Definition of "dioxin"

Dioxin is a specific organic unsaturated non-antiaromatic six-membered ring compound with a chemical formula of C4H4O2. However, the term dioxin is used generically by most authorities to include chlorinated dioxins with furans and many derivative compounds as a complex of at least 75 ubiquitous and environmentally persistent organochlorine compounds, of variable toxicity.

2011, Peter Stride, “Limited Bio-diversity and Other Defects of the Immune System in the Inhabitants of the Islands of St Kilda, Scotland”, in Oscar Grillo, Gianfranco Venora, editors, Biodiversity Loss in a Changing Planet, Rijeka, Croatia: InTech, section 11 (Dioxin), page 236

Dioxins are not a single chemical. They are a family of chemicals that contain two benzene rings connected by a pair of oxygen molecules. When chlorine atoms are connected to the benzene rings, we have a chlorinated dioxin. The particular chlorinated dioxin of greatest interest and concern is 2,3,7,8-tetrachlorodibenzo-p-dioxin (generally abbreviated TCDD).

1992, Ronald E. Gots, “Dioxins and Agent Orange”, in Toxic Risks: Science, Regulation, and Perception, Boca Raton, Fla., London: Lewis Publishers, CRC Press, page 173

The detection of dioxin (specifically, the 2,3,7,8-tetrachlorodibenzo-pdioxin TCDD) in 2,4,5-T raised the question whether dioxin might be present in other herbicides.

1974 May, Hazardous Materials Advisory Committee, “Chemistry and Analysis”, in Herbicide Report: Chemistry and Analysis, Environmental Effects, Agricultural and Other Applied Uses (EPA-SAB; 74-001), Washington, D.C.: Science Advisory Board, U.S. Environmental Protection Agency, page 17

Poisonous residues carelessly treated today can produce calamities miles away and decades later. One example is dioxin, a waste left behind in factories after the production of hexachlorophene, a potent antiseptic. Dioxins are lethal, capable of killing people in concentrations as diluted as one part in a million. Oils containing discarded dioxins have been sprayed on horse farms in Missouri to control dust. Horses subsequently died.

1986, Benjamin Walter, Malcolm Getz, “Social and Economic Effects of Toxic Waste Disposal”, in Sheldon Kamieniecki, Robert O’Brien, Michael Clarke, editors, Controversies in Environmental Policy (SUNY Series in Environmental Public Policy), State University of New York Press, page 223

Dioxins are polychlorinated isomers that form as by-products either during combustion of waste products or afterward in the incinerator stack. They include dibenzo-dioxins (PCDD), dibenzofurans (PCDF), and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). 2,3,7,8-TCDD is one of the extremely carcinogenic groups of dioxin compounds. A risk of exposure to humans occurs once dioxin compounds are released from the stack of the incinerator and are transported by the wind elsewhere.

1992, Merrie G. Klapp, “Bargaining with Uncertainty”, in Bargaining with Uncertainty: Decision-making in Public Health, Technological Safety, and Environmental Quality, Westport, Conn.: Auburn House, Greenwood Publishing Group, page 12

[page 6] Dioxins in food and the environment hae been intensively studied over the past twenty years [...]. The term ‘dioxins’ has come to be used for polychlorinated dibenzo-p-dioxins and in some cases also polychlorinated dibenzofurans. [...] [page 7] The sources of food contamination with dioxins are now known to be many more than was originally asserted when claims were made that incinerators were the main source of dioxins in the environment. Indeed known sources of dioxins now include vehicle exhausts, domestic coal fires, manufacture and use of organic chemicals, and metallurgical processors.

2001, D[avid] Waston, “Introduction”, in David H. Watson, editor, Food Chemical Safety (Woodhead Publishing in Food Science and Technology), volume 1 (Contaminants), Abington, Cambridgeshire: Woodhead Publishing; Boca Raton, Fla.: CRC Press, published 2005, section 1.4 (Persistent Environmental Chemicals), pages 6 and 7

EPA [the Environmental Protection Agency] characterizes 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) as a Human Carcinogen based on weight of evidence and characterizes other dioxins, furans, and PCBs [polychlorinated biphenyls] as Likely Human Carcinogens. The toxicity of all of the dioxin, furan, and PCB congeners considered in this analysis is based on the toxicity of the most highly characterized congener, 2,3,7,8-TCDD [...].

2002 May, Center for Environmental Analysis, RTI, “Hazard Identification/Dose-response Assessment”, in Exposure Analysis for Dioxins, Dibenzofurans, and CoPlanar Polychlorinated Biphenyls in Sewage Sludge: Technical Background Document: Draft, Washington, D.C.: Office of Water, U.S. Environmental Protection Agency, page 2-1