Most mattresses are made of PVC, polyester, foam. They are then doused with flame-retardant chemicals and PBDE's. These chemicals have been banned by the state of California but this is not to be implemented until 2008. What do you do until then? 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, or see these sites:

http://www.mst.dk/udgiv/Publications/1999/87-7909-416-3/html/tab0501.htm

http://www2.whdh.com/features/articles_p/specialreport/A358

http://www.ourstolenfuture.org/press/2003/2003-0810-NYT-cabanspbdes.htm

http://www.ewg.org/reports/inthedust/part5.php