This work introduces the outcomes of the first process for the identification and evaluation of sites potentially contaminated in the Region of the Bio Bio, Chile. The methodology combined qualitative and quantitative elements from Austrian and German risk assessment procedures, calibrated and adapted to the Chilean reality. The developed process consists of collecting historical and current registers on soil use, effects of materials handling on the population's health, and the description of the site conditions. The first analytical step corresponds to an image algebra analysis, through which the most vulnerable areas of the region are established. The sites identified inside the most vulnerable areas are classified into five priority classes, giving an approximate degree of endangerment from these sites. Through the experience, from a total of 507 sites identified as suspicious of contamination, five sites were classified under the highest priority. The results of this analysis have allowed Chilean authorities to focus their resources on the detailed investigations to be carried out in the five priority locations, whilst planning the future strategy to follow for the practical management of all sites found as currently posing a risk to the environment and to the society. (C) 2007 Elsevier Ltd. All rights reserved.