Plagued corpses, Greek fire, and mus­tard gas are just a few exam­ples of how chem­i­cal and bio­log­i­cal weapons have been employed through­out his­to­ry to cause wide­spread dev­as­ta­tion. These forms of war­fare have exist­ed since ancient times, with one of the ear­li­est uses of chem­i­cal war­fare being record­ed dur­ing the siege of Dura-Euro­pos in 256 CE. The Sas­san­ian Per­sians, seek­ing to defeat the Romans, dug tun­nels under the city and released sul­fur diox­ide gas when the Romans attempt­ed to invade. This method of war­fare was an ear­ly exam­ple of how chem­i­cal sub­stances could be used to gain a strate­gic advan­tage. Sim­i­lar­ly, in 1347, the Mon­gols cat­a­pult­ed infect­ed corpses into the city of Kaf­fa, trig­ger­ing the spread of the Black Death into Europe, fur­ther high­light­ing how dis­ease, like chem­i­cals, could be used as a weapon.

Through­out his­to­ry, the use of these dev­as­tat­ing weapons expand­ed with advance­ments in tech­nol­o­gy. The 20th cen­tu­ry saw the rise of indus­tri­al chem­i­cal weapons like mus­tard gas, first deployed by Ger­many dur­ing World War I. Mus­tard gas, also known as sul­fur mus­tard, is a blis­ter­ing agent that caus­es severe burns to the skin and res­pi­ra­to­ry dam­age, mak­ing it one of the most feared weapons of its time. Dur­ing World War I, chem­i­cal weapons were deliv­ered using can­is­ters or shells, with phos­gene gas being six times dead­lier than chlo­rine. This bru­tal tac­tic led to thou­sands of casu­al­ties and sparked the devel­op­ment of inter­na­tion­al treaties aimed at con­trol­ling such weapons. The Chem­i­cal Weapons Con­ven­tion (CWC) of 1993, which came into force in 1997, marked a sig­nif­i­cant step in ban­ning chem­i­cal weapon pro­duc­tion, though sev­er­al nations, such as Israel, have not rat­i­fied it, con­tribut­ing to ongo­ing con­cerns about the pro­lif­er­a­tion of these weapons.

In addi­tion to chem­i­cal weapons, the use of bio­log­i­cal agents has also played a sig­nif­i­cant role in war­fare. One noto­ri­ous exam­ple is the use of anthrax dur­ing the 2001 attacks in the Unit­ed States, where dead­ly spores were mailed to var­i­ous tar­gets, result­ing in five deaths. Bio­log­i­cal weapons, like those used by the Japan­ese dur­ing World War II, also include dis­eases like small­pox, which was alleged­ly giv­en to Native Amer­i­can tribes in the 18th cen­tu­ry. This form of war­fare, although banned by the Bio­log­i­cal Weapons Con­ven­tion of 1972, still pos­es a threat in mod­ern times. Despite the pro­hi­bi­tion, some nations, such as Israel, are sus­pect­ed of main­tain­ing bio­log­i­cal weapons pro­grams, rais­ing con­cerns about the poten­tial mis­use of these dead­ly sub­stances. The com­plex lega­cy of these weapons under­scores the impor­tance of inter­na­tion­al treaties and the ongo­ing efforts to curb the use of chem­i­cal and bio­log­i­cal agents.

Napalm, a par­tic­u­lar­ly grue­some weapon, became infa­mous dur­ing the Viet­nam War. This sub­stance, a mix­ture of flam­ma­ble liq­uid and a gelling agent, was used exten­sive­ly by the U.S. mil­i­tary under the oper­a­tion code-named Ranch Hand to defo­li­ate large areas of Viet­nam from 1962 to 1971. The hor­ri­fy­ing images of napalm burns left an indeli­ble mark on the glob­al con­scious­ness, fur­ther fuel­ing anti-war sen­ti­ment. Along­side napalm, oth­er chem­i­cal agents like Agent Orange, a dead­ly her­bi­cide, caused long-term health issues for both sol­diers and civil­ians. These weapons serve as a stark reminder of how the use of chem­i­cals in war­fare not only caus­es imme­di­ate dam­age but can lead to long-last­ing envi­ron­men­tal and health impacts, affect­ing gen­er­a­tions to come.

The use of such weapons has sparked intense debates about ethics and the rules of war­fare. For exam­ple, while the devel­op­ment and deploy­ment of chem­i­cal and bio­log­i­cal weapons have been banned by treaties such as the Gene­va Pro­to­col and the CWC, their use is still a sub­ject of con­cern. Coun­tries like Egypt, South Sudan, and North Korea, which have not signed the CWC, remain under sus­pi­cion for pos­si­bly har­bor­ing chem­i­cal weapons pro­grams. Fur­ther­more, his­tor­i­cal exam­ples such as the Hit­tite use of plague vic­tims in 1,324 BCE demon­strate how war­fare and dis­ease have long been inter­twined. The strate­gic use of dis­ease as a weapon, whether through the inten­tion­al spread of plague or the use of bio­log­i­cal agents, illus­trates the lengths to which com­bat­ants will go to desta­bi­lize their ene­mies, fur­ther com­pli­cat­ing the moral and legal land­scape of mod­ern war­fare.

Despite the hor­rif­ic nature of chem­i­cal and bio­log­i­cal weapons, they have unde­ni­ably shaped the course of his­to­ry. From ancient meth­ods like the release of sul­fur diox­ide dur­ing the Roman siege to the mod­ern-day con­cerns over weapons of mass destruc­tion, these weapons con­tin­ue to be part of the glob­al con­ver­sa­tion on war­fare. The con­tin­ued efforts of inter­na­tion­al orga­ni­za­tions to ban these weapons reflect a col­lec­tive desire to pre­vent fur­ther suf­fer­ing caused by such dev­as­tat­ing tools of destruc­tion. How­ev­er, the real­i­ty is that the fight against the use of chem­i­cal and bio­log­i­cal agents is ongo­ing, with new chal­lenges con­stant­ly emerg­ing. It is essen­tial for gov­ern­ments and inter­na­tion­al bod­ies to remain vig­i­lant in their efforts to elim­i­nate the threat posed by these weapons, ensur­ing that their cat­a­stroph­ic poten­tial does not become a tool in future con­flicts.