The three top auditors overseeing work in Iraq told a House committee their review of $57 billion in Iraq contracts found that ... about $10 billion has been squandered by the U.S. government on Iraq reconstruction aid because of contractor overcharges and unsupported expenses. Of the $10 billion in overpriced contracts or undocumented costs, more than $2.7 billion were charged by Halliburton Co., the oil-field services company once headed by Vice President Dick Cheney. Federal investigators warned Thursday that significantly more taxpayer money is at risk. More than one in six dollars charged by U.S. contractors were questionable or unsupported, nearly triple the amount of waste the Government Accountability Office estimated last fall. There is no accountability," said David M. Walker, who heads the auditing arm of Congress. "Organizations charged with overseeing contracts are not held accountable. Contractors are not held accountable. The individuals responsible are not held accountable." The investigators urged the Pentagon to reconsider its growing reliance on outside contractors. Layers of subcontractors, poor documentation and lack of strong contract management are rampant. Walker complained that GAO investigators have difficulty getting basic detail about reconstruction contracts such as expenses and subcontractors involved because many Pentagon divisions fail to consistently track or fully report them. Noting that auditors still have $300 billion of Iraq spending to review, Waxman said the total amount of waste, fraud and abuse "could be astronomical."