MORTALITY AMONG CHEMICAL WORKERS IN A FACTORY WHERE FORMALDEHYDE WAS USED

Objectives-An independent and updated historical cohort mortality stud y was conducted among chemical plant workers to investigate further an association between exposures to formaldehyde and particulates and ca ncers of the nasopharynx and lung reported in an earlier National Canc er Institute study of the same plant. Methods-Subjects were 7359 worke rs who were first employed between 1941 and 1984 in a factory in Walli ngford, Connecticut where formaldehyde was used. Vital status was dete rmined on 31 December 1984 for 96% of the cohort and death certificate s were obtained for 93% of 1531 known deaths. Exposures of individual workers were estimated quantitatively for formaldehyde, product partic ulates, and non-product particulates, and qualitatively for pigment. S tatistical analyses focused on 6039 white men in 1945-84. Cohort data that could not have been included in the National Cancer Institute stu dy were also analysed separately. Results-Mortality among long term wo rkers (employed greater than or equal to 1 y) was generally Biostatist ics similar to or more favourable than that of the general population, and there was little Department of evidence of a relation between eit her rates of lung cancer or standardised mortality ratios (SMRs) and s everal measures of exposure to formaldehyde, particulates, and pigment . For several causes including lung cancer, death rates among short te rm workers (employed <1 y) were significantly increased. Short term wo rkers did not seem to differ hom long term workers for the exposures c onsidered. Among all white men, a significant SMR of 550 (local compar ison) for nasopharyngeal cancer (NPC) was based on the same four index cases identified in the earlier study of this plant. Only one case of nasopharyngeal cancer had any appreciable exposure to formaldehyde. N o new cases of nasopharyngeal cancers were found among the cohort data that could not have been included in the National Cancer Institute st udy-that is, extended observation time and additional study members. C onclusions-Among workers employed for at least one year, this study pr ovides little evidence that the risk of lung cancer is associated with exposure to formaldehyde alone or in combination with particulates or pigment. The significant increases in both the rates and SMRs for lun g cancer seem to be primarily a phenomenon of short term workers, but the possibility remains that unmeasured occupational or non-occupation al factors may have played a part.