Gah!!! A pet peeve of mine!
I'll excerpt I previous post I made on the matter.
It isn't half as harmless as that implies. There are a several dead Postal Employees in Metro DC who would love to be able to argue the point.
Is Anthrax death on a stick? No, not compared to Smallpox or Cholera, but it is a very effective weapon, especially in the pre-antibiotic era (BTW: Cypro, the drug of choice to treat Anthrax, is a NASTY drug. I was given it once for an infection; still not sure that it wasn't better to just keep the infection). Serious use of Anthrax as an area weapon would have both caused considerable direct casualties, but, far more critically, would have knocked German (or any other target) food production into the creek. The RAF had somewhere in the neighborhood of 5,000,000 "cattle cakes" to scatter across Germany, as well as thousands of bombs. There would STILL be parts of Germany that would be "no go" zones.
Anthrax is also a lovely area denial weapon. I understand the British finally go the Island they used as a test site during WW II cleaned up a few years ago. Only took about half a century.