So much for BP's assurances

BP confidently claimed that almost all the oil spilled in the Gulf of Mexico has dissolved or has been cleaned up. Wrong again.

Scientists on a research vessel in the Gulf of Mexico are finding a substantial layer of oily sediment stretching for dozens of miles in all directions. Their discovery suggests that a lot of oil from the Deepwater Horizon didn't simply evaporate or dissipate into the water — it has settled to the seafloor.