The Dugway statement was issued in response to an article in The Sun yesterday revealing that the Army facility in the Utah desert has produced weapons-grade anthrax identical in important respects to the anthrax used in the postal attacks.
"This is very significant," said Barbara Hatch Rosenberg, a molecular biologist who heads a working group on biological weapons at the Federation of American Scientists. "There's never been an acknowledgment that any U.S. facility had weaponized anthrax."
Rosenberg, who has theorized that the anthrax in the letters might have come from a U.S. government program or contractor, said Dugway's assurances about security do not necessarily rule out leakage of the tiny amounts used in the bioterrorist attacks.
"The question is, could someone have gotten hold of a very small amount and used it in the letters?" said Rosenberg, of the State University of New York.
A sufficient dose produces inhalation anthrax, which is blamed for killing five people since October.
Some of the anthrax produced by Dugway has matched the fine particle size and extraordinary concentration of the powder mailed to Senate Majority Leader Tom Daschle, estimated at close to 1 trillion spores per gram, according to a government scientist.
In addition, the mailed anthrax is genetically indistinguishable from the Ames strain used by the Army, the most sophisticated test methods show.
Neither the physical nor the genetic match proves that the terrorist used anthrax from Dugway.
Ames-strain anthrax has been used in numerous laboratories, and a person with microbiology training and access to the right equipment might have been able to concoct the deadly powder.
But many experts think it more likely that the attacks are linked to a government program, either in the United States or another country.
A government official familiar with the Dugway program said about a half-dozen scientists there have the expertise to make dry anthrax. No one with such expertise has left the program in recent years, the official said.
The unsigned, two-page Dugway statement e-mailed to reporters last night says scientists there "routinely" make anthrax to test decontamination methods and equipment designed to detect biological agents. It confirms The Sun's report that most experiments use simulants or anthrax spores inactivated by radiation, but certain tests "must be performed with live agents."
It gives no details about the strain, production methods or physical qualities of the anthrax made at Dugway for aerosol testing.
"All anthrax used at Dugway has been accounted for," the statement says. "There is a rigorous tracking and inventory program to follow the production, receipt and destruction of all select agents. The facility is well-protected with robust physical and personnel security systems."
The statement says the Army is cooperating with the FBI and "will not comment further on any aspect of its bio testing program" until the investigation concludes.
The Environmental Impact Statement prepared in 1992 for the Life Sciences Test Facility at Dugway, where much of the work is done, lists some of the biological agents to be used there. They include not only anthrax but also the bacteria that cause the diseases tularemia and Q fever, as well as the virus that causes Venezuelan equine encephalitis.
The federal Centers for Disease Control and Prevention have confirmed 18 cases of anthrax since October, including 11 inhalation and seven cutaneous, or skin, cases. No new case has been reported since that of 94-year-old Ottilie Lundgren, a Connecticut woman who died Nov. 21.