Industrial facilities where relevant quantities of hazardous chemicals are stored or processed may be direct or indirect targets of malicious acts of interference, including cyber or physical attacks. In the case of direct attacks, one or more process units may be damaged within the installation, often with the clear willingness of triggering domino effects escalating the primary event and possibly involving the entire installation. Also indirect attacks may be relevant, where the damage or destruction of neighboring sensible civilian targets is the primary aim of the action, but domino effects may be generated by the effects of the interaction with primary, large-scale accidents occurring outside the physical border of the facility. Escalation may result in cascading events that may heavily involve and damage the industrial facility of concern.@en

Security threats are becoming an increasing concern for chemical sites and related infrastructures where relevant quantities of hazardous materials are processed, stored or transported. In the present study, security related events that affected chemical and process sites, and related infrastructures, were investigated. The aim of the study is to frame a clear picture of the threats affecting the chemical and process industry, and to issue lessons learnt from past events. A database of 300 security-related accidents was developed and populated, starting from European and American sources. Threat categories that caused such events were identified and analyzed. The attack modes were investigated. Important differences were found with respect to geographical areas and industrial sectors affected. The use of explosives (both military and improvised explosive devices) is by far the more frequent attack mode, although armed attacks and arson are also frequent events and may result in an in-depth penetration of the attackers. In recent years, cyber-attacks are also posing important threats. Lessons learnt call for the implementation of a specific security management system in the chemical and process industry, aiming at the physical and cyber protection of industrial sites.

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