I have also heard that tampons contain asbestos. Fortunately, there seems to be no cause for concern. In fact, Procter and Gamble, the manufacturer of Tampax brand tampons, has assured me that there never has been and never will be asbestos in any of their tampons.
Most tampons contain cotton and rayon.
Pure cotton tampons are also available. The cotton and rayon fibers are bleached to purify the material. A decade ago, dioxin was recognized as an unwanted byproduct of a particular type of bleaching process, with unclear health implications. Dioxin resulted from chlorine gas bleaching. All suppliers of cotton and rayon fibers used in tampons must now use appropriate bleaching techniques to supply dioxin-free materials.