Hi Zeno,
The first place I would start your research is post #1 here which has the basic information, steps, and guidelines you will need to make the best possible choices.
A mattress is only as good as its construction and the materials inside it and once you know that (which is the most important question to ask) you are in a good position to make meaningful comparisons with other latex mattresses which is a popular choice for people who are looking for more natural materials.
Once you get to step 3 then the better options I’m aware of in the Toronto area are listed in post #1 here and a forum search on Toronto (you can just click this) will bring up more feedback about some of them as well.
A forum search on Dormio (you can just click this as well) will also bring up more information about them as well.
Post #2 here also has some links that may help you answer a rather difficult question which is “how safe is safe enough for me” and which can really only be answered on an individual level.
Phoenix