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 0.71–3.64) 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. Received: 11 June 1999 / Accepted: 22 January 2000     

Lung and bladder cancer among workers in a Norwegian aluminium reduction plant

OBJECTIVE—To investigate the relation between exposure to polycyclic aromatic hydrocarbons (PAHs) and the incidence of lung and bladder cancer among aluminium production workers.
METHODS—The cohort comprised 1790 men employed for more than 5 years at a Norwegian aluminium plant contributing 36 587 person-years to the study. Historical exposure to PAHs was estimated by the use of industrial hygiene measurements and by a panel of three people familiar with the industry. Cancer incidence was investigated from 1953 to 1995. The observed cases of cancer among men were compared with expected numbers calculated from national rates for men, and dose-response relations were investigated by internal comparison by Poisson regression with age, period, smoking, and cumulative exposure included in the models. The effect of lagging exposure by 10, 20, and 30 years was also investigated.
RESULT—The present study showed no increased risk of urinary bladder cancer or lung cancer with increasing cumulative exposure to PAHs. No significant changes in risk were found for different lag times.
CONCLUSIONS—Due to the small size of this study, a minor increase in risk could not be excluded.


Keywords: cancer incidence; polycyclic aromatic hydrocarbons; Søderberg     

Mortality studies of aluminum reduction plant workers: potroom and carbon department

The purpose of this study was to investigate mortality patterns of aluminum reduction plant workers. A cohort was formed of 21,829 workers with five or more years employment in 14 reduction plants. Progress of the study was reported quarterly to a Tripartite Committee consisting of representatives from labor, management and government. Although the results of other studies relative to an excess of lung cancer in aluminum workers were not confirmed, there were indications of a higher than expected mortality in pancreatic cancer, lymphohematopoietic cancers, genitourinary cancer, nonmalignant respiratory disease and benign and unspecified neoplasms.     

Mortality study among workers producing chromate pigments in France

In a follow-up study of 294 men who had worked for at least 6 months in a chromate-producing factory in France between 1958 and 1987, only 16 were lost to follow-up and the number of person-years in the study was 5207. Occupational data were provided by the administration of the plant. The causes of deaths were ascertained from hospital and general practitioners' records. The observed numbers of deaths were compared with the expected numbers based on local rates with adjustment for age, sex and calendar time (standardized mortality ratio, SMR). The overall mortality did not differ significantly from that expected (SMR = 1.20, 95% CI = 0.98–1.47), whereas mortality due to lung cancer was in significant excess (SMR = 3.60, 95% CI = 2.13–5.68). Significantly higher lung cancer SMRs were found for workers whose duration of employment was more than 10 years. A non-significant excess was observed for all forms of digestive tract cancer (SMR = 1.30, 95% CI = 0.60–2.47). There were two cases of brain cancer when 0.24 was expected (SMR = 8.44, 95% CI = 1.02–30.49). No previous report has mentioned an association of brain cancer with chromate pigments; however, because of the small numbers involved, a chance excess should be considered.     

Mortality of female workers in rubber manufacturing plant

The ten-year mortality experience of a cohort of white female production workers in a large rubber manufacturing plant is presented. An analysis of the observed and expected numbers of death from numerous causes revealed a slightly elevated overall standarized mortality ratio with an excess of deaths from both lung cancer and myocardial infarction, and a deficit of deaths from breast cancer. About two-thirds of all women in this cohort had worked, for the longest period of employment, in the manufacture of industrial products, while the remainder were engaged mostly in the manufacture of tires. Some preliminary associations between type of job and mortality experience are discussed, but a more detailed analytic investigation is required before nonoccupational risk factors can be ruled out.     

Mortality of coke plant workers in The Netherlands

During the production of coke, large quantities of coke oven gas are emitted. People who work on the top or on the sides of coke ovens are exposed to this oven gas, which contains a range of carcinogenic chemicals. To investigate the cancer risks under these work conditions, a retrospective study was undertaken. In total 11,399 former workers were enrolled in the study. Of these, 5639 had worked in the coke plant for at least six months between 1945 and 1969. The other 5740 had worked in another plant during the same period and formed a non-exposed group for comparison. The study group was followed up until 1984 for mortality. The causes of death were obtained from the Central Bureau of Statistics. Among the coke oven workers significantly higher death rates were found for lung cancer and non-malignant respiratory disease. Mortality in the byproduct section was similar to that expected. Among workers in the tar distillery the rate for lung cancer was higher than expected. The risk for gastric cancer and non-malignant respiratory disease among the workers of the coke shipping department was increased but the SMRs did not reach statistical significance. No data were collected about individual smoking habits or socioeconomic state of the study subjects and the possibility that the risk found could be attributed to these factors cannot be ruled out. It has been stated by other investigators, however, that the effect of not controlling for smoking tends to be modest.     

Mortality in retired coke oven plant workers.

A previous study on 536 retired coke oven plant workers in Lorraine Collieries (France) reported an excess of deaths from lung cancer (standardised mortality ratio (SMR) = 251) compared with the French male population. Occupational exposures during working life were retraced for each subject, but the number of deaths during the observation period (1963-82) was small, and smoking habits were known only for dead subjects. In 1988, the cohort was re-examined (182 deaths occurred between 1963 and 1987) and smoking habits were determined for all the subjects. This study confirmed the excess of lung cancer (SMR = 238, p < 0.001). It showed an excess of mortality from all causes (SMR = 141, p < 0.001), overall cancers (SMR = 133, p < 0.05), and cardiovascular diseases (SMR = 133, p < 0.05). A significant excess of deaths was found for subjects who worked near the ovens for all causes (145, p < 0.01), lung cancer (SMR = 252, p < 0.01), colon cancer (SMR = 381, p < 0.05), and cardiovascular diseases (SMR = 155, p < 0.05). A significant excess mortality was also found from all causes (176, p < 0.05) and stomach cancer (SMR = 538, p < 0.01) in subjects who worked in byproducts, from lung cancer (SMR = 433, p < 0.001) in those in the workshops, and from cirrhosis of the liver and alcoholism (SMR = 360, p < 0.01) in those underground; but, due to small numbers, these figures were not robust. An excess of mortality from all causes (SMR = 163, p<001), lung cancer (SMR = 228, p<0.05) and cardiovascular diseases (SMR = 179, p<0.01) was shown also for non-exposed or slightly exposed subjects. The fact that, on the whole, mortality of various exposed groups was similar to that of non-exposed or slightly exposed workers may be explained in part by the selection at hiring and the healthy worker effect. As an increased risk of lung cancer was noted among subjects who worked in the old generations of plant compared with the other workers (although the relative risk was not significant) it is concluded that the role of occupational hazards could not be excluded.     

Mortality of coke plant workers in The Netherlands.

During the production of coke, large quantities of coke oven gas are emitted. People who work on the top or on the sides of coke ovens are exposed to this oven gas, which contains a range of carcinogenic chemicals. To investigate the cancer risks under these work conditions, a retrospective study was undertaken. In total 11,399 former workers were enrolled in the study. Of these, 5639 had worked in the coke plant for at least six months between 1945 and 1969. The other 5740 had worked in another plant during the same period and formed a non-exposed group for comparison. The study group was followed up until 1984 for mortality. The causes of death were obtained from the Central Bureau of Statistics. Among the coke oven workers significantly higher death rates were found for lung cancer and non-malignant respiratory disease. Mortality in the byproduct section was similar to that expected. Among workers in the tar distillery the rate for lung cancer was higher than expected. The risk for gastric cancer and non-malignant respiratory disease among the workers of the coke shipping department was increased but the SMRs did not reach statistical significance. No data were collected about individual smoking habits or socioeconomic state of the study subjects and the possibility that the risk found could be attributed to these factors cannot be ruled out. It has been stated by other investigators, however, that the effect of not controlling for smoking tends to be modest.     

Mortality and cancer experience of Quebec aluminum reduction plant workers, part 4: cancer incidence

OBJECTIVE: To describe the cancer experience of Quebec aluminum smelter workers. METHODS: Cancer incidence was compared with that of the Quebec general population and examined in relation to benzo[a]pyrene (B[a]P) and smoking exposure indices. RESULTS: There was a statistically significant increased incidence of stomach (two cohorts), pancreatic (one cohort), laryngeal (one cohort), lung (three cohorts), and bladder (four cohorts) cancers. Unlike lung and bladder cancers, pancreatic and stomach cancer risks do not relate meaningfully to cumulative B[a]P exposure. Laryngeal and buccal cavity cancer standardized incidence ratios (SIRs) seem to increase with increasing B[a]P exposure. SIRs from lung cancer have greatly diminished whereas bladder cancer SIRs remain elevated in all but one cohort. CONCLUSIONS: The cancer incidence results are consistent with those from mortality studies, but identify other cancers that deserve scrutiny in future follow-ups.     

Mortality study among workers producing ferroalloys and stainless steel in France

A mortality study was carried out among the workers of a plant that had produced ferrochromium and stainless steel, and was still producing stainless steel, in order to determine whether exposure to chromium compounds, to nickel compounds, and to polycyclic aromatic hydrocarbons (PAH) could result in a risk of lung cancer for the exposed workers. The cohort comprised 2269 men whose vital status were recorded between 1 January 1952 and 31 December 1982. The smoking habits of 67% of the cohort members were known from medical records. The observed numbers of deaths were compared with the expected ones based on national rates with adjustment for age, sex, and calendar time. A low mortality, achieving statistical significance, was found from all causes (observed = 137, standardised mortality ratio (SMR) = 0.82) and from benign respiratory diseases (observed = one, SMR = 0.15). With regard to mortality from lung cancer, a non-significant excess appeared in the whole cohort (observed = 12, SMR = 1.40). Among the exposed workers, however, a significant lung cancer excess was found (observed = 11, SMR = 2.04) that contrasted with a low SMR (0.32) in the non-exposed group. This excess is unlikely to be explained by smoking, as the tobacco consumption of these two groups was similar. No trend was observed for mortality from lung cancer either according to time since first exposure, or according to duration of exposure. A nested case-control study clearly suggested that this excess of deaths from lung cancer was attributable to former PAH exposures in the ferrochromium production workshops rather than to exposures in the stainless steel manufacturing areas.     

Biomonitoring of genotoxic exposure of aluminium plant workers.

Humans are environmentally and occupationally exposed to polycyclic aromatic hydrocarbons (PAH). PAH's are a class of tumorigenic compounds which act through metabolic transformation to chemically reactive forms, epoxides, which covalently bind to DNA forming DNA adducts. To evaluate the genotoxic effects of PAH's, air and urine samples were analyzed for PAH. Blood samples were analyzed for benzo(a)pyrene-diol-epoxide-DNA (BPDE-DNA) adducts. New methods for analyzing DNA adducts in lymphocytes have been used to study the genotoxic effects of human exposure to carcinogens. BPDE-DNA adducts in lymphocytes have been used as internal dosimeters of exposure to PAH's and several studies have been conducted. We measured BPDE-DNA adducts in aluminium plant workers with immuno-assay and physico-chemical methods. PAH-DNA adducts were detectable to a lesser extent in subjects working in an aluminium plant compared to subjects working in a coke oven plant.     

Altered immune status in aluminum reduction plant workers

From 1978 to 1985, B-cell lymphoma occurred in five employees of an aluminum reduction plant (expected = 0.2; Poisson distribution). As immunodeficiency is a known risk factor for B-cell lymphoma, we did a pilot study to evaluate immune function in apparently healthy plant workers. Twenty-three volunteers were selected for study from 350 workers, representing a range of experience in the potroom and with exposures to strong magnetic fields and volatilized aromatic hydrocarbons. Potroom workers had significantly higher T8 levels (mean = 1,227) than non-potroom workers (mean = 597) (p less than .05, Wilcoxon rank sums) or established normal values (median = 450). T4 levels were higher for potroom workers (mean = 1,017) than for non-potroom workers (mean = 558) or for established norms (median = 756) (p less than .10, Wilcoxon rank sums). Ten of 20 potroom workers had abnormal T4/T8 ratios (less than 0.91) due to disproportionate elevation of the T8 subpopulation. These data suggest an underlying immune alteration in the aluminum workers studied. Further study is needed to assess the implications of abnormal T-cell subsets in a worker population with high rates of lymphoma.     

Mortality study among workers producing ferroalloys and stainless steel in France.

A mortality study was carried out among the workers of a plant that had produced ferrochromium and stainless steel, and was still producing stainless steel, in order to determine whether exposure to chromium compounds, to nickel compounds, and to polycyclic aromatic hydrocarbons (PAH) could result in a risk of lung cancer for the exposed workers. The cohort comprised 2269 men whose vital status were recorded between 1 January 1952 and 31 December 1982. The smoking habits of 67% of the cohort members were known from medical records. The observed numbers of deaths were compared with the expected ones based on national rates with adjustment for age, sex, and calendar time. A low mortality, achieving statistical significance, was found from all causes (observed = 137, standardised mortality ratio (SMR) = 0.82) and from benign respiratory diseases (observed = one, SMR = 0.15). With regard to mortality from lung cancer, a non-significant excess appeared in the whole cohort (observed = 12, SMR = 1.40). Among the exposed workers, however, a significant lung cancer excess was found (observed = 11, SMR = 2.04) that contrasted with a low SMR (0.32) in the non-exposed group. This excess is unlikely to be explained by smoking, as the tobacco consumption of these two groups was similar. No trend was observed for mortality from lung cancer either according to time since first exposure, or according to duration of exposure. A nested case-control study clearly suggested that this excess of deaths from lung cancer was attributable to former PAH exposures in the ferrochromium production workshops rather than to exposures in the stainless steel manufacturing areas.     

Mortality patterns among workers in a US pharmaceutical production plant

PURPOSE: To examine mortality among workers in a pharmaceutical production plant and to address community concerns about 1980 to 1990 increases in local county cancer mortality rates. METHODS: Subjects were 1999 workers with some full-time employment during the period between 1970 and 1996. We identified deaths through the year 2000 and reconstructed exposures to nine chemical agents with available exposure measurements. Data analyses included standardized mortality ratios (SMRs) and time trends in local cancer mortality rates. RESULTS: We observed deficits in deaths from all causes combined, all cancers combined, and most cause of death categories examined. Male workers with potential plant exposure had excesses in deaths from all lymphatic-hematopoietic tissue cancers (LHTC), in particular non-Hodgkin's lymphoma (NHL), and respiratory system cancers (RSC) that were larger among long-term workers, but the pattern of findings suggested the excesses were probably not related to occupational factors at the plant. The increase in local county cancer mortality rates was simply the upward cycle of a periodic trend that peaked in 1990 and returned to 1980 levels in 2000. CONCLUSIONS: With the possible exceptions of LHTC, in particular NHL, and RSC, this study provided no evidence of elevated total or cause-specific cohort mortality risks. It does not appear that plant factors played a role in the 1980 to 1990 increases in local county cancer mortality rates.     

Industrial hygiene survey in an aluminium reduction plant in India

This study reports a work-environmental assessment and workers' exposure in a major prebake type aluminium smelter in India. Levels of known health hazards in and near the main smelting operations viz., the Potroom, the Carbon area, the Butt section, the Rodding shop, the Bath preparing area and the Casthouse were measured. Dustiness in general was high to excessively high. Mean levels of respirable dust (PM10) in air in the three dustiest areas were 24.07 mg/m3 in the Carbon areas, 27.57 mg/m3 in the Bath preparing and 4.44 mg/m3 in the Rodding shop. 40- 60% of the particles were less than 5 microm in size. 0.5- 2.82% particulate fluoride was obtained in the size fraction 0.4- 4.7 microm of the Potroom air. Naturally, exposures to total dusts were very high in these processes. The background levels of NOx and SO2 and fluorides (gaseous and particulate) were found to be within the prescribed Indian Standards. Higher exposures to gaseous and particulate fluoride, 3.85 and 6.53 mg/m3 respectively, were observed among the Rodding shop workers. The levels ofpolycyclic aromatic hydrocarbons (PAHs) were deemed to be excessive in the Carbon area. Measurements of heat stress were made in winter and were found to be lower than the prescribed limit.     

Mortality patterns among petroleum refinery and chemical plant workers

A historical cohort study was conducted to evaluate the mortality experience of 6,831 employees of the Shell Oil Company, Deer Park, Texas, petroleum refinery and chemical plant with emphasis on cancer mortality. Subjects were all workers with potential plant exposure who were employed for at least 3 months during 1948-72. Vital status was determined as of 12/31/83 for 98% of the cohort and death certificates were obtained for 95.4% of 1,180 observed deaths. The statistical analyses excluded 159 female study members. For all causes of death combined, all cancers combined, and for most of the nonmalignant disease categories examined, there were deficits in mortality among refinery workers, chemical plant workers, and workers with experience in both areas. These deficits were generally most pronounced for chemical plant workers. An analysis of specific cancer sites revealed patterns of increased risk suggestive of a possible relationship between occupational exposures in the refinery and lympho-reticulosarcoma. Patterns of increased risk were also observed among chemical plant workers for a category of lymphopoietic tissue cancers, including multiple myeloma, myelofibrosis, polycythemia vera, and certain non-Hodgkin's lymphomas. Some very limited evidence of a possible workplace association was also found among refinery workers for leukemia and cancers of the central nervous system and biliary passages/liver. No evidence was found of an increased risk for cancer of the respiratory system or stomach or for malignant melanoma. A work history review of all suspect cancer excesses failed to identify any common work areas, job assignments, or exposure potentials, although the lack of detailed data on specific chemical exposures precluded accurate assessments of exposure-response.     

Epidemiologic evidence of cancer in aluminum reduction plant workers.

This paper reviews the epidemiologic evidence of cancer risks among workers in aluminum reduction plants with emphasis on associations with specific work areas and exposures. Studies of workers manufacturing carbon products outside the aluminum industry were also reviewed since the work environment is similar to that encountered in the carbon area of aluminum plants. We obtained 22 reports from references cited in earlier reviews, through compact disc literature search 1980-1990, and from the Nordic Aluminum Industry's Secretariat for Health, Environment and Safety. Six reports were excluded because the material was included in later studies or because a critical evaluation was impossible. This left 16 publications from 11 separate studies. Work in potrooms with S?derberg electrolytic cells was associated with increased risk of bladder cancer, and the increase was correlated to duration of tar exposure. There was a suggestion of increased risk of leukemias and pancreatic cancers in potroom workers, and of kidney and brain cancers without any clear association with specific exposures or work areas. Singular results showed associations between lung cancer risk and tar exposure in S?derberg plants, and between lung cancer and work in prebake or carbon plants, but interpretation was limited by inadequate data on smoking and asbestos exposure, and by problems connected with the choice of reference populations in these studies.     

Mortality in a cohort of cement workers in a plant of Central Italy

Purpose  

Workers of cement production are exposed to alkaline dust with irritant effects on the respiratory system. Most previous studies have examined workers in cement/asbestos factories, but there is limited information of the effects of exposures to Portland cement alone. The present study examines the effects of cement dust in a cohort of Portland cement workers through the analyses of their mortality records.     

Mortality among flavour and fragrance chemical plant workers in the United States

Vital status on 1 January 1981 was determined for a cohort of 1412 white men employed in a flavour and fragrance chemical plant between 1945 and 1965 in order to investigate the risks from fatal diseases among men exposed to multiple chemicals in the manufacture of fragrances, flavours, aroma chemicals, and other organic substances. Cause specific standardised mortality ratios (SMRs) were calculated for the entire study population and for several subsets by likelihood of exposure to chemicals, duration of employment, and year of hire. SMRs for rectal cancer and ischaemic heart disease were raised among white male employees whose jobs were in production, maintenance, laboratory, or other jobs that would involve exposure to multiple chemicals used and produced in the plant. The excess of rectal cancer was confined to employees who had worked as chemical operators and mortality was significantly raised among men who worked for ten or more years. Traces of dioxin were recently found in and around plant buildings that used trichlorophenol in the production of hexachlorophene. The study group was small and had limited power to detect excess risk of rare causes of death; however, no soft tissue sarcomas were observed during the study period.