Some background on Agent Orange
During the Vietnam War, US military forces sprayed millions of gallons of herbicides (plant-killing chemicals) on lands in Vietnam and Laos to remove forest cover, destroy crops, and clear vegetation from the perimeters of US bases. This effort, known as Operation Ranch Hand, lasted from 1962 to 1971.
Different mixes of herbicides were used, but most were mixtures of 2 chemicals that were phenoxy herbicides:
2,4-dichlorophenoxyacetic acid (2,4-D)
2,4,5-trichlorophenoxyacetic acid (2,4,5-T)
Each mixture was shipped in a chemical drum marked with an identifying colored stripe. The most widely used mixture contained equal parts 2,4-D and 2,4,5-T. Because this herbicide came in drums with orange stripes, it was called Agent Orange. Today, Agent Orange is used to refer generally to all the phenoxy herbicides sprayed at the time. (Other types of herbicides were also used, including cacodylic acid and picloram.)
The 2,4,5-T in Agent Orange was contaminated with small amounts of dioxins, which were created unintentionally during the manufacturing process. Dioxins are a family of about 75 related chemicals. They can be formed during the making of paper and in some other industrial processes. The main dioxin in Agent Orange, 2,3,7,8-tetrachlorodibenzo-p-dioxin, or TCDD, is one of the most toxic.