Humans are exposed to bentonite particles (BPs) mainly through occupational pathways. Occupational exposure to BPs can cause pneumoconiosis in workers involved in mining and processing of bentonite [1–4], which is a chronic inflammatory and fibrotic lung disease. Recently, chronic inflammation has been accepted as a common and important factor in the pathogenesis of neopla- sia. Chronic inflammation provides a dynamic setting for oxidative stress and formation of free radicals. Interaction of reactive oxygen species (ROS) with DNA increases the likelihood of DNA structural and transcriptional errors [5]. Genotoxicity induced by BPs has been investigated regarding their varying quartz contents (less than 1% to more than 20%) and activations (eg alkaline, acidic and organic activations). Quartz has been classified as a human carcinogen by the International Agency for Research on Cancer (IARC) [6]. In vitro and in vivo studies showed that silica or quartz particles could induce the significant genotoxic effects including DNA damage, micronuclei (MN) and formation of premutagenic DNA lesion 8-hydroxydeoxyguanosine