Risk of lung cancer according to mild steel and stainless steel welding

OBJECTIVES: Whether the elevated risk of lung cancer observed among welders is caused by welding emissions or by confounding from smoking or asbestos exposure is still not resolved. This question was addressed in a cohort with a long follow-up and quantified estimates of individual exposure to welding fume particulates. METHODS: Male metal workers employed at least 1 year at one or more Danish stainless or mild steel industrial companies from 1964 through 1984 were enrolled in a cohort. Data on occupational and smoking history were obtained by questionnaire in 1986. Welders in the cohort who started welding in 1960 or later (N=4539) were followed from April 1968 until December 2003, when information on cancer diagnosis was obtained from the Danish Cancer Registry. During the follow-up, 75 cases of primary lung cancer were identified. Lifetime accumulated exposure to welding fume particulates was estimated by combining questionnaire information and more than 1000 welding-process-specific measurements of fume particulates in the Danish welding industry. RESULTS: The standardized incidence ratio (SIR) for lung cancer was increased among the welders [SIR 1.35, 95% confidence interval (95% CI) 1.06-1.70)]. Among the stainless steel welders, the risk increased significantly with increasing accumulative welding particulate exposure, while no exposure-response relation was found for mild steel welders, even after adjustment for tobacco smoking and asbestos exposure. CONCLUSIONS: The study corroborates earlier findings that welders have an increased risk of lung cancer. While exposure-response relations indicate carcinogenic effects related to stainless steel welding, it is still unresolved whether the mild steel welding process carries a carcinogenic risk.     

Lung cancer in mild steel welders

To investigate lung cancer risk, the authors conducted a historical cohort mortality study of 4,459 mild steel welders who had been employed at three midwestern plants which manufactured heavy equipment. Follow-up began in the mid-1950s and extended through 1988. All welders had at least 2 years welding experience (average duration, 8.5 years). This cohort had no occupational exposure to asbestos or stainless steel fumes (containing nickel and chromium), two potential confounders in previous welders studies. A comparison population of 4,286 nonwelders, all with at least 2 years employment at the same plants, was also studied. Nonwelders had never been welders and were allowed to have no more than 90 days employment as a painter, foundryman, or machinist. Sampling data collected from 1974-1987 indicated that welders were exposed to 6-7 mg/m3 of total particulate and 3-4 mg/m3 of iron oxide, while nonwelders had negligible exposures to welding fumes. When compared with the United States population, both welders and nonwelders had elevated rates for lung cancer (standardized mortality ratios (SMRs): welders, SMR = 1.07; nonwelders, SMR = 1.17), but neither SMR was significantly elevated. Limited smoking data based on a 1985 survey indicated that both welders and nonwelders smoked more than the United States population, possibly accounting for part of their elevated lung cancer rates. There was no trend of increased risk for welders with increased duration of exposure. The only other cause of death significantly elevated was emphysema among welders. Nonmalignant respiratory disease was not elevated for welders (SMR = 0.96). When welders were compared with nonwelders directly for lung cancer, the rate ratio was 0.90.     

A historical prospective study of European stainless steel, mild steel, and shipyard welders

A multicentre cohort of 11,092 male welders from 135 companies located in nine European countries has been assembled with the aim of investigating the relation of potential cancer risk, lung cancer in particular, with occupational exposure. The observation period and the criteria for inclusion of welders varied from country to country. Follow up was successful for 96.9% of the cohort and observed numbers of deaths (and for some countries incident cancer cases) were compared with expected numbers calculated from national reference rates. Mortality and cancer incidence ratios were analysed by cause category, time since first exposure, duration of employment, and estimated cumulative dose to total fumes, chromium (Cr), Cr VI, and nickel (Ni). Overall a statistically significant excess was reported for mortality from lung cancer (116 observed v 86.81 expected deaths, SMR = 134). When analysed by type of welding an increasing pattern with time since first exposure was present for both mild steel and stainless steel welders, which was more noticeable for the subcohort of predominantly stainless steel welders. No clear relation was apparent between mortality from lung cancer and duration of exposure to or estimated cumulative dose of Ni or Cr. Whereas the patterns of lung cancer mortality in these results suggest that the risk of lung cancer is higher for stainless steel than mild steel welders the different level of risk for these two categories of welding exposure cannot be quantified with precision. The report of five deaths from pleural mesothelioma unrelated to the type of welding draws attention to the risk of exposure to asbestos in welding activities.     

A historical prospective study of European stainless steel, mild steel, and shipyard welders.

A multicentre cohort of 11,092 male welders from 135 companies located in nine European countries has been assembled with the aim of investigating the relation of potential cancer risk, lung cancer in particular, with occupational exposure. The observation period and the criteria for inclusion of welders varied from country to country. Follow up was successful for 96.9% of the cohort and observed numbers of deaths (and for some countries incident cancer cases) were compared with expected numbers calculated from national reference rates. Mortality and cancer incidence ratios were analysed by cause category, time since first exposure, duration of employment, and estimated cumulative dose to total fumes, chromium (Cr), Cr VI, and nickel (Ni). Overall a statistically significant excess was reported for mortality from lung cancer (116 observed v 86.81 expected deaths, SMR = 134). When analysed by type of welding an increasing pattern with time since first exposure was present for both mild steel and stainless steel welders, which was more noticeable for the subcohort of predominantly stainless steel welders. No clear relation was apparent between mortality from lung cancer and duration of exposure to or estimated cumulative dose of Ni or Cr. Whereas the patterns of lung cancer mortality in these results suggest that the risk of lung cancer is higher for stainless steel than mild steel welders the different level of risk for these two categories of welding exposure cannot be quantified with precision. The report of five deaths from pleural mesothelioma unrelated to the type of welding draws attention to the risk of exposure to asbestos in welding activities.     

Ten-year update on mortality among mild-steel welders

OBJECTIVES: This study is an update on the lung cancer risk of mild-steel welders with no asbestos exposure using a cohort of nonwelders for comparison. METHODS: The subjects came from three United States (US) plants that manufactured heavy equipment. The follow-up was extended from 1988 to 1998. The welders were not exposed to asbestos (typical of shipyard welders) or to chromium or nickel (present in stainless steel). RESULTS: There were 108 lung cancer deaths among the welders and 128 such deaths among the nonwelders (double the previous number of lung cancer deaths). The standardized mortality ratio (SMR) for lung cancer was 1.46 [95% confidence interval (95% CI 1.20-1.76] for the welders and 1.18 (95% CI 0.98-1.40) for the nonwelders, both in comparison with the US general population. Direct comparison between the welders and nonwelders yielded a rate ratio of 1.22 (95% CI 0.93-1.59). Analyses using a 15-year lag time did not differ greatly from those of an unlagged analysis. There were no marked trends for lung cancer risk by duration of exposure or latency. Evidence from cross-sectional data from a sample of the cohort indicated that the welders smoked somewhat more than the US population and more than the nonwelders. An approximate adjustment of the rate ratios for possible confounding by smoking suggested that smoking may have accounted for about half of the excess lung cancer observed among the welders versus that of either reference population. CONCLUSIONS These data provide suggestive but not conclusive evidence of a modest lung cancer risk from mild-steel welding.     

Exposure to stainless steel welding fumes and lung cancer: a meta-analysis.

Stainless steel welding is associated with exposure to metals including hexavalent chromium and nickel. This study is a meta-analysis of five studies of stainless steel welders and the occurrence of lung cancer. Asbestos exposure and smoking habits have been taken into account. The calculated pooled relative risk estimate was 1.94 with a 95% confidence interval of 1.28-2.93. This result suggests a causal relation between exposure to stainless steel welding and lung cancer.     

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 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.     

Cancer incidence among mild steel and stainless steel welders and other metal workers

The cancer incidence in a historical cohort of 10,059 metal workers employed during the period 1964–1984 was investigated. Standardized incidence ratios (SIR) were calculated based on registry extracts from the Danish Cancer registry. Lifetime exposure data (occupational and other) were obtained by a postal questionnaire in living cohort members and interviews by proxy for deceased and emigrated subjects. The incidence of lung cancer was increased among workers ever “employed as welders” (SIR = 1.38, 95% C.I. 1.03–1.81). There was a significant excess risk of lung cancer among “mild steel (MS) only welders” (SIR = 1.61, 95% C.I. 1.07–2.33) and “nonwelders” (SIR = 1.69, 95% C.I. 1.23–2.26) (indicating carcinogenic exposures other than welding), a borderline significant lung cancer excess among “MS ever welders” (SIR = 1.32, 95% C.I. 0.97–1.76), and a nonsignificant excess risk of lung cancer among “stainless steel (SS) only welders” (SIR = 2.38, 95% C.I. 0.77–5.55). In spite of signs of inconsistency in the risk estimation by duration and latency, we find the results support the conclusions of other studies: employment as a welder is associated with an increased lung cancer risk. © 1996 Wiley-Liss, Inc.     

Lung cancer mortality in the German chromate industry, 1958 to 1998

OBJECTIVES: We conducted a mortality study of two German chromate production facilities and evaluated possible dose-response relationships between hexavalent chromium exposure and lung cancer. METHODS: Mortality was followed-up through 1998 and limited to those employed since each plant converted to a no-lime production process. More than 12,000 urinalysis results of chromium levels were available, as was smoking information. RESULTS: All-cause mortality indicated a healthy worker effect (standardized mortality ratio [SMR] = 0.80, 95% confidence interval [CI] = 0.67-0.96); however, lung cancers appeared to be increased (SMR = 1.48, 95% CI = 0.93-2.25). No clear dose-response was found in stratified analyses by duration of employment and time since hire. On the basis of urinary chromium data, lung cancer risk was elevated only in the highest exposure group (SMR = 2.09, 95% CI = 1.08-3.65). CONCLUSIONS: These data suggest a possible threshold effect of occupational hexavalent chromium exposure on lung cancer.     

Mortality of iron and steel workers in Korea

BACKGROUND: The mortality experience of iron and steel workers from modern plants in developing countries has not been extensively described. METHODS: Mortality at two Korean iron and steel manufacturing complexes was analyzed using Poisson regression methods with both direct and indirect standardization. Work histories were linked with a national mortality registry. Workers (44,974) hired beginning in 1968 were followed from 1992 to 2001. RESULTS: The 806 deaths observed during 10 years of follow-up comprised 2% of the population at risk and represented a large healthy worker effect (HWE) for all causes (SMR = 0.59, 95% CI = 0.55-0.63) and for cancer (SMR = 0.79, 95% CI = 0.70-0.90). Mortality at subsidiaries was considerably higher than at the parent plants (SRR = 1.71, 95% CI = 1.47-1.99). Relative mortality rates declined with employment duration: > 20 years had significantly reduced mortality (SRR = 0.59, 95% CI = 0.43-0.82) compared to duration < 1 year (test for trend: P = 0.0006). Fatal injury deaths in the first year were highly elevated (SMR = 3.10, 95% CI = 2.17-4.26) declining to less than that expected after 5 years. Cancer mortality was elevated in stainless steel production (SRR = 3.26, 95% CI = 1.37-6.49) and overall mortality was elevated for work in plant maintenance departments (SRR = 1.17, 95% CI = 1.00-1.37), particularly for fatal injuries (SRR = 1.67, 95% CI = 1.29-2.14). All-cause mortality increased with employment duration in the steel-production departments, as did fatal injuries in material handling/construction. CONCLUSIONS: This steelworker cohort exhibits excess mortality in some process areas. More detailed retrospective exposure assessment and future follow-up of this cohort will better define health risks in the modern iron and steel manufacturing.     

Cancer mortality study of employees at lead battery plants and lead smelters, 1947-1995

BACKGROUND: This study has examined cancer mortality of a cohort of male U.S. workers exposed to lead. METHODS: The cohort consisted of 4,518 workers at lead battery plants and 2,300 at lead smelters. Vital status was ascertained between 1947 and 1995. Site-specific cancer standardized mortality ratios (SMRs) and 95% confidence intervals (95% CIs), based on the mortality rates of the U.S. male population and adjusted for age and calendar time, were calculated for the total cohort as well as subcohorts stratified by various exposure parameters. In addition, a nested case-control study of stomach cancer (30 cases and 120 age-matched controls) was also conducted. RESULTS: Mortality from all cancers was as expected (897 observed deaths, SMR = 103.8, 95% CI: 97.1-110.8). Mortality was significantly raised for stomach cancer (SMR = 147.4, 95% CI: 112. 5-189.8), lung cancer (SMR = 116.4, 95% CI: 103.9-129.9), and cancer of the thyroid and other endocrine glands (SMR = 308.0, 95% CI: 133. 0-606.8). There was a nonsignificant mortality deficit from kidney cancer (SMR = 63.6, 95% CI: 33.9-108.7). For bladder cancer, mortality was significantly lower than expected (SMR = 55.5, 95% CI: 31.7-90.1). Nonsignificant mortality deficits were also reported for cancer of the central nervous system (SMR = 74.8, 95% CI: 41.9-123. 4) and lymphatic and hematopoietic cancer (SMR = 92.2, 95% CI: 72. 4-115.7). Additional analyses by type of facility (lead battery plants vs. lead smelters), length of employment, latency, and period of hire were also performed. In the nested case-control study of stomach cancer, odds ratios were calculated for various exposure indices, and none was found to be elevated. Furthermore, no exposure-response relationship between lead exposure and stomach cancer was found in the nested case-control study. CONCLUSIONS: A significant mortality increase from stomach cancer was found. However, based on the analyses in the cohort study and the nested case-control study, the increase did not appear to be related to lead exposure. A small, but statistically significant mortality increase from lung cancer was also observed. The small increase, in the absence of an exposure-response relationship, could be the result of confounding due to smoking, and was not likely causally related to lead exposure. Although the significant increase in cancer of the thyroid and other endocrine glands appeared to be consistent with an occupational interpretation, the small number of deaths (8), the lack of information on potential confounding factors, and the lack of reporting of a similar increase in other studies underscore the need to view this finding with caution. No increased mortality was found for kidney cancer, bladder cancer, cancer of the central nervous system, or lymphatic and hematopoietic cancer.     

Lung cancer mortality in stainless steel and mild steel welders: A nested case-referent study

The association between welding and lung cancer has been studied in a nested case-referent study within a cohort of 8,372 metal workers. Lifetime exposure data on welding and other occupational exposures, as well as alcohol and smoking habits, were obtained by interviews of spouses and colleagues. Analysis was based on 439 deceased referents and 94 deceased cases. There was 70% excess of lung cancer associated with “welding exposure ever” (OR ± 95% C.I.: 1.68, 1.02–2.78). Overall OR “mild steel (MS) welding ever” was 1.64, 0.99-2.72. The risk estimates for welding exposures showed an increasing tendency up to 15 years of exposure. The pattern of stainless steel (SS) welding resembles that of mild steel with an estimated OR of 1.65, 0.88–3.0. The general conclusion is that MS welding as well as SS welding seems to be associated with an increased risk of lung cancer. Further followup of the cohort will enhance precision of the estimates. © 1996 Wiley-Liss, Inc.     

Case-control study of lung cancer in Los Angeles county welders

A case-control study of lung cancer in white male welders was undertaken to investigate possible environmental and occupational causes of a 50% excess of lung cancer observed in this occupational group. The subjects were identified from a population-based cancer registry in Los Angeles County. A standardized questionnaire was administered to either subjects or proxy informants of 90 lung cancer cases and 116 non-lung-cancer controls. Significantly increased risks of lung cancer were associated with tobacco smoking (odds ratio 7.6, p less than .005) and shipyard welding with at least a 10-year latency since first exposure (odds ratio 1.7, p less than .05). Although there were elevated risks associated with some specific welding processes, none were statistically significant. Control subjects were more likely to have had exposure to confined-space welding (odds ratio 0.6, 95% CI = 0.3-1.2), and this association was greatest where there had been at least a 20-year latency since first exposure (0.5, 95% CI = 0.3-1.0). We conclude that the excess of lung cancer in this welding population is contributed to by a higher frequency of smoking and probable exposure to asbestos in shipyards. Other factors may be important, but probably because of limited power and reliance on proxy information, this study failed to detect other statistically significant risks.     

A mortality study of workers at seven beryllium processing plants.

The International Agency for Research on Cancer (IARC) has found that the evidence for the carcinogenicity of beryllium is sufficient based on animal data but "limited" based on human data. This analysis reports on a retrospective cohort mortality study among 9,225 male workers employed at seven beryllium processing facilities for at least 2 days between January 1, 1940, and December 31, 1969. Vital status was ascertained through December 31, 1988. The standardized mortality ratio (SMR) for lung cancer in the total cohort was 1.26 (95% confidence interval [CI] = 1.12-1.42); significant SMRs for lung cancer were observed for two of the oldest plants located in Lorain, Ohio (SMR = 1.69; 95% CI = 1.28-2.19) and Reading, Pennsylvania (SMR = 1.24; 95% CI = 1.03-1.48). For the overall cohort, significantly elevated SMRs were found for "all deaths" (SMR = 1.05; 95% CI = 1.01-1.08), "ischemic heart disease" (SMR = 1.08; 95% CI = 1.01-1.14), "pneumoconiosis and other respiratory diseases" (SMR = 1.48; 95% CI = 1.21-1.80), and "chronic and unspecified nephritis, renal failure, and other renal sclerosis" (SMR = 1.49; 95% CI = 1.00-2.12). Lung cancer SMRs did not increase with longer duration of employment, but did increase with longer latency (time since first exposure). Lung cancer was particularly elevated (SMR = 3.33; 95% CI = 1.66-5.95) among workers at the Lorain plant with a history of (primarily) acute beryllium disease, which is associated with very high beryllium exposure. The lung cancer excess was not restricted to plants operating in the 1940s, when beryllium exposures were known to be extraordinarily high. Elevated lung cancer SMRs were also observed for four of the five plants operating in the 1950s for workers hired during that decade. Neither smoking nor geographic location fully explains the increased lung cancer risk. Occupational exposure to beryllium compounds is the most plausible explanation for the increased risk of lung cancer observed in this study. Continued mortality follow-up of this cohort will provide a more definitive assessment of lung cancer risk at the newer plants and among cohort members hired in the 1950s or later at the older plants. Further clarification of the potential for specific beryllium compounds to induce lung cancer in humans, and the possible contribution of other exposures in specific processes at these plants, would require a nested case-control study. We are currently assessing whether available industrial hygiene data would support such an analysis.     

Welding and lung cancer in Central and Eastern Europe and the United Kingdom

Occupation as a welder has been associated with a 25%-40% increase in lung cancer risk. This study aims to elucidate to what extent confounding by smoking and asbestos drives this association and to evaluate the role of welding-related exposures such as chromium. The study included 2,197 male incident lung cancer cases and 2,295 controls from Romania, Hungary, Poland, Russia, Slovakia, the Czech Republic, and the United Kingdom from 1998 to 2001. Information on risk factors was collected through face-to-face interviews. Experts assessed exposure to 70 agents, and risk estimates were adjusted for smoking and occupational exposures. Occupation as a welder/flame cutter (prevalence controls: 3.7%) was associated with an odds ratio of 1.36 (95% confidence interval (CI): 1.00, 1.86) after adjustment for smoking and occupational exposures including asbestos. An odds ratio of 1.18 (95% CI: 1.01, 1.38) was found for welding fumes (prevalence controls: 22.8%), increasing to 1.38 for more than 25 exposure years (95% CI: 1.09, 1.75). A duration-response association was also observed for mild steel welding without chromium exposure. In this population, occupational exposure to welding fumes accounted for approximately 4% of lung cancer cases, to which both stainless and mild steel welding contributed equally. Given that welding remains a common task for many workers, exposure to welding fumes represents an important risk factor for lung cancer.     

Mortality at an automotive stamping and assembly complex

Mortality among workers with 2 or more years employment at an automotive stamping and assembly complex was analyzed using standardized mortality ratio (SMR), proportional mortality ratio (PMR), and mortality odds ratio (MOR) methods. The stamping plant all-cause SMR was considerably less than expected (for white men, SMR = 0.65, 95% confidence interval [CI] = 0.54, 0.79; for black men, SMR = 0.73, 95% CI = 0.45, 1.13). indicating a strong “healthy worker effect.” However, six stomach cancer deaths produced an SMR of 4.4 (95% CI = 1.62,9.6) and a PMR of 6.8 (95% CI = 2.5,15). Based on small numbers of cases, stomach cancer risk increased with duration in stamping and tool and die departments where exposures included drawing compound and other metalworking fluids. Stamping plant lung cancer mortality was elevated among production welders (MOR = 2.7, 95% CI = 1.2,6.3), and increased with duration. Welding was performed on sheet metal sometimes coated with drawing compound, primer, or epoxy resin adhesive. As was observed for the stamping plant, the all-cause SMR for the two assembly plants was unusually low (for white men, SMR = 0.64, 95% CI = 0.56,0.73; for black men, SMR = 0.57, 95% CI = 0.43,0.75). The lung cancer SMR was not elevated but the MOR was (MOR = 1.58, 95% CI = 1.1,2.4) and increased with assembly plant duration (MOR = 1.78, 95% CI = 1.02,3.1, at mean duration of cases). In the assembly plants, paint oven stack emissions had been reintroduced into the plant by the ventilation system.     

Acute respiratory effects of exposure to stainless steel and mild steel welding fumes

Over the past few years, many studies, including one on our previous work, have examined the chronic effects of fumes from stainless steel (SS) welding on the health of welders. These chronic effects have been related to concentrations of chromium and nickel in SS welding fumes. The present study examined the acute respiratory effects of welding fumes in the workplace by measuring the across-shift changes in a population of 144 SS and mild steel (MS) welders and 223 controls. Manual Metal Arc, Metal Inert Gas, and Tungsten Inert Gas welding processes were studied. Pulmonary function tests were performed at the start (ante, or A) and at the end (post, or P) of the work shift. The study of sensitization to harmful respiratory effects of welding was based on the study of the (P-A)/A ratio (%) of the spirometric variations during the shift. The means of these ratios in the control subjects were used to account for the circadian effect. In SS welders we observed a significant decrease in forced vital capacity (FVC) during the shift. Significant across-shift decrements in forced expiratory volume in 1 second (FEV1) and FVC were related to the SS welding exposure compared with MS welding. Moreover, the across-shift decreases in FEV1, FVC, and peak expiratory flow (PEF) were significantly related to the Manual Metal Arc welding process, compared with Metal Inert Gas techniques (respectively, PEF = -2.7% of baseline values [SD, 11.9] vs 2.0% of baseline values [SD, 7.7] P = 0.04; FVC = -1.5% of baseline values [SD, 4.8] vs 0.2% of baseline values [SD, 4.5] P = 0.05). We also demonstrated the influence of duration of SS welding exposure on the course of lung function during the work shift. After 20 years of SS welding activity, SS welders had more significant across-shift decreases than MS welders with a similar MS exposure duration (respectively, FEV1 = -2.7% of baseline values [SD, 5.9] vs 0.7% of baseline values [SD, 4.2] P = 0.008; PEF = -3.8% of baseline values [SD, 9.6] vs 2.3% of baseline values [SD, 6.5] P = 0.04). We concluded that welding-related lung function responses are seen in SS compared with MS welders and in those with a longer lifetime welding history.     

Upper aerodigestive cancer in battery manufacturers and steel workers exposed to mineral acid mists.

OBJECTIVE--To assess the risk of cancer from inhalation of mineral acid mists. METHODS--A cohort study and nested case-control study of upper aerodigestive tumours were carried out in men employed since 1950 at two battery plants and two steel works in Britain. The cohort was identified from personnel records and included 2678 men with definite exposure to acid mists (mainly sulphuric acid), 367 with possible exposure, and 1356 who were unexposed. Mortality was compared with that in the national population by the person-years method. Cases of upper aerodigestive cancer were identified from death certificates and cancer registrations, and their exposure to acids was compared with that of age matched controls (five per case) from the same plant by conditional logistic regression. RESULTS--In follow up to 31 December 1993, 93% of men were traced, including 1277 who had died. Among the men definitely exposed to acid mists, overall mortality was less than in the national population (standardised mortality ratio (SMR) 0.92, 95% confidence interval (95% CI) 0.85-0.98) as was mortality from all cancers (SMR 0.92, 95% CI 0.79-1.05) and specifically from cancer of the larynx (SMR 0.48, 95% CI 0.01-2.70) and lung (SMR 0.98, 95% CI 0.78-1.22). A total of 15 incident or fatal cases of upper aerodigestive cancer were identified during follow up. When these men were compared with controls, risk was moderately increased in those who had worked for at least five years in jobs entailing exposures to sulphuric or hydrochloric acid in excess of 1 mg/m3 (OR 2.0, 95% CI 0.4-10). CONCLUSIONS--These findings are consistent with those from other studies which have indicated a hazard of upper aerodigestive cancer from acid mists. However, they indicate that any risk from exposures to sulphuric and hydrochloric acid below 1 mg/m3 is small.     

鞍钢工人的肿瘤危险度——肺癌病例-对照研究

对鞍钢男工中６１０例肺癌新发病例及９５９例对照进行了访问调查。经吸烟、其他肺疾患、家族肿瘤史、食用水果等非职业因素调整后，岗位工龄等于或超过１５年的下列工人的肺癌危险度显著增高：冶炼工和轧钢工（ＱＲ＝１．５，９５％ＣＩ＝１．１～２．２），耐火砖厂工（ＯＲ＝２．９，９５％ＣＩ＝１．４～５．９），装卸工（ＯＲ＝２．５，９５％ＣＩ＝１．０～６．１），焦炉工（ＯＲ＝３．４，９５％ＣＩ＝１．４～８．５）。各种粉尘和Ｂ［ａ］Ｐ暴露与肺癌危险性呈显著的剂量－反应关系，但与粉尘的特殊成分未见此种关联。长期暴露于污染物的钢铁工人的肺癌的危险度增加４０％。