Abstract-The work presents the knowledge base of the expert system of the aggregate assessment of the level of industrial safety at a hazardous production facility, based on the use of the logico-axiological approach. The fundamental hypothesis: the reduction in production safety is due to the presence of "NE-factors": poor implementation of organizational measures, improper working conditions, inadequate personal protective equipment and so on. Failure to take measures to provide protection against industrial accidents leads to a reduction in the level of industrial safety. According to the approach used, the influence of "NOT-factors" on the level of "non-safety" of production is formalized by products of the type: АВ.