Oil spills are adverse events that may be very harmful to ecosystems and food chain. In particular, large sea oil spills are very dramatic occurrence often affecting sea and coastal areas. Therefore the sustainability of oil rig infrastructures and oil transportation via oil tankers are linked to law enforcement based on proper monitoring techniques which are also fundamental to mitigate the impact of such pollution. Within this context, in this study a meaningful showcase is analyzed using remotely sensed measurements collected by by Synthetic Aperture Radar (SAR) satellites. The Deepwater Horizon (DWH) oil accident that occurred in the Gulf of Mexico in 2010 is here analyzed. It is one of the world's largest accidental oil pollution event that affected a sea area larger than 10,000 km². In this study we exploit SAR data collected by the Italian COSMO--SkyMed (CSK) X--band SAR constellation showing the key benefits of multi--polarization HH--VV SAR measurements in observing such a huge oil pollution event.