Tampons, dioxins, and endometriosis.

Concern has been expressed that rayon tampons contain dioxins as a result of chlorine bleaching and, further, that the dioxins in tampons may increase the risk of endometriosis. Rayon tampons do not contain 2,3,7,8-tetrachlorodibenzo-p-dioxin, the chemical commonly meant when the generic term "dioxin" is used. In addition, rayon tampons contain only trivial amounts of dioxin-like environmental contaminants, similar to the amounts contained in unbleached cotton tampons. The amount of dioxin-like material that is theoretically available from tampons is at least six orders of magnitude lower than estimated daily food exposure levels to these contaminants. The evidence for a causal relationship between environmental exposure to dioxins and endometriosis is inconsistent. Prediction of the effective dioxin dose based on the most suggestive of the primate studies on endometriosis does not raise concerns about typical human food exposures to these compounds, let alone the considerably lower levels that could be present in tampons.