She added that informing consumers about the Affordable Care Act will be a "challenge" as the law is implemented.
There is a sense that "too few people know what is happening. That is what we are trying to get out ahead of and address," she said.
The "train wreck" comment made waves last week and became a rallying cry for critics of the healthcare law.
Baucus, an ObamaCare architect and chairman of the powerful Senate Finance Committee, announced Tuesday that he will not seek reelection.
Sebelius doubled down against his prediction Wednesday by touting a soon-to-launch campaign that will educate the public about healthcare reform.
She defended a decision to pay for "navigators" — people and groups that will explain the law's benefits to consumers — out of a preventive healthcare fund.
"We did not have the funding in our budget," she said. "It was a very tough choice."
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