US Edition The revelations from the National Oil Spill Commission come as the Democratic Party struggles to retain control of the US Congress in the elections on Nov 2.
The commission said that after the rig in the Gulf of Mexico exploded on April 20, killing 11 workers, the government was too optimistic about the oil company's ability to bring the ruptured well under control.
"For the first ten days of the spill, it appears that a sense of over-optimism affected responders. Responders almost uniformly noted that, while they understood that they were facing a major spill, they believed that BP would get the well under control," the commission wrote.
It said: "Though some of the command structure was put in place very quickly, in other respects the mobilization of resources to combat the spill seemed to lag."
Large sections of the Gulf of Mexico were closed to fishing, hundreds of miles of shoreline were polluted and the coastal economy, including tourism and fisheries, was disrupted before the well was capped on July 15 after the worst offshore oil leak in US history.
The commission also criticized the White House for blocking early worst case estimates of the oil spill, which it said may have affected how fast resources were assembled to fight it.
The panel said the National Oceanic and Atmospheric Administration (NOAA) wanted to release some of its worst-case spill models on the accident in late April or early May. But the White House Office of Management and Budget (OMB) blocked the move to make the information public.
The White House decision to block the estimates came as BP was being criticized for failing to provide accurate information on the amount of oil that was leaking.
In a joint statement, the directors of OMB and NOAA did not deny that NOAA's early spill estimate was blocked. Instead, they said NOAA's early analysis was incomplete because it did not take into account the measures to control the oil, like using floating booms, skimming the oil and burning it at sea.