Large volumes of Agent Orange and other defoliants were handled at former United States (U.S.) military bases during the U.S.-Viet Nam War. Agent Orange was contaminated by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), a toxic chemical that has been associated with a range of health concerns. The airports at Da Nang, Bien Hoa, and Phu Cat have been identified as the most contaminated of the installations studied, and are the Government of Vietnam (GVN) priority areas for remediation of soils and sediments to eliminate the risk of human exposure to TCDD. The GVN has requested assistance from the U.S. to remediate dioxin-contaminated soil and sediment at the Da Nang Airport (Airport), where studies conducted to date show that TCDD concentrations within certain areas substantially exceed international and Vietnamese standards for dioxin. These studies have also shown that TCDD comprises greater than 90% of the toxicity equivalent (TEQ), implying that Agent Orange was the source of contamination.