This “severity” scale was made official in February 1994 by the Committee of Competent Authorities (CCA) of EU Member States as a means of applying the SEVESO Directive.
It is based on a series of 18 technical parameters intended to objectively characterise the effects or consequences of accidents. Each of these parameters contains 6 levels, with the highest level determining the accident’s index rating.
Since 2003, France has used this European scale to represent 4 indices. The parameters taken into account and their rating protocol are explained in the table below.