List of gases used in World War I

benzyl bromide
German, tearing, first used 1915

bromacetone
Both sides, tearing/fatal in concentration, first used 1916

carbonyl chloride (phosgene)
both sides, asphyxiant, fatal with delayed action, first used 1915

chlorine
both sides, asphyxiant, fatal in concentration, first used in 1915, cylinder release only

chloromethyl chloroformate
both sides, tearing, first used in 1915, artillery shell

chloropircin
both sides, tearing, first used in 1916, artillery shell (green cross I)

cyanogen (cyanide) compounds
allies/Austria, asphyxiant, fatal in concentration, first used in 1916, artillery shell

dichlormethylether
German, tearing, first used 1918, artillery shell

dibrommethylethylketone
German, tearing, fatal in concentration, first used in 1916

dichloroethylsulphide (mustard gas)
both sides, blistering, artillery shell (yellow cross)

diphenylchloroarsine
German, asphyxiant, fatal in concentration, (dust - could not be filtered), first used in 1917, artillery shell (blue cross)

diphenylcyonoarsine
German, more powerful replacement for blue cross, first used in 1918

ethyldichloroarsine
German, less powerful replacement for blue cross, first used in 1918, artillery shell (yellow cross I, green cross III)

ethyl iodoacetate
British, tearing, first used in 1916

monobrommethylethylketone
German, more powerful replacement for bromacetone, first used 1916

trichloromethylchloroformate (diphosgene)
both sides, asphyxiant, fatal with delayed action, first used 1916

xylyl bromide
German, tearing, first used 1915