You changed my thinking!:)
Bio could kill millions more...but it would be tooooo slooooooow for a photo op spectacular and the plausible deniability thing as you say [we would deny it even if we knew it to be true most likely and the world would never know for sure perhaps.]
The chem and nuke would give them the instantaneous gruesome spectacular they desire and there would be no doubt it wasn't an accident.
Then a bio follow-up could be more easily claimed by the terrorists in advance; with us only being able to wait in shock and panic.
[I thought decon from VX was a shot of atrophine straight into the heart? ..LOL...TheRock-Nicholas Cage?] I do know one thing...it ain't "IF"...it is WHEN.
Oh my Gaaaaaawwwwd. Atropine is self injected with a spring loaded hypo right into the upper thigh and vigorously massaged. You can take up to three units of atropine in 15 min. But troopers are only issued one atropine injector. When I asked about this at the NBC School know what the sobering reply was? Sir, in the event of a real world chemical attack, there will be plenty of folks laying around who won't mind if you use their injectors, cause they won't be breathing....
If you saw that movie you'll remember the effects of the "agent" when it hits human skin. That's NOT nerve agent, but it's a fairly accurate picture of the results of the Mustard family aka Blister Gas. Another old friend from the first world war.
We're rapidly approaching the window of opportunity for a chemical attack. Won't happen as long as the weather is windy, cold wet and blustery. Let the winds calm, the humidity grow warmer and muggier and that will raise the persistency levels dramatically. Spring and summer are the target months. Figure Mid April through Late September.
'Zilla, you might want to make note of that for the summaries. Climatically, we are entering a favorable attack window for use of chemical WMDs.