Hi elskyz,
There is more about all the many factors that can affect the sleeping temperature of a mattress in post #2 here.
Post #2 here and the more detailed posts and information it links to have more information about safe, natural, organic, “chemical free”, and green mattresses and mattress materials that can help you sort through some of the marketing information and terminology that you will encounter in the industry and can help you differentiate between them and answer “how safe is safe enough for me” so you can decide on the types of materials you are most comfortable having in your mattress. These types of issues are complex and are generally specific to each person and their individual sensitivities, circumstances, criteria, and lifestyle choices.
I don’t make suggestions or recommendations for specific manufacturers or mattresses because only you can know the types of materials or mattresses you tend to prefer but the better options or possibilities I’m aware of in the general Boston area (subject to the guidelines here) are listed in post #2 here. You certainly have some very good options available to you.
Phoenix