o-chlorobenzylidene malononitrile
(CS), a
strong irritating riot control agent, was inserted into the
Branch Davidian Mount Carmel compound near Waco, Texas,to
induce the inhabitants to leave the building. The insertion
of CS started at 6.00 a.m. on April 19, 1993. Shortly after
noon fire broke out and destroyed the
whole compound. Seventy-five Branch Davidians, including 28
children, died inside the building. The question arose
whether CS
gas or the interaction of CS and methylene chloride (MC)
killed or contributed to the deaths of the Branch Davidians.
I was asked by the OSC to answer this question and I
prepared a report that tried to do so. My report is based on
numerous documents and scientific literature provided to me
by the OSC, on my own literature research, and on the report
of Dr. Havens for the OSC on the
CS and MC exposure scenario
which might have occurred in the various rooms of the Mount
Carmel building. The possible effects of methylene chloride
on the group of Branch Davidians staying in the Mount Carmel
compound on April 19, 1993, are dealt
with in Dr. George Lucier's report to the OSC.
There are various preparations of
CS and various techniques
to make CS airborne in an inhalable form. In Waco, a
solution of CS in MC, contained in non-explosive projectiles
and CO2 pressurized canisters, was used to insert the CS.
Dispersed as droplets from this fluid, fine particles of
crystalline CS
emerged after instantaneous evaporation of MC. Experimental
animals were exposed to CS to get information on toxic and
lethal effects of CS.
Most of these experiments reported in the literature were
already conducted 30 - 40 years ago when there were no OECD
and Good Laboratory Practice guidelines for standardized
toxicity tests in experimental animals.
Furthermore, only one of these studies used MC/CS and the
toxic potency of the various CS preparations (pulverized
CS, molten
CS,
CS from
thermal grenades) including
CS
dissolved in methylene chloride (MC/CS) was mostly
different.
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