Sebelius entered a hearing room so packed with lawmakers, photographers and others that she had trouble finding a path to her seat after shaking hands with the committee members.
Many in the crowd chuckled at her quandary, which was far easier to negotiate than the questions that awaited her about the messy launch of Obama's health care web site. The crowd parted, and she found her way to her seat at the witness table, facing a wall of expectant lawmakers.
The standing-room-only hearing room was silent when she swore an oath to tell the truth and began her statement. "I apologize," she told the rapt committee.
Sebelius faced questions about problems with the website as well as a wave of cancellation notices hitting individuals and small businesses who buy their own insurance.
Lawmakers also want to know how many people have enrolled in plans through the health exchanges, a number the Obama administration has so far refused to divulge, instead promising to release it in mid-November.
Some committee members expressed doubts about whether consumers' personal information is safe on such a balky website.
On Tuesday, Medicare chief Marilyn Tavenner was questioned for nearly three hours by members of the House Ways and Means Committee who wanted to know why so many of their constituents were getting cancellation notices from their insurance companies.
The cancellations problem goes to one of Obama's earliest promises about the health law: You can keep your plan if you like it. The promise dates back to June 2009, when Congress was starting to grapple with overhauling the health care system to cover uninsured Americans.
As early as last spring, state insurance commissioners started giving insurers the option of canceling existing individual plans for 2014, because the coverage required under Obama's law is significantly more robust. Some states directed insurers to issue cancellations. Large employer plans that cover most workers and their families are unlikely to be affected.