Agent Orange was the nickname given to a powerful herbicide and defoliant used by the U.S. military in its Herbicidal Warfare program during the Vietnam War. Agent Orange was used from 1961 to 1971, and was by far the most used of the so-called "rainbow herbicides" used during the program. Degradation of Agent Orange (as well as Agents Purple, Pink, and Green) released dioxins, which have caused harm to the health of those exposed during the Vietnam War.

Agents Blue and White were part of the same program but did not contain dioxins. Studies of populations highly exposed to dioxin indicate increased risk of various types of cancer and genetic defects; the effect of long term low level exposure has not been established. Since the 1980s, several lawsuits have been filed against the companies who produced Agent Orange, among them being Dow Chemical and Monsanto. U.S. veterans obtained $180 million in compensation in 1984, while Australian, Canadian and New Zealand veterans also obtained compensation in an out-of-court settlement the same year.

In 1999, 20,000 South Koreans filed a lawsuit in Korea; in January 2006, the Korean Appeal Court ordered Monsanto and Dow to pay $62 million in compensation to about 6,800 people. However, no Vietnamese have obtained compensation, and on March 10, 2005 Judge Jack Weinstein of Brooklyn Federal Court dismissed the lawsuit filed by the Vietnamese victims of Agent Orange against the chemical companies that produced the defoliants/herbicides.

http://en.wikipedia.org/wiki/Agent_orange