Chemical and biological warfare

Chemical and biological warfare, military use of chemical poisons or disease-causing agents against enemy troops, civilians, animals, and plants. In World War I chlorine, mustard gas (causing skin blistering), and phosgene (causing fatal lung irritation), killed 100,000. Newer, deadly nerve gases are weapons of mass destruction. In the war in Vietnam U.S. forces used riot-control gases and chemical defoliants with carcinogenic effects. The Iraqi regime of Saddam Hussein used poison gas against the Kurdish population in Iraq and against Iranian troops during the Iran-Iraq War (1980–88).