Quantitative and qualitative assessment of exposure among employees in Norwegian smelters.

OBJECTIVES: To generate a job exposure matrix (JEM) for dust exposure in Norwegian smelters to be used in an epidemiologic study of respiratory diseases and to identify determinants of exposure. METHODS: The arithmetic mean and geometric mean (GM) of 2619 personal dust exposure measurements were applied in constructing the JEM, which was assigned to 2620 employees participating in a respiratory survey including yearly spirometry and a respiratory questionnaire. A qualitative exposure classification was constructed: (i) line operators were those employed full time in the production line, (ii) non-exposed employees were those who did not work in production and (iii) the remainder were classified as non-line operators. RESULTS: In the ferrosilicon alloy and silicon metal production group (FeSi/Si-metal), the median GM of dust exposure was 2.3 mg m(-3) (0.04-5.6) (10-90% percentiles) compared with 1.6 mg m(-3) (0.02-2.3) in the silicomanganese, ferromanganese and ferrochromium production group (SiMn/FeMn/FeCr). Multivariate analyses showed that dust exposure concentration levels decreased significantly with increasing age (FeSi/Si-metal), was significantly lower in females than in males and was significantly higher in current smokers than in never-smokers. Dust exposure concentration levels were also higher in employees reporting previous exposure to dust, fumes and gases than in employees without such previous exposure, though, significant only in the FeSi/Si-metal production group. CONCLUSION: The dust exposure levels of the employees were higher in the FeSi/Si-metal production group than in the SiMn/FeMn/FeCr production group. Age, gender, smoking status and previous exposure were significant determinants of dust exposure and should be evaluated in future analyses of the relationship between health outcomes and dust exposure in this industry.

Decreased lung function among employees at Norwegian smelters.

BACKGROUND: In the smelting industry airborne pollutants are emitted into the workplace atmosphere during the production process. Our aim in this study was to investigate the relationship between production and lung function among employees at Norwegian smelters. METHODS: Spirometry was performed on 3,924 employees, who also completed a standardized questionnaire. The employees were classified by job functions: (i) line operators were employed full-time on the production line, (ii) non-exposed employees did not work in production, and (iii) the remainder of the employees were classified as non-line operators. RESULTS: The mean age of the participants was 38.6 (range 20.0-55.0) years, 88.5% were males. The multivariate analyses showed that, compared to the forced expiratory volume in one second (FEV(1)) in non-exposed employees, the FEV(1) (95% confidence interval) was 87 (33-141) ml and 65 (12-118) ml lower in line and non-line operators, respectively. The prevalence of airflow limitation (FEV(1)/forced vital capacity (FVC) below the 5th percentile of the predicted value) was 4.7% in non-exposed employees, 7.5% in non-line operators and 8.3% in line operators. CONCLUSION: Compared with non-exposed employees, impairment of lung function among employees at Norwegian smelters was significantly related to the job categories of line operator and non-line operator.

Production of silicon alloys is associated with respiratory symptoms among employees in Norwegian smelters.

OBJECTIVES: To develop a qualitative exposure classification of employees in Norwegian smelters and to investigate the relationship between respiratory symptoms and occupational exposure using this classification. METHODS: The 3,924 participants completed a standardised questionnaire including questions of respiratory symptoms, familial asthma, allergy, doctor-diagnosed asthma, smoking habits, previous exposure and occupation. The employees were classified according to their current job function: (1) line operators were employed full time on the production line, (2) non-exposed employees did not work in production, (3) the remaining employees were classified as non-line operators. The association between the prevalence of respiratory symptoms and job category was examined using multivariate logistic regression. RESULTS: The mean age of the participants was 38.6 years (standard deviation 9.2 years), 88.5% were males. The odds ratios (OR) (95% confidence intervals in parenthesis) for dyspnoea, cough and phlegm regarding previous exposure compared with no previous exposure were 1.4 (1.1-1.7), 1.4 (1.2-1.8) and 1.3 (1.0-1.7), respectively. The OR in line operators compared with non-exposed employees was 1.2 (0.9-1.7) for dyspnoea, 1.3 (1.0-1.8) for cough and 1.9 (1.4-2.7) for phlegm. The OR for respiratory symptoms was higher in relation to previous exposure than current job function except for phlegm. CONCLUSION: In Norwegian smelters respiratory symptoms appear to be positively related to both current job function and previous exposure. Previous exposure appears to be more important than current job function.