Products which are unbleached can be very clearly identified. We know the colour of tree barks right? If any paper product is anything but brown it has been bleached with some form chlorine. This bleaching process creates dioxins (in the chemical family of the very lethal Agent Orange) as a by-product, so therefore using unbleached paper products could increase our risk for cancer, autoimmune disorders and could affect the development of fetuses. Dioxins also persist (i.e. last a very long time) in the environment and accumulate in the fatty tissue of animals. Unbleached/Chlorine-free options should definitely be considered for any products which are used intimately (toilet paper/tampons).

Reference - http://www.dougieg.com/no_denial/dioxins.html