Chemical industrial areas may constitute potential targets for deliberate actions by terrorists. Terrorists having sufficient knowledge of chemical process operations or plant layout may take advantage of improvised explosive devices (IEDs) to cause major events such as fire, explosion and toxic gas dispersion with cross-border consequences in chemical clusters. Thus, an efficient cluster-wise emergency plan to enhance the promptness and efficacy of responding to such attacks is crucial. In this study, the effects of blast wave caused by IEDs are assessed and its potentiality in triggering domino scenarios are analysed. A decision tree is developed to determine the emergency level of each company within the cluster based on the attack outco...