The problem with the quality of oil coming from Russia to Belarus via the southern branch of Druzhba pipeline (running on the territory of Belarus, Ukraine and Poland to Germany) arose on April 19, when the Belneftekhim consolidated group announced the receipt of low-quality Urals export mixture with high organic chlorides content. Russia had to limit its exports to Europe. Transneft and the Ministry of Energy recognized the problem and promised to fix it. The situation was discussed at the highest level: President of Belarus, Alexander Lukashenko, discussed with the President of Russia the issue of supplying substandard oil to Belarusian refineries, law enforcement agencies opened a criminal case for deliberate oil pollution, investigations are taking place in Samara in the offices of several private companies (Transneft announced that substandard oil entered the pipeline through the accounting site in the Samara region, which was owned by Samaratransneft-Terminal and through which raw materials from several private oil companies of the Samara region arrived, that were not a part of vertically integrated companies).
About 700,000 tons of oil occurred to be polluted. Belneftekhim estimated the lost revenue from refining reduction due to the deterioration of the quality of Russian oil at $ 100 million (the company also had to replace some of the equipment that failed due to the high chlorine content in Russian oil), but reputational risks are much higher. The investigation produces several versions - up to sabotage.
Our comments on a sensitive issue appeared live on "Echo of Moscow" radio (as of April 26, 2019), issues of Vedomosti (as of February 26, 2019) and Kommersant (as of April 29, 2019) newspapers. "Denis Abakumov, managing partner of Bright consulting company, notes that it is impossible to overpass the Transneft quality control system without violating the law. “It’s impossible to overpass the system without leaving traces, especially on such a scale,” he says.“ All processes are technically secured and regulated in detail.” According to him, if the problem is not corrected, there will be the likelihood of crisis situations in the markets where Russian oil went through Belarus, “but it is very low.” Mr. Abakumov recalls that under contracts, Transneft is responsible for the oil supplied through its pipelines. “If Transneft has taken oil into its system, this means that it agreed that the raw materials in its system are of a good quality and therefore all the risks lie on it,” he says".
You can read more about the materials here: https://www.vedomosti.ru/business/articles/2019/04/26/800376-istochnik and https://www.kommersant.ru/doc/3960708.