Officials Say They Don't Know Cost of Health Website Fixes WASHINGTON - Obama administration officials working on the federal health insurance website were unable to tell Congress during a hearing on Wednesday how much it would cost to fix the site, a pillar of President Obama's plan to provide affordable coverage to millions of Americans. The administration has spent more than $600 million on the troubled website, HealthCare.gov, and is racing to meet a self-imposed Nov. 30 deadline for repairs. Todd Park, Mr. Obama's chief technology adviser; Henry Chao, the chief digital architect of the website; and Steven VanRoekel, the chief information officer for the federal government, could not answer questions about the cost of repairing the site, which has been plagued with scores of software and hardware problems since it opened on Oct. 1. The questions came from Representative John J. Duncan Jr., Republican of Tennessee, at a hearing of the House Committee on Oversight and Government Reform. Many questions focused on website procedures that required consumers to create password-protected accounts before they could see the exact cost of health plans for which they were eligible. Mr. Chao rebuffed Republican suggestions that the administration had blocked "anonymous shopping" because it feared consumers would be alarmed if they saw the full unsubsidized prices of insurance policies. In fact, Mr. Chao said, federal officials blocked the "anonymous shopping" function because it had failed tests. "It failed so miserably" that consumers could not use it, Mr. Chao said. Mr. Park acknowledged that millions of Americans had been frustrated trying to use the site. "These problems are unacceptable," Mr. Park said. The website is getting better each week, as we work to improve its performance, its stability and its functionality. As a result, more and more individuals are successfully creating accounts, logging in, and moving on to apply for coverage and shop for plans. The chairman of the oversight committee, Representative Darrell Issa, Republican of California, denounced the administration's decision to go forward on Oct. 1. "This was a monumental mistake to go live and effectively explode on the launchpad," Mr. Issa said. "We are here to examine the failure of technology not because the technology was so new, not because this was a moon shot," Mr. Issa said. We've discovered that efforts were taken to cut corners to meet political deadlines at the end. Under the new health care law, most Americans will be required to have health insurance or pay tax penalties. "The penalty is still in effect if the website is not working," Mr. Issa said. He said that "there were material failures in the security of the Obamacare website," and asserted that "hackers may soon find those vulnerabilities." Representative Elijah E. Cummings of Maryland, the senior Democrat on the committee, said the Centers for Medicare and Medicaid Services and its contractors "failed to fully deliver what they were supposed to deliver." But he said that Republicans were exploiting the problems for political gain. "They are attempting to use the congressional oversight process to scare Americans away from the website by once again making unsupported assertions about the risk to their personal medical information," Mr. Cummings said. David A. Powner, director of information technology issues at the Government Accountability Office, an investigative arm of Congress, raised questions Wednesday about whether the Centers for Medicare and Medicaid Services had the capabilities needed to serve as the quarterback for the creation of the website, a complex project involving dozens of contractors. The agency, he noted, was supposed to coordinate all the software and hardware pieces as the "systems integrator." Even while testimony was underway before Mr. Issa's committee, a separate House panel spent the morning questioning another group of senior administration officials about the security of the website. Republicans on the Homeland Security Committee suggested that the confidential personal information of thousands of consumers entered into the federal website each day might be vulnerable to cyberattack because of errors made in building the system.