Most mattresses are made of PVC, polyester, foam. They are then doused with flame-retardant chemicals and PBDE's. You can buy organic and guarantee that your baby will not be exposed to chemicals that have been proven to reduce breathing and are implicated in SIDS. To research further just go online and search for PBDE's.
All of our mattress in all sizes are 100% chemical free and Toxin-Free NO PBDE'S.