What fabric is fireproof?

Fireproof fabric are usually and mostly treated with fire retardants. 

But there is a naturally fire-retardant fabric. What is it?

Seaweed fabric

The limited oxygen index of alginate fiber is 48. Therefore, it's a naturally flame retardant fiber. It burns without odor and the smoke is small. The fabric will self extinguish. Moreover, the seaweed fabric is soft and skin care with calcium and many other mineral substance. It's one of the best choice for making fireproof undergarments.