We don't use whatever material is cheapest — we're proudly commited to making non-toxic mattresses. Doing so costs a little more, but because we own our workshops and make all our mattresses ourselves, we save money without a middleman and can afford to put a little extra care into making our mattresses completely non-toxic. For our natural flame retardants, we use GOTS organic certified wool — from collectives that we jointly-own in India — and natural hydrated silica, which is naturally derived from silicon dioxide, and found in abundance on the Earth's outer surface.