04 Nov 2002
American Scientists, December 10, 2001.
A Compilation of
Evidence and Comments on the Source of the Mailed Anthrax
Barbara Hatch Rosenberg, Federation of American
Scientists (revised December 10, 2001)
All the available evidence indicates that the
source of the mailed anthrax, or the information and materials to make it, is a
US government program.
1. ANTHRAX STRAIN
All letter samples contain the same
strain of anthrax, corresponding to the AMES strain in the N. Arizona State
University database (which has been used for identification). The Ames
substrain possessed by N. Arizona State is referred to herein as the
"reference strain." That strain was obtained from Porton Down (UK) in the
mid-90's (the sample was marked "October 1932"); Porton had gotten it from
A 2000 paper by M. Hugh-Jones, PJ
Jackson, P. Keim et al says that the Ames strain played a central role in the
US BW program [i.e., before 1969]. Hugh-Jones says he learned that from David
Huxsoll, Former Commander, USAMRIID. However, he says Vollum 1B was the strain
stockpiled (at least in the early days of the US biological weapons program).
The search for better strains undoubtedly continued, leading the US program to
prefer the Ames strain because of its high virulence.
The Ames strain is used now in the US
biodefense program for testing vaccines etc.
The Ames reference strain in the N.
Arizona collection is probably the earliest Ames substrain (isolated in 1925
and sealed in 1928, perhaps subcultured in 1932).
There are at least four Ames
substrains, all under the control of Fort Detrick. They were isolated by
laboratories in Ames, Iowa but were not subsequently studied or distributed by
Undoubtedly the confusion about Ames
substrains could be cleared up by USAMRIID, but they have been evasive.
"Weaponization" is used here to mean
preparation of the form of anthrax found in the Daschle letter: fine
particles, very narrow size range, treated to eliminate static charge so it
won't clump and will float in the air. The weaponization process used was
extraordinarily effective. The particles have a narrow size range (1.5-3
microns diameter), typical of the US process.
The extraordinary concentration (one
trillion spores per gram) and purity of the letter anthrax is believed to be
characteristic of material made by the US process.
A reporter who writes on anthrax
vaccine has privately stated that four labs have told him that under the
electron microscope the appearance of the sample is like that of unmilled
anthrax spores. Milled samples are identifiable because they contain debris.
The optimal US process did not use milling.
The US weaponization process is
secret-Bill Patrick, its inventor, says it involves a COMBINATION of
The Armed Forces Institute of
Pathology (Washington DC) is studying the anthrax using an energy dispersive
X-ray spectroscope, which can detect the presence of extremely tiny quantities
of chemicals; traces of several chemicals have been found.
The Senate sample contains a special
form of silica used in the US process. It does not contain bentonite (used by
All the letters probably contained
the same material. The clumping of the anthrax in the two letters mailed on
Sept 18 (to NBC and the NY Post) probably resulted from the letters getting
wet in the course of mail processing or delivery, according to Army
scientists. This conclusion is strengthened by the similarity of the Florida
anthrax (the first to be observed, probably also mailed on Sept 18) to that in
the Daschle letter, mailed Oct 9.
3. ANTHRAX PRODUCTION
A study of genetic drift at certain
locations in anthrax is underway at Northern Arizona State University. The
results are expected to give an idea of how many times the letter anthrax had
replicated, in comparison to the reference strain-ie, whether it was grown on
a very large scale (as in a State program) or on a very small scale, as would
be likely if recently made by a terrorist.
Analysis of trace contaminants could
also indicate the scale/method of production (ie, liquid medium, in a
fermenter, or solid medium, on petri dishes, a likely method for small-scale
4. OTHER ANALYSES
It has just been reported that the
complete sequence has been determined for the genomes of both the anthrax used
in the Florida attack and the Ames reference strain to which it corresponds.
This work was done under government contract by the Institute for Genomic
Research, a private non-profit organization. The results have not been made
public but they are in government hands and there has been no retraction of
the oft-repeated official statement that the letter anthrax matches the Ames
In addition, sequence data will
reveal whether the Ames reference strain is a mixture of types, as sequencing
has revealed to be the case for another anthrax strain. If so, the proportions
of the mixture may differ from lab to lab and could be used to identify the
Senator Bob Graham, Chairman of the
Senate Intelligence Committee, said in late October that investigators can
identify with great certainty which lab produced the anthrax, but it will be a
laborious, time-consuming process. (Chicago Tribune, 27 Oct 01).
5. SOURCE LOCATION
Contrary to early speculation, there
are no more than about 20 laboratories known to have obtained the Ames strain
from Fort Detrick. The names of 15 of these laboratories have been found in
the open literature (see Appendix). Of these, probably only about four in the
US might possibly have the capability for weaponizing anthrax. These include
both US military laboratories and government contractors.
6. INFORMATION REGARDING THE
Analysts believe the letters were not
written by a Middle-Easterner. The FBI publicly conjectures that the
perpetrator was a lone, male domestic terrorist, obviously one with a
scientific background and lab experience who could handle hazardous materials.
The perpetrator must have received
anthrax vaccine recently (it requires a yearly booster shot), whether or not
he made the material himself, because filling the letters was a dangerous
operation. The vaccine is in short supply and is not generally accessible.
Vaccination records must be available.
The perpetrator appears to be a
forensic expert. In preparing and mailing the letters he successfully covered
every personal trace.
There was only one week between Sept
11 and Sept 18, when the first two letters (and probably another letter, never
found, to AMI) were postmarked. This suggests that the anthrax was already in
hand before Sept 11.
Did the perpetrator have advance
knowledge of the Sept 11 attacks? Secretary of Defense Rumsfeld has said that
he does not believe al Qaeda was responsible for the anthrax attack, and other
public officials have increasingly indicated that the perpetrator was probably
8. PUBLIC STATEMENTS
At first, US officials provided
miscellaneous bits of information, some conflicting; then denied some of the
earlier information, then clammed up. They now have a great deal of
information that has not been made public. Under pressure from leaks, they
have started a gradual release of information again.
The US rejected a UN resolution
offered by France to condemn the anthrax attack, on the grounds that it could
have been domestic terrorism.
The Secretary of Health and Human
Services said in October that some of the relevant information is classified,
and some is restricted by the FBI.
John Bolton, Under Secretary of State
for Arms Control and International Security, spoke on Nov. 19 at the opening
of the five-yearly Review Conference of the Biological Weapons Convention in
Geneva. At a press conference following his talk, he said "We don't know, as I
say in the statement, at the moment, in a way that we could make public,
where the anthrax attacks came from." This statement, as well as other
information, indicates that US officials DO know where the anthrax came from.
The FBI says it is now investigating
government and contractor laboratories possessing the Ames strain, and
individuals who had access to them. Col. Arthur Friedlander, Sr. Research
Scientist at USAMRIID, said no one there knows how to make dry weaponsized
According to the New York Times (2
Dec 01), a law enforcement official close to the federal investigation called
the concept of a government insider, or someone in contact with an insider,
"the most likely hypothesis…it's definitely reasonable." An American official
sympathetic to this thesis was quoted in the same article saying that, in
addition to military laboratories, "there are other government and contractor
facilities that do classified work with access to dangerous strains, but it's
highly likely that the material in the anthrax letters came from a person or
persons who really had great expertise. We haven't seen any other artifacts
that point us elsewhere."
Senate Majority Leader Thomas
Daschle, recipient of one of the anthrax letters, has been in frequent contact
with investigators. He said on Dec 8 that the perpetrator was probably someone
with a military background.
9. MOST LIKELY HYPOTHESIS
The perpetrator is probably an
American microbiologist who has access to weaponized anthrax or to the
expertise and materials for making it, in a US government or contractor lab.
He does not live in or near Trenton, but more probably in the Washington, DC
area. Trenton is probably accessible to him (it is a stop on the Amtrak line
that runs along the East coast), but if he is smart enough to handle anthrax
he is smart enough not to mail it from his home town.
The anthrax in the letters was
probably made and weaponized in a US government or contractor lab. It might
have been made recently by the perpetrator on his own, or made as part of the
US biodefense program; or it may be a remnant of the US biological weapons
program before Nixon terminated the program in 1969.
The motive of the perpetrator
was not necessarily to kill but to create public fear, thereby raising the
profile of BW. He simply took advantage of Sept 11 to throw suspicion
elsewhere. The letters warned of anthrax or the need to take antibiotics,
making it possible for those who handled the letters to protect themselves;
and it seems unlikely that the perpetrator would have anticipated that the
rough treatment of mail in letter sorters etc, would force anthrax spores
through the pores of the envelopes (which were taped to keep the anthrax
inside) and infect postal workers and others.
The choice of media as targets
seems to have been cleverly designed to ensure publicity about the threat of
biological weapons. One can only speculate that the perpetrator may have
wished to push the US government toward retaliatory action against some
enemy, or to attract funding or recognition to some program with which he is
The choice of Senators Daschle and
Leahy as targets may be a clue that has yet to be deciphered.
The US government has
undoubtedly known for some time that the anthrax terrorism was an inside job.
They may be reluctant to admit this. They also may not yet have adequate hard
evidence to convict the perpetrator.
In opposition to most of the
countries of the world, the Bush administration turned down a Protocol to
monitor compliance with the ban on biological weapons last July. In so doing
it reversed the policy of the previous three administrations aimed at
strengthening the Biological Weapons Convention, which lacks verification
measures. The action put the US at odds with most of its allies and fueled
accusations of US unilateralism, according to the Washington Times (Dec 5).
The anthrax attacks have had no
effect on administration policy. At the start of a five-yearly Biological
Weapons Convention Review Conference last month, Under-Secretary Bolton
caused dissention by accusing several parties to the Convention of violating
it. On Dec 7, the last day of the conference, the US doublecrossed its
European allies by reversing a compromise agreement of the previous day,
thereby causing an uproar and derailing the Conference. According to
European diplomats, failure of the conference sends the message that the
international community is not willing to enforce the ban on biological
Conclusions: A recent report
by the Congressional GAO, as well as many recent statements by military and
non-governmental experts in the BW field, holds that terrorists are unlikely
to be able to mount a major biological attack without substantial assistance
from a government sponsor. The recent anthrax attack was a minor one but
nonetheless we now see that it was perpetrated with the unwitting assistance
of a sophisticated government program. It is reassuring to know that it was
not perpetrated by a lone terrorist without state support.
It is not reassuring, however, to
discover that a secret US program may have been the source of that support,
and that security is so dangerously lax in military or defense contractor
laboratories. US government insistence on pursuing and maintaining the
secrecy of elaborate biological threat assessment activities is undermining
the prohibitions of the Biological Weapons Convention and encouraging
biological weapons proliferation in other countries, which in turn may
support bioterrorist attacks on the American public.
LABORATORIES THAT HAVE WORKED WITH THE AMES STRAIN OF ANTHRAX
(Information obtained from open sources)
USArmy Medical Research Institute for
Infectious Diseases (Ft. Detrick, MD)#,*
Dugway Proving Ground (Utah)#,*
Naval Research Medical Center and
associated military labs (MD)#
Battelle Memorial Institute (Ohio;
plus laboratories in many other locations)#,*
Duke University Medical School,
Clinical Microbiology Lab. (NC)
VA Medical Center, Durham (NC)
USDA laboratory and Iowa State
College of Veterinary Medicine, Ames (Iowa)
LSU College of Veterinary Medicine*
Northern Arizona State University
Illinois Institute of Technology
Research Institute (IL)
University of New Mexico Health
Sciences Center, Albuquerque (NM)*
Institute for Genomic Research (MD)
Chemical and Biological Defense
Establishment, Porton Down (UK)*
Center for Applied Microbiology and
Research, Porton (UK)*
Defense Research Establishment,
In addition, CDC, NIH, and Los Alamos
and a few others may have the Ames strain.
* Obtained through a FOIA request by the Washington Post
(article Nov 30, 01)
# indicates laboratories in the US that are
probably more likely than the others to have weaponization capabilities.