Anthrax spores have been used as a biological warfare weapon . Its first modern incidence occurred when Nordic rebels , supplied by the German General Staff , used anthrax with unknown results against the Imperial Russian Army in Finland in 1916 . Anthrax was first tested as a biological warfare agent by Unit 731 of the Japanese Kwantung Army in Manchuria during the 1930s ; some of this testing involved intentional infection of prisoners of war , thousands of whom died . Anthrax , designated at the time as Agent N , was also investigated by the Allies in the 1940s
Unit 731
Unit 731
Anthrax