The oil and gas sector is an essential part of the technical and economic complex of the Russian Federation. The most significant hygienic significance in the oil and gas processing industry is the chemical factor, represented by a complicated complex of harmful substances of hazard class 1-4 with different effects on the body. The study aims to assess the content of benzene and its homologs in the blood of workers of the oil and gas processing industry due to the industrial exposure of chemical factors for five and more than 20 years. Materials and methods. Researchers carried out whole blood samples of 380 oil and gas processing industry workers. They selected two groups for comparison: the main groups of professions (observation group, n=290) and workers not employed in the technological process (comparison group, n=90). During the survey, the scientists have found that with an increase in work experience in the industry up to 10 years, the average group content of toluene, o-xylene, and p,-m-xylene in the blood of workers of the main groups of professions increased from 0.00075 mcg/cm3, 0.00028 mcg/cm3, and 0.00006 mcg/cm3, respectively, to 0.00083 mcg/cm3, 0.00039 mcg/cm3 and 0.00013 mcg/cm3 with more than 20 years of experience in the industry. Those working in the industry in contact with arenas for five and more than 20 years have an increase in the content of cyclic organic compounds in the blood up to 2 times, with an increase in the percentage of blood samples from workers of the primary professions with the content of toluene, o-xylene, and p,-m-xylene up to 83%, 26%, and 13%, respectively. This position confirms the established linear relationships and indicators of the correlation between the content of benzene and o-xylene in the blood of workers of the leading professions and work experience. Workers interacting with risk factors for more than 20 years may get occupational diseases (R2=0.82). With a work experience of more than 20 years, the concentration of aromatic hydrocarbons in workers' blood is 1.5-2 times higher relative to the group of workers not engaged in the technological process. Under experimental studies, we established a correlation between the level of aromatic hydrocarbons (hazard class 1-3 with unidirectional effects on the body) in the blood and work experience in the industry. It is pretty apparent the need to introduce biomonitoring in production to assess the complex intake of substances into the body of workers.