During the Iran-Iraq War (1980-1988), Iraq used chemical weapons against Iran. Usage of such weapons was clearly illegal under existing international law. At the end of the war Iraq also turned these weapons against the Iraqi Kurds because they had supported Iran in the war. General Ali Hassan Majid (a first cousin of Saddam Hussein and governor in the north of Iraq) became known by the Kurds as Ali Chemical for his ruthless usage of chemical weapons against them during the Anfal campaigns and the notorious attack against Halabja that killed some 5,000 Kurds on 15 March 1988.
Chemical weapons used by the Iraqi government included mustard, nerve, and cyanide gas, among others. There was very little international response to this clear violation of international law. This usage of chemical weapons illustrated Kurdish vulnerability and even genocide as defined by international law. However, accusations that Saddam Hussein still possessed chemical weapons in 2003 proved unfounded.
Historical Dictionary of the Kurds. Michael M. Gunter.