Bunker fuel testing and marine surveying business Maritec-Naias on Monday (10 August) issued an alert regarding high levels of chemical compounds found in multiple fuel oil bunker samples from vessels that have taken fuel/bunkered in Malaysia ports:
During the period of 15 April to 15 July 2026, Maritec-Naias tested multiple fuel oil bunker samples from vessels that took fuel/bunkered in Malaysia ports, which indicated the presence of high levels chemical compounds.
Five cases were found to have Phenolic compounds and Alkylresorcinols in the range of 1070 – 9994 PPM and three cases were found to have reactive hydrocarbons in the range of 4500 – 20000 PPM. Operational issues like excessive sludge formation in purifier and wear-and-tear of the fuel pump were reported.
Gas Chromatography-Mass Spectrometry (GC-MS) testing using the Solid Phase Extraction (SPE) method confirmed the presence of Alkylresorcinols in samples tested. In addition, GC-MS ASTM D7845 analysis identified a range of phenolic compounds and reactive hydrocarbons – including styrene and its derivatives, dicyclopentadiene, dihydro-dicyclopentadiene, and indene – providing comprehensive evidence of contamination.
The presence of Alkylresorcinols may originate from non-petroleum cutter stocks, such as Estonian shale oil, while the detected reactive hydrocarbons could stem from ethylene cracker by-products. In addition, the fuels appear to have been blended with low-quality marine fuels, a practice likely driven by sharply rising bunker prices amid the war in the Middle East.
Regulatory Implications:
Due to the high levels of these chemical compounds the fuel does not meet the general requirement and is considered as off-spec fuel as per clause 5 of ISO8217 and MARPOL Annex VI regulation 18, which states:
“The fuels shall be homogeneous blends of hydrocarbons derived from petroleum refining. This shall not preclude the incorporation of small amounts of additives intended to improve some aspects of performance. The fuels shall be free from inorganic acids and from used lubricating oils. The fuel should not include any added substance or chemical waste which,
- a) jeopardizes the safety of ships or adversely affects the performance of the machinery; or
- b) is harmful to personnel; or
- c) contributes overall to additional air pollution.”
MARITEC-NAIAS RECOMMENDATIONS
- Closely observe the vessel fuel system/s for signs of filter clogging and purifier sludging and additionally, increase vigilance on the centrifuges to monitor overloading.
- Increase frequency of their de-sludging cycle depending on the accumulated sludge.
- Possibly reduce the mean time between bowl cleaning of the purifier and fuel system filters.
- Avoid blending with other fuels, in particular marine diesel and gas oil and also other fuel oil as such mixing may well increase the sediment problem.
- Opt for Maritec-Naias’s highly cost-effective Marine Fuel Testing Programme (MFTP) PLUS testing for all residual bunker fuel. This package includes routine ISO 8217 Testing, targeted GC-MS screening for 38 high-risk compounds relevant to ship operations & P-value Stability Testing – providing crucial pre-burn protection against fouled purifiers, blocked injectors & engine failure.
Photo credit: Hans Reniers on Unsplash
Published: 11 August, 2026
