During unloading of a 2000-tonne barge carrying fuel oil no. 2 intended to supply a chemical plant’s boiler room, a leak was detected around 4 am between the wharf and the pier on the transfer pipeline between the barge and the storage tank (8″ diameter); 1000 to 2000 litres of fuel oil spilled into the Mardyck maritime basin. The site’s fuel supply process was as follows: reheating the fuel oil at the producer’s facility, then barge transport and transfer via insulated pipeline from the wharf. The plant operator proceeded with several measures: immediate shutdown of the transfer step by remote-controlled valve, notification of the port authority at 4:25 am, contact made with the site’s on-call staff at 4:30 am, deployment of floating booms as of 4:35 am, initiation of clean-up around 9, and lastly installation of a pipe collar. The hydrocarbon transfer activity resumed around 11 that morning. The specific pipe section was isolated by closing valves. The unloading pipe was bled by injecting diesel. Unsuccessful attempt was made to recover the spilled fuel oil by first pumping via a hose and then skimming. Manual collection (bucket and shovel) was then undertaken from a raft. Absorbent product was spread over a portion of the wharf. Iridescence could be seen outside the floating boom due to imperfect junctions between the flanges. Subsequent to this incident, the operator committed to redeploying the floating booms, as well as conducting an investigation into why the transfer pipe opened and verifying the structural integrity of this pipe between the other wharf available on-site and the storage tank, prior to service start-up. Once the hypothesis of a break in the 8″ pipeline due to external corrosion had been confirmed, the operator proceeded to verify all pipelines of the same age on the wharf and informed authorities about pipeline replacements either completed or scheduled. Moreover, the operator was requested to include all 8” and 10” lines connecting the wharf in question to the storage tank in the site’s inspection plans, in compliance with legislation on pressure equipment, in addition to submitting a detailed incident report to the inspection authorities for classified facilities.