VPS flags high shale oil components in Singapore VLSFO samples

Fuel testing firm VPS has observed an increase in the presence of shale oil components in VLSFO bunkers supplied in Singapore over the past two months, but no operational issues have been reported so far.

IMAGE: Bunker delivery in Singapore. Getty Images

VPS identified 90,000 mt of delivered VLSFO bunkers over the course of February and March 2026 that contained “compounds consistent with an Estonian shale oil derived stream”.

Why it matters?

Estonian shale oil is often used as a blend component in bunker fuel, but it is known to destabilise fuel, produce sludge and block ship filters.

Estonian shale oil contains high-boiling phenolic compounds such as, resorcinol and alkyl benzenediols, which can result in high acid numbers, often exceeding the limits prescribed under the ISO 8217 marine fuel specification.

Phenolic compounds are organic chemicals commonly found in refinery streams that can affect fuel combustion and lead to operational challenges.

Following its findings, VPS contacted each vessel that received these fuels, and all confirmed that they have not experienced any operational issues while burning the fuels so far.

However, the company said that based on its experience and industry findings, these fuels require "close operational monitoring and cautious handling".

By Nachiket Tekawade 

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