These barriers are blends of fibers. Those fibers in the blend that take part in blocking or slowing down mattress fire are inherently fire retardant.

In case of Celestia Fire Barriers, the fire retardant fiber is modified rayon. It is modified in such way that at time of burn, part of the fiber turns in to silica, which is nothing but like sand. During this process the fibers only loose water and as a result there is no off gassing of toxic substance(s) from the fire barrier.

The rest of the fibers in blend are commodity polyester, which consumers have been using for years. During normal use of these barriers in the mattress, there is no off gassing of any toxic gases or substance.