You are using an outdated browser For a better experience using this site, please upgrade to a modern web browser. Subscribe Get Daily Email Subscribe --> Contact Us Sign in Home News & Features Compliance Costs Bunker Prices Bunker Intelligence Asia/Pacific News Latest Features World Americas EMEA Asia/Pacific Home News & Features Asia / Pacific Maritec-Naias Finds Elevated Catfines and Acid Numbers in Singapore VLSFO Maritec-Naias Finds Elevated Catfines and Acid Numbers in Singapore VLSFO by Ship & Bunker News Team Monday June 15, 2026 Tweet Follow @shipandbunker The firm analysed fuel samples from two bunker suppliers. File Image / Pixabay A recent advisory from testing firm Maritec-Naias has flagged elevated levels of catfines and acid numbers in some VLSFO samples delivered in Singapore . The fuel testing company analysed five VLSFO samples from two suppliers collected between May 20 and June 2 and found aluminium and silicon (Al+Si), known as catfines, at levels ranging from 61 mg/kg to 68 mg/kg , it said in a statement on its website on Friday .  The results were above the ISO 8217 specification limit of 60 mg/kg , although still within the accepted testing tolerance. Catfines are abrasive particles that can cause increased wear of fuel system components, piston rings and cylinder liners if not effectively removed by onboard fuel treatment systems. Maritec-Naias also tested 15 VLSFO samples with acid numbers ranging from 2.0 mg KOH/g to 2.5 mg KOH/g . While the fuels remained within specification limits, the company said the values were elevated and could be linked to contaminants associated with sludge formation, fuel pump seizures and injector fouling. The company recommended additional monitoring and testing of fuels with elevated acid numbers and advised buyers to request a Certificate of Quality before bunkering in Singapore . Ship & Bunker News Team To contact the editor responsible for this story email us at [email protected]