Dioxin TCDD Finally Listed as ‘Known’ Human Carcinogen

March 1, 2001

BETHESDA, Md-An addendum to the National Toxicology Program’s Ninth Report on Carcinogens moves the dioxin TCDD (2,3,7,8-tetrachlorodibenzo-p-dioxin) from the "reasonably anticipated" to cause human cancers category to the "known to be a human carcinogen" designation. A legal challenge to the change prevented the new designation from being published in the full report last May.

BETHESDA, Md—An addendum to the National Toxicology Program’s Ninth Report on Carcinogens moves the dioxin TCDD (2,3,7,8-tetrachlorodibenzo-p-dioxin) from the "reasonably anticipated" to cause human cancers category to the "known to be a human carcinogen" designation. A legal challenge to the change prevented the new designation from being published in the full report last May.

TCDD is present as a contaminant in some herbicides and pesticides, and it is formed as an inadvertent byproduct in the incineration of waste.