Dioxin is a highly toxic and persistent chemical that can cause cancer.
What are dioxins?
Dioxin is the common name for the chemical 2,3,7,8-tetrachlorodibenzo-p-dioxin, or TCDD. The term “dioxins” refers to a group of dioxin-like chemical compounds that share similar chemical structures. They all contain carbon, hydrogen, oxygen, and chlorine. In pure form, dioxins are crystals or colorless solids. Dioxins include some polychlorinated biphenyls (PCBs). Dioxins and PCBs are all persistent organic pollutants and endocrine disruptors.
TCDD is the most toxic and potent of the dioxins. The chemical formula for TCDD is C12H4Cl4O2. TCDD may be white to colorless and is odorless.
Dioxins are highly toxic and persistent in the environment and accumulate exponentially as they move up the food chain. They may be transported long distances.
Most dioxins are produced through burning and other industrial activities. Major sources of dioxin emissions are incineration of waste, chlorine bleaching of pulp and paper, copper smelting, chemical manufacturing, cement kiln burning, coal-fired electricity generation, wood burning, forest fires, and backyard burning of household trash. Other sources of dioxin emissions include cigarette smoking, drum and barrel reclamation facilities, motor vehicles, residential oil furnaces, scrap electric wire recovery, and tire burning.
TCDD was an ingredient of the herbicide Agent Orange, which was used as a defoliant by the U.S. military during the Vietnam War. Pentachlorophenol (PCP), which is used to preserve wood, contains dioxins.
Because dioxins are so widespread, everyone has some level of dioxins in their bodies. You can be exposed to small amounts of dioxins through the food you eat, especially animal products and fats, and fish. You can be exposed through the air you breathe and the water you drink. Handling pesticides and herbicides, burning wood or trash, smoking cigarettes, and breathing automobile exhaust may also expose you to dioxins.
Nursing infants can be exposed to dioxins through breast milk, cow’s milk, and infant formula. Fetuses can be exposed through the pregnant woman’s placenta.
You can be exposed to dioxins if you live near a hazardous waste site that contains dioxins or an incinerator that releases dioxins. Dioxins are released during manufacturing, burning, or landfilling of polyvinyl chlorides (PVCs). You can be exposed if you are near the burning of old electrical equipment that contains PCBs or near forest fires. You can be exposed to higher levels of dioxins through roads or soils that have been treated with TCDD, such as in Times Beach, Missouri.
At work, you can be exposed to dioxins if you work at a facility that manufactures pesticides, herbicides, or chemicals; a waste incinerator; cement kiln; coal-fired power plant; drum and barrel reclamation facility; petroleum refining plant; or copper smelter. You can be exposed if you work with PCP-treated wood products, bleach materials at a pulp or paper mill, apply or incinerate sewage sludge, or recover scrap electric wires. Dioxin exposure can also occur if you work in hazardous waste clean-up, emergency clean-up of PCB transformers, or firefighting.
If you worked or served in the military in Vietnam during the Vietnam War, you may have been exposed to dioxin through the application of the herbicide Agent Orange.
TCDD dioxin is listed as a human carcinogen in the Fourteenth Report on Carcinogens published by the National Toxicology Program because it causes cancer, particularly lung cancer and non-Hodgkin lymphoma.
Exposure to high levels of dioxins can cause reproductive and development problems, suppression of the immune system, increased heart disease and diabetes, changes in hormonal levels, liver damage, and abnormalities of the pancreas, circulatory, and respiratory systems.
Exposure to low levels of TCDD can cause dermatitis, gastrointestinal problems, and excessive body hair.
Exposure to low levels of all dioxins can cause a burning sensation in the eyes, nose, and throat; headache; dizziness; fatigue; blurred vision; urinary tract disorders; muscle and joint pain; impaired muscle coordination; nausea; and vomiting.
If you think your health has been affected by exposure to dioxins, contact your health care professional.
For poisoning emergencies or questions about possible poisons, please contact your local poison control center at 1-800-222-1222.
This description is based on the information found in the Web links listed with this topic.
2,3,7,8-Tetrachlorodibenzo-p-Dioxin (TCDD). Hazardous Substances Data Bank (National Library of Medicine)
Chlorinated Dibenzo-p-dioxins (CDDs). ToxFAQs (Agency for Toxic Substances and Disease Registry)
Dioxins (National Institute of Environmental Health Sciences)
Dioxins and Their Effects on Human Health (World Health Organization)
Tetrachlorodibenzo-p-Dioxin. Haz-Map (National Library of Medicine)
What is Dioxin? (Navy and Marine Corps Public Health Center) (PDF — 167 KB)
Last Updated: April 19, 2017