WASHINGTON - The Interior Department needs "adult supervision" across the board to change its culture of waste, fraud and abuse, the Republican chairman of the House Government Reform Committee said Thursday.

Chairman Tom Davis, R-Va., cited the department's "well-documented" problems with Indian recognition rights and a mistake in offshore drilling leases that has already cost the government $2 billion in lost revenue, among other problems.

"It just looks to me like there needs to be adult supervision across the board," Davis said.

He oversaw a hearing titled, "Interior Department: A Culture of Managerial Irresponsibility and Lack of Accountability?"

Davis called for immediate reforms to combat the "culture of waste, fraud and abuse" in the agency that oversees agencies including the Bureau of Land Management and National Park Service.

The hearing focused primarily on why the Interior Department failed to include price thresholds in oil and gas drilling leases for deep coastal waters in 1998 and 1999, a mistake that could cost the government more than $10 billion in lost revenue.

Through this and other hearings, members of Congress have been trying to determine which individuals caused the error and why the department covered up the mistake for years.

But lawmakers on both sides of the aisle said Thursday that problem was just one part in a larger problem of bad management at Interior.

Rep. Henry Waxman of California, the panel's top-ranking Democrat, said the committee should begin a "series of hearings on how the Department of Interior is broken and how we can fix it."

Energy Subcommittee Chairman Darrell Issa, R-Calif., said the drilling mistake is part of a larger culture of "irresponsibility and unaccountability that pervades the entire department."

Inspector General Earl Devaney, in charge of independently investigating and auditing the department, issued a stinging critique of its management culture this week.

"Simply stated, short of a crime, anything goes at the highest levels of the Interior Department," he said. "Ethics failures on the part of senior department officials - taking the form of appearance of impropriety, favoritism and bias - have been routinely dismissed with a promise 'not to do it again.'"

Interior Deputy Secretary Lynn Scarlett defended the agency, saying, "Both senior managers and their staff are dedicated public servants."

She said some put their lives at risk fighting fires and performing search-and-rescue missions and that she often finds those in the budget and finance offices working 12- or 14-hour days.

Unacceptable decisions and actions may sometimes occur in a department the size of a "small city," she said.

"We take extremely seriously any and all instances in which we find waste, fraud, ethical violations and other inappropriate action," she said.

She also said that in the past five years the department has repaired weaknesses in program or financial controls, significantly changed its ethics program, created a new appraisal office for land transactions, put controls on government-issued credit cards and made other improvements.

Davis and other officials expressed hope that new Interior Secretary Dirk Kempthorne will change the way the department operates.

At a subcommittee hearing Wednesday, Devaney noted that previous reports from his office have chronicled attempts to hide the true nature of agreements with outside parties, deviations from statutory and regulatory requirements, procurement irregularities, massive project collapses, bonuses awarded to people whose programs fail and failure to correct deplorable conditions in Indian country.

But his findings during his seven years on the job have been routinely ignored by the department, Devaney said.

He said high level employees leaving the department under the cloud of an inspector general investigation into misconduct were sent off with parties celebrating their good work.

In a 2004 survey of Interior employees, 46 percent said discipline for misconduct was administered fairly only sometimes, if ever.

Devaney is conducting an investigation into why price thresholds were excluded from the leases in 1998 and 1999 and why the mistake was kept secret for years after it was discovered. He attributed it to "bureaucratic bungling" and said he had not found any criminal behavior.

No one has been fired, suspended or reprimanded as a result of the cover-up, he said.

Scarlett said the department disagrees with Devaney's "broad brush" and "vague" allegations. The department records all recommendations from the inspector general's office, tracks the actions taken to address them and meets regularly with Devaney, she said.

Scarlett said that the situation of 1998 and 1999 has not happened again and that the department is working diligently to ensure it will not reoccur.

She also noted that the Department is conducting voluntary renegotiations with oil and gas companies to insert price thresholds into those agreements.

Issa said he plans more hearings on the Interior management culture either this year or early next year.