| Agent Name |
2,3,7,8-Tetrachlorodibenzo-p-dioxin |
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| Alternative Name |
TCDD |
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| CAS Number |
1746-01-6 |
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| Formula |
C12-H4-Cl4-O2 |
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| Major Category |
Other Chemicals |
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| Synonyms |
2,3,7,8-Czterochlorodwubenzo-p-dwuoksyny [Polish]; 2,3,7,8-TCDD; 2,3,7,8-Tetra polychlorinated dibenzo-p-dioxin; 2,3,7,8-Tetrachlorodibenzo(b,e)(1,4)dioxin; 2,3,7,8-Tetrachlorodibenzo-1,4-dioxin; 2,3,7,8-Tetrachlorodibenzo-p-dioxin; 2,3,7,8-Tetrachlorodibenzo-p-dioxin [Dioxin and dioxin-like; compounds]; 2,3,7,8-Tetrachlorodibenzodioxin; Dibenzo(b,e)(1,4)dioxin, 2,3,7,8-tetrachloro-; Dibenzo-p-dioxin, 2,3,7,8-tetrachloro-; Dioksyny [Polish]; Dioxin; Dioxin (herbicide contaminant); Dioxine; TCDBD; TCDD; Tetrachlorodibenzo-p-dioxin; Tetrachlorodibenzodioxin; Tetradioxin; [ChemIDplus] UN2811 |
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| Category |
Halogenated Cyclic Hydrocarbons |
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| Description |
Colorless to white, crystalline solid. [Note: Exposure may occur through contact at previously contaminated worksites.]; [NIOSH] |
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| Comments |
Dioxins accumulate in adipose tissue; they are animal carcinogens. Chloracne is the only overt clinical sign of dioxin exposure in humans. For the general population, the principal route of dioxin exposure is ingestion of food. Minor sources of dioxin exposure include diesel exhaust, chlorine-bleached paper products, and emissions from incinerators. [ATSDR Case Studies] Of the 22 isomers of tetra-chlorinated dioxin, 2,3,7,8-TCDD is the one that contaminated the production of 2,4,5-trichlorophenol, Silvex, and 2,4,5-T. In acute animal studies, TCDD is toxic to the liver. No elevation of liver enzymes were found in studies of chlorophenol production workers and Vietnam veterans reporting exposure to Agent Orange (a 50/50 mixture of 2,4-D and 2,4,5-T). [LaDou, p. 474-8] "There is no evidence that environmental exposure to the ubiquitous dioxin has led to identifiable acute or chronic hepatic injury in humans." [Zimmerman, p. 418] |
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| Restricted |
NIOSH recommends lowest feasible level of exposure. TCDD product contamination is limited to 0.01 to 0.05 ppm. For drinking water, MCL is 0.05 ppt. FDA limit for dioxins in fish is 25 ppt. [ATSDR Case Studies] |
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| Exposure Assessment |
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| Skin Designation (ACGIH) |
Not evaluated |
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| Bioaccumulates |
Yes |
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| MAK |
1 x 10 -08 mg/m3, inhalable fraction |
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| Vapor Pressure |
1.5 x 10 -09 mm Hg |
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| Half Life |
Whole body: 7.1 years (2.9 to 26.9 years); [TDR, p. 1111] |
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| Reference Link |
ATSDR - ToxFAQs - Chlorinated Dibenzo-p-Dioxins (CDDs) |
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| Adverse Effects |
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| Dermatotoxin |
Chloracne |
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| Hepatotoxin |
Hepatotoxin, Secondary |
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| IARC Carcinogen |
Known Carcinogen |
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| Links to Other NLM Databases |
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| Health Studies |
Human Health Effects from Hazardous Substances Data Bank: 2,3,7,8-TETRACHLORODIBENZO-P-DIOXIN
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