One of the biggest problems related to mandatory tanks of oil and oil derivatives are evaporative losses in the tanks. It is well known that the storage, manipulation, and transport of oil and oil derivatives results in the evaporation of the liquid. In the case of tanks where commodity reserves are stored for a long period of time, the most pronounced problems are “breathing” losses and degradation of the quality of petroleum products. Many of these volatile organic compounds also have a strong negative impact that is harmful to human health and the environment. The aim of this research is to improve system in order to reduce evaporative losses in the tanks which are used for mandatory reserves of oil and oil derivative in warehouse in location near Požega in Serbia as well as to reduce the harmful impact on the environment with the proposed improvement measures.