Hi LemonPan,
None of the latex you are likely to encounter contains any fire retardant chemicals and all of it (whether it’s Dunlop or Talalay or made from synthetic rubber, natural rubber, or a blend of the two) has been certified for harmful chemicals and VOC’s. The chart you linked to is somewhat misleading and in some cases completely incorrect.
Latex … synthetic, natural or otherwise … is a very different material than polyfoam or memory foam.
It would probably also be worth mentioning that most of the foams that are used in the mattress industry don’t contain fire retardant chemicals because mattresses tend to use barrier systems to pass the fire regulations. Fire retardant foams are much more common with furniture than they are with mattresses (see post #5 here and post #13 here).
I would personally have no issues with the “safety” of any type of latex or any “chemicals” in latex that would be harmful. All of them are tested for safety using the same testing protocols. Even the word “chemical” itself is often used as a scare tactic because even water is a “chemical substance”. While there are some legitimate “chemical” concerns … safety is the real issue that most people are most concerned about.
If you decide that for personal reasons that you are more comfortable with only natural latex (whether it’s Dunlop or Talalay) then SleepEz has this option available as well but in most cases any concerns with the safety of synthetic or blended latex are unfounded and are based more on “fear based” marketing than they are on any factual information.
Phoenix