This paper focuses attention on emergency management associated with a terrorist attack in the transport of hazardous materials in urban areas. The case study is in an urban area, a potential target for terrorist attacks due to its high Vulnerability. Since it is not possible to predict where and when an attack will occur, the risk associated with terrorism is complex It is only possible to identify the critical points for potential actions where counter measure must be applied. In the case of incidents which evolve relatively slowly, mitigation actions can be applied. The use of dynamic geoevents permits the immediate location of the event on a georeferenced map and the possibility of having a dynamic evolution of the scenario and of the number of people involved The dynamic scenario has been created using the output of a consequence simulation code and a GIS software. Sonic assumptions were necessary but, since the aim of the paper is to define the procedure for the construction of the dynamic geoevent, these can be considered acceptable. The method will be further implemented in future. (C) 2009 Elsevier Ltd. All rights reserved