A highly toxic and possibly illegally traded chemical substance was the main culprit in the crisis with contaminated oil, which had Russia interrupt oil flows on its Druzhba pipeline to?

A highly toxic and possibly illegally traded chemical substance was the main culprit in the crisis with contaminated oil, which had Russia interrupt oil flows on its Druzhba pipeline to Europe for around two months this spring, Reuters reported on Wednesday, quoting the results of three different tests.

At the end of April, Russia?halted supplies?via the Druzhba oil pipeline to several European countries due to a contamination issue, which the Russians said?was deliberate. ? ?

Russia said at the time that the oil was contaminated with organic chlorine, a substance used in oil production to boost output but dangerous in high amounts for refining equipment. The amounts of the chemical were found to be at levels much higher than the maximum allowable amount. ?

A month after the crisis started, supplies were not restored and analysts and traders were saying the progress in restarting oil flows was very slow while?costs could be very high, despite Russia's assurances that clean oil would resume flowing through the pipeline westward to Europe in the second half of May.?

Supplies were restored only in early July, while Russia continues its investigation into how the oil was contaminated.

Now three separate tests?one from the Russian state laboratory in Moscow, one from a European refiner and one from an international oil trading company?showed one and the same chemical as the substance that had contaminated the oil, sources with knowledge of the results told Reuters.

This is carbon tetrachloride, which is used for manufacturing other chemicals.

Related: IEA: An Oil Glut Is Inevitable In 2020

Carbon tetrachloride is part of the Montreal Protocol on Substances that Deplete the Ozone Layer, which all countries have signed to phase out chemicals depleting the ozone layer.

Production of the substance is heavily controlled, and Russia has two plants that are allowed to make carbon tetrachloride.

The fact that the compound was found during the tests of the contaminated pipeline oil flow suggests that Russia hasn't eradicated the illegal trade of carbon tetrachloride, oil industry sources told Reuters.

By Tsvetana Paraskova for Oilprice.com

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