Dioxins are chemical compounds often arising as a by-product of other chemical processes. They are frequently found in industrial waste. Only 17 of the 210 compounds which could be defined as dioxins are regarded as toxic or carcinogenic.
While consuming food containing one of these dioxins on a once-off basis is not regarded as dangerous, long exposure to such foods might cause cancer.
The World Health Organisation has set a very low limit for human exposure to dioxins, particularly because they readily accumulate in the body. It recommends an intake of no more than one-millionth of a millionth of a gram per day.
Dr Stanley McElhinney of the Chemistry Department, Trinity College Dublin, points out that cooking or excessive heat does not destroy a dioxin. The dioxin got into a production line making grain-based animal feedstuffs. These were fed to chickens, pigs and cattle and the dioxin worked its way through into the milk, eggs and meat derived from these animals.