This mattress uses glass fibers, a  fire retardant material. This wasn't listed on the website, and I didn't find this out until I brought the mattress home and was about to break the plastic seal when I saw the mattress tag stating 60% glass fibers. If you plan on taking the protective cover off to wash: do not buy this mattress. The glass fibers will get everywhere on your carpet and clothes and potentially cause an allergic reaction.