skip12001,
From a post on this subject I found in the forum from Phoenix (easier to copy than type over):
In post #2 here I describe in more detail the use plant based polyols in polyfoam. In a nutshell, part of the polyol portion used to create polyurethane foam is replaced with a plant-based polyol. There’s a brief explanation of this from one of the polyol manufacturers here.
Polyurethane foam (which is where these plant-based polyols are used) in its simplest form is a mixture of polyol, isocyanate and water. There are still quite a few different chemicals involved to make it. As for “healthiest” (being able to pass testing such as Oeko-Tex for harmful substances and VOCs), the use of plant based polyols wouldn’t necessarily indicate that. There are some polyurethane foams that have passed Oeko-Tex standards, but I don’t have a listing of those, but I think quite often they involve using MDI instead of TDI as the isocyanate in the production of that polyfoam. Being able to test such “safety standards” like Oeko-Tex or eco institute and so on would be the best way to conclude if a product meets certain standards for harmful substances and VOCs.
Density is the mass per unit volume, which is commonly converted an expressed as weight when speaking of foams.
Jeff Scheuer, The Beducator
Beducation / Mattress To Go
jeff,
im gonna avoid poly and just go for all latex, dont wanna chance it with poly.
question about the natures embrace aria mattress, how does it pass the flame test since it has no wool or rayon cover. its 50% Organic Cotton / 50% Polyester cover. do they add flame retardant to the latex?
been really busy thats why i havent had a chance to test out any mattresses yet. also, want to research before i go and test them out. the aria is dual zone with each layer 40 ILD. not sure why they wouldnt go with a single 6" 40 ILD. it wouldve been nice if the base layer was 40 ILD and the comfort layer perhaps 30 ILD.
From their web site in their FAQ section:
[i]What fire retardants do you use?
We use several barrier options depending on the mattress and destination. For all Canadian mattresses, our combination of organic cotton and wool is sufficient to pass all flammability standards set out by Health Canada. For our American customers, we use a silica rayon barrier.[/i]
The best reference for such questions is always the manufacturer. I’m sure they could provide you with more exact details. Their phone number and email address are listed on their site.
I’m not familiar with their layering, but I have read that there are different density options in their line, so it may be possible they could prepare a custom layering for you. Again, I’d suggest to phone them directly for the potential of such a customization. Memory Foam Comfort carries some Nature’s Embrace models, some of which are actually customizable, and they may also be a good reference for you. I understand that they are quite knowledgeable.
the cover for the aria is listed as cotton/polyester blend, with no wool, i wonder if that combo is a natural fire retardant. calling them is a good idea like you said, they dont respond to my emails.
yes, maybe natures embrace can do a custom order. the aria is 2 layers of 40 ILD which, is firm. i did look at mfc presto customizable mattress but, the 8" is out of my price range. but, maybe they can do a customizable 6" with 2 layers, firm support core and medium firm comfort layer.
Web site specifications aren’t always complete, and it doesn’t say if the cover is quilted to anything. I’ll always recommend to phone versus email to get faster answers. Many smaller companies can take a while to reply to all of their emails. Phone them and you’ll have your answer and won’t have to speculate any longer. 
hi jeff
i asked snugsleep about their 6 inch generic latex mattress and what the ILD of it was.
this was their response, can ya decipher it for me? thanks.
Our basic 6" has a 4" 65 core with 1" 75 on one side and 1" 65 on the other so mattress has two difference support levels.
There’s a 4" center core of Dunlop latex at a density of 65 kg/m3. On top of that on one side is 1" of Dunlop latex at 75 kg/m3, and on the other side is 1" of Dunlop latex at 65 kg/m3. Density tends to be more accurate for relating softness in Dunlop latex than ILD. Depending upon how it is measured, or estimated, for converting to ILD, 65 kg/m3 would be considered quite plush and usually an estimate of an ILD in the upper teens. 75 kg/m3 would be more of a medium firm, maybe in the mid to upper 20s ILD. I’d be surprised if the 4" core was actually 65 kg/m3 - that is incredibly soft for a core - 75 kg/m3 or 85 kg/m3 are more common. But maybe it is. Overall that would be a quite plush product from the specifications. I believe their latex is natural and GOLS certified.