U.S. politicians and scientists have accused the UK oil company, BP, of trying to conceal the extent of what many believe is already the worst oil spill to hit the U.S.

BP had been estimating that the leak from the Deepwater Horizon spill in the Gulf of Mexico was flowing at a rate of 5,000 barrels a day, until that number was questioned by scientists and the U.S. government.
Many scientists dismissed the estimate, saying it could be as high as 70,000 barrels (11 million liters) per day or more.
""It's very clear that BP has not been telling the truth,"" Ed Markey, a Massachusetts Democratic representative and chair of the select committee on energy independence and global warming, told CNN news channel on Friday.
""BP has mismanaged this entire incident from day one. They should not be trusted,"" he said.
BP denied any cover-up and said some third-party estimates of the leak were inaccurate.