The subject of study in this article is the processes of increasing the level of the environmental and fire safety during the degassing of the vertical cylindrical tanks with the remaints of the light petroleum products. The purpose of this work is concluded in controlling the level of the environmental and fire safety of the territories in the zone of the influence the oil saving objective complexes using the application of the method proposed by U.S. Environmental Protection Agency. The Office of Emergency Management Center, EPA, developed the ALOHA® software product that is used to calculate the distribution of the concentrations during the evaporation of pollutants due to their getting into the oil processing station under different conditions. The task is to assess the level of anthropogenic pressure on the environment, and the influence oil product vapors by the forced decontamination of light oil storage tanks. The methods used here are researching conducted with the use of gas analysis to establish the qualitative and quantitative composition of the gas mixtures at the outlet of the tanks, using the modern test equipment. The following results have been obtained. Due to the researching, the methodology for calculating and forecasting the level of the technogenic load on the atmospheric air by modeling and forecasting the zones of the active pollution by emissions of the vapor-air hydrocarbon mixtures has been developed further. The conclusions. On the basis of the conducted studies, an active contamination zone was determined when performing forced degassing with the air supply, which was carried out using the traditional method, using software for modeling dispersion of pollutants. It has been established that by the forced ventilation of RVS-5000 reservoir, 1.5 tons of the vapor-air mixture get into the natural environment. Using the ALOHA® software product, the hazardous area was estimated, and the area of possible explosion of the gasoline vapors during the natural degassing of the tanks with the storage of light oil products. The size of the zone of the strong toxic influences on the population reaches 1.2 km, it was calculated for the given initial conditions, the zone of the fire danger is 80 m, the explosion zone does not exceed 13 m. K e ywor d s : a forced ventilation; an evaporation rate; a tank cleaning; the environmental pollution; a risk of the explosion.