WASHINGTON – An environmental whistleblower group charges in a lawsuit that the Obama administration is withholding documents that would reveal why it issued an estimate on the gravity of the Gulf of Mexico oil well blowout that later was proved to be far too low.

Public Employees for Environmental Responsibility sued Thursday in federal court, claiming that federal officials are withholding hundreds of pages of reports and communications between scientists on the Flow Rate Technical Group, who were tasked with making the estimates, and Marcia McNutt, the head of the U.S. Geological Survey, who chaired the technical group and released a summary of its findings.

The controversy over the oil flow estimates is part of a broader question about whether political appointees at the top of the Obama administration have manipulated and publicized incorrect or incomplete scientific information in an attempt to tamp down anxiety and anger over the world’s worst oil accident.

The failure to assess the damage from BP’s spill also is seen as hampering the government’s continued efforts to clean up the Gulf.

“This lawsuit will produce Exhibit A for the case that science is still being manipulated under the current administration,” Jeff Ruch, the executive director of the environmental organization, said in a statement.

“Our concern is that the administration took, and is still taking, steps to falsely minimize public perception about the extent and severity of the BP spill, a concern that the administration could start to dispel by releasing these documents,” Ruch said.

Ruch said that some of the missing information was thought to show that the USGS knew in May, when it released an estimate of 12,000 to 19,000 barrels a day, that there was a completed estimate that was much higher.

In August, after the well had been capped, the government produced a new estimate as much as five times higher, based on better information from pressure readings and other analysis.

It said that the oil flowed at a rate of 62,000 barrels of oil per day at first and later slowed to 53,000 barrels a day, with a margin of error of plus or minus 10 percent.