Tetrachlorodibenzodioxin

Tetrachlorodibenzo-p-dioxin, commonly abbreviated as TCDD, is a highly toxic synthetic organic compound. It belongs to the class of chlorinated dibenzodioxins, which are a group of 75 related compounds. TCDD is not intentionally produced for any commercial use but is rather an unwanted byproduct formed during the synthesis of certain chemicals, such as chlorinated phenols, and during uncontrolled combustion processes. It can also be formed as a contaminant in the production of some pesticides and herbicides.

TCDD is known for its extreme persistence in the environment, meaning it does not readily break down. This persistence, combined with its lipophilicity (tendency to dissolve in fats), leads to its bioaccumulation in the fatty tissues of organisms and biomagnification up the food chain. Humans and animals can be exposed to TCDD through consumption of contaminated food, particularly fatty meats, dairy products, and fish, or through direct contact with contaminated soil or dust.

The health effects of TCDD exposure in humans can be severe and varied. It is classified as a human carcinogen. Exposure has also been linked to a range of other health problems, including reproductive and developmental issues, immune system damage, endocrine disruption, and skin conditions like chloracne. The severity of effects depends on the dose, duration, and route of exposure. Due to its toxicity and persistence, TCDD is considered a persistent organic pollutant (POP) and its presence is strictly monitored and regulated globally.