THE White House has already been accused of gagging the US Environmental Protection Agency and NASA on the subject of global warming. Now the US Centers for Disease Control may have suffered the same fate.

On 23 October, CDC director Julie Gerberding addressed the US Senate on the health effects of global warming. It has emerged that her original speech was cut from 12 pages to six by the White House's Office of Management and Budget, which is authorised to vet presentations to the Senate by government agencies.

Among the passages omitted from the final speech were details of how global warming may affect millions of Americans through more frequent heatwaves, increased air pollution and the spread of waterborne diseases.

Although Gerberding and the CDC say there has been no censorship, others disagree. Senator Barbara Boxer of California wrote to the White House demanding that it release a copy of ...