Hi nsan2001,
Welcome to the Mattress Forum! 
[quote]The problem though is the silica-rayon FR cover. I read the safety discussion about crystalline and amorphous silica
(here and here) but
I want to be fairly certain that I am not trading one toxicity (of foam with FR chemicals) for another.[/quote]
Since youâve already read a bit about this on the site, you are already aware that there are different types of Silica besides âsilica glassâ (crystalline) and they donât pose a respiratory hazard at all in the form they are used in an inherent viscose/silica fire barrier. As the link shows, Crystalline Silica is the form that can cause Silicosis and is both toxic and fibrogenic. Amorphous silica is toxic but not fibrogenic, and silica gel or silicic acid (the form in inherent fire barrier fabrics) is neither toxic or fibrogenic. You can read more about this in post #2 here (which you already linked to) but I would consider a viscose/silica fire barrier to be a very safe material. However, if you donât feel that the material is âsafe enoughâ for your personal PPP, you certainly can choose to look for a product that uses wool (which wouldnât necessitate the use of a viscose/silica fiber barrier) with the componentry you prefer.
Youâll usually be looking at either a natural flame retardant barrier, like wool, or a non-toxic rayon fiber blended with silica to meet federal flammability standards for the items youâre considering. In case youâd want to pursue this option, there is more about purchasing a prescription mattresses that donât have a fire barrier and donât pass the fire regulations in post #4 here and the posts it links to.
[quote]1) spindle mattress: shop.spindlemattress.com/products/latex-âŚ-8?variant=261680854 - $1699
3x3" dunlop latex + 1" Eco wool (not organic latex or wool)[/quote]
This uses wool to pass FR regulations. If your concern is about organic versus eco versus natural wool, that is another discussion, but that wouldnât have an effect with regards to passing FR regulations.
[quote]2) The Leaf - Latex Mattress | Talalay & Dunlop by Sleeping Organic $1995 (with Black Friday deal)
3" talalay + 2x3" dunlop + 1" cotton+ wool cover (all organic)[/quote]
This also uses wool to pass the FR barrier, and this also uses Eco-Wool.
[quote]3) Ultimate dreams from Dreamfoam - Dream Foam - Dream Foam - $750
3" Talalay Latex + 6" foam (1.8lb) + Bamboo Knit cover (no additional details on the use of silica)[/quote]
This does not use wool for the FR barrier, but a version of the non-toxic viscose/silica barrier youâre looking to avoid.
[quote]4) SleepEZ - www.sleepez.com/organic-latex-mattress.html?model=10000 - $2195
3 x 3" organic latex, 1" wool+cotton cover (all organic)[/quote]
This product uses wool to pass the FR barrier, and it is organic certified wool.
I would also keep in mind that some of the non organic wool that you will find in several of the mattresses you listed is also a very high quality material so you may not wish to exclude the ones that use organic cotton quilted with natural wool that isnât certified organic (see post #2 here and post #2 here about organic certifications).
If you havenât already, you could also look online and use the expertise of the members listed in post #21 here who are all very experienced and knowledgeable and specialize in providing the type of help and guidance that youâre looking for and perhaps they could produce a product like youâre desiring.
[quote]I wish there was a mattress with these specs with a price of around $1000-1000:
2" talalay + 2" dunlop and 6" polyfoam (2lb) + org. wool + org. cotton cover[/quote]
Unfortunately, I donât keep a record of the individual mattresses or their specs that the retailers and manufacturers in the hundreds of forum lists throughout the forum carry on their floor or have available online - it would be a bigger job than anyone could keep up with in a constantly changing market. Additionally, it might be difficult to find a mattress using your exact componentry, as people usually interested in using an organic certified cotton and wool cover are also usually interested in using more natural materials on the inside and would commonly eschew the use of a polyfoam core.
If youâre attracted to the idea of DIY mattress, take a look at the different vendors in the component post here and you could certainly acquire a cover, polyfoam base and the latex layers you desire.
If you have a concern about being in contact with the viscose/rayon FR barrier, you wouldnât be in contact with it in any of the mattresses you described, so adding a mattress protector wouldnât make a difference. If youâre concerned about inhaling the silica, which is made inherent through the fiber formation process and becomes part of the fiber in these instances (as opposed to a power that is added to the fiber that could become airborne), but even for the sake of your concern saying that there is something that is âoff-gassedâ or âbreaks awayâ from the FR barrier, a mattress protector wouldnât make a difference, as they still allow the mattress to âbreatheâ, so any concerns you had of something escaping from the FR barrier (which if there was something âescapingâ would more than likely be smaller than the common micron pore size of the polyurethane film commonly used in mattress protectors) would still not be stopped by a mattress protector.
Perhaps some of the more knowledgeable people on the site are familiar with a company that is producing a mattress with the particular specifications youâre desiring and they can provide that information here on this thread as well.
Phoenix