Check out this Article from http://www.bbc.co.uk/:
Detailed simulations of the Gulf of Mexico oil leak show that crude is likely to start spreading into the Atlantic Ocean soon.
Once oil becomes caught in the Gulf of Mexico's fast moving Loop Current, it could be carried thousands of miles, around Florida, up the Atlantic coast of the US, and then out into the open ocean.
An animation by the US National Center for Atmospheric Research (NCAR) suggests that concentrations of oil in the water south of Florida will start to become detectable around 70 to 90 days after a leak starts. The Deepwater Horizon rig sank on the 22nd April.
The animation, given to the BBC World Service's Science in Action programme, is based on a computer model of ocean currents and eddies, and assumes that conditions will be similar to those found in a typical year.