July 2011
Introduction
Accident investigation is an important part of any safety management system. Without a detailed and thorough investigation, management has no true knowledge of the reasons why accidents occur and how to prevent 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 incidents then accidents. The results of such studies have been represented as triangles.
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 accidents including unsafe practices at the bottom of the pyramid, rather than just targeting the serious accidents at the top. In theory such practices will cause reductions from the base of the pyramid upwards.
How to investigate an Accident and Incident.
1 Major injury or illness 7 Minor injuries or illnesses 189 Non-injury Accidents/Illnesses
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Stages in an Accident/Incident Investigation
The stages in an accident/incident investigation are shown in the following diagram:
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 the 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.
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 sever 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 can 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.
Deal with immediate risks
Select the level of investigation
Investigate the event
Record and analyse the results
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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 than 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.
Interviews
Interviewing the person(s) involved witnesses to the accident is of prime importance. Ideally it should take place in familiar surroundings so as not to make the person uncomfortable.
These 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 investigation 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 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
Observation Information from physical sources including:
• Premises and place of work
• Access and egress • Plant and substances
in use
• Location and relationship of physical particles • Any post event
checks, sampling or reconstruction
• Checking reliability, accuracy • Identifying conflicts and resolving
differences.
• Identifying gaps in evidence
Documents Information from • Written instructions Procedures, risk assessments, policies • Records of earlier inspections, tests, examinations and surveys Interviews Information from: • Those involved
and their line management;
• Those observed
or involved prior to the event, e.g. inspection & maintenance staff.
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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.
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.
• 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 and 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 eventsl. The appropriate preventative measures may also have to be implemented by such supervisors. Information
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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.
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 number of incidents, near misses, injury and ill health events: • Checking that all events are being reported.
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