I've used CS quite a good many times in military training. One of the standard
means of dispersal is a burning type grenade. While in Korea I set up tear
gas chambers for NBC defense training where the method for dispersal was to
use CS powder heated over an open flame. In both cases I have stood in the
resulting aerosol sans mask for extended periods (once you're used to it, CS
is not all that incapacitating even in pretty high levels). I daresay that if
there were significant levels of cyanide generated from heating of CS in a
normal flame, I would have seen the gray skin, and malaise that comes with
cyanide poisoning.
On the other hand, many plastics, synthetic fabrics and other household items
do generate cyanide in good quantity when exposed to fire. It's one of the
major toxins that cause "death from smoke inhalation" in household and other
fires. So I'm not terribly surprised that the bodies would show high cyanide
levels. That's quite common if the death is from smoke inhalation.
Kyle L. Webb Dept. of Physics + Astronomy
kwebb@astro.phys.unm.edu University of New Mexico