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This retrospective follow-up study evaluates the mortality experience of 4,388 employees of the Ciba-Geigy Corporation McIntosh plant. The subjects were all men who had worked in a production-related job for at least one month before January 1, 1987. Vital status was determined as of January 1, 1987, for 97% of the cohort. On average, there were 18 years of follow-up per subject during the study period. The overall and cause-specific observed numbers of deaths among the cohort members were compared with the numbers expected on the basis of United States (US) and Alabama (AL) general population mortality rates in order to estimate standardized mortality ratios (SMRs).
White cohort members had a favorable mortality experience based on US rates, limited primarily to men employed at the plant for at least five years (all causes: SMR = 77, 95% confidence interval (CI) = 61-97 and all cancer: SMR = 86, 50-138). Among black subjects, the mortality rates for all causes combined and for all major disease categories were much lower than the rates of black men in the US and AL general populations.
White subjects had more than expected deaths from several cancers including cancer of the buccal cavity and pharynx (5 observed/1.3 expected; SMR = 393, 127-918), esophagus (4/0.95; SMR = 422, 114-1082) and lung (22/14; SMR = 152, 95-203). This study cannot determine whether the increases are related to work place exposures, because each of the latter three cancers have strong nonoccupational determinants, the roles of which were not assessed. Also, the study did not evaluate the possible effects of chemicals used or produced at the plant, other than triazines. Black men had 2 observed versus 0.08 expected soft tissue sarcoma deaths (p = 0.006). The increase is based on small numbers and may be due to change or to some unidentified occupational or nonoccupational exposure.
The subjects who had worked in the production of triazine herbicides did not experience any unusual excesses or deficits of deaths. Among 1,720 men with definite regular work with triazines, there were 81 observed/94 expected deaths from all causes and 13 observed/14 expected deaths from cancer.