Bunker fuel contamination by chemicals onboard


Published: 8 April 2021

Marine engineer officer repairing vessel engines and propulsion in engine control room ECR. Ship onboard maintenance
Credit to: Igor Kardasov / Shutterstock.com

The focus of this advisory is prevention of damage to the main engine, auxiliary engine and boiler plant caused by fuel oil contaminated by chemicals such as cleaning solvents.

In a recent matter the bunkered fuel test results gave no reason to suspect that engine and auxiliary engines problems would be encountered. However, further testing carried out at various points in the engine fuel system showed that organic chlorinated compounds were present, even though there was no trace of it in the bunker fuel sample test received from the fuel laboratory. Such compounds are present in some cleaning products and it was therefore suspected that the source of contamination was to be found on board.

The cause of the contamination may have been that the cleaning chemicals were disposed of in the fuel oil drain tank and then transferred to the fuel settling tank.

The presence of these solvent chemicals in the fuel might lead to poor engine combustions, bad effect on engine lubrication, fuel pump seizures and it will lead to damage to piston rings and engine liners. It may also possibly lead to boiler misfire due to delayed ignition.

To prevent fuel contamination onboard by chemicals:

  • Use only recommended cleaning chemicals/solvents.
  • If chemicals which contain organic compounds like those used in cleaning air coolers are used, the purifiers discs should be strictly monitored.
  • Ensure that the chemicals are properly disposed of.
  • Do not clean any save-alls with any substance which contains organic substances that will drain to the fuel oil drain tank.
  • Do not add any cleaning solvents to the fuel oil drain tank.
  • The engine management team should ensure that all maintenance onboard is properly supervised and cleaning substances are to be used only as per manufacturer's recommendations and guidelines.
  • The engine management team should ensure that disposal of used chemicals is properly monitored.