Agent Pink is the code name for a powerful herbicide and defoliant used by the U.S. military in its herbicidal warfare program during the Vietnam War Vietnam War. The name comes from the pink stripe painted on the barrels to identify the contents. Agent Pink was only used during the early “testing” stages of the spraying program before 1964.
Agent Pink’s only active ingredient was 2,4,5-trichlorophenoxyacetic acid (2,4,5-T), one of the common phenoxy herbicides of the era. Agent Pink contained about 60%–40% of this active substance. Even prior to Operation Ranch Hand (1962–1971) it was known (TCDD), is produced as a byproduct of the manufacture of 2,4,5-T, and was present in any of the herbicides that used it, but to greater proportion in the earlier Agents, such as Pink.
Source: Wikipedia – https://en.wikipedia.org/wiki/Agent_Pink