for
Objectives of this Section

To define the reasons for investigating accident and incidents.

To outline the process for effectively investigating accidents and incidents.

To facilitate an effective investigation.

1.0 Introduction
Accident investigation is an important part of any safety management system. Without a detailed and through investigation, management has no true knowledge of the reasons why accidents occur and how to prevent their reoccurrence. The primary purpose of accident investigations is to improve health and safety performance by:

Exploring the reasons for the event and identifying both the immediate and underlying causes;

Identifying remedies to improve the health and safety management system by improving risk control, preventing a recurrence and reducing financial losses.
What to Investigate
All accidents whether major or minor are caused. Serious accidents have the same root causes as minor accidents and so do incidents with a potential for serious loss. It is these root causes that bring about the accident, the severity is often a matter of chance. Accident studies have shown that there is a consistently greater number of less serious accidents than serious accidents and in the same way a greater number of incidents then accidents.
The results of such studies have been represented as triangles. Many accident ratio studies have been undertaken and the one shown below is based on studies carried out by the
Health & Safety Executive 1 .
1
Major injury
Or illness
7
Minor injuries or illnesses
189
Non Injury Accidents/Illnesses
In all cases the ‘non injury’ incidents had the potential to become events with more serious consequences. Such ratios clearly demonstrate that safety effort should be aimed at all
1 HSE (1997) Successful Health & Safety Management, HS(G)65, HSE Books.
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accidents including unsafe practices at the bottom of the pyramid, rather then just targeting the serious accidents at the top. In theory such practices will cause reductions from the base of the pyramid upwards. Peterson 2 (1978) in defining the principles of safety management says that “ an unsafe act, an unsafe condition, an accident are symptoms of something wrong within the management’s system.” All events represent a degree of failure in control and are potential learning experiences. It therefore follows that all accidents should be investigated to some extent.
This extent should be determined by the loss potential, rather then just the immediate effect.
2
Peterson D. (1978) Techniques of Safety Management, 2nd Edition, McGraw Hill, New York.
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Accident & Incident Investigation

2.0 Stages in an Accident/Incident Investigation
The stages in an accident/incident investigation are shown in the following diagram.
Deal with immediate risks.
Select the level of investigation.
Investigate the event.
Record and analyse the results.
Review the process.
Dealing with Immediate Risks
When accidents and incidents occur immediate action may be necessary to:

Make the situation safe and prevent further injury; and

Help, treat and if necessary rescue injured persons.
An effective response can only be made if it has been planned for in advance. Although the timing of accidents and incidents is unpredictable it is usually possible to foresee the majority of events and prepare emergency plans to deal with them when they occur.
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Selecting the level of investigation
As stated earlier all accidents and incidents need investigating to some extent. The greatest effort should be put into:

Those involving severe injuries, ill-health or loss; and

Those which could have caused much greater harm or damage.
These types of accidents and incidents demand more careful investigation and management time. The effort in investigating these accidents needs to be proportionate to the actual or potential risk. This can usually be achieved by:

Looking more closely at the underlying causes of significant events; and

Assigning the responsibility for the investigation of more significant events to more senior managers.
Investigating the Event
The purpose of investigations is to establish:

The way things were and how they came to be;

What happened – the sequence of events that led to the outcome;

Why things happened as they did analysing both the immediate and underlying causes;

What needs to be done to avoid a repetition and how this can be achieved.
A great deal of information is available after every accident. Establishing what is relevant and what is not, can be time consuming, and some facts will be of greater importance then others. The investigators problem is to determine and concentrate on the most important. A few sources should give the investigator all he needs to know. These are shown below
(HSE, 1997):
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Observation
Information from physical sources including:
 Premises and place of work
 Access & egress
 Plant & substances in use
 Location & relationship of physical particles
 Any post event checks, sampling or reconstruction
Documents
Information from:
 Written instructions;
Procedures, risk assessments, policies
 Records of earlier inspections, tests, examinations and surveys.
 Checking reliability, accuracy
 Identifying conflicts and resolving differences
 Identifying gaps in evidence
Interviews
Information from:
 Those involved and their line management;
 Witnesses;
 Those observed or involved prior to the event e.g. inspection
& maintenance staff.
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Interviews
Interviewing the person(s) involved and witnesses to the accident is of prime importance.
Ideally it should take place in familiar surroundings so as not to make the person uncomfortable.
Ferry (1988) 3 states that it is impossible to provide interviewing technique guidelines that can be used in all situations, but there are some broad guidelines that can be used with care.

The style of interviewing is important. It should be re-stated time after time that the purpose of the investigate is not to blame but to prevent reoccurrence.

A more co-operative attitude will come if management can promote this positive culture by demonstrating the need to determine cause rather than to blame or punish.

The persons should give an account of what happened in their terms rather than the investigators.

Interviews should be separate to stop people from influencing each other.

Questions when asked should not be intimidating as the investigator will be seen as aggressive and reflecting a blame culture.
Observation
The accident site should be inspected as soon as possible after the accident. After looking at the site as a whole, particular attention should/must be given to individual factors/items such as:

Positions of people;

Personnel protective equipment (PPE);

Tools and equipment, plant or substances in use;

Orderliness/Tidiness;
3
Ferry T. (1988) Modern Accident Investigation and Analysis, John Wiley & Sons, Canada.
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Documents
Documentation to be looked at includes:

Written instructions, procedures and risk assessments which should have been in operation and followed. The validity of these documents may need to be checked by interview. The main points to look for are:
 Is it adequate/satisfactory?
 Was it followed on this occasion?
 Were people trained/competent to follow it?

Records of inspections, tests, examination and surveys undertaken before the event.
These provide information on how and why the circumstances leading to the event arose. The knowledge, skill and competence of those carrying out the tasks in the records may have to be assessed.
Determining Causes
It is important that all the information and facts which surround the accident are collected before thinking about causes. As soon as the investigator starts thinking about causes, the
‘fact finding’ stops, the cause has been found and anything else is incidental. This is known as the ‘Stop Rule’.
Immediate causes are obvious and easy to find. They are brought about by unsafe acts and conditions and are the ACTIVE FAILURES as described earlier in the course. Unsafe acts show poor safety attitudes and indicate a lack of proper training. If the investigator determines that an unsafe act was a contributing factor, then the reason for this must be found. In the same way if an unsafe condition was found to be an obvious cause then its source must be determined and corrected.
These unsafe acts and conditions are brought about by the so called ‘root causes’. These are the LATENT FAILURES as described earlier in the course and are brought about by failures in organisation and the management’s safety system.
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Determine what changes are needed
The purpose of the investigation is to prevent a re-occurrence. To do this some practical measures must be recommended and carried out that will demonstrate that management are committed to this. The investigation should determine what control measures were absent, inadequate or not implemented and so some form of remedial action should be implemented to correct this. Generally, remedial actions should follow the hierarchy of risk control shown below (HSE, 1997).

Eliminate Risks by substituting the dangerous by the inherently less dangerous .

Combat risks at source by engineering controls and giving collective proactive measures priority;

Minimise risk by designing suitable systems of working;

Use PPE as a last resort
Recording & Analysing the Results
The findings of every investigation need to be recorded in a similar and systematic manner.
This is so that the report can be read by the appropriate people who are responsible for reviewing and implementing necessary changes and to provide a basis for communication.
The report also provides a historical record of the accident that will be useful in the future. A description of the accident, analysis of the causes and recommended preventative protective measures should be listed. This report or form should be completed as soon after the accident as possible.
Information on the accident and remedial actions should be passed to all supervisors who should ensure that employees under them who may or may not encounter similar accidents are knowledgeable in the events. The appropriate preventative measures may also have to be implemented by such supervisors. Information can also be transferred in a number of other ways which are effective, such as through bulletin boards, meetings, inspections and in particular through safety audits.
Investigation reports and accident statistics should be analysed from time to time to identify common causes, features and trends that may not be apparent from looking at events in isolation.
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Reviewing the Process
Reviewing the accident/incident investigation process should consider:

The results of investigations and analysis; and

The operation of the investigation system (in terms of quality and effectiveness).
Line managers should follow through and action the findings of investigations and analysis.
Follow up systems should be established where necessary to keep progress under control.
The investigation system should be examined from time to time to check that it consistently delivers information in accordance with the stated objectives and standards. This usually requires:

Checking samples of investigation forms to verify the standard of investigation and the judgements made about causation and prioritisation of remedial actions.

Checking the numbers of incidents, near misses, injury and ill-health events;

Checking that all events are being reported.
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