Hi Need2Sleep,
The first place I would start your research is the mattress shopping tutorial here which has all the basic information, steps, and guidelines that can help you make the best possible choice … and know how and why to avoid the worst ones.
There is more information about organic, natural, chemical free, green, and “safe” materials in post #2 here and the other posts it links to that can help you decide which materials you are comfortable with having in your mattress and that can help answer your questions about “how safe is safe enough for me?” because these types of issues are complex and are generally specific to each person and their individual sensitivities and circumstances.
Post #2 here also has more about the different ways to choose a mattress (local or online) that can help with how to make the most suitable choice in terms of PPP (Posture and alignment, Pressure relief, and Personal preferences) and how to minimize the risks of making an unsuitable choice with each of them.
The choice of material is always a personal preference and while latex is a very high quality, “safe” and durable material … like all materials not everyone will like how it feels so it makes sense to test a range of latex mattresses that use different types and blends of latex in different firmness levels to get a sense of how you feel about latex in general.
The better options and possibilities I’m aware of in and around the Charlotte, NC area (subject to the guidelines here) are listed in post #2 here.
Phoenix