The post-war era has seen limited, though devastating, use of chemical weapons. During the Vietnam War, between 1962 and 1971, the United States military sprayed nearly 20,000,000 U.S. gallons (76,000 m3) of various chemicals – the "rainbow herbicides" and defoliants – in Vietnam, eastern Laos, and parts of Cambodia as part of Operation Ranch Hand, reaching its peak from 1967 to 1969. Some 100,000 Iranian troops were casualties of Iraqi chemical weapons during the Iran–Iraq War. Iraq used mustard gas and nerve agents against its own civilians in the 1988 Halabja chemical attack. The Cuban intervention in Angola saw limited use of organophosphates. The Syrian government has used sarin, chlorine, and mustard gas in the Syrian civil war generally against civilians. Terrorist groups have also used chemical weapons, notably in the Tokyo subway sarin attack and the Matsumoto incident. See also chemical terrorism.