The article covers analysis of work conditions for aluminium plant workers, through workplaces certification. The authors specified work condition classes according to the jeopardy degree. Number of workplaces with conditions having occupational hazards' MAC and MAL excess 10-fold and over (class 3.3 and 3.4) approached 30%. Materials on occupational morbidity in 9 aluminium plants over recent 6 years are presented, with parameters and structure of the morbidity. Findings are that 60.4% of the occupational diseases are diagnosed among electrolysis workers with average length of service of 26.3 years. Results of the workplaces certification are compared in accordance with work conditions and occupational morbidity parameters.