Press proves immune to FBI's anthrax corrective

The posting to the net of a transcript of the FBI's briefing to the press on the science behind the anthrax case is remarkable for two things: first, for its explanation of the development of microbial forensics and the team of scientists behind it; and second, for the determination of some members of the press to run off on a conspiracy theory hinging upon whether or not the anthrax was ever weaponized.

As to the second part, the FBI and its team of independent scientists unequivocally said it wasn't, after repeated badgering by one journalist - unnamed in the transcript - who insisted other scientists at Ft. Detrick and the Armed Forces Institute of Pathology had determined the anthrax to be weaponized because silica was allegedly seen on the surface of the spores.

Dr Joseph Michael, a materials scientist at Sandia National Laboratories who had, with others, analyzed the anthrax powders in depth, flatly denied this. "They are mistaken," the man replied to repeated questioning.

The explanation was that silicon had been detected in the attack samples but it was inside the spores - not on the surface. Scientists had determined that Bacillus species sequester silicon from the environment in protein and that the purpose of this was thought to be a natural process to "make the spore heartier." They had gone back in the literature to find a paper published in 1982 which discussed the matter and then, for comparative purposes, tracked down the original samples which the paper described.

Attack sample 'very different'

"We found no additives; no exogenous material on the outside of the spores," said Michael. "We did have the opportunity to look at weaponized material to compare it to the letter material and they were very different. And [in] the weaponized material the additives appear on the outside of the spore. Again, in the letter materials the silicon and oxygen were co-located on the spore coat [which is] within the spore. In fact, we found some vegetative cells that were going through the sporulation process and the spore within the mother cell had this same signature."

To grasp the importance of this it's necessary to understand where those obsessed with whether or not the anthrax was weaponized are coming from. After the initial mailings, weaponization was thought to be the trademark of a state-run biological weapons program. Different programs had different methods of production and the differences, it was alleged, constituted unique signatures. In the initial hysteria, this was said to point to Iraq.

More recently, the weaponization argument has been used to insist that Bruce Ivins could not have been the anthrax mailer because he had no experience in such methods. This was heard coming from Ft. Detrick personnel, who have an obvious professional interest in not being seen as the workplace of the anthraxer, and those who are still utterly convinced the FBI had the wrong man.

And weaponization with silica was what made the mailed anthrax so hazardous, the argument concludes.

This was not so, countered the scientists at the FBI's press briefing, reluctantly discussing a matter which many microbiologists know but which they wish not to be common knowledge: microbial powders are very fragile. The cells tend to generate fine dusts upon handling.

"In fact, many biological single-cell organisms when you dry them, like algae, they - they're very buoyant..." said Dr. Vahid Majidi of the FBI. "That is, you know, you open the contained, they do fly all over."

And sorting through mail machines pulverized the anthrax, too.

The FBI did not have "any answers for what process was used to grow additional spores or what methodology was used to dry them."

"I think that a lot of folks focus on the issue of [a] lyopholizer," said Majidi, describing a common biochem lab piece of hardware used to freeze-dry biological preparations. "You can ask any of the folks and the panel members, and they will tell you that you can dry biological samples in one of dozens of ways."

Was it unusual that the anthrax was so easily dispersible? No, said the FBI scientist.

"There is a misconception going around this room that very simple spore preparation, simply spores washed in water, when dried, are not dangerous and friable," added one unidentified official. "That is a misconception."