Dioxin is a promoter blocker, a promoter, and a net anticarcinogen.

An ad hoc panel of dioxin experts convened by EPA's Science Advisory Board found the Agency's claim of cancer causation by dioxin unacceptable. This paper uses the very same two studies [Fingerhut (NIOSH) and Kociba] EPA relied upon to test the observations made in an unused third study [Bertazzi] to conclude that dioxin is (1) a promoter blocker of certain cancers, including all the cancers Agency scientists claimed dioxin promoted; (2) a promoter of some other cancers that EPA scientists failed to identify; and (3) a net anticarcinogen. Three independent total tumor reductions provide evidence of both cancer prevention and quantifiable risk reductions tied to specific dioxin levels. The author indirectly suggests a general cancer prevention treatment, even for cancers already initiated.