Lung cancer mortality among pottery workers in the United States.

A proportionate mortality study suggested that members of the International Brotherhood of Potters and Allied Workers in the United States had an elevated frequency of deaths from non-malignant respiratory disease (PMR = 1.54) and lung cancer (PMR = 1.21). The lung cancer excess occurred exclusively among pottery workers employed in the manufacture of plumbing fixtures (PMR = 1.80). A subsequent cohort study examined mortality among 2055 white men employed in three ceramic plumbing fixture factories. There was a significant excess of non-malignant respiratory disease (SMR = 1.73). Lung cancer mortality was also higher than expected (SMR = 1.43) and was highest among workers whose jobs involved simultaneous exposure to silica and non-fibrous talc (SMR = 2.54). Lung cancer mortality risk increased with increasing number of years of exposure to non-fibrous talc and showed no pattern by number of years of exposure to silica. Among men exposed to talc, lung cancer risk increased with years since first non-fibrous talc exposure and decreased with age at first exposure. The data suggested an association between exposure to non-fibrous talc and excess lung cancer risk; however, the role of silica as a co-factor or promoting agent could not be ruled out.