Her testimony before the Senate Environment and Public Works Committee had much less information on health risks than a much longer draft version Gerberding submitted to the White House Office of Management and Budget for review in advance of her appearance. "It was eviscerated," said a CDC official, familiar with both versions, who spoke on condition of anonymity because of the sensitivity of the review process.

The official said that while it is customary for testimony to be changed in a White House review, these changes were particularly "heavy-handed." The White House office had no comment on Gerberding's testimony. Gerberding could not be reached late Tuesday for comment.

The deletions directed by the White House included details on how many people might be adversely affected because of increased warming and the scientific basis for some of the CDC's analysis on what kinds of diseases might be spread in a warmer climate and rising sea levels, according to another official who had seen the original version. Sen. Barbara Boxer (D-Calif.), the committee chairwoman, said the Bush administration "should immediately release Dr. Gerberding's full, uncut statement, because the public has a right to know all the facts about the serious threats posed by global warming."