“…Silicosis was identi®ed by compensation claims, rather than by systematic radiographic or other medical surveillance, in studies of Italian pottery workers [Forastiere et al, 1986], Italian miners [Mastrangelo et al, 1988], Italian refractory brick workers [Puntoni et al, 1988], German slate quarry workers [Mehnert et al, 1990], and Australian gold miners [de Klerk and Musk, 1998]. The absence of quanti®ed silica exposure data is a severe limitation affecting most of these investigations [Forastiere et al, 1986;Mastrangelo et al, 1988;Mehnert et al, 1990;Amandus and Costello, 1991;Hua et al, 1994;Finkelstein, 1995;Dong et al, 1995;Meijers et al, 1996;Qiao et al, 1997]. Interestingly, Finkelstein [1995] was able to derive quantitative estimates for radon exposure, and demonstrated that this was a very unlikely explanation for an excess lung cancer risk in silicotics; unfortunately, quanti®cation of silica exposure was not possible.…”