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Seveso sites: assessment of integrated safety-security hazards and risks and related domino effects


Chemical and process plants, energy facilities, oil and gas installations and industrial facilities are the potential target of physical and cyber-attacks. These may trigger cascading ‘domino’ effects such as the release of flammable, explosive, toxic or noxious substances into the environment and accidents in other areas of the plant not initially attacked.

Security-related threats could affect coasts, rivers, lakes and densely populated areas at regional and national scale. The Major Accident Reporting System reported 557 accidents in EU for the period 1990-2020; 23 of these accidents resulted in domino effects causing €1.1 billion of damages and €3.2 million of environmental damage.

The European Programme for Critical Infrastructure Protection promotes the prevention, preparedness and response to terrorist attacks to energy and transport installations. The European Seveso-III Directive (2012/18/EU) asks for an assessment of the domino effects focusing on safety and related issues but does not address security vulnerability. The link between the two policies has not been established and no guidance is available to identify potential domino effects on lifelines and Seveso establishment, and to assess and control security-related scenarios. Some tools and free software are available, but they do not support safety and security quantitative indicators or security scenarios. Lack of awareness and of prevention and mitigation strategies, along with the absence of specific tools for an integrated safety-security evaluation, is hindering competent authorities in the EU from making safety and security assessments and from effectively managing industrial sites.



Chemical and petrochemical sites, energy facilities, oil and gas installations, and more in general, industrial facilities storing relevant quantities of hazardous substances are characterized by a potential for severe environmental disasters when affected by external acts of interference. Indeed, physical attacks trough explosions, shooting, vandalism, etc. or cyber-attacks trough sabotage of process control systems may trigger complex cascading effects and the consequent release of large amount of flammable, explosive, toxic, or noxious substances in the environment.

Also, domino effects are likely, due to multiple, simultaneous scenarios triggered by the propagation of accidents from the attacked units to the rest of the plant.

Accidents caused by security-related threats and domino effect in the process industry may affect coasts, rivers, lakes, and densely populated urban areas at regional and national scale.


Risk assessment and monitoring

Pollution control

Human health protection

Industrial risks – Hazardous substances


SEVESO III Directive

(Directive 2012/18/EU)

Integration Policies

Contribution to other policies

EU Action Plan COM (2017)610

Industrial Emissions Directive