Learning (and unlearning) from failures: 30 years on from Bhopal to Fukushima an analysis through reliability engineering techniques

• Analysis of Bhopal Gas Tragedy using fault tree analysis and reliability block diagrams.
• This incident is compared with Fukushima Nuclear incident.
• Evaluation of different models for root cause analysis is carried out.

Reliability engineering techniques such as failure mode effect analysis (FMEA), fault tree analysis (FTA), and reliability block diagrams (RBD) have been used to analyse the case of the Bhopal disaster (Labib and Champaneri, 2012), and subsequently used in the analysis of other disasters (Labib, 2014b), where it has been shown how such techniques can help in building a mental model of describing the causal effects of the disaster. The same case study of Bhopal was also investigated (Ishizaka and Labib, 2014) and a new logic gate in the fault tree method was proposed for analysing disasters and the benefits of using hybrid techniques of multiple criteria and fault analysis to evaluate and prevent disasters were demonstrated.In this paper an analysis of learning, and un-learning, from failures is carried out using a comparison between Bhopal and Fukushima, although they occurred in different industries, by comparing them we observe many similarities. This is followed by a compilation of different models based on FTA and RBD analysis of the Bhopal disaster which were an outcome of a series of workshops that were carried out to investigate the Bhopal disaster. This approach shows how the same case study can be viewed from different perspectives although the same modelling techniques were used. The paper then explores few interesting research questions such as how to evaluate different models? Do multiple models lead to better understanding of the case study? And are there any practical guidance to follow when studying root cause analysis?