This document sets out a diagnostic approach regarding the mechanical resistance of silos to an internal explosion that could occur within them. Even though prevention is logically a priority, risk analysis is about studying contingencies and vulnerability. Presented herein are risk assessment methods-including methods for quantifying the effects of an explosion on structure, as well as methods for assessing structure vulnerability. The data required for the vulnerability research approach are defined. The location of sampling holes, which may prove necessary for diagnosis purposes, is more fully developed for tower silos. A stability analysis for the different silo components is established. This approach is useful for risk analysts and allows them to highlight the sensitive elements in order to integrate the protection aspect into an existing facility or a facility to be constructed. (C) 2003 Elsevier Science Ltd. All rights reserved.