The characteristics of Ukrainian oil transportation system are presented; the emergency risks of Ukrainian oil pipelines are established. The analysis of the accident rate of oil pipeline transportation in Ukraine, Russia and the USA was carried out. The processes of initiation and progression of man-made emergencies in Ukraine during the oil pipelines operation are considered. The article presents the technique of specifying the incidental pressure in a pipeline, depending on the amount of oil loss at the site of oil leaks. It gives an opportunity to calculate the amount of oil loss and to evaluate the environmental hazards caused by oil pipeline transportation emergencies. It is based on the equations of motion and continuity of fluid flow. This technique makes it possible to calculate the pressure at each point of a pipeline in transient mode caused by changes in pressure at the beginning and at the end of the section and the emergence of concentrated oil offtake. It also gives an opportunity to monitor the change in mode parameters along the pipeline under conditions of pipeline depressurization. Maximum discrepancy in calculation results becomes typical when the range of fluctuations is maximal. It has been established that discrepancy increases when the distance from the source of perturbation becomes bigger. The discrepancy in calculation results is practically non-existent for the pressure fluctuations at the point of perturbation start ( x L= ). Based on the results of calculations, the author constructs a graph of pressure change of the oscillatory process in the oil pipeline caused by the jump in the pressure at the beginning and at the end of the section, and the presence of probable leaks at the certain point of the pipeline route. The line section of the main oil pipelines is the most dangerous part since all emergencies are associated with emergency processes of different intensity in the form of outflow of oil into the environment, and are dangerous because of system breakdowns can take place. Both the process of the generation of the oil pollution zone and its time period depend on the amount of oil leakage, its intensity and depth of the oil pipeline