This article explores two questions that can be answered by transforming major risk management systems into digital models. 1/ A pragmatic question: How can we successfully integrate the regulatory requirements, risk assessment and safety management of a Seveso plant into a non-static picture, in order to reduce the gap between risk studies and the ever-changing reality of installations and practices? 2/ An epistemological question: How can we ensure that this non-static picture is an intelligible and acceptable model (validity, veracity sufficient to make decisions)? The pragmatic question and the epistemological one are interlinked, as two sides of the same coin. They are born from a criticism of a certain bureaucracy which leads to be satisfied with a paper documentation of the control of the risks for the “administration”, that is static in nature and does not necessarily represent a true picture of the ground truth of safety. This article presents the result of a work started in the TOSCA project (Total Operations Management for Safety Critical Activities), a European Project funded within the context of the 7th Framework Programme (see Leva et al. 2019, Anzirsi et al. 2019). This project aimed at developing an innovative approach able to integrate method and IT tool for improving risk management in the field of environmental and major hazard issues. Within this project, in 2013, INERIS started a case study with the Service National des Oléoducs Interalliés (SNOI). SNOI is responsible for the French part of the NATO pipeline network in Central Europe (CEPS), known as the Common Defense Pipeline (ODC). It thus operates a network of 2,300 km of pipelines and 14 SEVESO depots, including 7 classified as high threshold, for a total capacity of 500,000 m3 distributed among more than 80 buried tanks. Since 2013, INERIS and SNOI continued to work together, every day, to develop a method and a web tool dedicated to the combined management and assessment of major risk, where the data from daily monitoring can also be integrated alongside the requirements from the regulations and the required inspections.