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Key Points



  • The term dioxins refers to a group of 210 compounds with similar chemical structures but greatly varying toxicity
  • The most toxic dioxin is 2,3,7,8-tetrachlorodibenzo-p -dioxin (TCDD) and most of the available data refer to this compound



  • Non flammable
  • Decomposes when exposed to UV light
  • Emits toxic fumes of hydrogen chloride and chlorine when heated to decomposition or on exposure to UV light



  • Dioxins are toxic by inhalation or ingestion
  • Ingestion of dioxins in humans can lead to adverse effects on the skin, including a severe and persistent acne (chloracne), skin rashes or discolouration, and excessive body hair
  • Changes in the blood and urine, liver damage or changes in hormone levels may also occur
  • Exposure to very high levels of dioxins may cause vomiting, diarrhoea, lung infections and damage to the nervous and immune systems
  • TCDD is classified as causing cancer in humans
  • TCDD produces a range of toxic effects on reproduction relating to both fertility and developmental toxicity in animals



  • Avoid releases to the environment 
  • Inform Environment Agency of substantial release incidents


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Compendium of Chemical Hazards