The USCG has issued a safety alert about contaminated fuel oil bunkers, involving blended fuel oils such as IFO 380. The contamination has caused filters to clog and pumps to fail. Fuel testing organisations have found that fatty acids were present in the fuel, specifically 4-Cumyl-Phenol (CAS No. 599-64-4) which is used in the manufacture of epoxy resins and as an emulsifier in pesticides.

It is thought that the source of the contamination is associated with the use of fuel cutter stocks (lighter petroleum products) which are added to heavy fuel oil to reduce its viscosity. The problem is compounded by the fact that standard fuel oil test methods will not detect the presence of this contaminant.

The advice from the USCG is to:
• Pay attention to the terms of the bunker requisition.
• Specify that the fuel must be free of abnormal components.
• Determine the acid number of the fuel.
• Carefully pay attention to the fuel supply and fuel injection equipment on board the ship.

Further information is available here.