FAS Note: Following are excerpts from a letter sent by Milton Leitenberg of the University of Maryland to the authors of a May 2004 Congressional Research Service report on "Small-Scale Terrorist Attacks Using Chemical and Biological Agents".

(1) page 5, footnote #14. You continue to use Kaplan as a source. As regards the Sarin-related events, that is reasonably safe, but almost all of the contentions regarding the efforts of the Aum group and biological agents in Kaplan's publications are in error. I have enclosed a paper widely distributed here in DC in 1999 and published in 2000 that reviews the relevant evidence in detail.

(2) Page 6, regarding my own positions (the paper referenced in footnote 20 among them), I have never written or said that "past trends will be equally applicable to the future", although past trends are certainly relevant to beginning to make an assessment.

(3) Page 8, footnote 27. The Ali/Rodrigues/Moodie volume is a relatively poor source, containing a substantial number of factual errors. I would think that SIPRI volumes I and II (one of which you list as reference 86 on page 28) and several of the subsequent SIPRI-Scorpion volumes that deal with BW history are very much more reliable.

(4) Page 8, the sentence preceding footnote 30, and the Tucker paper: Yes, the USSR was "accused", but you make no mention of the analyses of samples and conclusions published by the governments of the UK, Canada, Australia and Sweden, as well as independent US researchers, all of whom concluded that the Yellow Rain allegations are spurious and a natural artifact. Tucker is virtually the last remaining non-US government analyst that accepts the official US government position on this question, but you provide no other sources.

(5) Page 9, "Aum Shinrikyo developed an array of chemical and biological agents…" : the phrasing "developed" and biological agents is misleading. The Aum certainly tried, but failed in its efforts to "develop" either of the two biological agents it attempted to work with. (again see the enclosed paper and comment number 1 above).

(6) Page 9, Footnote # 35. Ron Purver's volume was an excellent first try, but was unfortunately written before Tucker's Toxic Terror was published, and so Purver included all the events that were subsequently demonstrated to have been apocryphal.

(7) Page 21, Aum and "developed other chemical agents such as phosgene and VX"; In the words of Ron Manley, former UK CW official, on 10/7/2003, "The reason VX is not easy to produce is because the chemistry is incredibly difficult". Canadian and Swedish CW specialists have privately expressed doubts that the Aum successfully synthesized VX. The claim that the Aum produced VX depends to date on verbal testimony; no one has ever yet presented chemical spectrographic corroboration of that claim.

(8) Page 27, "Some biological agents were reportedly developed by either the Soviet Union's or the United States' former biological weapons program". From my own work, I am certain that the former USSR did do that, although there are, of course, no official Russian or Soviet statements to that effect. But for the US there is no reason to use the ambiguous "reportedly". The US government officially released the names of the agents that had been weaponized and the precise quantities of each that had been stockpiled by the time the US offensive BW program was halted in 1969, and those stocks were destroyed in the next two years. That data was already available and published in SIPRI volumes, the first of which you have footnoted as reference number 86 on page 28.

(9) In this regard - and I have misplaced the page on which you refer to Dark Winter and Top Off I and II exercises - the US and UK BW programs prior to 1969 both failed in attempts to weaponize and aerosolize the agent that produces plague, (although the USSR did succeed in that during the 1980s). There is no indication in your discussion of plague on page 28 and in your reference to the three exercises that the parameters of all three were essentially " cooked" and fraudulent, for different reasons: