SENTIERI Project evaluates the health impact of environmental exposures on residential population of National Priority Contaminated Sites (NPCSs). It takes into account a priori etiological hypotheses, based on the epidemiological evidence of an association between those exposures and selected diseases or causes of death. Building on the previous chapter, this one acts as a blueprint for future causal inferences based on scientific evidence relating to the health effects of exposure to specific pollutants present in the sites. In order to select the relevant pollutants, we make use of data concerning soil, aquifers, the food chain and the atmosphere. For each pollutant, we indicate cancer site and target organs, for non-neoplastic diseases, based on scientific assessment by international Agencies. We have chosen to focus on two sites: Brescia-Caffaro and Priolo. This method may conceivably be used by SENTIERI in the future to carry out more specific studies and provides the basis for a systematic analysis of contaminated sites.