Vulnerabilities of information and operational technologies and control of major accident hazard

Over the last decade, the establishments subject to legislations major accident hazard MAH have been affected by a growing integration between IT information technologies and OT operating technologies, due to Digital Transition. This leads to consider IT and OT as a single layer, defined ‘cyber layer’. It includes the IT resources supporting safety management system, hardware and software for process control and all cyber-physical systems used in plant management. Possible incidents in the cyber layer include software failures, obsolescence, as well as intentional attacks. The difficulty of updating OT systems opens the door for intentional and unintentional events, which can have major physical consequences. Bowtie method was used to analyse 65 minor accidents and near misses recorded in recent years in the Italian plants under MAH legislation, triggered by events in the cyber layer. The Italian events were compared with 28 minor events occurred in France and 6 major accidents occurred in the European Union. The definition of a logical model based on the bowtie analysis and the use of AI were essential to analyse the available data and extract useful information to understand emerging risks and to give practical indications to all stakeholders, including establishment operators, inspectors and regulators.