The Human Costs of Bombing Iran

“The number of deaths could exceed a million, and the number of people with increased cancer risks could exceed 10 million,” according to a backgrounder by the Union of Concerned Scientists from May 2005.

The National Academy of Sciences studied these earth-penetrating nuclear weapons last year. They could “kill up to a million people or more if used in heavily populated areas,” concluded the report, which was sponsored by the U.S. Department of Defense.

Physicians for Social Responsibility examined the risks of a more advanced buster-bunker weapon, and it eerily tabulated the toll from an attack on the underground nuclear facility in Esfahan, Iran. “Three million people would be killed by radiation within two weeks of the explosion, and 35 million people in Afghanistan, Pakistan, and India, would be exposed to increased levels of cancer-causing radiation,” according to a summary of that study in the backgrounder by the Union of Concerned Scientists.

Bush called it “wild speculation,” and McClellan said the United States would go ahead with "normal military contingency planning."

Those are hardly categorical denials