The billion-dollar oil and gas rig was evacuated last Friday in anticipation of the hurricane. On Monday, a passing ship noticed that it was leaning more than 20 degrees to one side following the passage of the hurricane.

But an inspection of its hull and buoyancy pontoons had found no damage to the structure, raising the possibility of human error, according to a report in The Times of London.

BP and the US Coast Guard have said there has been no evidence of pollution, according to an Associated Press report.

Meanwhile, back onboard Thunder Horse, crews have restored partial power and started pumping operations to right the tilting platform.

The crews have also retrieved the platform's data recorders – to be used to determine the cause of the stability imbalance.

Thunder Horse is located in Mississippi Canyon block 778 in the Gulf of Mexico, about 220 kilometres south-east of New Orleans. BP (75% interest) and Exxon Mobil (25%) plan to begin daily production of 250,000 barrels of oil and 200 million cubic feet of gas from the platform late this year.