Considering critical infrastructures in the land use planning policy around Seveso plants

•The risk is underestimated in the LUP by not taking account the CIs.•A protection of critical infrastructures is essential to the safety of populations.•The failure of a CI can have a much larger impact than the accident himself.•A adaptation of the walloon risk quantification approach is proposed.•A new approach can be developed to manage exclusion zones around Seveso sites. The damages following major accidents in chemical facilities highlight civil society vulnerability to these risks. Many countries have drafted guidelines to prevent such accidents and to reduce the consequences for humans and environment. However, the consequences of such accidents on critical infrastructures (CI) and the cascading effect that may result are rarely considered. In Europe, the Seveso Directives set out the major principles underlying prevention policy for these risks. Consequently, European Member States must assess the risks to which establishments (schools, hospitals, …) are exposed. However, in evaluating risks, only scenarios involving accidents which directly harm humans are generally studied. Damages which could cause the failure of a CI, necessary for the proper functioning of the territory, are not directly considered. This study briefly presents the risk quantification approach used in the Walloon Region (Belgium), which does not consider CIs interdependencies but can be adapted to do so. To illustrate the benefits of considering CI, the results of a simulated explosion in Montreal (Canada) are presented and show that taking CIs into account is more than relevant. A possible line of approach is proposed to allow the risks related to CI failures to be addressed in the Walloon method.