Epidemiologic study of lung cancer mortality in workers exposed to titanium tetrachloride.

A study was done to examine whether workers exposed to titanium tetrachloride had significantly higher risks of lung cancer, chronic respiratory disease, pleural thickening/plaques, or pulmonary fibrosis than referent groups. A total of 2477 employees from two titanium dioxide plants were studied. Of that group, 969 employees exposed to titanium tetrachloride were observed from 1956 through 1985 for cancer and chronic respiratory disease incidence and from 1935 through 1983 for mortality. A cross-sectional sample of 398 employees was evaluated for chest roentgenogram abnormalities. Cohort analyses showed that the risk of developing lung cancer and other fatal respiratory diseases was not statistically significantly higher for the titanium tetrachloride-exposed workers than for the referent group. Nested case-control analyses found no statistically significant association between titanium tetrachloride exposure and risk of lung cancer, chronic respiratory disease, and chest roentgenogram abnormalities. No cases of pulmonary fibrosis were observed among titanium tetrachloride-exposed employees. Smoking was found to be a strong predictor of lung cancer mortality in the nonexposed employees with an increased risk of dying from lung cancer up to 7-fold higher in current smokers than in nonsmokers.

A case-control study of cancer among du pont employees with potential for exposure to dimethylformamide.

This case-control study was undertaken to determine whether the risk of developing cancers of the buccal cavity and pharynx (N = 39), liver (N = 6), prostate (N = 43), testis (N = 11), or malignant melanoma of the skin (N = 39) is related to exposure to dimethylformamide (DMF). Case and control subjects were obtained from four Du Pont plants. DMF is produced at one plant and used at the other three. Cancer cases identified from the company Cancer Registry comprise those reported among active male employees at the study plants during 1956 to 1985. For each case, two control subjects were selected, matched on sex, payroll class (wage or salary), birth year, and plant. To determine whether an employee could have been exposed to DMF during his career at the plant, all jobs with potential for exposure to DMF were identified. Each job was assigned an exposure ranking based on DMF industrial hygiene air monitoring, DMF metabolite (measured as N-methylformamide in urine) monitoring, and knowledge of the evolution of manufacturing processes and workplace exposure controls. Each employee's DMF exposure pattern was then characterized as (a) ever v never having been exposed to DMF and (b) highest DMF exposure experienced. Summary analyses for all plants combined showed no statistically significant association between ever having been exposed to DMF and subsequent development of cancers of the buccal cavity and pharynx, liver, malignant melanoma, prostate, and testis. Examined by plant site, prostate cancer at one plant was significantly elevated, based on three case subjects exposed out of four.(ABSTRACT TRUNCATED AT 250 WORDS)