In The Doomsday Book there are chapters on both chemical attacks and biological attacks. As suggested by this video, anthrax was cultivated by several countries for use as a bioweapon in WWII and has appeared several times on the world stage. In the United States the most famous appearance involved mailing anthrax to people:
“The Doomsday Book” by Marshall Brain lays out this scenario in amazing detail and offers solutions to prevent this doomsday scenario from unfolding. You can order the book today on Amazon and other retailers.