Saatva claims its flame barrier is just natural thistle and wool. However, Saatva’s “natural thistle” is just silica-based visil rayon blended with polyester. Only the Latex Hybrid and Zenhaven use wool as a flame barrier.
Since Sealy seems to avoid the topic of fiberglass on their website, almost to a point of suspicion, it can be hard to discern whether they use it or not. But, Sealy support directly admits the use of fiberglass in its mattresses.
Zinus told me that its mattresses still consist of a fiberglass flame barrier. The lawsuits never stopped Zinus from using fiberglass, they just forced Zinus to adequately label their products. However, Zinus is transitioning to a Rayon.
Tulo mattresses definitely have fiberglass, but some popular websites might lead you to believe they are fiberglass-free when they are not. I wanted to cut through the smoke and mirrors, so I went straight to the source to find out about the fiberglass in Tulo mattresses.