Polychlorinated dibenzodioxins
Dioxin is the term used to describe a family of toxic chlorinated organic compounds that can travel long distances and bioaccumulate in humans and wildlife due to their fat solubility. The most notorious of those is 2,3,7,8-tetrachlorodibenzo-p-dioxin, often abbreviated as TCDD.
Dioxins cause a severe form of persistent acne (known as chloracne) in humans and developmental abnormalities and cancers in animals. The U.S. government has recently listed dioxin as a known human carcinogen, but debate on human effects continues.
Dioxin was one of the contaminants that forced the evacuation of the Love Canal neighborhood of Niagra Falls, New York. Large amounts were also released in an industrial accident at Seveso in 1976.
Dioxins are produced when organic material is burned in the presence of chlorine, whether the chlorine is present as chloride ions, or as organochlorine compounds, so they widely produced in many contexts such as:
- incinerators for municipal waste;
- iron ore sinter plants;
- incinerators for clinical waste;
- facilities of the non-ferrous metal industry;
- A contaminant produced in the manufacture of chlorinated herbicides such as 2,4-dichlorophenoxyacetic acid and 2,4,5-trichlorophenoxyacetic acid. (see Agent Orange)