Managing major accident risk: Concerns about complacency and complexity in practice

• Invoking complacency issues to explain major accidents reveals concerns about how we relate to complexity in practice.
• What complexity in practice entails is defined through seven conditions of prudent practice.

In this paper, we are concerned with understanding safety issues presented as complacency issues in relation to major accidents. Using insights gained through accident reports as well as theoretical analysis, we seek to understand why current practices often induce a misleading overconfidence in risk management. We argue that the main challenge lies with our ability to acknowledge complexity in practice. From this basis, we propose to define what acknowledging complexity means through seven conditions of prudent practice. These concern the incompressibility of complexity, system boundaries and behaviour, contextualisation and differentiation, understanding of uncertainty, normality of ambiguity and the importance of language. These conditions of prudent practice can improve risk management related to major accidents, and ensure a prudent approach to the prevention of major accidents.