There are recent allegations of kids residing close to a lead smelter, which shut down in 1993, who have high Cd levels in their blood. The study’s goal is to identify the source of Cd pollution and other potentially harmful elements, with a particular emphasis on the chimney dust, which were used for this characterization investigation. Chemical, physical and mineralogical methods were used in this investigation. The principal phases in the dust are: sulfur, anglesite and kaolin. After sulfur removal the chemical analysis revealed that the following elements constitute the majority of the dust (wt%): 10.4% of S, 44.37% of PbO, 17.34% of SiO2, 6.28% of Al2O3, 1.22% of ZnO, 0.93% of As2O3. The amount of Hg was 4670 mg/kg and the amount of Cd was higher than 5000 mg/kg. Anglesite was highly concentrated in the dust. According to the leaching investigation, the chimney dust was unstable in mildly acidic conditions for only brief contact durations, releasing significant amounts of Pb, Zn, and Sb as well as a significant quantity of Cd. Therefore, given the toxic elements, this dust should be considered a very hazardous material.