A top Democrat who helped write President Barack Obama's health care law says he fears it is headed for a "huge train wreck."

Democratic Sen. Max Baucus of Montana confronted Obama's health secretary Wednesday during a routine budget hearing that turned tense.

Baucus, who chairs the Senate Finance Committee, said he is "very concerned" that new health insurance marketplaces going live next year in every state will be a flop. Consumers and small business owners are not getting enough information, and the administration has not been forthcoming with lawmakers, he said.

Health and Human Services Secretary Kathleen Sebelius blamed Congress for blocking implementation funding for the law, which is supposed to bring coverage to nearly 30 million uninsured Americans.