All Pure-Rest mattresses feature no polyester backing (most companies have hidden fibers inside their mattresses). No additives in the wool or the organic cotton. The mattresses feature the only wool in the country that is processed organically and certified Organic by Oregon Tilth so you know it is pure. The rubber in the rubber mattresses is Latex Green, tested for Pure-Rest by a third party lab in Pasadena. Most other companies use rubber with toluene, which is toxic. Pure-Rest uses cotton tape edge and the only non-organic thing in the mattress lines is the untreated polyester thread. This thread tests with no VOCS. Each fiber in the mattresses is GOTS certified organic. No plastic outer, no finishes, and no additives are used.