10. The History, Toxicity and Adverse Human Health and Environmental Effects Related to the Use of Agent Orange

Agent Orange consist of 50% n-butyl esters of 2,4,5-trichlorophenoxy acetic acid and 50% 2,4-dichlorophenoxyacetic acid. These compounds are chemical plant growth regulators, which mimic the effect of plant hormones, provoking plants into frantic growth before they wither and die. The toxicity of Agent Orange is attributed to the contamination with dioxin, which was perhaps the most toxic molecule ever synthesized by man. Agent Orange’s actual effect on human health remained controversial because even though dioxin at certain levels was clearly capable of causing serious diseases, those same diseases could also result from other causes. Dioxin is a persistent organic pollutant that will accumulate in animal fat and plant tissues and therefore can enter the food chain. The US National Toxicology Program has classified dioxin as “known to be a human carcinogen”, causing namely, chronic lymphocytic leukemia, soft tissue sarcoma, non-Hodgkin lymphoma and Hodgkin disease with sufficient evidence of an association. Severe acute intoxication of dioxin caused chloracne, porphyria, transient hepatotoxicity, and neurotoxicity. Chronic persistence of dioxin in the human body may contribute to development of atherosclerosis, hypertension, diabetes, vascular changes, and neuropsychological impairment several decades after massive exposure. However, such chronic effects are nonspecific and multifactorial. This paper elaborates the aforementioned and other health effects of Agent Orange.