President Bush is lining up to be among the first Americans to receive the smallpox vaccination.

Bush said Friday that he will join people thought most likely to face a biological attack -- one million military units and emergency first responders -- in receiving the vaccine.

"This particular vaccine does involve a small risk of serious health considerations. As commander in chief I do not believe that I can ask others to accept this risk unless I am willing to do the same. Therefore, I will receive the vaccine along with our military," Bush said at at the Eisenhower Executive Office Building, next door to the White House.

Bush said neither his family nor members of his staff would be inoculated "because our health and national security experts do not believe that vaccination is necessary for the general public."

In proposing the administration's smallpox vaccination plan on Friday, Bush said he is not recommending that every American receive a smallpox vaccination, but that over the next 12 to 15 months, inoculations will be made available to every American who wants one.

The first groups of soldiers and civilian defense personnel will likely be inoculated within the coming weeks before they are sent off to Southwest Asia, which includes areas of Afghanistan and Iraq suspected of having unauthorized stocks of the disease.

"We believe regimes hostile to the United States may possess this dangerous virus," Bush said.

"In response, we are evaluating old threats in a new light ... the government has no information that a smallpox attack is imminent, but we must prepare for the possibility that terrorists who kill indiscriminately will use disease as a weapon," he said.

The Defense Department said it will begin its inoculation program based on occupational responsibilities, starting with forces performing critical missions.

"We cannot quantify the threat of it being used as a bioweapon; we know the consequences of its use could be great," said William Winkenwerder, assistant secretary of defense for health affairs. "Vaccinating servicemembers before an attack is the best way to ensure that our troops are protected and that they can continue their missions if a smallpox outbreak occurs."

According to the Centers for Disease Control and Prevention, an estimated 15 out of every one million people vaccinated could face life-threatening illness brought on by the vaccine. Another one or two could die. That means that if the entire nation were vaccinated, nearly 3,000 life-threatening complications and at least 170 deaths could occur. Those numbers are led the administration to allow people to choose for themselves whether they want to be vaccinated.

The vaccine will not be available to every American until 2004, but clinical trials of an unlicensed version are already under way.

According to a recent Fox News/Opinion Dynamics poll, 59 percent of people surveyed said they would get vaccinated despite the risks.

Smallpox, the disease so named to avoid confusion with the "Great Pox" syphilis, had plagued various parts of the world for nearly two millennia.

A smallpox vaccine -- the first for any disease -- was discovered in 1789, though it was only available in small quantities to those who could afford it. In 1967, the World Health Organization set out to eradicate the disease for good.

Routine smallpox vaccinations were discontinued in the United States in 1972, after it was no longer detectable in the population. In 1979, the World Health Organization said smallpox had been eradicated worldwide. The United States declared it officially extinct in 1980.

Small stocks of the disease, however, were kept in storage in the United States and Russia and used by only a handful of doctors and scientists for research. The last remaining stockpiles were scheduled for destruction in 1999, but the government kept 100 million doses of the vaccine on hand. A Pennsylvania company found 85 million more doses in March 2002 and donated them to the government

An airborne illness spread through close proximity, infected bed sheets or clothing, smallpox can kill at least 20 percent of victims. There is no cure for it.

People with weak immune systems are considered at highest risk to suffer health complications after receiving the vaccine. Cancer patients, organ transplant recipients, HIV carriers, pregnant women and people with a history of eczema are the highest risk groups.

Those who have been vaccinated previously are not considered immune, though they are considered to be less likely to suffer any complications from a re-vaccination.

The White House is preparing a wide education campaign to teach the population about the disease. Administration health officials were hosting a long question-and-answer period after the president's announcement.

The Defense Department may meet some resistance in vaccinating all military members, if its experience with the anthrax vaccine is any indication. Some military personnel believed the anthrax vaccine caused health problems, and hundreds were forced from the armed forces after refusing to take it.

Fox News' James Rosen and the Associated Press contributed to this report.