
Trevor Kletz

There is an old story about two manufacturers of shoes
who sent representatives to an undeveloped country
to look into the opportunities for sales there. Both of
them soon sent reports back. One said, ‘No business
here. People don’t wear shoes’. The other said, ‘Creat
opportunities here. People don’t wear shoes’. Both
representatives had the same data but their interpretations
of it were different and told us more about them than
about the opportunities for sales.

Similarly, different accident investigators can draw
different conclusions from the same evidence and propose
different actions. The collection of evidence is usually
adequate, at least in the oil and chemical industries, but
the interpretations of the evidence vary and we often miss
opportunities to learn from it. Some accident reports tell
us more about the interests, experiences and beliefs of
the investigators than about the best ways of preventing it
happening again.

In a paper presented at the Hazards XVI Conference in
2001 ̂ I described a number of learning opportunities that
are frequently missed, during or following the preparation
of a report. Having paid the ‘tuition fee’, we should learn
the lessons. This paper summarises the 2001 paper,
with a few changes, and illustrates some of the missed
opportunities by different examples.

Accident investigations often find only a
single cause

Many accident reports identify only a single cause, though
many people, from the designers, down to the last link in
the chain, the operator who closed the wrong valve, had
an opportunity to prevent the accident. The single cause
identified is usually this last link in the chain of events that
led to the accident. Just as we are blind to all but one of the
octaves in the electromagnetic spectrum so we are blind
to many of the opportunities that we have to prevent an
accident. But just as we have found ways of making the rest
of the spectrum visible, so we need to make all the ways of
preventing an accident visible.

Accident investigations are often superficial

Even when we find more than one cause, we often find only
the immediate causes. We should look beyond them for ways
of avoiding the hazards, such as inherently safer design and for
weaknesses in the management system.

For example, consider the official report^ on the explosion
at Flixborough in 1974, the worst accident in the UK chemical

industry, if we exclude explosives. The rupture of a temporary
pipe caused a large leak of hot flammable liquids, which
vaporised and exploded, destroying the plant and killing
28 people. The report identified the lack of any procedure
for the management of change and the lack of mechanical
engineering expertise on the plant at the time. It also described
in great detail the events that led to the rise in pressure that
ruptured the temporary pipe. Though of interest this was
of minor importance as the plant could have withstood the
pressure change beforethetemporary pipe was installed. All
plants undergo pressure changes from time to time for many
reasons and are fitted with relief systems to prevent damage
by pressures greater than design. The rise in pressure that
ruptured the pipe did not reach the set point of the relief valve.
Nevertheless the reason for the rise in pressure has been
debated ever since.̂

The most important lesson to be learned from the explosion
was missed by the inquiry and by most commentators—the
leak and explosion were so big because the plant contained
about 400 tonnes of hot flammable liquid under pressure. It
contained so much because the conversion was low, about 6%,
so 94% of the feed got a free ride and had to be recovered and
recycled many times. If we could increase the conversion then
the inventory in the plant, and the maximum size of leak, would
be lower. The plant would be inherently safer. One company
did start to develop a more efficient process but abandoned
the research when they realised that they would need no new
plants in the foreseeable future. Nevertheless, Flixborough
drew attention to the value of inherently safer designs and
much progress has been made in developing such processes
and equipment.

Accident investigations list human error
as a cause

Human error is far too vague a term to be useful. We should
ask, ‘What sort of error?’ because different sorts of error
require different actions if we are going to prevent the errors
happening again”.

Was the error a mistake due to poor training or instructions,
so that the intention was wrong? If so, we need to improve the
training and instructions and, if possible, simplify the task.

Was the error due to a violation or non-compliance, that is,
a deliberate decision not to follow instructions or recognised
good practice? If so, we need to explain the reasons for them,
as we do not live in a society in which people will uncritically
do what they are told. We should simplify the task if possible
because it is difficult to persuade everyone to use the correct
method if an incorrect method is easier to use; we should
check from time to time to see that instructions are being

Loss Prevenfion Bulletin 227 October 201 2 | 7

followed and never turn a blind eye. Remember also that many,
perhaps most, violations occur when people think they have
found a better way of doing a job.

Was the task beyond the ability of the person asked to do it,
perhaps beyond anyone’s ability? If so, we need to redesign
the task.

Was it a slip or lapse of attention? In contrast to mistakes, the
intention may have been correct but it was not fulfilled. It is no
use telling people to be more careful as no one is deliberately
careless. We should remove opportunities for error by
changing the design or method of working.

Designers, supervisors and managers make errors of all
these types, though slips and lapses of attention by designers
and managers are rare as they usually have time to check their
work. Errors by designers produce traps into which operators
fall, that is, they produce situations in which slips or lapses
of attention, inevitable from time to time, result in accidents.
Errors by managers are signposts pointing in the wrong
directions.

Accident reports look for people to blame

The gut reaction of many people, including the press, after
an accident is to ask, ‘Who is to blame?’ However, blame is
only relevant when the error is a violation and even then most
violations occur because a blind eye has been turned to them
in the past or because the people concerned thought they had
found abetterway of carrying out the job. If the instructions
are wrong or do not cover all situations, violations can prevent
an accident.

However, blaming human error for an accident diverts
attention from what can be done by better design or better
methods of operation. In recent years the tendency to blame
operators has decreased but there is now a greater willingness
to blame managers. The press and politicians argue that
accidents occur because managers put costs and output before
safety. The vast majority do not do so. Managers, even those
at the top, are not superhuman. Like everyone else they make
errors because they lack knowledge, do not realise they could
do more, cannot do everything at once and so on.

We change procedures rather than designs

There are several different actions we can take after we have
identified a hazard as a result of an accident (or in some other
way) to prevent it causing another accident or to mitigate the
consequences if it does: Our first choice should be to remove
the hazard by inherently safer design. For example, can we use
a safer material instead of a toxic or flammable one? Even if we
cannot change the existing plant we should note the change
for possible use on the next plant.

If we cannot remove the hazard then our next choice should
be to keep it under control by adding passive protective
equipment, that is, equipment that does not have to be
switched on or does not contain moving parts. The third choice
is active protective equipment, that is, equipment switched on
automatically; unfortunately the equipment may be neglected
and fail to work or it may be disarmed.

The fourth choice is reliance on actions by people, such as
switching on protective equipment; unfortunately the person
concerned may fail to act due to forgetfulness, ignorance.

distraction, poor instructions or, after an accident, because he
or she has been injured.

Finally, we can use the techniques of behavioural science
to improve the extent to which people follow procedures and
accepted good practice. By listing this as the last resort I do not
intend to diminish its value. Safety by design should always
be our aim but may be impossible and experience shows that
behavioural methods can bring about substantial improvement
in the everyday types of accident that make up most of the
lost-time and minor accident rates. However, the technique has
little effect on process safety. Behavioural methods should not
be used as an alternative to the improvement of plant design or
methods of working when these are reasonably practicable.

To make these various ways of preventing incidents clearer,
let us consider a simple but common cause of injury and even
death in the home-falls on the stairs.

The inherently safer solution is to avoid the use of stairs
by building a single storey building or using ramps instead of
stairs.

If that is not reasonably practicable a passive solution is to
install intermediate landings so that people cannot fall very far
or to avoid particular types of stair, such as spiral staircases,
which make falls more likely. An active solution is to install a lift.
Like most active solutions it is expensive and involves complex
equipment that is liable to fail, expensive to maintain and easy
to neglect.

The procedural solution is to instruct people to always use
the handrails, never to run on the stairs, to keep them free
from junk and so on. This can be backed up by behavioural
techniques-specially trained fellow workers (or parents in the
home) look out for people who behave unsafely and tactfully
draw their attention to the action.

In some companies the default action after an accident
is to start at the wrong end of the list of alternatives and
recommend a change in procedures or better observation of
procedures, often without asking why the procedures were not
followed. Were they, for example, too complex or unclear, or
have supervisors and managers turned a blind eye in the past?
Changing procedures is, of course, usually quicker, cheaper
and easier than changing the design, but is least effective.

For example, rainwater and spray passed through the intake
of a ventilation fan and fell onto a switchboard. This occurred
on a ship but could have occurred elsewhere. A short circuit
started afire; it was soon extinguished but all power was lost.
The ship had to ask for help and was towed back to port.

The water entered through the ventilation intake as the
louvres in it had been installed so that they directed spray and
rain into the engine room rather than away from it. (The report^
said that they had been installed upside-down but the author
must have meant back-to-front.)

The report’s first recommendation was that louvres should
be checked to make sure they are fitted correctly. The author
did not realise that they should also be designed so that they
could not be fitted wrongly, or so that it was obvious if they
were, or at least so that the inside and outside, top and bottom
were clearly labelled. The report did, however, recommend
that switchboards should be covered to prevent water entering
from above.

Computers provide many other examples of an unrealistic
attitude to human error. A control room operator was asked

8 Loss Prevention Bulletin 227 October 2012

Rain

Louvres
installed

Incorrectly

Louvres
installed
correctly

Eigure 1 : the louvres were installed so that they directed
rainwater and spray through them

to switch a spare transformer on line in place of the working
one. He inadvertently isolated the working transformer before
switching on the spare one. He realised his error almost
immediately and the supply was restored within a minute.
The report on the incident blamed distraction, as the control
room was used as a thoroughfare for people moving about
the building. The report also suggested greater formality
in preparing and following instructions when equipment is
changed over. However, it did not recommend that when
the computer is asked to isolate a transformer it should
display a warning message such as, ‘Are you sure you want
to shut down the electricity supply?’ We get such messages
on our computers when we wish to delete a file-there is no
need for control programs to be less user-friendly than word
processors.

Notice again that the default action of the people who
wrote the report was to describe ways of changing someone’s
behaviour rather than to look for ways of changing designs or
methods of working.

Operators provide the last line of defence against errors
by designers and managers. It is a bad strategy to rely on the
last line of defence and neglect the outer ones. Good loss
prevention starts far from the top event, in the early stages of
design. Blaming users is a camouflage for poor design.

Accident reports list causes that are difficult or
impossible to remove

For example, a source of ignition is often listed as the cause of
afire or explosion. But it is impossible on the industrial scale
to eliminate all sources of ignition with 100% certainty. While
we try to remove as many as possible it is more important to
prevent the formation of flammable mixtures.

Which is the more dangerous action on a plant that handles
flammable liquids—to bring in a box of matches or to bring in

a bucket? Many people would say that it is more dangerous
to bring in the matches, but nobody would knowingly strike
them in the presence of a leak and in a well-run plant leaks are
small and infrequent. If a bucket is allowed in, however, it may
be used for collecting drips or taking samples. A flammable
mixture will be present above the surface of the liquid and may
be ignited by astray source of ignition. Of the two ’causes’ of
the subsequent fire, the bucket is the easier to avoid.

I am not, of course, suggesting that we allow unrestricted
use of matches on our plants but I do suggest that we keep
out open containers as thoroughly as we keep out matches.
{Editor’s note: See page 28 for a description of an incident of
this type).

As we have already seen, listing human error as a cause
leads people to think only of ways of reducing human error,
often by simply telling them to take more care. It does not
encourage them to look for the improvements in design that
can reduce the opportunities for human error Instead of
listing causes we should list the actions needed to prevent
a recurrence. This forces to people to ask if and how each
so-called cause can be prevented in future.

Some people list a wrong attitude as the cause of an
accident. But attitude is generalisation deduced from people’s
actions. Instead of tryingto change attitudes directly we should
help people to change their actions, by better training and all
the other ways previously suggested. Others will then say that
they have changed their attitude.

We may go too far

Sometimes after an accident people go too far and spend time
and money on making sure that nothing similar could possibly
happen again even though the probability is low. If the accident
was a serious one it may be necessary to do this to re-assure
employees and the public, but otherwise we should remember
that if we gold-plate one unit there are fewer resources
available to silver-plate the others. Here is a simple example:

While a welder was burning a hole in a pipe, 150 mm
diameter, with walls 12 mm thick, in a workshop, a sudden
noise made him jerk. His gun touched the pool of molten
metal and a splash of metal hit him on the forehead. If the wall
thickness had been above 12 mm a hole would have been
drilled in the pipe first and the accident report said that this
technique should be used in future for all pipes. However, this
would be troublesome, as a crane would be needed to move
the pipe to the drilling bay and back. In practice, nothing was
done.

The welder had cut thousands of holes before without
incident, the chance of injury was small and it may have been
reasonable to do nothing and accept the slight risk of another
incident. However, the foreman and his engineer were not
willing to say so and instead they recommended action that
they had little or no intention of enforcing.

UK law does not require everything possible to prevent an
accident, only what is ‘reasonably practicable’. This phrase
implies that the size of a risk should be compared with the cost
of removing or reducing it, in money, time and trouble. When
there is a gross disproportion between them it is not necessary
to remove or reduce the risk. In recent years HSE has provided
detailed advice on the levels of risks they consider tolerable
and the costs they consider disproportionate.^

Loss Prevenfion Bullefin 227 October 201 2 | 9

We do not let others learn from our experience References

Many companies restrict the circulation of incident reports, as
they do not want everyone, even everyone in the company, to
know that they have blundered, but this will not prevent the
incident happening again. We should circulate the essential
messages widely, in the company and elsewhere so that others
can learn from them, for several reasons:

• Moral: If we have information that might prevent another
accident we have a duty to pass it on.

• Pragmatic: If we tell other organisations about our
accidents they may tell us about theirs.

• Economic: We would like our competitors to spend
as much as we do on safety. The industry is one-every
accident affects its reputation.

When information is published people do not always learn from
it. A belief that ‘our problems are different’ is a common failing.

When reports are published they often lack impact as the
essential message is obscured by detail of only local interest.
Those who spread safety messages are, like teachers, parents
and tax collectors, giving information that many of their listeners
would rather not hear, so the messages have to be clear.

We read or receive only overviews

Lacking the time to read accident reports in detail, senior
managers consume pre-digested summaries of them, full
of generalisations such as, ‘There has been an increase in
accidents due to inadequate training’. They describe this as
taking a helicopter view. However, from a helicopter we see
only forests. To understand the causes of accidents we need
to land the helicopter and look at individual trees or even
twigs and leaves. As already mentioned, the identification of
underlying causes can be very subjective and is inftuenced
by people’s experience, interests, blind spots and prejudices.
One factory manager had realised that failure to learn from
past experience had been a major cause of accidents and
was lookingfor ways to improve it. But none of the individual
reports, nor the annual summary of them, referred to this at all.
All managers should read at least some of the accident reports
written by their subordinates to see if they agree with the
assignment of underiying causes.

We forget the lessons (earned and allow the
accident to happen again

Even when we prepare a good report and circulate it widely,
all too often it is read, filed and forgotten. Organisations have
no memory^. Only people have memories and after a few years
they move on taking their memories with them. Procedures
introduced after an accident are allowed to lapse and ten years
later the accident happens again, even on the plant where it
happened before. If, by good fortune, the results of an accident
are not serious, the lessons are forgotten even more quickly.

Unless we take action to improve the learning from
experience, nothing will happen except a repetition of the
accident. The main purpose of an accident investigation is to
prevent it happening again. If it is allowed to, the investigation
was a waste of time.

7. Kletz, T.A., Accident Investigation, Missed Opportunities,
Hazards XVI – Analysing the Past, Planning the Future,
Symposium Series No 148, Institution of Chemical
Engineers, Rugby, 2001, pp. 7-77. Reprinted in Process
Safety and Environmental Protection, 80B(V:3-8, Jan
2002.

2. Parker, R.I., The Elixborough Disaster – Report of the Court
of Inquiry HMSO, London, 1975.

3. See the letters pages of The Chemical Engineer in the
issues dated 20 April, 7 7 May, 25 May, 22 June, 14 Dec
(article), 2000 and Eeb 2001. See also Venart, J.E.S.,
Froude Modeling of the Flixborough ‘By-Pass’ Pipe,
Hazards XV – The Process, its Safety and the Environment,
Symposium Series No 147, Institution of Chemical
Engineers, Rugby, 2001, pp. 139-153, 2000.

4. Kletz, TA., An Engineer’s View of Human Error, 3rd
edition. Institution of Chemical Engineers, Rugby, 2001.

5. Anon., Upside down louvres. Safety Digest – Lessons from
Marine Accident Reports, No. 2/2001, Marine Accident
Investigation Branch of the UK Department of Transport,
Local Covernment and the Regions, London, 2001, p. 40.

6. Health and Safety Executive, Reducing Risks, Protecting
People – HSE’s Decision Making Process, HSE Books,
Sudbury 2001.

7. Kletz, T.A., Lessons from Disaster – how organisations
have no memory and accidents recur, Institution of
Chemical Engineers, Rugby, 1993

Loss Prevention Panel comment

In his globally recognised distinguished career Professor
Trevor Kletz has written many papers but this one in
particular offers us the opportunity to reftect on what went
wrong and the lessons we should learn in order to prevent
incidences.

Generally speaking, people often leave organisations
without ever leaving their experiences behind so that
others may learn and benefit. As such, organisations and
those running them have a duty and moral responsibility
to capture and retain within organisational memory the
lessons learnt so that others may make better use of them
to prevent accidents from happening again. If we do
not do this, sadly the cost will be very heavy to burden
and above all reputations lost may be very difficult to
regain. Major accidents such as the likes of Flixborough,
Chernobyl, Piper Alpha, Bhopal, Texas City, Deep Water
Horizon and more recently the Fukushima nuclear
accident in Japan are there by way of examples for us to
reflect on.

As Trevor asserts ‘Unless we take action to improve the
learning from experience, nothing will happen except
a repetition of the accident. The main purpose of an
accident investigation is to prevent it happening again. If it
is allowed to, the investigation was a waste of time.’

Iqbal Essa
HSE& Chairman of Loss Prevention Panel

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Running Header: EVENTS AND CAUSAL FACTORS CHART PROJECT

EVENTS & CAUSAL FACTORS CHART PROJECT

Title

Student Name

Course Title

Lecturer’s Name

Date of Submission

Part 1:

Part II

The likely causal factors for the witnessed explosion include failure to satisfy the acceptable measures as well as the inability to ensure the installation of proper metrics. There was a dire need for the technician on call to fulfil the necessary standards and controls during the process of repairing the valves. This step could have prevented the occurrence of the explosion. The state of the appliances affected the overall performance of the propane system thereby resulting in a blast. Among the goals of the assessment of the effectiveness of any system is the need to ensure all the installed tools and equipment are appropriate as well as efficient for the work (Oakley, 2012). Failure to observe this vital requirement exposes the entire system to plenty of defects which could have severe effects.

Constant checking of the system is an essential prerequisite aimed at correcting defects such as leaks of the propane gas. The CSB report indicates clearly that the junior technician was incompetent to perform his duties. He lacked the necessary skills needed to effectively carry out repairs on the malfunctioning valves. This allowed for emission of the gas and its subsequent vaporization and explosion. Ensuring the valves are well fixed and that no amount of leakage is witnessed is a necessary step that the technician would have taken to avoid any uncertainty from occurring. Failure to observe this amount to negligence and must be punishable bearing in mind the fatality of the witnessed explosion.

The report by CSB has an intricate correlation to the identified causal factors. Both reflect that the unfortunate event was due to lack of proper inspection as well as audit programs that could have helped in the identification process of the defective tank. Proper controls and audits would have enhanced the transfer of the defective tanks from against the building thus mitigating any eventuality. The second causal factor identified revolves around the fact that the emergency responders lacked the necessary skills needed for them to effectively perform their roles. The respondents failed to act accordingly for fifteen minutes thus allowing the explosion to occur (Oakley, 2012). The respondents could have helped to prevent the explosion had they moved swiftly with speed in seizing the reported Propane leakage.

In conclusion, this occurrence implies that employee training initiatives are critical for the safety and efficiency of organizational processes. Moreover, organizations should establish adequate inspection procedures to ensure the existence of a friendly and less risky operational environment as well as the suitability of tools and equipment used. Such measures if implemented would help to identify and mitigate causal factors for various tragedies thus saving organizational resources.

REFERENCE

Oakley, J. S. (2012). Accident investigation techniques: Basic theories, analytical methods, and

applications (2nd ed.).Des Plaines, IL: American Society of Safety Engineers.

Employment; Junior Propane Service Technician employed for transfer liquid propane

Propane Gas released unexpectedly

Plug of Existing Tank Removed

10.50 am

Responders come but ignore the release of Propane.

10.00a.m

Plug of Existing Tank Removed

10:53 am; Huge explosion due Propane ignition

10:25 am

Propane Gas released unexpectedly

10:40 am

911 Called after 15 minutes of release

Gas Vapour forms due to release

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