A mortality study among workers in a French aluminium reduction plant.

OBJECTIVE: A mortality study on the association between lung cancer and occupational exposure to polycyclic aromatic hydrocarbons (PAHs) was carried out in a French aluminium reduction plant. This study updated a previous mortality study. METHOD: The historical cohort included every male worker who had been employed in the plant for at least 1 year between 1950 and 1994. Workers were followed-up for mortality from 1968 to 1994. Causes of death were obtained from death certificates. Standardised mortality ratios (SMRs) and 95% confidence intervals (CI) were computed using regional mortality rates as external reference to compare observed and expected numbers of deaths, adjusted for gender, age and calendar time. RESULTS: The cohort comprised 2,133 men, of whom 335 died during the follow-up period. The observed mortality was lower than expected for all causes of death (SMR = 0.81, CI 0.72-0.90) and for lung cancer (observed = 19, SMR = 0.63, CI 0.38 0.98). No lung cancer excess was observed in workshops where PAH exposure was likely to have occurred, and no trend was observed according to duration of exposure and time since first exposure. This low lung cancer mortality could be partly explained by a marked healthy worker effect and a possible negative confounding by smoking. An excess was observed for bladder cancer (observed = 7, SMR = 1.77, CI 0.713.64) in the whole cohort, that was higher among workers employed in workshops where PAH exposure was likely to have occurred (observed = 6, SMR = 2.15, CI 0.79-4.68). In addition, an SMR higher than unity was observed for "psychoses and neuro-degenerative diseases" (observed = 6, SMR = 2.39, CI 0.88-5.21), that could not be related to occupational aluminium exposure. CONCLUSION: No lung cancer risk was detected. Non-significant excesses were observed for bladder cancer and for psychoses and neuro-degenerative diseases.

Mineralogical analysis of the respiratory tract in aluminium oxide-exposed workers.

A retrospective study was conducted in order to characterize the retention of fibrous and nonfibrous mineral particles in the respiratory tract in subjects with previous occupational exposure in the aluminium industry. Bronchoalveolar lavage (BAL) fluid (three samples) or lung parenchyma (two samples) were studied using analytical transmission electron microscopy in five patients. A high concentration of aluminium fibres (> 10(7) fibres.g-1 dry lung) was identified in two lung tissue samples, and aluminium fibres were also identified in BAL fluid in three patients. All fibres were short (mean length: 1-2 microns), with no fibre longer than 5 microns. Some biopersistence of these fibres in the respiratory tract is suggested from these observations, since fibres were identified in biological samples collected more than 4 yrs after cessation of exposure in four out of five patients. Occupational physicians should be aware of possible exposure to short, thin aluminium fibres during primary aluminium production. Further studies are needed to assess the potential health effects of these fibres. Industrial hygiene measurements should also be performed to document the potential sources of exposure to aluminium fibres in this industry.