CM Technologies Raises Alarm Over Recent Shipping Fuel Quality Concerns

German testing specialist CM Technologies (CMT) advises that shipowners and operators need to maintain close checks on fuel quality following a series of off-specification alerts at major bunkering ports and warns that contaminated or unstable fuels can result in costly engine damage and vessel downtime.

The advisory follows reports of fuel quality problems at Antwerp, Rotterdam, Houston, Singapore, Hong Kong, Piraeus and other bunkering locations during the past six months, involving excessive catalytic fines, poor fuel stability, high sediment levels and low flash points.

In part, the drop in fuel quality can be attributed to the supply chain disruption caused by the current geopolitical landscape and conflict, said David Fuhlbrügge, joint managing director at CM Technologies (CMT). 

In August, fuel testing specialist VPS identified the Middle East conflict as a major factor behind both rising bunker prices and deteriorating fuel quality. It also issued 29 bunker alerts during the first seven months of 2026, with excessive catalytic fines and fuel stability problems accounting for 72% of them. Data published by West P&I in September, covering fuel samples tested between April and September 2026, found technical off-specification rates for heavy fuel oil (HFO) of 46.2% in Antwerp, 41.4% in Norfolk, 38% in the Panama Canal region and 35.5% in Rotterdam.

The same report identified elevated sulphur off-specification rates among very low sulphur fuel oil (VLSFO) samples tested in Rotterdam and Antwerp, although the club cautioned that the sample populations were comparatively small.

Fuhlbrügge said the findings reinforced the need for shipmanagers to remain vigilant over the quality of fuels taken onboard, irrespective of the bunkering location. "Fuel quality should never be taken for granted. The consequences of getting it wrong can be expensive, not only in terms of machinery repairs but also the time spent dealing with blocked filters, damaged components and interrupted operations."

In July, alerts were also published concerning high abrasive content in HFO supplied in Houston and the Amsterdam–Rotterdam–Antwerp region, severe fuel stability concerns in Piraeus, high sediment in Las Palmas and low flash point fuels in Hong Kong and Singapore.

“Catalytic fines are particularly damaging if they are not adequately removed during fuel treatment. The abrasive particles can accelerate wear in fuel injection equipment, cylinder liners and piston rings, potentially shortening component life and increasing maintenance requirements,” said Fuhlbrügge.

Fuhlbrügge added that the risks do not necessarily end once a bunker delivery had passed its initial laboratory checks. "Shipowners need to know how the fuel will behave once it is onboard, particularly when different batches are stored or mixed. Two fuels may be stable individually but incompatible when combined. Finding that out after sludge has formed in the tanks can mean considerable cleaning work and avoidable expense."

The commercial consequences are reflected in claims data from marine insurer Gard, which handled more than 70 bunker-related claims between January and May 2026, an increase of 50% over the corresponding period last year. Almost all involved fuel quality, with some vessels disabled or requiring towage.

Lloyd's Register FOBAS has also suggested that fuels meeting routine ISO 8217 specifications can still cause operational problems, particularly where unusual blending components or poor compatibility affect fuel handling and treatment.

CMT supplies onboard test equipment for checking fuel compatibility, catalytic fines, water content, viscosity and density. Its compatibility tester, for example, allows engineers to assess the behavior of different fuel batches before mixing, while its other instruments provide additional checks on fuel condition.