Here’s a bit of information about the fire resistant material commonly used today in the mattress industry:
Viscose rayon fiber is often blended with polyester, and perhaps other fire resistant fibers to create an “inherent” fire resistant barrier. “Inherent” means that there are no chemical additives or finishes used to achieve the fire resistant feature of this barrier, and these barriers are usually referred to as non-toxic (your own personal definition of course may differ). This type of a barrier is commonly used in the form of a “sock” that fits over the mattress materials, or a mattress pad-like fitting that is placed over the foams, or more commonly as a thin fiber batting layer that is quilted to the reverse side of the mattress ticking material.
To achieve this fire resistance, the viscose rayon fiber is commonly combined with silica during the fiber extrusion process. When exposed to an open flame, the polyester and the cellulosic portion of the viscose rayon will burn away, but the silica will remain to form a char barrier that will interrupt the flame enough to prevent the mattress components from catching fire during the timeframe mandated by CPSC 16 CFR Part 1633.
As viscose rayon is a bio-based textile with a raw material of cellulose (derived from trees, eucalyptus, cotton, thistle, etc.), some refer to it as natural. However, this fiber is certainly man-made through the use of various chemical and mechanical processes and is not found naturally in nature. And as the viscose rayon used in most mattress FR barriers is blended with polyester and other materials (for fire resistance, loft, ease of handling or elasticity), and referring to them as “natural” or “more natural” could certainly be considered a stretch of the truth. At the very least you’d want to lay out the framework of the comparison.
There are many other ways to create a fire resistant batting layer. Here’s another one.
When people ask about a non-chemical fire resistant barrier, they’re usually looking for something completely natural, like wool. I’d advise that you check first with the manufacturer to find out exactly what they are using for their FR barrier, and then do your own objective learning about those particular products. When researching, I would be especially skeptical of the recent proliferation of sites dedicated to specific brands where promo coupons are offered for purchases of those particular mattresses. These sites tend to simply parrot the claims of the manufacturers they promote, and it’s one of the ways many of the newer online brands are currently marketing their products. Rely more upon information from unrelated sites and organizations, like The Mattress Underground.
There’s also quite a bit of greenwashing in the mattress industry, with claims that every mattress made (perhaps except the particular mattress that a website may be promoting) is drenched in chemicals that will cause your ultimate demise. That’s why I again recommend that you be provided with the type of FR barrier used in a product that you are considering and make up your own mind what you personally feel is or isn’t safe. I can say that most brands use variations of the FR fiber I described previously, or use wool for a more natural style of FR barrier. Some brands will produce a product without any FR barrier with a note from your healthcare provider (like a latex line I offer).