The Joint Research Centre of the European Communities, and in particular the Institute for Systems Engineering and Informatics (ISEI) at Ispra, have weil established competences in risk analysis, uncertainty analysis and statistical data treatment. More recently, work on Environmental Impact Assessment (EIA), particularly on environmental indicators and indices and on a "system engineering approach" to EIA, has started. This approach attempts to move towards "unified" procedures to investigate normal operation and acciclental risks; these are problems concerned within both the EIA Directive...