Hi SAFE4Kids,
The question of “how safe is safe enough for me” is specific to each person or parent and their individual sensitivities, circumstances, criteria, beliefs, and lifestyle choices (just like some people may choose an organic or even a vegan diet and would consider other diets to be “unsafe” for their children) but post #2 here and the topics it links to also has much more information about mattresses and children and “safe” materials including a link to some general guidelines for children in post #2 here. It also includes a number of links to the better forum posts and topics about mattress and children as well which also include more information about many good options for children which would be well worth considering.
I personally think that some combination of latex, natural fibers, and innersprings can all make good and “safe” choices for a child and if budget is a major consideration then polyfoam that is CertiPUR certified can also make a good lower budget choice as well but just like buying clothes for your children or deciding on the type of diet you feed them and are most comfortable with this would be a choice based on the parent’s “best judgement” and their lifestyle choices. A latex comfort layer is also a very durable choice so a mattress that uses it in an appropriate firmness level can maintain its initial comfort and support well into their teen years and would still be in good enough condition to add a topper as they grow and develop more adult proportions if they need some additional softness and pressure relief to extend the useful life of the mattress.
I’m not sure where you are in west Michigan but the better options or possibilities I’m aware of in the Grand Rapids area (subject to the quality/value guidelines here) are listed in post #273 here. If you are further south then there is also a forum list for the Portage/Kalamazoo area in post #2 here and for the South Bend/Fort Wayne areas in post #4 here (with some overlap between them).
All mattresses (including children’s mattresses) need to pass some very stringent fire regulations before they can be sold to the public but it’s also possible to purchase a mattress that doesn’t meet the regulations with a prescription from a health professional that is licensed in your state (a doctor, naturopath, chiropractor etc). There are also some very “safe” methods of passing the fire regulations as well that will pass the fire regulations and don’t require a prescription (see post #2 here and post #4 here).
I don’t have any specific suggestions because there are too many variables and specific criteria involved in choosing a mattress that are unique to each person but I would be very cautious about brand shopping because you are buying a specific mattress not the brand and all manufacturers have access to the same or similar components and materials. Most of the more heavily advertised and most commonly available brands that you would recognize are the ones I would avoid anyway (see the guidelines here) and many of the better manufacturers are smaller and are only available locally or regionally (or online). The name of the manufacturer on the label also won’t tell you anything about whether a specific mattress is suitable for a child or whether there are any lower quality materials or weak links in the design. There is more about the risks of brand shopping in post #5 here and post #12 here). I would focus much more on the materials inside a mattress (which are important to know anyway) than I would on the name of the manufacturer on the label.
Phoenix