The Combe du Saut mining and industrial complex has been located for many years in the region north of Carcassonne (Aude), near the village of Salsigne, in the Orbiel River valley. Available environmental data and documented industrial activities—including mining, pyrometallurgical, and hydrometallurgical operations—indicated the presence of various pollutants that may be toxic to humans, particularly lead, cadmium, arsenic, and cyanides. However, these environmental data were too fragmented to precisely quantify and delineate the population’s exposure. This situation led the health authorities (DDASS of Aude) to request the assistance of the National Public Health Network to estimate, within the general population, the potential health impact associated with pollutant emissions from this industrial complex. To this end, two studies—an epidemiological study of population exposure to various pollutants and a cancer mortality study—were proposed to the Prefect of the Aude department, who approved them. These studies, coordinated by the National Public Health Network, were carried out in collaboration with the Departmental Directorate of Health and Social Affairs, the Southeast Interregional Epidemiology Unit, the INSERM Cancer Research Unit (U351), and the Fernand Widal Poison Control Center in Paris. Other partners in these studies included the Regional Directorate of Health and Social Affairs and the Languedoc-Roussillon Regional Health Observatory, as well as the General Directorate of Health and the Carcassonne School of Nursing.