Exploring the relationship between major hazard, fatal and non-fatal accidents through outcomes and causes

[Note: this is an update and repost of a really old summary which had a different format back then.]

ABSTRACT

Smaller severity more frequent accidents can provide information about the direct and underlying causes of bigger severity more catastrophic accidents but only if looking within the same hazard category. Use is made of a database of around 23,000 Dutch serious reportable accidents 1998–2009 that have been analysed in Storybuilder? in 36 hazard specific bow-ties using a management-task-safety barrier model of failure causation. The data are first developed as hazard specific accident triangles to show differences in lethality. Then comparisons of fatal and non-fatal accident causes are carried out, showing commonality in causes. The same is done for two case studies of catastrophic accidents – the Amercentrale power station scaffold collapse in the Netherlands and the major chemical accident at the Buncefield oil storage depot in the UK.

Results indicate that, provided accidents from different hazard bow-ties are not mixed together, small severity more frequent accidents can be used to consider the causation and hence prevention of the bigger severity rarer accidents. This leads to the conclusion that the analysis of occupational accidents can help in addressing major ones providing it is restricted to the same hazard type, contradicting the view that personal and process safety are totally unrelated.

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From the full-text paper:

·        “The evidence shows that fatal and non-fatal accidents share the same causes but not in the same proportions” (p6);

·        "There is no one fatal accident barrier failure cause which has not also occurred in non-fatal accidents" (p6), and further, “The numbers of fatal and non-fatal accidents do not significantly correlate within the same barrier type failure but there are no fatal accidents with different types of barrier failures to the non-fatal accidents" (p6);

·        “Analysis of the database of 23,030 Dutch serious occupational accidents … shows a relationship between the smaller severity outcome more frequent accidents and the more severe outcome rarer accidents when the data are scrutinised within the same hazard category.” (pg. 10);

·        The most lethal hazards (hazard exposures resulting in less recoverable or permanent injuries compared to fatalities) were found not to be the biggest killers;

·        The author further states that: “This contradicts what Hopkins (2009) has said regarding occupational versus process accident risks, that the distinction between personal and process safety ‘‘is really a distinction between different types of hazards.’’ On the contrary, it is shown here that there is a link between occupational and process safety and between fatal and nonfatal occupational accidents, and that link is the hazard.” (pg. 10);

·        “Within hazards the number of rarer fatal accidents correlate with the number of non-fatal accidents suggesting common underlying factors. When analysing safety barrier failures, fatal and non-fatal accidents were found to share the same underlying causes except in different proportions” (pg. 10).

In summarising the findings, it’s said that these findings suggest that investigating the factors of more minor more frequent incidents and fixing the safety barrier issues with a higher severity potential could help prevent the bigger accidents of the *same hazard type*.

However, this involves looking beyond just tracking the frequency of incidents or using their decline as an indicator and involves more deeper analysis and thought, including the contributing factors, potential severity ratio and the safety barrier issues.

Link in comments.

Author: Bellamy, L.J. (2015). Exploring the relationship between major hazard, fatal and non-fatal accidents through outcomes and causes. Safety Science, 71(B), 93-103.