Purpose of Accident Investigations

An important element of a safety and health program is accident investigation. Although it may seem to be too little too late, accident investigations serve to correct the problems that contribute to an accident and will reveal accident causes that might otherwise remain uncorrected. 

The main purpose of conducting an accident investigation is to prevent a recurrence of the same or a similar event. It is important to investigate all accidents regardless of the extent of injmy or damage. The kinds of accidents that should be investigated and reported include 

Nondisabling injury accidents that require medical treatment 

Circumstances that have contributed to acute or chronic occupational illness 

Noninjury property damage accidents that exceed a normally expected operating cost 

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Centre for Chemical Process Safety (CCPS) (Sklet, 2004) described three main purposes of accident investigation techniqnes as follows ... 

The accident investigation report is written using the principles of technical documentation. Items 1-4 are objective and should not include the authors opinions. Items 5-7 appropriately contain the opinions of the authors (investigation team). This technical style allows readers to develop their own independent conclusions and recommendations. As a result of these criteria, the accident investigation report is a learning tool, which is the major purpose of the investigation. 

Explain the purpose of the investigation (accident prevention) and put each... 

Accidents and incidents are investi ted so that measures can be taken to prevent a recurrence of similar events. Investigation represents an after-the-fact response as far as any particular mishap is concerned. However, a thorough investigation may uncover hazards or problems which can be eliminated before-the-fact for the future. After causes have been determined, prompt follow-up action is required to achieve the purpose of the investigation. 

Recommended preventive actions should make it very difficult, if not impossible, for the incident to recur. The investigative report should list all the ways to foolproof the condition or activity. Considerations of cost or engineering should not enter in at this stage. The primary purpose of incident investigations is to prevent future occurrences. Beyond this immediate purpose, the information obtained through the investigation should be used to update and revise the inventory of hazards, and/or the program for hazard prevention and control. For example, the Job Safety Analysis should be revised and employees retrained to the extent that it fully refiects the recommendations made by an incident report. Implications from the root causes of the accident need to be analyzed for their impact on all other operations and procedures [6]. 

During new-employee orientation, employees should be told that they are not only empowered to report any accident they witness, it is also their duty. It should also be emphasized that the purpose of an investigation is to discover cause-and-effect relationships in the accident and to develop corrective actions. The purpose is not to assign blame but to determine how to improve system operation and reduce the chance for further errors. 

The purpose of accident and incident investigation is therefore to trace the developments backwards from the observable outcome to the efficient cause. Similarly, risk assessment projects the developments forwards from the efficient cause to the possible outcomes (cf., Figures 4.1 and 4.2). 

The ILCI model has been applied in the design of accident investigation checklists according to the second principle. Such checklists are relatively easy to apply in accident investigations and in the subsequent analysis and coding of the results for statistical purposes. They suffer from a poor reliability (different investigators will come up with different results) and from an inadequate coverage of the detailed circumstances of the accidents and near accidents. 

Accident investigations, when the events and physical causes are not obvious, often make use of a hazard analysis technique, such as fault trees, to create scenarios to consider. STPA can be used for this purpose. Using control diagrams of the physical system, scenarios can be generated that could lead to the lack of enforcement... 

Approaches to accident investigations seem as diverse as the investigators The absence of a common approach and differences in the investigative and analytical methods used have resulted in serious difficulties in the safety field... including... barriers to a common understanding of the phenomenon... (and) popular misconceptions about the nature of the accident phenomenon The purpose of this paper is to call attention to the... 

Five of the 15 forms received require entry of codes for causal factors, incident types, and injury t)q)es. When computer analysis programs first became available, I had been an aggressive promoter of the entiy of causal factor codes for later analysis. That proved to be inappropriate because accurate causal data are often not included in supervisors investigation reports or in insurance claims reports. Now, I recommend that computer-based analysis systems not include provision for causal data entry. They serve analysis purposes quite well for types of accidents, injury types, parts of body injured, and identification data (location, age, job title, etc.). 

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