Agent Orange is an herbicide and defoliant used by military forces. Many Seabees were exposed to the defoliant herbicide while in Vietnam. Agent Orange is a herbicide and defoliant chemical, one of the "tactical use" Rainbow Herbicides. He suffered from complications arising from exposure to the Agent Orange defoliant used in Vietnam. President Kennedy approved a "selective and carefully controlled joint program of defoliant operations" in Vietnam. The 315th ACG was responsible for Operation Ranch Hand Defoliant operations missions. Up to four million people in Vietnam were exposed to the defoliant. Harris attributes the rapid expansion of the US defoliant programs to these early successes.