Chloride contamination cases: IBIA proposes steps to mitigation

Chloride contamination cases: IBIA proposes steps to mitigation

IBIA notes that the widely reported cases of problem bunker fuels supplied in Singapore during February and March have raised fears that the industry could be facing something similar to the 2018 episode of problem bunker fuel cases originating in Houston, and later spreading to other areas.

These fears are understandable, but there are some key differences. Moreover, the Maritime and Port Authority of Singapore (MPA) has taken steps to bring the situation under control to prevent further supply of the affected fuels in Singapore. IBIA would like to offer a practical and targeted approach to ensure the problem doesn’t spread this time; but we need help and cooperation from stakeholders. Read on for IBIA’s suggestion.


Fuel testing agencies have reported finding high sulphur fuel oil (HSFO) contaminated with chlorinated compounds supplied to ships in Singapore during February and March 2022. Reports indicated that two suppliers and at least 10 barges were involved. MPA confirmed on April 13 that, to date, Glencore and PetroChina had supplied the affected fuel to about 200 ships in the port of Singapore, and that about 80 of these ships have reported various issues with their fuel pumps and engines.

The regular suite of tests to confirm that a fuel meets the ISO 8217 quality standard do not cover chlorides, hence routine testing will not pick up their presence. The Singapore cases have so far been confirmed using investigative gas chromatography–mass spectrometry (GC-MS) testing.

Chlorides are not commonly found in crude oil or marine fuels beyond trace amounts. Significant concentrations of organic chlorides in bunker fuels, like those reported in the Singapore cases, are highly unusual. Chlorinated hydrocarbons are widely used as solvents and raw materials for various products. They do not belong in bunker fuels.

Testing for chlorides

There appears to be universal agreement between fuel testing agencies that have reported on the cases from Singapore that they involved high concentrations, often in excess of 2,000 parts per million (ppm) of chlorinated compounds, or chlorinated hydrocarbons. Many mention dichloroethane, which is an organic solvent.

So far, the fuel testing agencies have reported using investigative GS-MS testing to identify the chlorides.

One such method, ASTM D7845 provides a standardised test method for GC-MS to provide quantitative determination of 29 aromatic and oxygenated compounds in marine fuel oil, mainly phenols and styrenes. Chlorines do not feature on the list of chemical compounds ASTM D7845 test method provides precision statements and limits of detection for, so the Singapore cases will not have been found by using this standard (which is not part of ISO 8217) as a default either.

The ASTM D7845 test method may be used to detect other compounds than the ones specified based on in-house development, such as chlorides, but strictly speaking it is outside its scope.

It is for these limiting reasons that testing agencies may use, for example, GCMS Head Space screening, as well as GCMS Vacuum Distillation & Acid Extraction techniques. 

IBIA has learned that other test methods may be applied to identify the presence of chlorides in petroleum products, namely UOP 779 Chloride in Petroleum Distillates by Microcoulometry (organic and inorganic chlorides) and EN 14077 Petroleum products – Determination of organic halogen content – Oxidative microcoulometric method (organic chlorides). Neither of these are part of regular tests done on marine fuels (as chlorides are so rare), but they may be of use at a time when there is more testing than usual to eliminate the risk of fuels containing chlorides continuing to be supplied.

When should we test for chlorides?

Exactly how to test for chlorides will vary between fuel testing for agencies, depending on how laboratories are set up and equipped.

The big question now is: when should we be testing fuels for chlorides?

Of course, there is huge concern in the market that fuels containing chlorides continue to be supplied and as such those who are worried will ask for extra testing.

However, it may be more efficient to target areas and circumstances when there is reason to suspect that there is a risk of chloride contamination.

At present, that could be HSFO bunkered in Singapore during February and March from the suppliers/barges affected. As MPA says it has informed all the ships that received these fuels, those should be known.

Some ships may choose to use the affected fuels, depending on concentration level and dilution, in which case they should closely monitor operations for potential adverse effects, and stop using them if they observe problems that may relate to these fuels. This will be the nature of advice from some fuel testing agencies and classification societies

Others that received affected fuel may choose to debunker, in particular if they have used some of it and experienced operational issues, or they have test results indicating a very high concentration of chlorides.

There are fears that these chlorinated hydrocarbons could find their way into the supply chain either from the contaminated cargo being shipped out of Singapore, or these fuels being debunkered and subsequently blended into the supply chain in other ports.

One general piece of advice to bunker buyers who are afraid of this happening is to seek assurance from your supplier that the fuel is fit for purpose. Also, to pay close attention to the collection, witnessing and documentation of bunker samples.

Help IBIA help you

There are two main ways the chlorinated hydrocarbon problem could spread in the bunker market; either from the cargo containing the contaminated HSFO being shipped somewhere else and blended in a bid to dilute the chloride concentration, or attempts to do the same with contaminated fuel that has been debunkered.

IBIA therefore calls for relevant stakeholders to:

  1. Report to us which ports where ships have, or will, debunker HSFO contaminated with chlorides, and
  2. Report to us if you have reason to believe cargoes containing chloride contaminated HSFO is headed for specific ports.

IBIA would collate this information and share it with relevant parties, who in turn can take steps to monitor the situation.

IBIA assures strict confidentiality as an international association with a robust governing Board.

This could help target at-risk areas with measures such as extra testing to ensure bunkers containing chlorinated hydrocarbons do not cause further damage to ships and, by extension, to the trust and reputation in the marine fuels industry. If you have information to share with IBIA on this, please e-mail us at

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