Fuel testing agency Maritec-Naias has identified high concentrations of chemical compounds in multiple bunker fuel samples collected from vessels that bunkered at Malaysian ports between April 15 and July 15. Malaysia is one of Southeast Asia's major bunkering hubs, with Port Klang ranking among the region's busiest refueling centers for vessels transiting the Strait of Malacca.

According to an emailed update issued on Monday, five samples contained phenolic compounds and alkylresorcinols at concentrations ranging from 1,070 to 9,994 ppm, while three separate samples showed reactive hydrocarbons at levels between 4,500 and 20,000 ppm.

Gas chromatography–mass spectrometry (GC-MS) testing detected compounds including styrene and its derivatives, dicyclopentadiene, dihydro-dicyclopentadiene, and indene. Such compounds are not naturally present in refined marine fuels and typically indicate the introduction of non-standard blending components.

Several affected vessels reported excessive sludge buildup in purifiers as well as accelerated wear on fuel pumps. These operational problems can lead to engine failures, vessel delays, and costly repairs if not addressed promptly.

Maritec-Naias indicated that the alkylresorcinols may have originated from non-petroleum cutter stocks, such as Estonian shale oil. Cutter stocks are blending agents used to adjust fuel viscosity or volume, and the use of cheaper non-petroleum alternatives can compromise fuel integrity. The reactive hydrocarbons, the agency added, could have come from ethylene cracker by-products.

The company stated that the affected fuels appeared to have been blended with low-quality marine fuels, a practice that may have become more prevalent amid elevated bunker prices driven by the conflict in the Middle East.

Maritec-Naias considers the identified fuels to be off-specification under Clause 5 of ISO 8217 and MARPOL Annex VI Regulation 18. ISO 8217 is the international standard governing marine fuel specifications, while MARPOL Annex VI Regulation 18 requires that fuel supplied to ships be free from inorganic acid or added substances that could jeopardize vessel safety or performance. Similar contamination incidents have surfaced periodically at other major bunkering hubs, including a widely reported 2018 case in the U.S. Gulf Coast that affected dozens of vessels.

The agency recommended that ship operators monitor purifiers and filters more closely, increase the frequency of de-sludging operations, and avoid commingling the affected fuels with other marine fuel stocks.

Maritec-Naias emphasized that these findings do not reflect the overall quality of bunker fuel supplied across Malaysian ports.

Source: Ship & Bunker