Terrorist actions in the transport of dangerous goods in urban areas

Recent historical events have shown that the number of terroristic actions has increased in these last years, furthermore the analysis of accidental scenarios caused by terrorist attacks or sabotage during the handling and the transportation of dangerous goods shows a significant number of this type of event. In the past the hypothesis of terrorist attack or sabotage had an almost negligible value and, generally, these events were considered security themes rather than safety matters, today, the value of the frequency for such an «accidental scenario» has become significant. Therefore it is obvious that a complete risk analysis must include the potential scenarios caused by terrorist attack or sabotage and therefore it must evaluate the increase of the risk level due to these events. As well as chemical plants and storage tanks, characterized by the presence of large quantities of dangerous substances, also road/rail tankers used for the transport of such goods constitute a potential target, moreover the hazard associated with transportation depends on the vulnerability of the territory. This paper focuses attention on the description of a methodology for the analysis of incidental scenarios caused by terrorist attacks and the identification of some aspects to improve. Finally an application of this method has been shown. Furthermore in order to obtain a complete risk risk aanalysis, it is necessary to take into account that, beyond substances transported, risk the consequences depends on the modality of the attach, the characteristic of infrastructure and territory