On 12 March last, the Grande America sank in the Bay of Biscay. The data provided by the ship-owner lists 365 containers, 45 of which are listed as containing hazardous substances and just over 2000 vehicles. Apart from this cargo, the ship’s holds contained approximately 2,200 tonnes of heavy fuel oil, which was used to propel the ship. How can the extent of the spill be monitored? CLS, a subsidiary of CNES, ARDIAN and IFREMER, based in Toulouse and Brest, has been supporting the European Maritime Safety Agency by monitoring pollution for more than 10 years. CLS is now providing satellite imagery to monitor the changing situation of Grande America.