Evaluation of Total and Respirable Dust and Crystalline Silica in the Refractory Process of Metal Melting Furnaces

Regarding the possibility of existence of crystalline silica in production process or usage of refractory materials, the workers of this industry are exposed to the risk of silicosis. Silicosis is a type of pneumoconiosis that is a risk factor for lung cancer and also one of the causes of temporary or permanent occupational disabilities. This study aimed to examine the toxicity of refractory materials during destruction in metal melting furnaces. The study was done in the refractory process of one of the metal melting industries in refractory destruction job. For the evaluation of total and respirable dust in workplace air, gravimetric method was used according to the National Institute for Occupational Safety and Health (NIOSH) 0500 and NIOSH 0600, respectively. For evaluation of crystalline silica in total and respirable dust in workplace air, the samples were analyzed by NIOSH 7601 spectrophotometry. Findings: Average total dust concentration in the furnaces during the destruction of refractory materials was obtained 153.6 mg/m3 that was 15.3 times more than the permissible limit of Iran's occupational standards. The average concentration of respirable dust during destruction of refractory materials in furnaces was reported 27.98 mg/m3 that was 9.3 times more than the permissible limit of Iran's occupational standards. The average concentration of crystalline silica dust in the total air in furnaces during the destruction of refractory materials was obtained 0.2235 mg/m3 that was 8.9 times more than the permissible limit of Iran's occupational standards. The average concentration of crystalline silica dust in the respirable air in furnaces during destruction of refractory materials was 0.1008 mg/m3 that was 4 times more than the permissible limit of Iran’s occupational standards. The average concentration of total and respirable dust and also crystalline silica produced during destruction of refractory materials in the furnaces is higher than the permissible level of Iran’s occupational standards