The amplification of accident consequences should be deeply considered in risk assessment studies carried out at chemical plants where the European Union's Major Accident Hazard (MAH) legislation is enforced. Several approaches have been discussed and applied to evaluate external domino effects (i.e., where damage areas affect external areas): these approaches are traditionally based on analytical models that are usually time-consuming due to both the large amount of information required and the inherent complexity characterizing analytical models. On the other hand, if accident consequences are located within establishment boundaries-the so called knock-on effect-the application of these models would be not suitable as they are characterized by high complexity. This article proposes an effective and fast approach for evaluating the most efficient actions to prevent internal knock-on risks by a structured approach: the model aims to support the competent authority for evaluating both technical and procedural control measures in chemical installations. A multi-criteria decision method, based on Saaty's Analytic Hierarchy Process (AHP), has been proposed. The model structure has been developed starting from the well-known Mond index; moreover, it evaluates several criteria, including equipment and plant vulnerability. The proposed model has been tested in a real case study regarding a chemical warehouse.