The Geneva Convention is a set of international laws designed to protect civilians and soldiers in times of war. Anthrax is not specifically addressed in the Geneva Convention, however, its use in warfare is prohibited under international law.
The use of anthrax in warfare dates back to the early twentieth century. During World War I, Germany used anthrax as a weapon to attack livestock in the United Kingdom. In World War II, Japan used anthrax as an experimental weapon against Chinese civilians.
The use of biological weapons, such as anthrax, is prohibited under the 1925 Geneva Protocol. This protocol states that "the use in war of asphyxiating, poisonous or other gases, and of all analogous liquids, materials or devices, is prohibited." This language is broad enough to encompass the use of anthrax as a weapon.
The 1972 Biological Weapons Convention also prohibits the use of biological weapons, including anthrax. This treaty states that "each State Party undertakes never in any circumstances to develop, produce, stockpile or otherwise acquire or retain microbial or other biological agents, or toxins whatever their origin or method of production, of types and in quantities that have no justification for prophylactic, protective or other peaceful purposes."
Therefore, it is clear that the use of anthrax in warfare is against the Geneva Convention. The use of this weapon would violate both the 1925 Geneva Protocol and the 1972 Biological Weapons Convention. Any nation found to be using anthrax as a weapon would be subject to international condemnation and possible legal action.