SENTIERI Project (Mortality study of residents in Italian polluted sites) studies mortality of residents in 44 sites of national interest for environmental remediation (Italian polluted sites, IPS). The epidemiological evidence of the causal association between causes of death and exposures was a priori classified into one of these three categories: Sufficient (S), Limited (L) and Inadequate (I). In these sites various environmental exposures are present. Asbestos (or asbestiform fibres as in Biancavilla) has been the motivation for defining six sites as IPSs (Balangero, Emarese, Casale Monferrato, Broni, Bari-Fibronit, Biancavilla). In five of these, increases in malignant neoplasm or pleura mortality are detected; in four of them, results are consistent in both genders. In six other sites (Pitelli, Massa Carrara, Aree del Litorale Vesuviano, Tito, "Aree industriali della Val Basento", Priolo), where other sources of environmental pollution in addition to asbestos are reported, mortality from malignant neoplasm of pleura is increased in both genders in Pitelli, Massa Carrara, Priolo, "Litorale vesuviano". In the time span 1995-2002, a total of 416 extra cases of malignant neoplasm of pleura are detected in the twelve asbestos-polluted sites. Asbestos and pleural neoplasm represent an unique case. Unlike mesothelioma, most causes of death analyzed in SENTIERI have multifactorial etiology; furthermore, in most IPSs multiple sources of different pollutants are present, sometimes concurrently with air pollution from urban areas: in these cases, drawing conclusions on the association between environmental exposures and specific health outcomes might be complicated. Notwithstanding these difficulties, in a number of cases an etiological role could be attributed to some environmental exposures. The attribution could be possible on the basis of increases observed in both genders and in different age classes, and the exclusion of a major role of occupational exposures was thus allowed. For example, a role of emissions from refineries and petrochemical plants was hypothesized for the observed increases in mortality from lung cancer and respiratory diseases in Gela and Porto Torres; a role of emissions from metal industries was suggested to explain increased mortality from respiratory diseases in Taranto and in Sulcis-Iglesiente-Guspinese. An etiological role of air pollution in the raise in congenital anomalies and perinatal disorders was suggested in Falconara Marittima, Massa-Carrara, Milazzo and Porto Torres. A causal role of heavy metals, PAH's and halogenated compounds was suspected for mortality from renal failure in Massa Carrara, Piombino, Orbetello, "Basso bacino del fiume Chienti" and Sulcis-Iglesiente-Guspinese. In Trento-Nord, Grado and Marano, and "Basso bacino del fiume Chienti" increases in neurological diseases, for which an etiological role of lead, mercury and organohalogenated solvents is possible, were reported. The increase for non-Hodgkin lymphomas in Brescia was associated with the widespread PCB pollution. Mortality for causes of death with a priori Sufficient or Limited evidence of association with the environmental exposure exceeds the expected figures, with a SMR of 115.8% for men (90% IC 114.4-117.2; 2 439 extra deaths) and 114.4% for women (90% CI 112.4-116.5; 1 069 extra deaths). These excesses are also observed when analysis is extended to all the causes of death (i.e. with no restriction to the ones with a priori Sufficient or Limited evidence): for a total of 403 692 deaths (both men and women), an excess of 9 969 deaths is observed, with an average of about 1 200 extra deaths per year. Most of these excesses are observed in IPSs located in Southern and Central Italy. The procedures and results of the evidence evaluation are presented in a 2010 Supplement of Epidemiology & Prevention devoted to SENTIERI.