A. SAVCHENKO1 1Institute of Human Ecology, Federal Research Center of Coal and Coal Chemistry, Siberian Branch, Russian Academy of Sciences, Kemerovo, Russia E-mail: vminina@mail.ru 2Kemerovo State University, Kemerovo, Russia Abstract The DNA damage in peripheral blood lymphocytes in employees of Kuzbass coal enterprises and men, non-exposed to the coal dust, was studied. <...> In total, 501 donors were included in our research (137 coal miners, the average length of service is 28 years and 104 thermal power plant workers, the average length of service is 25 years). <...> The average concentration of coal dust in miners workplace reached to 190 mg/m3, the content in power plant workers varied from 11 to 23 mg/m3. <...> As a control group, 260 non-exposed men of similar age living in the same area were studied. <...> Their blood samples were obtained from the ulnar vein. <...> Cell cultivation, slides preparation and chromosomal aberrations assessment were performed in a similar way for all groups. <...> Increasing the frequency of chromosomal breaks (chromosome as well as chromatid type) and chromosome exchanges was registered. <...> The results obtained are the evidence of the expressed genotoxic exposure in the workers occupationally associated with the coal dust. <...> Key words: coal dust, chromosomal aberrations, coal miners, thermal power plants 545 INTRODUCTION The coal dust is a mixture of various organic and inorganic chemical agents that can induce the DNA damage. <...> Combined exposure to these radioactive and chemical factors can induce various types of DNA damage, formation of adducts, single and double DNA strand breaks, structural and quantitative chromosomal abnormalities. <...> The investigation of animals caught in the mining regions indicated cytotoxic and genotoxic effects of the exposure to coal dust. <...> The increased degree of the DNA damage was discovered in wild rodents and Iguana iguana from the coal mining areas of Brazil and Colombia [2, 3]. <...> Such alterations are accumulated in various cells (buccal epithelium and blood lymphocytes) and can be registered using such tests as chromosomal aberrations and sister chromatid exchanges (SCE) assessment, micronucleus assay and DNA comet assay. <...> In the Kemerovo Region a positive correlation <...>