Chemical warfare is the use of chemicals to kill, injure, or incapcitate and enemy in a warfare situation. Chemical warfare is much different from conventional weapons because the effects are not due to any explosive force. The use of living organisms is considered biological warfare as opposed to chemical warfare. Over 70 different chemicals have been used as chemical agents during the 20th century. Chemical weapons are now classified as weapons of mass destruction and were outlawed by the United Nations in 1993.
Modern chemical warfare agents first surfaced in World War I. The French used tear gas and the German's used bromide. Over 85,000 died directly from the agents and 1,176,500 were non-fatal casualties during the course of the wars. Both sides used Chlorine, Phosgene, and Mustard gas among other agents. To this day chemical ammunition is still uncovered when the ground is dug in former battle areas, this poses many threats to civilians in Belgium and France.
In World War II the Imperial Japanese Army used mustard gas and the recently developed Chinese troops and guerillas. Experiments involving chemical weapons were conducted on live prisoners. But the major advances in chemical warfare were in Nazi Germany's discovery of the nerve agents tabun and Sarin by Gerhard Schrader. The Nazis developed and manufactured large stockpiles of these and others agents, but chemical warfare was not used extensively by either side in the European theatre. Over 60,000 US military personnel were used as subjects during the war to test mustard gas and lewisite.
The next conflict to use large amounts of chemical agents was the Iran-Iraq war in 1980. Early in the conflict, the Iraqi army began to use mustard gas and tabun inside of bombs. 5% of Iranian casualties during the war are directly linked to the use of these chemical agents. About 100,000 Iranian soldiers were victims of Iraq's chemical attacks. Many were hit by mustard gas. The official estimate does not include the civilian population contaminated in bordering towns or the children and relatives of veterans, many of whom have developed blood, lung and skin complications, according to the Organization for Veterans. Nerve gas agents killed about 20,000 Iranian soldiers immediately, according to official reports. Of the 80,000 survivors, some 5,000 seek medical treatment regularly and about 1,000 are still hospitalized with severe, chronic conditions. Iraq also targeted Iranian civilians with chemical weapons. Many thousands were killed in attacks on populations in villages and towns, as well as front-line hospitals. Many still suffer from the severe effects.