No single property can be used for assessing the fire hazards of chemical substances and materials; different methods use different fire hazard properties in their assessment. On the other hand, current methodologies and classification systems usually use linguistic variables corresponding to specific range of values, for the classification of different hazards. Moreover, many uncertainties are present in the assessment of industrial hazards or industrial accidents consequences. In this paper, a new approach for the rapid assessment and relative ranking of the hazards of chemical substances, as well as units and installations, is presented. This approach is based on employing a multi-criteria decisionmaking technique (the Analytic Hierarchy Process) for the hazard assessment of substances and installations. The multi-criteria approach aims in the better incorporation of the different properties or parameters in hazard assessment. This approach is also based on fuzzy logic. Fuzzy logic is considered better for dealing both with linguistic variables and uncertainties. A number of Indices have been developed, based on the proposed methodology and are presented: the 'Substance Fire Hazard Index', (SFHI), which is focused on the major-accident hazards of the substances, and the 'Consequences Index', (CI), for the assessment of the consequences potential of an accident at the facility. The challenges and limitations of using the multi-criteria approach for the development of such indices are also discussed.