Where standard mattresses use flame-retardant chemicals polybrominated diphenyl ether (PBDE) or fibers like Kevlar, organic mattresses use unique flame-resistance techniques to comply with federal law. Most of the time they use organic wool as a natural fire retardant material, some use rayon and cloth made of hydrated silica and baking soda. By using these natural components they comply with the law and also provide toxin free sleeping surface.
Some manufacturers use removable cover that contains fire-retardant chemicals but can be removed by consumers who are worried about long-term effects of these chemicals. This way, manufacturers comply with the federal regulation and the decision of removing the cover is up to the consumer.
Some manufacturers can legally avoid the fire safety law by making mattresses without the required fire retardants for consumers who have medical condition and have to avoid fire-retardant chemicals to prevent allergic reactions. Obviously, these products are not intended for general public and are prescribed by a physician.