Pulmonary function status of refractory workers in a steel plant: A cross-sectional study design


Background: A lot of dust is generated during various operations in the refractory section of a steel plant. Refractory bricks contain chemicals such as aluminum, silica, magnesium, chromium, dolomite and tar. During walk-through surveys in the steel-making shop, we found refractory workers chronically exposed to occupational dust, but rarely using face masks. Most took chewable tobacco, yet none gave a history of any chronic complaint of a respiratory nature. Aims: To assess the pulmonary function of refractory workers in a steel plant using spirometry; determine the variability of ventilatory impairment across work sections; and test the association between pulmonary function and years of exposure. Methods: We carried out a cross-sectional study from November to December 2016 in the refractory area of a steel-making shop, part of an integrated steel plant, in eastern India. Dust was measured in the ambient air at the shop floor level during entire shifts on three consecutive days by gravimetric method. Parameters measured included total suspended particulate matter (TSPM) and particles with a diameter of less than 10μm (PM10). The all-male workforce consisted of masons and non-masons. Of a total of 70 workers, 35, comprising 11 masons and 24 non-masons, were selected by simple random sampling. Spirometry and peak expiratory flow (PEF) measurements were carried out as per standard guidelines. Data were analyzed using the statistical software Statistica, Version 13. Results: Geometric means of TSPM and PM10 were 2,928.35 and 839.04µg/m³, respectively. Ventilatory impairment was found in 14 (40%) of the workers. Of these 14 workers, impairment was chiefly obstructive in nature – in 11 workers (78.57%). The severity of defects were mainly of a mild type – 71.43% (10 workers). In the work area where non-masons worked, ventilatory impairment was 50% (12 workers); where masons worked, the proportion was 18.18% (two workers). Regression analysis showed a significant relationship between pulmonary function deterioration and years of work in the refractory area (P = 0.0038). Conclusions and recommendations: In our study, we found ventilatory impairment in refractory workers in a steel plant to be mainly of obstructive type and mild in severity. Pulmonary function deterioration was significantly (P < 0.01) affected by years of exposure. Ethiop .J. Health Dev. 2019; 33(4):203-211] Key words: Pulmonary function, refractory workers, steel industry, exposure, spirometry, ventilatory impairment, obstructive defect