WASHINGTON – As wildfires raged through southern California early this week, the nation’s chief health official was prepared to tell Congress about one impact of climate change: “Forest fires are expected to increase in frequency, severity, distribution and duration.”

But those words were never spoken. They were part of six pages of testimony deleted by White House officials before Dr. Julie Gerberding, director of the Centers for Disease Control, spoke Tuesday to the Senate Environment and Public Works Committee on the health impacts of climate change.

A source in the CDC leaked to the committee the draft testimony that was edited or deleted. Sen. Barbara Boxer, the California Democrat who chairs the committee, said Thursday “it’s dangerous in the United States when the administration stops the American people and Congress from getting the facts.”

A White House spokesman said Gerberding’s testimony was heavily edited to make sure its findings matched the science from a U.N. climate report, and referred reporters to the CDC. Gerberding said that she was able to say what she wanted to the committee, and was not censored.

Boxer and Rep. Bart Gordon, D-Tenn., chairman of the House Science and Technology Committee, demanded documents from the White House on the testimony, and said the episode fit a pattern of the Bush administration suppressing scientific findings on global warming.

Boxer and other committee members ridiculed the notion that Gerberding’s testimony conflicted with the U.N. science findings.

They showed parts of the International Panel on Climate Change report they said supported the CDC director’s original findings.

Gerberding’s deleted testimony, first obtained by the Associated Press, contained specific findings on the health impacts of climate change, from extreme weather to insect-borne diseases, and how different regions would be affected.

The West Coast, she said in prepared testimony, “is expected to experience significant strains on water supplies as regional precipitation declines and mountain snowpacks depleted.” That finding was followed by the warning on wildfires.