From: gbizzigo@mitretek.org (Dr. George O. Bizzigotti)
Newsgroups: rec.aviation.military,sci.military.naval
Subject: Re: Oooops?  US officials cover their arses over Sudan strike.....
Date: Wed, 02 Sep 1998 13:14:14 GMT

On Tue, 1 Sep 1998 04:28:43 -0000, "steven j forsberg"
<SFORSBERG@prodigy.net> wrote:

>            The 'sole' piece of evidence is a soil sample that supposedly
>turned up a chemical called EMPTA.  However, there are some hard questions
>arising.  For starters, as reported in the foreign press last week (and
>mentioned in some US coverage), a former US Army chemical warfare guru
>stated that it is quite possible to confuse EMPTA for a related chemical,
>IIRC something like "FORFIDOR" or some other God-awful acronym.  The latter
>chemical is commonly associated with insecticides found on the African
>continent.  He said the mistake has been made before, but without knowing
>the details of analysis done it is of course impossible to determine if
>someone goofed in this particular case.

The former "US Army chemical warfare guru" was Hank Ellison, who I
have seen described elsewhere as "a counterterrorism  expert who ran
the Army's chemical and biological warfare programs at Fort Campbell,
Ky., in the 1980s." He suggested that EMPTA could have been confused
with Fonofos, or more properly O-ethyl-S-phenyl ethylphosphonothiolate
(CAS reg. no. 944-22-9; it _is_ an insecticide which is specifically
exempted from the CWC Schedule 2). Fonofos differs from EMPTA at two
specific points in the molecular structure, moderately at one place
and rather significantly at another. There's been a thread going on
sci.chem, "VX Precursor Chemical Found in Sudan," for anyone really
interested in the details.

More important here is that Mr. Ellison is likely being quoted out of
context. The Army's chemical and biological defense programs required
rapid response and no false negatives; if there is a toxic cloud
coming over that hill they need to know it fast so they can don their
masks and suits. They prefer  to do this for a false alarm every so
often rather than learn of a chemical attack because a few sentries
start twitching on the ground. As a result the Army's experience (and
Mr. Ellison's, by inference) tends to focus on field methods that are
very quick and give an occasional false positive. However, in
Tuesday's washington Post, an unnamed government official was quoted
as saying that multiple samples were sent to a private laboratory in
the US. I could believe that EMPTA and Fonofos could be confused in a
rapid field test, but I am skeptical that a "normal" laboratory
(defined as instruments designed to operate indoors in a fixed place
by scientists in white coats) would confuse the two, expecially not if
multiple samples were analyzed.

>There is still also
>the possbility that EMPTA might be a byproduct of non chem-war work.

Not very likely. The only known use of EMPTA is as a precursor to VX;
it has no uses in pharmaceuticals of which I am aware. It almost
certainly was not made accidentally as a by-product of legitimate
pharmaceutical manufacturing. From a synthetic chemist's standpoint,
one has to go to quite a bit of trouble to make the carbon-phosphorus
bond in EMPTA, and none of the pharmaceuticals made in the Sudan
include that chemical bond. It is three steps removed from any
precursor that could legitimately be present in a pharaceutical plant
(and that one is regulated on Schedule 3 of the CWC). Thus, unless the
"accident" involved running three separate chemical reactions, one of
which is rather tricky, EMPTA was not there due to mistake. To the
best of my knowledge, EMPTA is really a smoking gun.

In sum, if the press accounts are true and the sample was analyzed in
a fixed laboratory using industry-standard instruments, the
identification of EMPTA should be reliable, certainly better than Mr.
Ellison indicates. The presence of EMPTA is a very strong indicator of
involvement in a chemical warfare program; it was not a mistake.

Regards,

George

**********************************************************************
Dr. George O. Bizzigotti                 Telephone: (703) 610-2115
Mitretek Systems, Inc., MS Z310          Fax: (703) 610-1556
7525 Colshire Drive                      E-Mail: gbizzigo@mitretek.org
McLean, VA 22102-7400
**********************************************************************

From: gbizzigo@mitretek.org (Dr. George O. Bizzigotti)
Subject: Re: VX Precursor Chemical Found in Sudan
Date: 28 Aug 1998
Newsgroups: sci.chem

On Thu, 27 Aug 1998 10:31:06 -0500, borsom@ix.netcom.com (Douglas H.
Borsom) quotes the NY Times:

>       [EMPTA's] structure resembled that of an agricultural
>       insecticide, known as FONOFOS, which is commercially available
>       in Africa.

>       While the two are not identical, they have molecular similarities
>       and could be confused in a laboratory test performed under
>       less-than-ideal conditions, said Hank Ellison, a counterterrorism
>       expert who ran the Army's chemical and biological warfare
>       programs at Fort Campbell, Ky., in the 1980s.

As Bruce Hamilton has noted in another post to this thread, there's a
lot of speculation in the Times piece,  but let me add a bit more to
the fire.

Fonofos is actually O-ethyl-S-phenyl ethylphosphonothiolate (CAS reg.
no. 944-22-9; it's specifically exempted from the CWC Schedule 2).
Thus it differs from EMPTA as follows: (1) ethylphosphonyl rather than
methylphosphonyl, (2) S-phenyl thiophosphonic ester rather than
thiophosphonic acid. GC/MS should be able to tell the difference
between the two under just about any circumstances I can imagine,
because of difference no. 1. Ordinary GC in a decent laboratory should
be able to distinguish EMPTA and fonofos provided the phenyl group is
not hydrolyzed away before it gets to the lab (a reasonable
proposition for a soil sample, even one not promptly stored at 4
degrees), even assuming that the EMPTA must be derivitized for the
analysis. Using LC techniques, where no derivitization is required,
difference no. 2 makes the analysis a slam dunk.

I think  one needs to be careful to distinguish the conditions under
which the soil sample was obtained (one presumes these were less ideal
than is customary in the environmental business) and the conditions
under which they were analyzed. The Army's chemical and biological
defense programs required rapid response and no false negatives; if
there is a toxic cloud coming over that hill they need to know it fast
so they can don their masks and suits. They prefer  to do this for a
false alarm every so often rather than learn of a chemical attack
because a few sentries start twitching on the ground. As a result the
Army's experience (and Mr. Ellison's, by inference) tends to focus on
field methods that are very quick and give an occasional false
positive.

Although  the papers do not say, there seems to be no reason to assume
that analysis of the soil samples from the Sudan was conducted under
conditions where "we need the answer in 5 minutes or else you comrades
might die." Unless someone knows differently, it seems to me fair to
presume that the analyses were performed using techniques and
instrumentation capable of distinguishing a diester of
ethylphosphonothioic acid from a monoester of methylphosphonothioic
acid.

Finally, according to EPA:

>Fonofos is immobile in sandy loom and silt loam soils.  It is mobile in quartz
>sand.  It decomposes in aerobic soils by microbes i 4-8 weeks.  Fonofos is
>non-volitile from soil but volatile from water.  It degrades in aerobic soils with
>a half like of 3-16 weeks.  Fonofos is moderately persistent.

Fonofos is used mostly on corn, but it is used on ornamental turf. For
fonofos to turn up at the plant in Khartoum, it would thus appear that
either (a)  the plant had a nice lawn that had been treated relatively
recently, or (b) there had been some recent spraying activity nearby
and there was either overspray or blowing dust. I do find it
interesting that it is the NY Times that raised this possibility; I
would imagine given the high visibility PR campaign that had fonofos
(or for that matter, any organophosphate) been used anywhere near the
plant the government of the Sudan would have been loudly proclaiming
the fact.

In sum, it could have been a fonofos false positive, but I remain
skeptical of the possibility.

Regards,

George

**********************************************************************
Dr. George O. Bizzigotti                 Telephone: (703) 610-2115
Mitretek Systems, Inc., MS Z310          Fax: (703) 610-1556
7525 Colshire Drive                      E-Mail: gbizzigo@mitretek.org
McLean, VA 22102-7400
**********************************************************************

From: gbizzigo@mitretek.org (Dr. George O. Bizzigotti)
Subject: Re: VX Precursor Chemical Found in Sudan
Date: 26 Aug 1998
Newsgroups: sci.chem

On 25 Aug 1998 22:15:18 GMT, thweatt@prairie.NoDak.edu (Superdave the
Wonderchemist) wrote:

>Does anybody know exactly what the chemical was that was found in the soil
>near the "chemical weapons plant" in Sudan?  I am curious.  I mean, VX is
>not a very exotic molecule.

See the article from the Washington Post at:

http://www.washingtonpost.com/wp-srv/WPlate/1998-08/25/066l-082598-idx.html

which states:

:But most attention was focused on the soil sample bearing
: what the official identified as o-ethylmethylphosphonothioic
: acid, or EMPTA. The official said EMPTA's only known
: function is as a precursor agent for the production of VX
: and that it is "difficult to make."

EMPTA contains a methyl group bonded to phosphorous, which places it
on Schedule 2 of the Chemical Weapons Convention (accessible at
http://www.opcw.nl/), This reflects the fact that there are few
legitimate uses for methylphosphonates as a class; the comment that
EMPTA's only known function is as a VX precursor thus appear to be
reasonable. Superdave may not consider VX to be a very exotic
molecule, but the "methylphosphono" functionality (as well as the
diisopropylaminoathyl functionality) are hardly common.

Regrading the contention that EMPTA is difficult to make, I think it
would be more accurate to state that it is several steps removed from
common industrial compounds that are not CWC-scheduled, and that those
steps are difficult to carry out on a scale sufficient to make
strategically significant amounts of VX. (It may not be particularly
difficult to make in small quantities in the lab if one has the
patience to carry out multiple steps and  _if_ one can obtain the
precursors without arousing anyone's suspicions.)  I suspect that what
the unnamed official was trying to convey is that (a) EMPTA didn't get
there by accident, and (b) whoever was responsible for it getting
there had to go to a lot of trouble to produce it.

Regards,

George

**********************************************************************
Dr. George O. Bizzigotti                 Telephone: (703) 610-2115
Mitretek Systems, Inc., MS Z310          Fax: (703) 610-1556
7525 Colshire Drive                      E-Mail: gbizzigo@mitretek.org
McLean, VA 22102-7400
**********************************************************************