A recent cohort mortality study of 19,608 male employees of a major Texas chemical production facility had suggested that they might be at higher risk of lung cancer compared with the male population of the United States or Texas but not with the male population of the five-county area in which they reside. An occupational exposure was a possible explanation for this pattern, and a nested case-control study was undertaken of the 308 lung cancer deaths observed between 1940 and 1981. Two control groups, one a decedent and the other a "living" series, were individually matched to cases one-for-one. Interviews were conducted with subjects or their next of kin to collect information on smoking and other potential confounders. These data were combined with employee work history records and industrial hygiene data to form the basis of the analyses. Traditional stratification methods and conditional logistic regression were employed to examine for effect modification and to control confounding. Statistically significant, positive and negative associations were found for assignment to several work areas within the facility. Suggestive associations were observed for exposure to sulfur dioxide and heat. These and additional associations are discussed relative to evidence from other studies.

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Cause-specific mortality was surveyed among 19,608 male employees with 1 or more years of service between 1940 and 1980 at the Texas Operations of Dow Chemical U.S.A. Vital status was ascertained through 1980 for 97.3% of the cohort members, and death certificates were obtained for 96.4% of the 3,444 decedents. Mortality risks were found to vary, depending upon which of 3 population groups (United States, Texas, and local counties) was used for comparison, although significantly fewer than expected deaths from all causes was a common finding due to significant deficits in diabetes, diseases of the circulatory system, and cirrhosis of the liver. Significantly more deaths were from ill-defined conditions and cancers of unspecified sites. Lung cancer was significantly elevated in comparisons with the incidences in the United States and Texas, but not in comparison with those in the local counties. The influence of age at hire, period of hire, duration of employment, interval since entry into cohort, employment status, and two measures of social class--educational level and job category--were explored with the use of the Mantel-Haenszel method as adapted for a cohort study. Findings from these analyses are discussed in relation to the observations of other investigators and in the context of the possible impact of these findings on future studies of this work force.

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