Richard Carmona, M.D., the U.S. Surgeon General who recently released a major report on the dangers of secondhand smoke, is leaving the job as his term expires this month, the Associated Press reported July 31.

Carmona's report on secondhand smoke was widely hailed as a defining statement on the dangers of passive smoking, and he said that he would consider his tenure as Surgeon General a success if he persuaded one mother to stop smoking.

"I think that report is going to turn out to be the nail in the coffin to the tobacco industry," said Georges C. Benjamin, president of the American Public Health Association. "I certainly hope so."

The Department of Health and Human Services made no public announcement about Carmona's departure, but an internal memo was circulated and Carmona wrote a letter to colleagues in the U.S. Public Health Service. Carmona offered no hint about why he was leaving his post.

"I know that in the end, people will ask if my four years as the surgeon general did any good, and, honestly, only time will tell," Carmona wrote.

A spokesperson for HHS Secretary Make Leavitt said Carmona "helped provide good leadership and counsel to the department on prevention issues. I would point to the recent smoking report he did, which got unprecedented attention. He also raised the profile of childhood obesity."

No successor has been named.