This book disscused the occupational exposure to metal dust particularly, Aluminium and Iron and its diverse effects on the lung.Dysplasia was detected in four individuals, all of them were cases particularly iron workers. Notably, there were 168 individuals with metaplasia, of whom, 77(59%) were identified among cases and the remaining 91(58%) were among controls, in the cases, metaplastic cells were found in Iron workers and 11 in Aluminum workers. In respect to the presence of human papilloma virus, 18 were found in cases (17 in Iron, 1 in Aluminum) and 8 in controls. Inflammatory cells were present in 182 individuals of whom 96 (74%) were cases and the rest of them were controls (43%), Infltration in iron workers were found three times countervailed in Aluminum workers. Presence of bacteria and moniliasis were found higher in cases than in controls particularly Iron workers. All these findings and changes regarding to their relation with exposure to iron and Aluminum were found statistically significant.