FWIW, as a firefighter who wouldn't go near a burning mattress, new or old, without breathing apparatus, I use latex and wool mattresses for our beds!
BINGO Mayaness. Go the latex - plus mould and mildew refuse to go near it as they cannot breed in it - therefore you eliminate the risk of the toxic gases from flame retardant chemicals mixed with mould, as well as hayfever and asthma related allergies.
Shame they are so damned expensive though.

We splurged this time around and got the Organic Pod moses basket with latex breatherhole mattress & organic cotton casing - (which can be removed and washed) so now I can put DS on his tummy where he likes to be, and keep my peace of mind!