"Alarming lapses" of security are still occurring at the nation's airports despite new security measures introduced by the Bush administration, Kenneth Mead, the inspector general of the Transportation Department, told a Senate Committee Wednesday. While the Bush measures have tightened aviation security, they have not resolved persistent weaknesses that leave airports vulnerable to attack, Mead said. For example, despite a Federal Aviation Administration rule requiring airlines to use machines to screen checked baggage for explosives, Mead said that less than 10 percent of checked baggage is actually being screened for bombs. "I think we've been woeful on the use of explosive detection machines," Mead told a joint hearing of the Senate Governmental Affairs Committee and the Subcommittee on Oversight of Government Management, Restructuring, and the District of Columbia. Sen. Joseph Lieberman, D-Conn., the chairman of the Committee, was visibly surprised by the 10 percent figure. "That's really stunning. I didn't realize it was that low," Leiberman said. Other FAA reforms have led to marginal security improvements, according to Mead. The FAA is conducting criminal background checks on new airport employees at the nation's largest airports, but checks have not been performed on current employees or any workers at small airports. Mead praised the "zero tolerance" policy for potential security breaches at airports that Transportation Secretary Norman Mineta announced in late October. Under the policy, airport officials must empty airport concourses and re-screen passengers if a possible security breach is detected. Since Nov. 3, 90 such incidents have occurred, Mead told the panel. Mead did not take a position on whether baggage screeners should be federal employees, but he did recommend that a new airport security office be placed in the Transportation Department, as would be the case under a House-passed bill. FAA Administrator Jane Garvey, who testified for the Bush administration, said her agency is developing new performance measures for airport security that could be transferred to a new airport security office. Performance standards must be a part of the new airport security system, both Mead and Garvey said. "This is an opportunity for a real world application of the  Government Performance and Results Act," said Mead. Garvey expressed the administration's preference for allowing contract employees to screen bags, a view that prompted scorn from some senators. "Continuing to allow the American people to rely on these contract people is like relying on the Boston strangler to massage your neck," said Sen. Max Cleland, D-Ga. At present, airlines contract out security to private companies, which must follow FAA rules. A Senate-passed bill would put baggage screeners at the nation's largest airports on the federal payroll, while the House-passed bill would allow the government to use contractors to provide security. Under the Bush plan, airlines would no longer be involved in airport security, a point Garvey made to Sen. George Voinovich, R-Ohio. "Contractors would be working for the government," she said. No matter who screens baggage, many security issues will take years to resolve, Mead and Garvey said. Explosive detection machines will not be available in all of the nation's airports until 2004 at the earliest. But Mead said existing machines could quadruple the number of bags screened if they were used properly. "We found that there were not always enough trained operators to effectively staff checked baggage screening operations," he said. On Nov. 12, Mead's staff witnessed one screener fall asleep in the midst of a 20-hour shift. Mead urged the FAA to issue a rule requiring security workers using the machines to screen at least 125 bags an hour.