Insulators (Luggers)
Workers who applied asbestos insulation (called lagging) typically had heavy exposures to loose fibers of chrysotile, amosite, and crocidolite. Among 17,800 American and Canadian insulators, 458 mesothelioma deaths (285 peritoneal) were determined by "best evidence" method for the 1967-1986 time period. This cohort had 301,000 person-years of average exposure at a cumulative level of 500 f/ml-yr (Seidman and Selikoff, 1990; Hodgson and Darnton, 2000, Table 2). The cancer morbidity study of 3787 workers of a shipyard that was abandoned in 1972 found 4 cases of mesothelioma (Sanden and Jarvholm, 1987). Seven cases of peritoneal mesothelioma, none pleural, were observed among 248 insulation workers (Jarvholm and Sanden, 1998). Dr. Selikoff and colleagues reported 8 mesothelioma deaths among 440 U.S. shipyard insulation workers, and all had over 20 years since onset of employment to diagnosis. Chrysotile and amosite (starting just before World War II) were the fiber types for exposures noted in the article (Selikoff et al., 1979). A retrospective study of cancer among 7971 shipyard workers with 5191 of them exposed to asbestos based on job title, including those in the pipecoverer/insulator trade, is included in Table 2, although asbestos measurements are not documented. The authors thought amosite and chrysotile were the major types of asbestos used at the Pearl Harbor Naval Shipyard in terms of this study. Of 9 observed mesothelioma cases, 1 was in the major job category of insulator (Kolonel et al., 1980, 1985). Mortality of 41 insulation workers was also studied for a shipyard in Genoa, Italy, but the authors did not provide the asbestos fiber types (Puntoni et al., 1979), and therefore the study is not in a table of this review. No mesotheliomas were reported for these Genoan insulators.