Flame retardants are substances utilized (not water) to reduce the flammability of a material when that material is exposed to heat or flame directly or via proximity.  In the case of textiles such as safety garments, the supplies are treated with flame retardant chemicals that help to decrease combustion potential within the material via chemically induces charring or cooling of the garment materials.  Fire fighting crews use comparable chemical reactions in gels and foams.  The textile industry relies on coating supplies.