Throughout history there has been continued use of chemicals in warfare. Ancient armies burned painted wood to create smoke screens or to force enemies from hiding places. Two thousand years before Christ, Indian soldiers used smoke screens, incendiary weapons, and toxic fumes in battle. The Spartans used sulfur dioxide against their rivals, the Athenians, during the Peloponnesian War in 429 b.c. by burning pitch and sulfur on wood to create poisonous sulfur smoke near an enemy city. The Byzantine's were able to destroy enemy ships by using Greek fire, a chemical mixture that burst into flames when it came into contact with water. During the Middle Ages, a group of Christians saved Belgrade from advancing Turks by dipping rags in poison, lighting them, and fanning the fumes at the enemy. Chemical warfare was put to greater use during World War I. When England set up a...