Vulnerability of industrial facilities to attacks with improvised explosive devices aimed at triggering domino scenarios

•Improvised explosives possibly used for terrorist attacks were described.•The TNT efficiency of ANFO and TATP was characterized.•Domino effects caused by an attack with improvised explosive were analyzed.•Domino scenarios induced by an attack were compared to conventional scenarios.

Process- and chemical plants may constitute a critical target for a terrorist attack. In the present study, the analysis of industrial accidents induced by intentional acts of interference is carried out focusing on accident chains triggered by attacks with home-made (improvised) explosives. The effects of blast waves caused by improvised explosive devices are compared with those expected from a net equivalent charge of TNT by using a specific methodology for the assessment of stand-off distances. It is demonstrated that a home-made explosive device has a TNT efficiency comprised between 0.2 and 0.5. The model was applied to a case study, demonstrating the potentiality of improvised explosives in causing accident escalation sequences and severe effects on population and assets. The analysis of the case-study also allowed obtaining suggestions for an adequate security management.