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.     

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.     

A mortality study among mild steel and stainless steel welders.

A mortality study was carried out in conjunction with the European mortality study among welders coordinated by the International Agency for Research on Cancer (IARC). The study was aimed at assessing risks for lung cancer in relation to exposure to asbestos, welding fumes containing chromium and nickel, and tobacco smoke. The study included a cohort of 2721 welders and an internal comparison group of 6683 manual workers employed in 13 factories in France. The mortality of the two cohorts was studied from 1975 to 1988 by the historical prospective method. Job histories of welders were traced including welding processes used, metals welded, and proportion of worktime spent in welding. Data on smoking habits were collected from medical records. The observed number of deaths were compared with those expected (standardised mortality ratio (SMR)) based on national rates with adjustments for age, sex, and calendar time. The smoking habits of 87% of the whole study population were known. The distribution of welders and controls according to smoking was not statistically different. The overall mortality was slightly higher for welders (SMR = 1.02, 95% confidence interval (95% CI) 0.89-1.18) than for controls (SMR = 0.91, 95% CI 0.84-0.99). For lung cancer, the SMR was 1.24 (95% CI 0.75-1.94) for welders, whereas the corresponding value was lower for controls (SMR = 0.94, 95% CI 0.68-1.26). The SMR for lung cancer was 1.59 among non-shipyard mild steel welders (95% CI 0.73-3.02). This contrasted with the results for all stainless steel welders (SMR = 0.92, 95% CI 0.19-2.69), and for stainless steel welders predominantly exposed to chromium VI (SMR = 1.03, 95% CI 0.12-3.71). Moreover, SMRs for lung cancer for mild steel welders tended to increase with duration of exposure and time since first exposure, leading to significant excesses for duration > or = 20 years and latency > or = 20 years. Such a pattern was not found for stainless steel welders.     

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.     

Semen quality and sex hormones among mild steel and stainless steel welders: a cross sectional study

Welding may be detrimental to the male reproductive system. To test this hypothesis, semen quality was examined in 35 stainless steel welders, 46 mild steel welders, and 54 non-welding metal workers and electricians. These figures represent a participation rate of 37.1% in welders and 36.7% in non-welding subjects. The mean exposure to welding fume particulates was 1.3 mg/m3 (SD 0.8) in stainless steel welders using tungsten inert gas, 3.2 mg/m3 (SD 1.0) in low exposed mild steel welders using manual metal arc or metal active gas (n = 31), and 4.7 mg/m3 (SD 2.1) in high exposed mild steel welders (n = 15). The semen quality of each participant was defined in terms of the mean values of the particular semen parameters in three semen samples delivered at monthly intervals in a period with occupational exposure in a steady state. The sperm concentration was not reduced in either mild steel or stainless steel welders. The sperm count per ejaculate, the proportion of normal sperm forms, the degree of sperm motility, and the linear penetration rate of the sperm were significantly decreased and the sperm concentration of follicle stimulating hormone (FSH) was non-significantly increased in mild steel welders. A dose response relation between exposure to welding fumes and these semen parameters (sperm count excepted) was found. Semen quality decreased and FSH concentrations increased with increasing exposure. Significant deteriorations in some semen parameters were also observed in stainless steel welders. An analysis of information from questionnaires obtained from the whole population including subjects who declined to participate indicated an underestimation of effects due to selection bias. Potential confounding was treated by restriction and statistical analysis. The results support the hypothesis that mild steel welding and to a lesser extent stainless steel welding with tungsten inert gas is associated with reduced semen quality at exposure in the range of the Danish process specific threshold limit values of welding.     

Semen quality and sex hormones among mild steel and stainless steel welders: a cross sectional study.

Welding may be detrimental to the male reproductive system. To test this hypothesis, semen quality was examined in 35 stainless steel welders, 46 mild steel welders, and 54 non-welding metal workers and electricians. These figures represent a participation rate of 37.1% in welders and 36.7% in non-welding subjects. The mean exposure to welding fume particulates was 1.3 mg/m3 (SD 0.8) in stainless steel welders using tungsten inert gas, 3.2 mg/m3 (SD 1.0) in low exposed mild steel welders using manual metal arc or metal active gas (n = 31), and 4.7 mg/m3 (SD 2.1) in high exposed mild steel welders (n = 15). The semen quality of each participant was defined in terms of the mean values of the particular semen parameters in three semen samples delivered at monthly intervals in a period with occupational exposure in a steady state. The sperm concentration was not reduced in either mild steel or stainless steel welders. The sperm count per ejaculate, the proportion of normal sperm forms, the degree of sperm motility, and the linear penetration rate of the sperm were significantly decreased and the sperm concentration of follicle stimulating hormone (FSH) was non-significantly increased in mild steel welders. A dose response relation between exposure to welding fumes and these semen parameters (sperm count excepted) was found. Semen quality decreased and FSH concentrations increased with increasing exposure. Significant deteriorations in some semen parameters were also observed in stainless steel welders. An analysis of information from questionnaires obtained from the whole population including subjects who declined to participate indicated an underestimation of effects due to selection bias. Potential confounding was treated by restriction and statistical analysis. The results support the hypothesis that mild steel welding and to a lesser extent stainless steel welding with tungsten inert gas is associated with reduced semen quality at exposure in the range of the Danish process specific threshold limit values of welding.     

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.     

Incidence of cancer among Norwegian boiler welders.

OBJECTIVES: The cancer incidence among 2957 boiler welders was investigated. The subjects were registered electrical welders from 1942 to 1981. A subcohort of 606 stainless steel welders was studied separately. METHODS: The investigation was a historical prospective cohort study based on a national registry. The loss of follow up was 4.9%. RESULTS: There were 625 deaths (659 expected). There were 269 cancer cases (264 expected). An excess of lung cancer was found; 50 cases v 37.5 expected. There were three cases of pleural mesotheliomas v 1.1 expected. The subcohort of stainless steel welders had six cases of lung cancer v 5.8 expected, and one case of pleural mesothelioma v 0.2 expected. CONCLUSIONS: The welders in the study were assumed to represent a qualified work force. These welders had a small excess risk of lung cancer. The excess risk did not seem to be associated with stainless steel welding. Smoking and asbestos exposure were potential confounders.     

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.     

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.     

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.     

Fertility among Danish male welders

Welding may be detrimental to the male reproductive system. Fertility was examined in a Danish cohort of 3702 male metalworkers over a follow-up of 47 674 person-years. Occupational histories were gathered by postal questionnaires. Information on births was obtained by record linkage to the Danish Central Population Register. Among persons who had ever worked as welders, the probability of having a child was slightly reduced the year after a year of welding exposure, even after control for differences in age, birth cohort, paternal parity, birth of a child in the preceding five years, smoking, and consumption of alcoholic beverages (odds ratio 0.89, 95% confidence interval 0.83-0.97). The reduction in fertility was associated with the welding of mild steel, but not with the welding of stainless steel. These findings are consistent with results of previous studies of time to conception and semen quality in welders.     

Incidence of cancer among welders of mild steel and other shipyard workers.

The incidence of cancer among 4571 shipyard workers with first employment between 1940 and 1979, including 623 welders of mild steel, was investigated in a historical cohort study. The loss to follow up was 1.1%. The total number of deaths was 1078 (974.5 expected) and there were 408 cases of cancer v 361.3 expected. Sixty five cases of lung cancer were found v 46.3 expected based on the national rates for males. Four pleural mesotheliomas had occurred (1.2 expected), none among the welders. An excess of lung cancers was found among the welders (nine cases v 3.6 expected). There were six cases of lung cancer v 1.6 expected in a high exposure group of 255 welders. A survey of the smoking habits as of 1984 indicated 10%-20% more daily smokers among the shipyard production workers than among Norwegian males. Exposure to smoking and asbestos were confounding variables in this study.     

Incidence of cancer among welders and other shipyard workers with information on previous work history

The incidence of cancer among 4480 shipyard workers, including 861 welders, was investigated for a potential relationship between exposure to welding fumes and lung cancer. A subcohort of 3150 workers with information on previous work history was studied separately. This investigation is a historical prospective cohort study. Environmental air samples were collected in 1973, 1977, and 1989. Information on smoking habits was surveyed in 1976 and 1984. The employment work histories were collected from the personnel register. There were 411 observed cancers of all sites versus 387.5 expected, and 45 cases of lung cancer versus 51.3 expected. Nine cases of lung cancer were found among the welders versus 7.1 expected. Among 310 former seamen with welding experience, there was 1 case of lung cancer versus 2.1 expected. These shipyard workers showed no excess risk of lung cancer. Tobacco smoking and asbestos exposure are potential confounders in the study. There was no clear relationship between exposure to welding fumes and lung cancer, but welders with the longest experience had a relative risk of 1.9 for lung cancer. The differences in lung cancer incidence among the different shipyard workers could not be attributed to differences in recruitment patterns or previous work history.     

Occupational exposure to carcinogens and risk of lung cancer: results from The Netherlands cohort study.

OBJECTIVES: To investigate risk of lung cancers associated with common established carcinogenic occupational exposures (asbestos, paint dust, polycyclic aromatic hydrocarbons, and welding fumes) in a prospective cohort study among the general population, and to estimate the proportion of lung cancer cases attributable to these occupational exposures. METHODS: A prospective cohort study on diet, other lifestyle factors, job history, and cancer risk that started in 1986 in The Netherlands on 58,279 men, aged 55-69 years. Based on information about job history obtained from a self-administered questionnaire, case by case expert assessment was carried out to assign to each study subject a cumulative probability of occupational exposure for each carcinogenic exposure. For analysis, a case-cohort approach was used, in which the person-years at risk were estimated from a randomly selected subcohort (n = 1688). After 4.3 years of follow up, 524 lung cancer cases with complete job history were available. RESULTS: After adjustment for age, each of the other occupational exposures, and for smoking habits and intake of vitamin C, beta-carotene, and retinol, significant associations were found between risk of lung cancer and cumulative probability of occupational exposure to asbestos (relative risk (RR) highest/no exposure = 3.49, 95% confidence interval (95% CI) 1.69 to 7.18, trend P < 0.01 or paint dust (RR highest/no exposure = 2.48, 95% CI 0.88 to 6.97, trend P < 0.01). The population attributable risks (PARs) for the four exposures based on the multivariately adjusted RRs for ever exposed versus never exposed workers were calculated. The PAR of lifetime occupational exposure to asbestos was calculated to be 11.6%. CONCLUSIONS: This prospective cohort study among the general population showed that occupational exposure to asbestos or paint dust is associated with higher RRs for lung cancer. This study shows that after adjustment for smoking and diet about 11.6% of the cases of lung cancer in men is attributable to lifetime occupational exposure to asbestos.     

Incidence of cancer among welders and other workers in a Norwegian shipyard

The incidence of cancer among 4778 male shipyard workers, including 783 mild steel welders, was investigated in a historical cohort study. The workers had been employed for at least three months between 1 January 1946 and 31 March 1977. The incidence of cancer was observed from 1 January 1953 through 1986. The loss during follow-up was only 0.9%. There were 53 observed cases of lung cancer in the whole cohort versus 31.3 expected on the basis of the national rates for men. There was an increased incidence of lung cancer among the welders, with seven observed cases versus 3.2 expected. Twenty-two cases of bladder cancer were observed versus 15.2 expected. Two malignant mesotheliomas had occurred (0.7 expected). Smoking was likely to be a confounder in the present study. Due to concomitant exposure to asbestos, the results are inconclusive concerning the possible relationship between exposure to welding fumes and lung cancer.     

Incidence of cancer among welders, platers, machinists, and pipe fitters in shipyards and machine shops

The incidence of cancer in 12,693 shipyard and machine shop male workers (1689 welders, 4308 platers, 6003 machinists, 693 pipe fitters) employed for at least one year between 1945 and 1960 was investigated in a retrospective cohort study. The welders had welded only mild steel and had not been exposed to hexavalent chromium containing fume. The follow up was 99.7% complete and the total number of person-years was 304,682. The incidence of cancer in 1953-81 was ascertained through the Finnish Cancer Registry. The observed numbers of cases of cancer were compared with the expected numbers based on regional urban rates. The smoking habits of the cohort were surveyed with a postal questionnaire sent to a sample of 961 workers. The smoking habits of the cohorts were similar and smoking was not more common than among the general population. The total number of cases of cancer was 611 (exp 629) among the shipyard workers and 376 (exp 388) among the machine shop workers. The incidence of lung cancer was increased among the shipyard workers (obs 227, exp 192). This excess was observed in all the worker groups and was most evident for the pipe fitters and platers. Among the machine shop workers, the incidence of lung cancer was lower than expected with the exception of the welders who had a slightly raised risk of lung cancer (obs 14, exp 10). The incidence of laryngeal cancer was slightly raised among the shipyard workers (obs 24, exp 20) but not in the machine shop workers. No excess risk was observed among the welders. The incidence of cancer of the prostate was increased among the machine shop workers (obs 39, exp 31) but not in the shipyard workers. The excess was statistically significant for the welders. No pronounced excess could be found for other types of cancer. Analysis by the duration or exposure showed that the excess of lung cancer in the shipyard workers was most evident during the last period of observation (1972-81). No other trends were obvious and the slight excess of lung cancer observed among the welders did not increase with increasing follow up time. No excess risk for mesothelioma was found. The small excess of lung cancer in welders could be due to chance. The fact that only a small and statistically insignificant excess of lung cancer could be found among this group of heavily exposed welders suggest that if the risk of lung cancer was associated with welding this risk must nowadays be low and probably too low to be unequivocally detected in most epidemiological studies.     

Incidence of cancer among welders, platers, machinists, and pipe fitters in shipyards and machine shops.

The incidence of cancer in 12,693 shipyard and machine shop male workers (1689 welders, 4308 platers, 6003 machinists, 693 pipe fitters) employed for at least one year between 1945 and 1960 was investigated in a retrospective cohort study. The welders had welded only mild steel and had not been exposed to hexavalent chromium containing fume. The follow up was 99.7% complete and the total number of person-years was 304,682. The incidence of cancer in 1953-81 was ascertained through the Finnish Cancer Registry. The observed numbers of cases of cancer were compared with the expected numbers based on regional urban rates. The smoking habits of the cohort were surveyed with a postal questionnaire sent to a sample of 961 workers. The smoking habits of the cohorts were similar and smoking was not more common than among the general population. The total number of cases of cancer was 611 (exp 629) among the shipyard workers and 376 (exp 388) among the machine shop workers. The incidence of lung cancer was increased among the shipyard workers (obs 227, exp 192). This excess was observed in all the worker groups and was most evident for the pipe fitters and platers. Among the machine shop workers, the incidence of lung cancer was lower than expected with the exception of the welders who had a slightly raised risk of lung cancer (obs 14, exp 10). The incidence of laryngeal cancer was slightly raised among the shipyard workers (obs 24, exp 20) but not in the machine shop workers. No excess risk was observed among the welders. The incidence of cancer of the prostate was increased among the machine shop workers (obs 39, exp 31) but not in the shipyard workers. The excess was statistically significant for the welders. No pronounced excess could be found for other types of cancer. Analysis by the duration or exposure showed that the excess of lung cancer in the shipyard workers was most evident during the last period of observation (1972-81). No other trends were obvious and the slight excess of lung cancer observed among the welders did not increase with increasing follow up time. No excess risk for mesothelioma was found. The small excess of lung cancer in welders could be due to chance. The fact that only a small and statistically insignificant excess of lung cancer could be found among this group of heavily exposed welders suggest that if the risk of lung cancer was associated with welding this risk must nowadays be low and probably too low to be unequivocally detected in most epidemiological studies.     

Non-invasive magnetopneumographic determination of lung dust loads in steel arc welders.

Magnetopneumography was used to measure non-invasively the concentration of the ferrimagnetic fraction of retained welding fume in the thoraces of steel arc welders. This was done by measuring the remanent magnetic fields due to ferrimagnetic particles. The 11 welders studied had concentrations of thoracic ferrimagnetic mineral several orders of magnitude greater than three machinists, 16 former asbestos insulators and 24 control subjects. These concentrations correlated well with total years welding (p less than 0.01) and radiographic evidence of small rounded densities (p less than 0.05), but not with smoking history. There was a higher concentration of ferrimagnetic mineral over the hilar regions. Magnetopneumography offers a non-invasive indicator of the accumulation of welding fume in the thorax.