In the 1950s and 60s, the seven-story building at this U.S. Army base outside Annapolis stood at the center of a burgeoning biological weapons program, producing anthrax for bombs, aerosols and other delivery systems.

Now, the sealed building stands as a silent reminder to the persistence of the deadly bacterium.

Samples of anthrax spores found in Senate Majority Leader Tom Daschle's office were tested in the laboratories here of the U.S. Army Medical Research Institute of Infectious Diseases, said AMRIID spokeswoman Caree Vander Linden.

It was here 40 years ago, that scientists working with primates first started exploring how much anthrax it would take to kill a person. Huge brewing pots that look like those found in today's microbreweries were used to produce large quantities of anthrax slurries, said Norman Covert, former Fort Detrick installation historian and public affairs chief.

When President Richard Nixon signed a 1969 executive order ending the offensive biological weapons program, the usefulness of the Anthrax Tower — officially known as building 470 — came to an end. Specialists tried three times in the late 1960s and early 1970s to decontaminate it, with no success.

"When it gets into spore form it can hide just about anywhere," Covert said of anthrax.

Electric frying pans with a solid form of the compound paraformaldehyde were placed throughout the building then heated, releasing clouds of poisonous gas inside the sealed structure. Bacteria, similar to anthrax, were left inside to serve as "markers" indicating whether the gas worked.

"But, because it was anthrax, they could only say that it was 99.9 percent safe," Covert said, adding that everything inside the building had potentially been exposed to the microscopic bacterium.

In the cracks crisscrossing a concrete floor or in a building's ventilation system, the bacterium can wait, dormant, for years until it finds its way into a warm, moist environment like the mucus membrane of a human.

During the tower’s heyday, two Fort Detrick workers died from inhalation anthrax, the same form of anthrax that has been blamed in the recent deaths this month of an American Media Inc. worker in Florida and two postal workers in Maryland. The first Detrick anthrax casualty was a microbiologist in 1951, and the other, an electrician, in 1958, said Covert.

Since the building, with catwalks instead of floors, would not be easily converted to another purpose and the threat of anthrax can not be totally eradicated, it has stood unused for decades.

"The only way it could be torn down would be to capsulize and implode it," said Covert.

Responsibility for the building now falls to the National Cancer Institute, which took over nearly 70 acres of facilities surrounding the tower in 1976.

The NCI-Detrick research facilities have been a popular tour destination for groups from the former Soviet republics to see how investment made in biological weapons programs can be converted to productive and positive ventures.

Today the facility conducts groundbreaking research in the race to cure cancer and AIDS, but at the center, the Anthrax Tower "is like a big museum," said Covert. "It doesn't represent any danger to anyone."

Capitol News Service Contributed to this report.