Industry body IBIA has responded to recent concerns over bunker fuel quality, saying current evidence does not link shale oil compounds to the operational issues that have been reported.

IBIA said in a statement issued on Monday that it is aware of reports highlighting operational issues involving certain residual bunker fuels, and that its Technical Working Group has reviewed the available information. In an industry where fuel can change hands and be blended through multiple supply steps, the association said the focus should remain on verified fuel characteristics and the requirements of the applicable standard.

"While these reports raise legitimate questions that warrant further investigation, the available evidence does not establish a direct causal relationship between the presence of these compounds and the operational issues reported," the association said.

Lloyd's Register testing service FOBAS and testing firm VPS had previously identified marine fuels supplied in Singapore with increased levels of shale oil components.

VPS said no vessels using these fuels had reported operational issues, but it urged caution over the potential for delayed impacts linked to fuel stability and composition.

IBIA noted that shale oil-derived hydrocarbons are permitted under the ISO 8217 marine fuel standard and that their presence alone should not be regarded as evidence of poor fuel quality or non-compliance. The key consideration, it said, is whether the fuel as delivered meets the standard's requirements.

The association said the cases highlight the need for greater transparency, traceability, quality assurance and information sharing as marine fuel blends become more complex, especially when testing results raise questions that are not resolved by composition data alone.

It also backed further technical investigation and industry collaboration to improve understanding of fuel performance and maintain confidence in bunker fuel quality.