(1) Now obviously all of that wasn't mustard, a lot of the deaths were actually due to phosgene and chlorine.(2) However, its immediate precursor compound, thiodiglycol, is used industrially, although in quantities that don't come anywhere near chlorine or phosgene .(3) The primary gaseous agents used were chlorine, phosgene , a combination of the two, and mustard gas.(4) Greenpeace found that perc breaks down into the toxic byproducts phosgene , vinyl chloride, carbon tetrachloride and trichloroacetic acid.(5) New agents, notably phosgene (an asphyxiating agent) and mustard (a blister agent called a vesicant), had been developed and used.
