Two years after the anthrax letter attacks, senior administration officials say they have new concerns about the nation's vulnerability to terrorist attacks with the deadly germ.
Officials said their fears had intensified in part because they now recognize that anthrax spores can be more widely dispersed than previously thought. In addition, they said, terrorist suspects with ties to al-Qaida have told questioners that the group has been trying to obtain anthrax for use in attacks.
One indication of concern was a secret Cabinet-level "tabletop" exercise conducted last month that simulated the simultaneous release of anthrax in different types of aerosols in several U.S. cities.
The drill, with the codename Scarlet Cloud, found that the country was better able to detect an anthrax attack than it was two years ago, said officials knowledgeable about the exercise. But they said the exercise also showed that antibiotics in some cities could not be distributed and administered quickly enough and that a widespread attack could kill thousands. "The exercise was designed to be very stressful to the system, and it was," a senior government official said.
Veterans of America's biological warfare program of the 1950s and 1960s said the recent recognition of the ability of anthrax to spread widely appeared to be in line with research conducted decades ago that remains secret.
"The new generation of biological and chemical experts is simply unfamiliar with the earlier studies," said William C. Patrick III, a former head of product development at Fort Detrick in Frederick, then the military's center for developing germ weapons.
Another factor fueling concern about anthrax is the questioning of senior al-Qaida agents in U.S. custody, administration officials said.
One official said that after his arrest in March, Khalid Shaikh Mohammed, one of Osama bin Laden's top lieutenants, confirmed to U.S. officials earlier reports that al-Qaida, and particularly its second in command, Ayman al-Zawahiri, a physician, had long been eager to acquire biological agents, particularly anthrax. The official noted that al-Qaida agents had inquired about renting crop-dusters to spread pathogens, especially anthrax.
According to an article by Milton Leitenberg, a biological warfare expert at the Center for International and Security Affairs at the University of Maryland, computer hard drives and handwritten notes seized at the home where Mohammed was arrested included an order to buy anthrax, along with other evidence of an interest in acquiring anthrax and other dangerous germs.
"Nothing so far translated implies access to the most dangerous microbial strains or to any advanced processing or delivery methods," Leitenberg concluded in a survey of recent developments in bioterrorism published in the journal Politics and Life Sciences.
U.S. officials said in interviews that Mohammed had told questioners that until the U.S. invasion of Afghanistan, al-Qaida's anthrax program was based in Kandahar, and was led by two men: Riduan Isamuddin, known as Hambali, and Yazid Sufaat, a Malaysian member of Jemaah Islamiyah, an al-Qaida-affiliated group.
Sufaat, who received a degree in biological sciences in 1987 from California State University, was a technician in the Malaysian military. In 1993, he set up a company to "test the blood and urine of foreign workers and state employees for drug use," Leitenberg wrote. Government officials say his company appears to have been involved in transferring money and buying ammonium nitrate for explosives for al-Qaida groups in Indonesia, Malaysia and the Philippines.
Although Sufaat tried to acquire anthrax, there is no evidence that he was able to procure the appropriate strain used in attacks, officials said. Sufaat was arrested in 2001 as he tried to enter Malaysia and is being held at an undisclosed location, officials said. He has reportedly confirmed numerous details about al-Qaida's effort to develop anthrax and other biological agents.
So, too, has Hambali, who like Sufaat fled to neighboring Pakistan after the United States invaded Afghanistan. He was arrested in August in Thailand and has been cooperating with U.S. officials, several officials said.
CBS News reported in early October that Hambali had been trying to open a new biological weapons program for al-Qaida in the Far East when he was arrested.
Officials said recent notices from the Department of Homeland Security also reflected the concern about a bioterrorism attack. A Nov. 21 warning from the department to law enforcement agencies stated that although al-Qaida is not known to have executed an attack using chemical or biological agents, "the acquisition, production, or theft of these materials and subsequent dissemination is a top al-Qaida objective."