NRC report on Amerithrax science shows rigor and prudence

Posted in Bioterrorism at 11:09 am by George Smith

The National Research Council’s report today on the science of the FBI’s Amerithrax investigation upheld the value of careful rigorous work.

It stopped well short of condemning any of the FBI’s work on the case and did not particularly lend itself to cries for the exoneration of Bruce Ivins. It also generated enough confusion and furrowed brows among attending journalists to guarantee the mists swirling around the case would probably continue in subsequent stories.

The presentation, headed by Alice Gast, president of Lehigh University, got right down to business at, what was here, 8:00 PST in video stream.

The salient point was this:

The scientific link between the letter material and flask number RMR-1029 is not as conclusive as stated in the DOJ Investigative Summary.

And it left the reporters who’d covered the story from the beginning with a dilemma.

New York Times reporter Scott Shane was the voice of it when, at one point, he essentially asked Gast and her colleague David Relman, to put forward a conclusion that would be more distinct to non-scientists.

Were laymen to believe the NRC had concluded that it was not likely the mailed anthrax came from RMR-1029, the mother flask at Fort Detrick/USAMRIID maintained by Bruce Ivins? Or might it have been the other way around, that the FBI/DoJ conclusion was the best one to make.

“Do you think the FBI has done a good job?” he asked.

When it came up, DD laughed. Careful science would not furnish that answer.

As it stood, Gast and Relman explained repeatedly, the forensic science on the anthrax mailings, RMR-1029 and the FBI’s sample repository was an evolving process. Science was developed in conjunction with the investigation. And that science, while good (my opinion), could not alone furnish the definitive answer given the nature of it and the existence of another fermentation — produced at Dugway at a much earlier date, which was morphotypically the same. As far as could be determined. By the science.

David Relman explained further by discussing the 1029 flask at USAMRIID.

Roughly, the NRC concluded that the source flask was complex and heterogeneous. And every time one dipped into it one was not bringing out the same material, or leaving it perfectly as it was.

This meant that there would, of necessity, be error in the assays used to examine it and the FBI’s samples and that such lab work would not provide consistent results every time.

That being said, the NRC did not discredit the conclusions brought by the FBI.

When asked what it thought of the FBI/DoJ’s closing of the case, Relman replied:

We note the closing of the case with due interest.

The NRC report did put another spike through the heart of the idea that silicon was added to the mailings to Leahy and Daschle for purposes of weaponization and dispersion.

It won’t kill the crazies who continue to pursue the argument. But that’s more due to the nature of the people who cleave to it.

“Silicon was present in the letter powders but there was no evidence
of addition of dispersants,” Gast said.

And the report reads:

The bulk silicon content in the Leahy letter could be completely explained by the amount of silicon incorporated in the spores during growth …

The inability of laboratory experiments to duplicate silicon characteristics of the latter samples is not surprising given the uptake mechanism (in the anthrax microbe).

The NRC determined the anthrax could be dried in a number of ways and that the equipment and materials for doing so was available. Additionally, the time frame, or window, for such activity was variable enough that it could fit FBI conclusions. In other words, Ivins could have done it in the time frame outlined by the FBI and Department of Justice.

The report comments:

There are several methods for drying spore suspensions to produce powders like those found in the letters: these include chemical desiccation, air drying and freeze drying, any of which could require several hours to several days. Drying of surrogate spore preparations using various methods produced particle size distributions similar to those found in letter samples …


The committee finds no scientific basis on which to accurately assess the amount of time or skill set needed to prepare the spore material in the letters. The time might vary from as little as 2 to 3 days to as much as several months.

Arguments on the skill set required to make the anthrax have been commonly employed to argue that Ivins could not have done it.

Near the end of the conference one reporter asked about a Fort Detrick scientist who last year had gone before the committee to advise it on the science and techniques involved in producing the attack material.

This was probably a reference to Henry S. Heine, a supervisor of Ivins’ who had attempted to clear the suspect. I discussed it here, noting that the story had only been publicized at ProPublica by one of the journalists deeply involved in anthrax conspiracy promotion, Gary Matsumoto.

Relman averred that the committee had considered the information, disassociated it from the source, and that there was nothing more to be said.

Other items of interest which came to light in the NTC briefing:

1. The government examined the ruins and remains of Flight 193 for anthrax. No other information was provided.

2. The US government made three missions to unnamed foreign sites, looking for anthrax. Polymerase chain reaction assays determined samples to be positive from two of these sites but that no live bacteria could be produced from them. The third mission provided negative results.

These missions were shrouded in secrecy, although it was stated that intelligence agencies were involved. The NRC was kept from knowing much about them and the classification got in the way of any conclusions which could have been drawn.

Alice Gast said that, as a result, the National Research Council made a recommendation to review the classified materials.

The National Research Council’s conference at the National Academies of Science is on-line here.

The full report is here. A .pdf can be purchased or it can be read, for free, online through the website’s set up viewer.

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