Risk assessment is a well established procedure for the analysis of the adverse impacts of pollutant substances emitted by waste treatment plants. The aim of the present study was the determination of the impact on human health associated with the activities of an incinerator in the Emilia-Romagna region (Northern Italy). The dispersion of heavy metals and organic pollutants monitored at plant stacks was predicted by the Gaussian model ISC3 (US-EPA). This analysis led to the estimation of risk, connected with various pollutants showing toxic and carcinogenic activities, for different receptors. The values obtained were first compared with the acceptability limits set by US-EPA, and then graphically represented as a territorial dispersion. A cautious approach was followed to calculate risk, by considering the worst, albeit realistic and reliable, estimate for the different parameters. The calculated exposure pathways resulted in different contributions depending on the receptor category (children and adults), even if direct exposure (via inhalation) is generally predominant. However, the resulting risk for both single pollutants studied and their combination all together proved to be within the acceptable limits (all lifetime individual risks being below 10(-6)), according to the procedure followed. The obtained results highlight the importance of using reliable monitoring data on the studied contamination source and, in particular, suggest the advisability of a more in-depth study on the pollution from incineration stacks.