While every mattress sold in the U.S. must pass fire retardant laws, there is no regulation dictating what is to be used or regulating what materials are used, whether chemical or natural. Basically, if it passes, that is all that matters.
This leaves it up to companies to make their mattresses fire retardant by whatever means they see fit. There are a variety of materials that will pass the fire retardant requirements, including natural wool. Some companies will use synthetic materials, such as Kevlar, while others will use caustic materials and chemicals.
While you are shopping around the local area, ask detailed questions about what is used and ask for documentation, as you do not want to be sold something under false pretense. Take responsibility for your health. There are local mattress makers out there, here in the Bay Area in particular, who put the sales of their mattress over your long term health by not being forthcoming about what is actually in their foam and fire barrier materials.
In fact, here are some of the chemicals found in local fire barrier materials.
Guanidine Phosphates, which is used in rocket fuel!
Guanidine, also called carbamidine, is a strongly alkaline and water-soluble compound, NHC(NH2)2 It is formed by the oxidation of guanine in urine as a normal product of protein metabolism in the body. In industry, guanidine, containing nitrogens and N=C solid bond, and its modified derivatives are versatile intermediates used in the manufacture of plastics, resins, rubber chemicals, nitroguanidines (explosives), photo chemicals, fungicides, and disinfectant. It has also biotechnological application of protein separation, purification and as a protein denaturant. It can be used as an oxygen scavenger to prevent corrosion damage. It is used as a component of rocket propellants because it produce a large amount of heat when burned.
Guanidine Phosphate is used as a fire retardant and anticorrosive agent for wood, fiber and pulp.
Triethanolamine or TEA
Can cause tumors! Reports indicated that TEA causes an increased incidence of tumor growth in the liver in female B6C3F1 mice, but not in male mice or in Fischer 344 rats. A 2004 study concluded "TEA may cause liver tumors in mice via a choline-depletion mode of action and that this effect is likely caused by the inhibition of choline uptake by cells."
Another difficult to say and element you don't want to be sleeping on, has been used in rocket fuel as well.
These are just some of the many things used to make your mattress pass the fire retardant laws. Please be careful when purchasing a new mattress and do your homework. Your new memory foam mattress or even latex mattress can have much more inside than the brochure says.