Spirometric abnormalities among welders

A group of manual welders (N = 57) engaged in gas welding joint faces of moulded brasswares, age group 13-60 years (mean: 29.2 +/- 1.37 years), having a mean exposure period of 12.4 +/- 1.12 years (range: 1-35 years) were subjected to spirometry to evaluate the prevalence of spirometric abnormalities. The findings were compared with those obtained from a reference group (N = 131) (mean age: 31.2 +/- 1.35 years) engaged in nonwelding jobs such as packing, labelling, and transportation of the finished brassware articles. The welders showed a significantly higher prevalence of respiratory impairment (28.0%) than that observed among the unexposed controls (6.1%) (P less than 0.001), as a result of exposure to welding gases which comprised fine particles of lead, zinc, chromium, and manganese. This occurred despite the lower concentration of the pollutants at the work place. In the exposed group, the smoking welders showed a prevalence of respiratory impairment significantly higher than that observed in the nonsmoking welders (40.0 vs 18.7%) (P less than 0.10). A similar trend was observed in the control group indicating that smoking had a deteriorating effect on spirometric tests. The results of the pulmonary function tests showed a predominantly restrictive type of pulmonary impairment (12.3%) followed by a mixed ventilatory defect (8.7%) among the welders. The effect of age on pulmonary impairment was not discernible either in the exposed or unexposed group. The analysis of data in relation to duration of exposure showed significant correlation between the prevalence of respiratory abnormalities and length of exposure. Welders exposed for over 10 years showed a prevalence of respiratory abnormalities significantly higher than those exposed for less than 10 years (44.4 vs 13.3%) (P less than 0.01) thereby showing that occupational exposure to welding fumes resulted in increased prevalence of pulmonary impairment in the welders. Smoking also had a contributory role thereby suggesting an interaction between smoking and welding exposure on the prevalence of pulmonary impairment in the welders engaged in brassware industries.     

Cancer risk of arc welders exposed to fumes containing chromium and nickel

A retrospective follow-up study among chromium- and nickel-exposed welders, which took into consideration welding procedures, duration of exposure, and smoking habits, yielded an increased cancer risk in a comparison with an internal reference group of turners, milling cutters, and drillers, as well as in a comparison with the general population of the Federal Republic of Germany. Due to the cohort size (1 224 welders, 1 694 turners) and the fact that the observation period is still too short, confirmed statements as to the target cancer sites cannot yet be made. However, it emerges that welding with coated electrodes shows a higher cancer risk as compared to the other welding processes observed. This finding may be explained by the fact that the share of hexavalent chromium compounds in the welding fumes is greater with coated electrodes than with other processes so that a follow-up study observing the health risks of chromium and nickel fumes separately would be warranted. For the confirmation of a more favorable outcome with gas-shielded welding, a larger investigation group or a longer observation period would be required.     

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.     

Respiratory symptoms in Danish welders

In order to study the effect of welding fumes on respiratory symptoms a cross sectional study was performed in 1982 among 2,660 welders, primarily shipyard welders, compared with a control group of 881 electricians. Only workers more than 34 years of age and in work at the time of the study were selected. Information about respiratory symptoms (using standardized BMRC questions) and exposure was obtained through a self-administered questionnaire. Seventy-four never-smoking welders and 31 never-smoking controls were selected for detailed clinical interviews and extended lung function tests. This article presents the results of the questionnaire study. The welders showed a significantly higher prevalence of chronic bronchitis: 21% versus 9% in the control group (p less than 0.01). The difference could neither be explained by differences in age or smoking habits nor by exposure to other air polluting substances. Other symptoms from the lower and upper respiratory system were also significantly increased among the welders. A dose-response relationship was found between exposure to welding fumes and the prevalence of symptoms from both the upper and lower respiratory system.     

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.     

Absences attributed to respiratory diseases in welders.

Certified sickness rates of 36 male welders were examined for the period 1970-9. They were compared with 36 male controls from the same petrochemical plant, matched for age, smoking habits, duration of employment, and social class. Indices of severity (average annual duration), duration (average length of spell), and frequency (inception rate of spells and inception rate per worker) were calculated. Absences for all diseases were similar, but absences attributed to respiratory diseases were slightly higher in welders in severity, duration, and frequency. The proportion of days lost attributed to respiratory diseases was 2.3 times higher in welders compared with controls. This was due to a large increase in absences attributed to lower respiratory tract diseases, the ratio of welders to controls being more than four to one for both severity and inception rate of spells. The comparison between welders and controls in smokers and non-smokers confirms other studies which show that smokers tend to be more affected by welding fumes than non-smokers.     

Chronic effects of welding exposure on pulmonary function tests and respiratory symptoms.

OBJECTIVES--The respiratory effects of exposure to welding fumes have been investigated in numerous studies; but results of these studies have not been consistent. The aim of the present study was to investigate the respiratory effects of welding exposure in a large group of manual are welders exposed primarily to mild steel welding processes in confined spaces without respiratory protection. METHODS--Respiratory symptoms and spirometry were studied in 110 welders and 55 controls. The welders and controls were of similar average age and height; smoking habits of the groups were similar. Chest x ray films were taken to exclude people with radiological abnormalities that may influence pulmonary function tests. Welders were grouped according to smoking habits and duration of employment (< 20 years or > 20 years). RESULTS--No gross radiological abnormalities were found. Respiratory symptoms and chronic bronchitis were more prevalent in welders (P < 0.05). Welders who were smokers showed a higher frequency of chronic bronchitis than controls who smoked (P < 0.05). No significant difference in the occurrence of chronic bronchitis was found between welders who smoked and welders who were non-smokers or exsmokers. Compared with the controls, forced vital capacity (FVC), forced expiratory volume in one second (FEV1), peak expiratory flow (PEF), and maximum midexpiratory flow (MMEF) were significantly lower in welders (mean values of FVC for welders and controls were 86.06 (25.74) and 96.40 (13.03); and values for FEV1 were 87.54 (13.70) and 95.36 (12.40) respectively; P < 0.01). There was no significant difference in pulmonary function tests between welders who were non-smokers and controls who were non-smokers; whereas FVC, FEV1, PEF, and MMEF were significantly lower in welders who smoked than controls who smoked (P < 0.01). There were no significant differences in pulmonary function tests and occurrence of chronic bronchitis between welders with more or less than 20 years at work. CONCLUSION--Welders working in conditions of inadequate ventilation, have increased risk of chronic bronchitis and impairment of pulmonary function.     

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.     

Exposure and urinary excretion of aluminum during welding

The exposure and urinary excretion of aluminum was studied among three previously unexposed volunteers and six welders exposed to welding fumes containing aluminum. The aluminum concentrations in air and urine were determined. The urinary aluminum concentrations rose rapidly in volunteers exposed only for 1 d and returned to the preexposure levels with an estimated half-time of about 8 h. The welders were monitored for one workweek. During the subsequent weekend a decrease in the urinary concentrations occurred in the three welders exposed for two years or less, but such a decrease was not observed among welders exposed for more than 15 years. The urinary concentrations of aluminum were dependent partly on the level of current exposure and partly on the duration of exposure. The data suggest that welders exposed to welding fumes containing aluminum may retain some of the inhaled metal fume for extended periods of time.     

Lung function and clinical findings in a cross-sectional study of arc welders

Summary An epidemiological, cross-sectional study was conducted in order to assess non-neoplasic effects on the lung due to chronic exposure to arc welding fumes and gases. The study involved 346 arc welders and 214 control workers from a factory producing industrial vehicles. These workers (welders and controls) had never been exposed to asbestos. Respiratory impairments were evaluated by using a standardized questionnaire, a clinical examination, chest radiophotography and several lung function tests (spirometry, bronchial challenge test to acetylcholine, CO transfer tests according to the breath-holding and the steady-state methods, N₂ washout test). The only significant differences between the welders overall compared to the controls were a slightly higher bronchial hyper-reactivity to acetylcholine and a lower lung diffusing capacity for CO in the welders. However, non-specific, radiologic abnormalities (reticulation, micronodulation) and obstructive signs were more frequent in the most exposed welders (welding inside tanks) than in welders working in well ventilated workplaces. The nature of the metal welded (mild-steel, stainless steel, aluminium) did not seem to have an influence on respiratory impairments. In the mild-steel welders, respiratory symptoms (dyspnoea, recurrent bronchitis) and obstructive signs were more frequent in the welders using a manual process than in the welders involved with the semi-automatic process (MIG). For all the workers (welders and controls), smoking had a markedly adverse effect on respiratory symptoms and lung function. Moreover, smoking seemed to interact with welding since CO lung transfer was more impaired in smoking welders than in smoking controls.     

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.     

Respiratory symptoms and pulmonary function in welders of mild steel: A cross-sectional study

Pulmonary function measurements, respiratory symptoms, smoking history, and occupational history were obtained from 91 male welders of mild steel, with mean welding exposure of 108 months, and 80 male factory controls. Nonsmoking welders compared to nonsmoking controls reported higher frequencies of respiratory symptoms and the differences were statistically significant for two symptoms: phlegm, and episodes of cough and phlegm. In comparisons of smoking welders and smoking controls, no significant differences were found in the prevalence of respiratory symptoms. Nonsmoking welders and smoking welders, compared to respective controls, did not have significantly decreased mean values of forced vital capacity or forced expired volume in 1 sec. Mean mid-expiratory flow rates and forced expiratory flow rates at 75% of forced vital capacity were lower, but not significantly different, for welders, compared to controls. These decrements in peripheral flow rates could be trivial or they could represent the initial stages of chronic obstructive pulmonary disease. Long-term follow-up, provided by a large prospective study, is needed to make this distinction.     

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.     

Acute changes in vascular function among welders exposed to metal-rich particulate matter

BACKGROUND: Although welding fume exposure is associated with adverse cardiovascular outcomes, the mechanisms remain unclear. To investigate the role of vascular function, we assessed levels of the augmentation index (a correlate of arterial stiffness) after short-term exposure to welding-derived fine particulate matter (PM2.5). METHODS: In a panel study, we monitored 26 male welders over 24 hours on a welding day (n = 25), a non-welding day (n = 15), or both (n = 14). Augmentation index (expressed as a percent) was obtained in the morning before exposure (baseline) and after exposure in the afternoon and the following morning. Personal PM2.5 exposure was measured over 6 hours of welding or an equivalent non-welding period. We used linear mixed models adjusting for baseline augmentation index, smoking, age, and time to evaluate the effects of welding (binary) and PM2.5 (continuous) on augmentation index levels. We also assessed modification by welding exposure the day before monitoring (binary). RESULTS: Welding was associated with a 2.8% increase in afternoon augmentation index (95% confidence interval = -1.4 to 7.0) and a 2.4% decrease (-6.9 to 2.2) in next-morning augmentation index. Additional exposure the day prior to monitoring was associated with a greater afternoon increase (5.1%; 0.8 to 9.5). Using PM2.5 concentration, a positive association was observed in the afternoon and an inverse association the next morning; results differed by previous day's welding status after excluding outliers. CONCLUSIONS: Subsequent to welding fume exposure, there is an increase in afternoon augmentation index and a decrease in next-morning augmentation index, with greater changes after consecutive days of exposure. These results suggest that exposure to the PM2.5 component of welding fume elicits acute adverse vascular responses.     

Semen quality in welders before and after three weeks of non-exposure

In a cross sectional field study concerning the male reproductive system in metalworkers, the major findings were a moderate deterioration of semen quality in mild steel welders and less reliable changes in semen quality in low exposed stainless steel welders. In the present study, a longitudinal design was adopted to deal with methodological drawbacks inherent in the cross sectional approach. The study relies on the assumption that the effect of welding is causal and reversible. The semen quality of 19 mild steel welders, 18 stainless steel welders and 16 non-welding metal-workers, was examined before and three, five, and eight weeks after a three week break in exposure (summer vacation). No consistent improvement in any semen parameter in the follow up period relative to the prevacation period was found in either mild steel or stainless steel welders. The results indicate either a non-causal nature of reported associations between welding exposure and poor semen quality, or that the effect of welding is non-reversible within the rather short non-exposure period.     

Semen quality in welders before and after three weeks of non-exposure.

In a cross sectional field study concerning the male reproductive system in metalworkers, the major findings were a moderate deterioration of semen quality in mild steel welders and less reliable changes in semen quality in low exposed stainless steel welders. In the present study, a longitudinal design was adopted to deal with methodological drawbacks inherent in the cross sectional approach. The study relies on the assumption that the effect of welding is causal and reversible. The semen quality of 19 mild steel welders, 18 stainless steel welders and 16 non-welding metal-workers, was examined before and three, five, and eight weeks after a three week break in exposure (summer vacation). No consistent improvement in any semen parameter in the follow up period relative to the prevacation period was found in either mild steel or stainless steel welders. The results indicate either a non-causal nature of reported associations between welding exposure and poor semen quality, or that the effect of welding is non-reversible within the rather short non-exposure period.     

Respiratory effects from work-related exposure to welding fumes in Hamadan, Iran

The authors studied respiratory symptoms and lung function among welders at welding workshops, and among nonwelders, in Hamadan, Iran. They used a questionnaire to record demographic data, smoking habits, and respiratory symptoms. The authors measured pulmonary functions with subjects standing upright. They collected metal fume samples from the respiratory zone of workers and analyzed the samples by atomic absorption spectroscopy. The concentrations of iron and manganese were higher than threshold limit values. The prevalence of asthma and clinical symptoms was higher in welders than nonwelders. Also, bronchitis was more common among welders (17.45%) than among nonwelders (2.56%). The average respiratory function values of welders were lower than those of nonwelders, with a significant difference between the means (p < 0.001 for all terms). The results of this study also strongly suggest a synergistic relationship between the effects of smoking and welding exposure.     

Chronic bronchitis, work related respiratory symptoms, and pulmonary function in welders in New Zealand

OBJECTIVES: A cross sectional study of respiratory symptoms and lung function in welders was performed at eight New Zealand welding sites: 62 current welders and 75 non-welders participated. METHODS: A questionnaire was administered to record demographic data, smoking habit, and current respiratory symptoms. Current and previous welding exposures were recorded to calculate a total lifetime welding fume exposure index. Forced expiratory volume in one second (FEV1), forced vital capacity (FVC), and peak expiratory flow (PEF) were measured before the start of the shift. RESULTS: There were no significant differences in ethnicity, smoking habits, or years of work experience between welders and non-welders. Symptoms of chronic bronchitis were more common in current welders (11.3%) than in non-welders (5.0%). Of those workers with a cumulative exposure index to welding fume > or = 10 years, 16.7% reported symptoms of chronic bronchitis compared with 4.7% of those with a cumulative exposure index < 4 years (odds ratio (OR) 4.1, 95% confidence interval (95% CI) 0.90 to 17.6). Workers with chronic bronchitis had significantly lower measures of baseline PEF (p = 0.008) and FEV/FVC ratio (p = 0.001) than workers without chronic bronchitis. Multivariate analysis showed that current smoking (OR 9.3, 1.0 to 86.9) and total exposure index to welding fumes > 10 years (OR 9.5, 1.3 to 71.9) were independent risk factors for chronic bronchitis. The report of any work related respiratory symptom was more prevalent in welders (30.7%) than non-welders (15.0%) and workers with these symptoms had significantly lower FEV, (p = 0.004) and FVC (p = 0.04) values. Multivariate analysis identified a high proportion of time spent welding in confined spaces as the main risk factor for reporting these symptoms (OR 2.8, 1.0 to 8.3). CONCLUSION: This study has documented a high prevalence of symptoms of chronic bronchitis and other work related respiratory symptoms in current welders. Also, workers with chronic bronchitis had reduced PEF and FEV/FVC compared with those without chronic bronchitis. These symptoms related both to cigarette smoking and a measure of lifetime exposure to welding fume.

 

     

The potential hazardous effect of exposure to iron dust in Egyptian smoking and nonsmoking welders

Exposure to iron dust and welding fumes is widespread and may increase the risk of lung inflammation. The aim of this study was to identify associations between exposure to iron/welding fumes and the levels of inflammatory parameters and allergic mediators among 120 Egyptian men. Forty nonsmoking and 40 smoking Egyptian welders as well as 40 healthy volunteers who were never exposed to welding fumes and were nonsmoking were enrolled in the study. Peak expiratory flow rates (PEFR) assessed at the end of the shift of work on working days revealed an impairment in lung function, with the smoking workers showing the worse results, followed by nonsmoking workers, as compared to healthy volunteers. Moreover, the results of the present study showed a significant increase in serum iron and immunoglobulin E, as well as plasma thiobarbaturic acid reactive substances, C-reactive protein, tumor necrosis factor-alpha, haptoglobin, interleukin-2, interleukin-6 and interleukin-23 histamine, lactate dehydrogenase isoenzyme-3, and calcitonin. In addition, the results revealed significant decrease in plasma α-1-antitrypsin and serum transferrin, as well as blood activities of antioxidant enzymes: catalase, superoxide dismutase, glutathione peroxidase, and glutathione reductase (as compared with control group). However, there was a nonsignificant change in arginase and α-L-fucosidase in smoking and nonsmoking welders exposed to iron dust and welding fumes. In conclusion, occupational exposure to iron dust and welding fumes increases lung inflammation risk among Egyptian blacksmith workers, a condition that worsens with smoking.