This The purpose of the work described in this paper is to improve the production and assessment of the different types of safety analyses by searching for errors at system level and in the hardware and software by following two directions of investigation: - A methodological direction, which attempts to improve the methods which are normally used for safety analyses and suggests methods and strategies for the appraisal of these analyses as regards coherence, completeness and traceability, - An operational direction, which aims to develop software tools to aid in the design and examination of safety analyses. In particular these include systems for the acquisition, modelling, storage and appraisal of these analyses. The approach used to achieve this is mainly based on the use of artificial intelligence techniques, in particular knowledge acquisition and modelling techniques, knowledge- based systems, automatic symbolic learning techniques and knowledge validation techniques. This paper presents a general description of four mock-ups of tools which are intended to aid in the analysis and investigation of safety.