WASHINGTON - The Obama Administration failed to act upon or fully inform the public of its own worst-case estimates of the amount of oil gushing from the blown-out BP well, slowing response efforts and keeping the American people in the dark for weeks about the size of the spill in the Gulf of Mexico, according to preliminary reports from the staff of the presidential commission investigating the accident.
The government repeatedly underestimated how much oil was flowing into the Gulf and how much was left after the well was capped in July, leading to a loss of faith in the government's ability to handle the spill and a continuing breach between federal authorities and state and local officials, the commission's staff members found in a series of four reports issued Wednesday.
"By initially underestimating the amount of oil flow and then, at the end of the summer, appearing to underestimate the amount of oil remaining in the Gulf," one of the reports stated, "the federal government created the impression that it was either not fully competent to handle the spill or not fully candid with the American people about the scope of the problem."
The April 20 explosion on the Deepwater Horizon drilling rig killed 11 workers, spewed 206 million gallons of oil from the damaged oil well, and sank the drilling rig.
The reports also say that about two weeks after the rig exploded, the National Oceanic and Atmospheric Administration asked the White House for permission to make public its worst-case models. The Office of Management and Budget initially denied the request, according to government officials interviewed by the commission's staff members.
The White House responded vigorously to the assertions Wednesday, saying it never concealed its most dire estimates of the spill and quickly threw everything the government had at the problem.
As for the NOAA report, White House officials said it was a flawed and incomplete study and that they sent it back to the agency for more analysis. It was released in early July.
The four reports, from the staff of the National Commission on the BP Deepwater Horizon Oil Spill and Offshore Drilling, make clear that the President-appointed panel does not intend to spare the administration as it prepares a final report to be delivered to the White House early next year.
It has not completed work on the causes of the well explosion or the efforts to contain the oil, but the tenor of Wednesday's reports indicates that White House, Cabinet officers, Coast Guard commanders, and senior government scientists will shoulder a fair amount of blame for the response to the accident.
The government stuck to its flow-rate report of 5,000 barrels a day for more than a month, even though BP officials and government scientists acknowledged that the rate could be as high as 110,000 barrels a day.
Although the higher figures were used as the basis for the government's response to the spill - they appeared on an internal Coast Guard situation report and on a dry-erase board in NOAA's Seattle war room - they were never announced to the public, according to the report.
Ultimately, government and independent scientists established that the uncontrolled flow was roughly 60,000 barrels a day for much of the spill, discharging nearly 5 million barrels of oil into the Gulf.
The well was capped on July 15 and officially declared dead in late September, when a cement plug was fixed to the bottom of the 18,000-foot-deep well.
Government officials have acknowledged they miscalculated the amount of oil pouring into the Gulf and, at least early on, relied on data from BP. But they said they based their response not on those figures but on worst-case estimates, including the figure of 162,000 barrels a day that BP used in its 2009 drilling-permit application.
The government deployed thousands of vessels to try to collect and contain the oil and used nearly 2 million gallons of dispersants.
In August, top administration officials proclaimed that 75 percent of the oil had evaporated, dissolved, or been collected, implying that ecological damage had been limited.
Carol Browner, White House coordinator for energy and climate change, proclaimed on Aug. 4: "I think it's also important to note that our scientists have done an initial assessment and more than three-quarters of the oil is gone. The vast majority of the oil is gone."
But the commission staff members said the government's own figures did not support such sweeping conclusions, which were later scaled back.
A number of respected independent researchers have concluded that as much as half of the spilled oil remains suspended in the water or buried on the sea floor and in coastal sludge.
The Associated Press contributed to this report.