- Accident date
- Accident area
- Cherbourg Harbour
- Spill area
- Cause of spill
- Product transported
- marine diesel
- Nature of pollutant
- gazole marine
- Quantity spilled
- 40 to 60 m3
- Ship / structure type
At around 6 am on 15th October 2015, the Belgian-registered marine work barge Nijptangh was carrying out dredging work when it struck the bottom in Cherbourg roadstead, releasing an estimated 40 to 60 m3 of marine diesel into the port from a damaged fuel tank.
Emergency measures, assessment and operational communication
The emergency response mobilised the naval fire-fighters at Cherbourg naval base (personnel and fireboat) and an operational centre was activated mid-morning at the Manche Prefecture (Saint Lô).
The naval base rapidly provided 2 tugs, containment booms and pumping equipment, and a French Navy EC225 helicopter carried out several overflights of the area to monitor the spread and evolution of the spill. The port authority contacted Cedre's duty officer to notify them and request on-site assistance to advise the services in charge of the spill response.
One of the main actions consisted in assessing the risk of further leakage from the source. With this as a backdrop, the clearance divers for the Manche area provided support by carrying out initial inspections of the hull of the Nijptangh. Based on these inspections of the structure in addition to observations carried out on the water, it appeared that the leak had stopped: the barge was towed into dock the same day, before the fuel was pumped out of its tanks by a local company.
Protection of sensitive areas
In terms of spill response, actions to protect nearby sensitive sites proved necessary, in particular boom deployment (lined with a row of sorbent booms) around a salmon farm adjacent to the incident site, and the preventive closure of water intakes at the sea discovery centre, Cité de la Mer. To prevent health risks, temporary fish bans and shipping bans in the affected area were issued.
Response at sea and survey missions
On the water, the weather conditions and properties of the oil, which was relatively light, caused the
oil to spread extensively, making it difficult to concentrate and contain it, and ultimately preventing mechanical recovery. Collection operations on the water therefore proved inappropriate, and the low persistence of marine diesel implied a high short term natural dissipation potential of the majority of the oil spilt, due to the local hydrodynamics.
This scenario was backed by forecasts produced by the weathering model used by Cedre and was confirmed by aerial observations throughout the day, which revealed that the wide spread of the floating oil led to the presence of a metallic and rainbow film. The following day, the oil dissipated thanks to choppy conditions, relatively strong winds and the renewal of the water mass in Cherbourg's outer roadstead due to tidal movements. Aerial surveys carried out in the morning confirmed that no sheen was present at the water surface and surveys were also conducted from the military police boat VSMP HEAUME, during which no floating oil was observed visually.
On-foot surveys carried out jointly by Cedre and the port authority only revealed light, discontinuous traces of sheen in a few places, which were being dispersed naturally and therefore did not require any response actions.
- Sea & Shore Technical Newsletter, 2015, n°42