Organophosphate pesticides sometimes wee used for nerve gases by the miiltary becuase they come from the same chemical family. The may be some with the same or almost the same lethality in some industrial chemical storage facilities. " Secrets Of Lockpicking" by Stephen Hampton and his more advanced books like safecracking and stuff would help. There may be other industrial chemicals that would make good improvisaed crude chemical weapons, perhaps in a detonated in a truck bomb or wiith other large explosives. "The Black Book Companion State Of The Art Improvised Munitions" by Paladin Press and "The Poor Mans James Bond" series would help. A truck bomb could perhaps be built like an extremely large pipe bomb, instead of 6 inches of a pipe bomb the truck back storage part would be welded airtight, packed with something like fertilizer explosive(which is traceable by people like the FBI) and fitted with blasting caps, fuses and stuff to explode it.