Hi LookingNow,
The most effective way to know the “safety” of a material is with the results of any testing and certifications for harmful substances and VOC’s because all materials emit VOC’s (volatile organic compounds), even fruits and vegetables, so the question is more about the “safety” of VOC’s and the specific type rather then whether a material has any at all.
All “chemicals” are not harmful.
PBDE’s aren’t used in North American foam manufacturing any longer and foams don’t generally contain them or phthalates. Some pthalates are also more harmful than others and the low molecular weight pthalates that are most commonly found in some vinyl or glues (or some of the other things mentioned in the Wikipedia article) are generally being replaced or banned in some countries. Formaldehyde is also not generally used in foam materials but all of these are part of what is tested for with testing protocols and certifications such as CertiPur (in the case of memory foam or polyfoam) or with the more stringent testing standards such as Oeko-Tex or Eco-Institut (in the case of latex). All of the latex you are likely to encounter has been tested through Oeko-Tex or Eco-Institut to be essentially free of these types of substances and VOC’s regardless of whether it is organic, 100% natural, or synthetic.
Mountaintop foam is now making 100% natural latex that has no synthetic latex in the formula. All of their latex though (regardless of whether it uses synthetic or natural rubber) has been certified to the same Oeko-Tex standard 100 certification (regardless of whether it uses natural or synthetic rubber).
All latex foam manufacturing uses some chemicals in the formulation to foam and make the latex (whether it is synthetic, 100% natural, or organic) which includes foaming agents, curing agents, antidegradents, gelling agents and others) and the GOLS organic certification for latex only requires that the foam core uses 95% organic rubber raw materials. There is more about organic certifications including for latex in post #2 here and the posts it links to.
The subject of mattress “safety” is very complex and and there is a great deal of misleading and inaccurate information all over the web (on both sides of the argument) but post #2 here may be a useful starting point that can help each person answer the question of “how safe is safe enough for me?” on an individual level because each person may be have different levels of sensitivity or be sensitive to different substances or levels of VOC’s and it’s generally not possible to find out all the chemicals that are in every material that you are considering. Some chemicals may also be fully reacted with others and be “bound” in the final product when they are combined (such as sodium and chlorine in salt aren’t harmful when they are reacted together but chlorine can be harmful by itself).
For those who are unusually sensitive or have medical conditions such as MCS (multiple chemical sensitivities) asking for a sample of the material can be a good idea as this can tell you if you are likely to react or be sensitive to the material you are considering.
Phoenix