LMO, even a biological agent has to have a certain chemical structure, why shouldn't the properly programed scanning devise be able to identify it. As I understand it, to be really dangerous the anthrax particles must be ground to a very fine powder, I would hope the scanner could determine that as well.
I believe that if scanners can identify which brand of Scotch I'm drinking and determine if it's not what it's supposed to be, if it can differentiate between name brand and generic drugs, etc. it should also be able to identify anthrax and other agents if it's been programmed to find those agents.
Gary