hexachlorobenzene
hexa·chlo·ro·ben·zene (hek″sə-klor″o-benґzēn) a compound used in organic synthesis and as a fungicide; it is toxic, causing cutaneous porphyria and liver disease, and may be carcinogenic. Since it does not break down easily, when used to preserve livestock feeds it may build up in the tissues of the animals.
Medical dictionary.
2011.