Clinical findings of irritation among chromium chemical production workers

BACKGROUND: Several reports of workers in chromate production and chromeplating have indicated that exposure to hexavalent chromium is associated with skin and nasal irritation. METHODS: A cohort of 2, 357 workers first employed between 1950 and 1974 at a chromate production plant was identified. Clinical findings of irritation were identified by a physician as a result of routine examinations or visits to the medical clinic by members of the cohort. Percentages of the cohort with various clinical findings, the time from hire to occurrence of the first finding, and the mean and median annual hexavalent chromium (measured as CrO(3)) concentration for the job title where the clinical finding first occurred were determined. A proportional hazards model was used to evaluate the relationship between hexavalent chromium exposure and first occurrence of each of the clinical findings. RESULTS: Nasal irritation and nasal ulceration were the most common clinical findings reported, occurring in more than 60% of the cohort. The average time to first occurrence of these findings was less than 3 months, whereas the time to first occurrence of the other findings ranged from 10 to 22 months. Median exposure to hexavalent chromium at the time of occurrence for most of the findings was about 20 microg/m(3). The proportional hazards model indicated that ulcerated nasal septum, irritated skin, and perforated eardrum were significantly associated with ambient hexavalent chromium exposure; all clinical findings with the exception of conjunctivitis and irritated skin were associated with the calendar year of hire, with the risk being lower as the calendar year of hire became more recent. Annual average ambient hexavalent chromium concentrations generally dropped in the plant over the period of the study. CONCLUSIONS: Workers in the chromate production plant in this study experienced a variety of nasal and skin irritations. Irritated and ulcerated nasal septa, in particular, were quite common clinical findings, occurring in over 60% of the cohort, and they occurred in relatively short periods of time-less than 3 months from date of hire. Annual average concentrations of chromium may not be a good predictor of clinical findings of irritation. Am. J. Ind. Med. 38:127-131, 2000. Published 2000 Wiley-Liss, Inc.     

Lung cancer mortality among chromate production workers

Aims: To assess mortality in 1997 among 493 former workers of a US chromate production plant employed for at least one year between 1940 and 1972.

Methods: Cohort members were followed for mortality to 31 December 1997. Standardised mortality ratios (SMRs) were calculated for selected cause specific categories of death including lung cancer. Lung cancer mortality was investigated further by calculation of SMRs stratified by year of hire, duration of employment, time since hire, and categories of cumulative exposure to Cr(VI).

Results: Including 51 deaths due to lung cancer, 303 deaths occurred. SMRs were significantly increased for all causes combined (SMR = 129), all cancers combined (SMR = 155), and lung cancer (SMR = 241). A trend test showed a strong relation between lung cancer mortality and cumulative hexavalent exposure. Lung cancer mortality was increased for the highest cumulative exposure categories (1.05 to <2.70 mg/m³-years, SMR = 365; 2.70 to 23 mg/m³-years, SMR = 463), but not for the first three exposure groups. Significantly increased SMRs were also found for year of hire before 1960, 20 or more years of exposed employment, and latency of 20 or more years.

Conclusions: The finding of an increased risk of lung cancer mortality associated with Cr(VI) exposure is consistent with previous reports. Stratified analysis of lung cancer mortality by cumulative exposure suggests a possible threshold effect, as risk is significantly increased only at exposure levels over 1.05 mg/m³-years. Though a threshold is consistent with published toxicological evidence, this finding must be interpreted cautiously because the data are also consistent with a linear dose response.

     

Lung cancer among rock and slag wool production workers

BACKGROUND: Previous cohort studies have found an elevated risk of lung cancer among rock and slag wool (RSW) production workers. The aim of the present study was to investigate the risk of lung cancer associated with exposure to RSW while controlling for other occupational exposures and tobacco smoking. METHODS: Since 1971, a total of 196 lung cancer cases occurred among men who worked in seven plants in Denmark, Norway, Sweden, and Germany, with start of production between 1937 and 1950. We obtained information on occupational history and extra-occupational factors from either the subject or the next of kin for 133 cases and 513 matched controls. We assessed occupational exposure on the basis of interview data combined with information from expert panels set up in each factory. RESULTS: For cumulative exposure to RSW assessed with a 15-year lag, the smoking-adjusted odds ratios in the second, third, and fourth quartiles of exposure were 1.3 (95% confidence interval [CI] = 0.7-2.3), 1.0 (CI = 0.5-1.9), and 0.7 (CI = 0.3-1.3). Similar results were obtained when we included only those workers employed for more than 1 year, when we included other indicators of RSW exposure, and after control for co-exposures. CONCLUSIONS: This study provides no evidence of a carcinogenic effect on the lung of rock and slag wool under exposure circumstances in the production industry during the last four to five decades.     

Mortality in chromium chemical production workers: a prospective study

Mortality among male employees was studied in a chromium chemical production plant, part of which was rebuilt in 1950-51 and the remainder in 1960, to reduce exposure to chromium bearing dusts. Of 2 101 employees initially employed between 1945 and 1974 and having worked at least 90 days, the vital status of 88% was ascertained, as of mid-1977. Lung cancer mortality for hourly workers initially employed between 1945 and 1959 was significantly higher than in the comparison Baltimore City population (SMR = 2.0), yet it was lower than that reported in previous studies of this industry. A dose response effect was evident from the relationship between duration of employment and mortality. The lung cancer mortality among those employed for three or more years exclusively in the new facility was similar to that observed for such long-term workers in other parts of the plant. Specific job positions were examined. A history of employment in the Bichromate and Special Products Department (production of chromic acid and other products), known as the 'wet end', was associated with the increased lung cancer mortality in contrast to the Mill and Roast Department, known as the 'dry end'. Because of the long latency period associated with chromium exposure and cancer, it was not possible to adequately assess the risk of cancer for workers initially employed after 1960. Methodological issues related to these findings are discussed.     

Lung cancer among glass fibre production workers: a case-control study

A cohort study among 4734 employees at an English glass fibre plant previously reported no excess of lung cancer mortality either overall or when examined in broad occupational groups. To investigate occupation in more detail, and to test the hypothesis that processes producing or using finer (respirable) fibres may be related to a higher risk of lung cancer, a nested case-control study has now been carried out. Included are 73 cases of lung cancer and 506 matched controls, for whom jobs held and processes worked on have been blindly recorded in more detail than for the cohort study. Workers known to have been employed on processes containing respirable fibres had a relative risk of lung cancer of 1.2 (95% confidence interval 0.7-2.0) compared with other workers. There was no evidence of a relationship of lung cancer to fibre diameter, duration of exposure, or time since first exposure. The results by broad occupational group were similar to those of the cohort study, and although some of the many detailed occupational categories examined had significantly raised relative risks, these did not appear to be related to exposure to respirable glass fibre. Although the study has not indicated a differential risk of lung cancer among workers exposed to finer diameter glass fibres, the exposure levels were low and the number of cases small.     

Lung cancer among long-term steel workers

A case-control study in an industrialized area of eastern Pennsylvania involving interviews with the next of kin of 335 men who died of lung cancer and of 332 controls who died of other causes revealed a significantly increased risk associated with employment in the steel industry, the area's major employer. The excess was primarily among long-term employees, particularly those who began work before 1935. Adjusted for cigarette smoking, the odds ratio associated with career employment was 1.8 (p = 0.01, 95% confidence interval, 1.2, 2.8). The increase was higher among steel workers who worked in foundry operations, but was seen for broad categories of jobs within the industry. No significant associations were found for other industries, although a 60% increase (p = 0.27, 95% confidence interval, 0.7, 3.7) was noted for zinc smelter workers employed at least 15 years. The findings help clarify the role of occupation as a risk factor for lung cancer in the area, and suggest that exposures in the steel industry contribute to an extent greater than previously recognized.     

Lung cancer prevalence among shipyard workers

The prevalence of lung cancer has been ascertained during a survey of 286 shipyard workers all 20 to 45 years from onset of asbestos exposure in shipyard work. Two men had had previous thoracic surgery for lung cancer. In addition, bronchogenic carcinoma was found in five men. One was among the 35 men less than 30 years in the yard; three were in the 191 who had begun work 30 to 39 years before, and one was in the group of 60 men who were 40+ years from onset. The potential usefulness of large-scale surveillance programs for the early detection of lung cancer among current and former shipyard workers is discussed.     

Lung cancer among glass fibre production workers: a case-control study.

A cohort study among 4734 employees at an English glass fibre plant previously reported no excess of lung cancer mortality either overall or when examined in broad occupational groups. To investigate occupation in more detail, and to test the hypothesis that processes producing or using finer (respirable) fibres may be related to a higher risk of lung cancer, a nested case-control study has now been carried out. Included are 73 cases of lung cancer and 506 matched controls, for whom jobs held and processes worked on have been blindly recorded in more detail than for the cohort study. Workers known to have been employed on processes containing respirable fibres had a relative risk of lung cancer of 1.2 (95% confidence interval 0.7-2.0) compared with other workers. There was no evidence of a relationship of lung cancer to fibre diameter, duration of exposure, or time since first exposure. The results by broad occupational group were similar to those of the cohort study, and although some of the many detailed occupational categories examined had significantly raised relative risks, these did not appear to be related to exposure to respirable glass fibre. Although the study has not indicated a differential risk of lung cancer among workers exposed to finer diameter glass fibres, the exposure levels were low and the number of cases small.     

Lung cancer risk among textile workers in Lithuania

Background  

The textile industry is one of the largest employers in Lithuania. IARC monograph concludes that working in the textile manufacturing industry entails exposures that are possibly carcinogenic to humans. The purpose of this study was to investigate risk of lung cancer incidence in textile industry workers by the type of job and evaluate the relation between occupational textile dusts exposure and lung cancer risk in a cohort.     

Respiratory cancer among soap production workers

Employment in the soap production industry in Italy has entailed some exposure to sulfuric acid vapors and nickel dusts, both agents under suspicion of being carcinogenic for the respiratory tract. A mortality study, together with an incidence study for laryngeal cancer, has been conducted among 361 men with a minimum employment of one year in soap production. Mortality from all causes was lower than expected, but lung cancer and laryngeal cancer deaths were increased, although without statistical significance. Five new laryngeal cancer cases were detected during the study period, while about one was expected. All the men with respiratory cancer had been working for several years, and the latency time was greater than 10 years. Even though the mechanism of a causal link is difficult to assess, the possibility of a carcinogenic effect of sulfuric acid is suggested.     

Risk of lung cancer among former chromium smelter workers

Hexavalent chromium is a known carcinogen. Previous epidemiologic studies in the 1950s of United States workers from seven facilities producing chromium compounds from chromite ore have reported a markedly increased risk for dying from lung cancer. As part of a high risk notification project of workers from four of these facilities, a mortality study was performed. The cohort was assembled in 1990–1991 from the Social Security records of four former chromate producing facilities in northern New Jersey. The study subjects were known to have worked at these facilities some time between 1937 and 1971. Proportionate mortality and proportionate cancer mortality ratios (PCMR) were calculated. The overall risk for lung cancer was a PCMR of 1.51 (confidence limits [CL] 1.29–1.74) for white men and 1.34 (CL 1.00–1.75) for black men. These risks increased with increasing duration of employment and latency since time of first employment. The PCMR for greater than 20 years duration of work and more than 20 years since first exposure was 1.94 (CL 1.15–3.06) for white men and 3.08 (CL 1.13–6.71) for black men. The risk for lung cancer for white men remains elevated more than 20 years after exposure has ceased (PCMR, 1.29; CL 1.03–1.60). The PCMR for nasal cavity/sinus cancer was also found to be a significantly increased, 5.18 (CL 2.37–11.30). A cluster of bladder cancer was seen among black workers from one facility, (PCMR, 3.30; CL 1.42–6.51). Despite the cessation of exposure, former chromium workers remain at significantly increased risk of lung cancer. Although there have been case reports of nasal cavity/sinus cancer in association with chromium exposure, this is the first epidemiologic study to report a significant increase in these cancers. Limitations in this study include lack of exposure data and lack of information on smoking habits. The lack of increase in other smoking-related diseases besides lung cancer indicates that the increase in lung cancer cannot be attributed to cigarette smoking. The ongoing elevated risk of lung cancer after cessation of exposure emphasizes the need for developing early detection tests for lung cancer. © 1996 Wiley-Liss, Inc.     

Liver and biliary tract cancer among chemical workers

A recent cohort mortality study of male, hourly wage employees of a large Michigan chemical production and research facility had found a greater than expected number of deaths coded to liver and biliary tract cancer. In response, an additional investigation was then undertaken of the 44 liver and biliary tract cancer deaths observed between 1940 and 1982. A random sample (N = 1,888) of subjects was selected from the total cohort (N = 21,437) to serve as referents. Company work history records were used to classify cases and referents by work area assignment and potential for exposure to 11 selected chemical agents which have been shown to produce cancer of the liver or biliary passages in experimental animals. Statistically significant associations in both positive and negative directions were found for several work areas within the facility. A suggestive association was found for vinyl chloride monomer, based on five cases with presumed exposure.     

Lung cancer mortality among workers in the European production of man-made mineral fibers--a Poisson regression analysis.

One hundred and eighty-one lung cancer deaths among workers during 301,085 person-years in European man-made mineral fiber production between 1930-1955 and 1982 were analyzed according to Poisson regression models including age, calendar period, country, and exposure variables. Time since first employment was the variable most strongly associated with lung cancer risk in both the rock-slag wool and glass wool subcohorts. Workers in the early technological phase were at higher risk than those in other categories, particularly in rock-slag wool production. No clear trend with duration of employment was suggested. No major changes occurred in the interpretation of the results when workers with less than one year of employment or less than 20 years since first exposure were excluded. The original results, based on analyses for standardized mortality ratios, were confirmed, and workers with a short duration of employment or a short time since first employment did not need to be excluded from the analysis.     

Lymphohaematopoietic cancer risk among chemical workers exposed to benzene

Aims: To determine cause specific mortality in a cohort of 2266 chemical workers exposed to benzene in various manufacturing processes after 1935.

Methods: The cohort has accumulated over 80 000 person-years of observation; about 70% of the workers were followed for more than 30 years since first exposure.

Results: Mortality from non-malignant diseases of the blood was increased (SMR 2.17, 95% CI 0.87 to 4.48), and correlated with duration of benzene exposure, although risk had decreased from the previous investigation of this cohort. The risk for leukaemia was slightly above background (SMR 1.14, obs 12, 95% CI 0.59 to 1.99) but has also decreased since the earlier study of this cohort. SMRs for acute non-lymphocytic leukaemia (ANLL), chronic lymphatic leukaemia, and non-Hodgkin's lymphoma were 1.11, 0.42, and 1.06 respectively. There was evidence of a weak trend of increasing SMRs for leukaemia and possibly ANLL with increasing low-level cumulative exposure but not with other measures.

Conclusion: Leukaemia and ANLL results were consistent with the mildly increased risk estimates from lower exposure subgroups of the Pliofilm cohort.

     

Nested case-control study of lung cancer among chemical workers

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.     

Cohort mortality study of prostate cancer among chemical workers

A retrospective cohort mortality study was conducted at a chemical plant producing acetic acid and acetic anhydride, two chemicals essential in the synthesis of cellulose triacetate fiber. Previously, we reported excess mortality from biliary tract and prostate cancers among workers in cellulose triacetate fiber manufacturing plants. In the present investigation, an excess of prostate cancer (SMR = 330.4; 95% confidence interval = 121.3–719.1) was observed among former chemical plant workers, some of whom had been exposed to both acetic acid and acetic anhydride. These apparent increases in mortality are difficult to interpret biologically, particularly in light of recent suggestions concerning the role of endocrine factors. Additional work is planned to more fully characterize potential occupational exposures that might explain the etiology of prostate cancer. Am. J. Ind. Med. 33:293–296, 1998. © 1998 Wiley-Liss, Inc.     

Lung cancer among pesticide workers exposed to inorganic arsenicals.

Cancer mortality was studied in 1,393 persons exposed to high air concentrations of inorganic arsenicals for varying lengths of time during the manufacture and packaging of pesticides at a plant in Baltimore, Maryland. Employees consisting of 1,050 males and 343 females were traced for the period 1946 to 1977, and vital status was determined for 86.9% of males and 66.8% of females. The observed number of deaths from all and selected causes was compared with the number expected from the Baltimore City mortality experience in terms of the Standardized Mortality Ratio (SMR). A significantly increased SMR was found for lung cancer and anemias in males. The SMR for lung cancer was especially high in males with presumed high exposure to arsenicals. A dose-response relationship was suggested by the SMR for lung cancer which increased with increasing duration of exposure to arsenicals, but no such relationship was evident for nonarsenicals. Although smoking habits could not be examined in the study subjects, the authors believe that the findings provide additional epidemiologic evidence on the respiratory carcinogenicity of occupational exposure to airborne inorganic arsenicals.     

Lung cancer among industrial sand workers exposed to crystalline silica

In 1997, the International Agency for Research on Cancer determined that crystalline silica was a human carcinogen but noted inconsistencies in the epidemiology. There are few exposure-response analyses. The authors examined lung cancer mortality among 4,626 industrial sand workers, estimating exposure via a job-exposure matrix based on 4,269 industrial hygiene samples collected in 1974--1995. The average length of employment was 9 years, and estimated average exposure was 0.05 mg/m(3) (the National Institute of Occupational Safety and Health Recommended Exposure Limit). Results confirmed excess mortality from silicosis/pneumoconioses (standardized mortality ratio = 18.2, 95% confidence interval: 10.6, 29.1; 17 deaths). The lung cancer standardized mortality ratio was 1.60 (95% confidence interval: 1.31, 1.93; 109 deaths). Limited data suggested that smoking might account for 10--20% of the lung cancer excess. Exposure-response analyses by quartile of cumulative exposure (15-year lag) yielded standardized rate ratios of 1.00, 0.78, 1.51, and 1.57 (p for trend = 0.07). Nested case-control analyses after exclusion of short-term workers, who had high overall morality, yielded odds ratios by quartile of cumulative exposure (15-year lag) of 1.00, 1.35, 1.63, and 2.00 (p for trend = 0.08) and odds ratios by quartile of average exposure of 1.00, 0.92, 1.44, and 2.26 (p = 0.005). These data lend support to the labeling by the International Agency for Research on Cancer of silica as a human carcinogen. There are approximately 2 million US workers exposed to silica; 100,000 are exposed to more than 0.1 mg/m(3).