Zinc Stannate (branded as Flamtard S) is a flame retardant synergist for use in "antimony-free" polymer formulations, especially designed for polymers that melt at high temperatures. Flamtard S acts by two mechanisms that extinguish flames in te gas phase and prevent the formation of smoke and toxic gas in the solid phase. This dual functionality gives Flamtard S a major performance advantage over antimony tioxide, which is as active for extinguishing flame but has no effect on toxic gas and smoke.

Zinc Stannate is non-hazardous and environmentally friendly and is being used increasingly in green, "antimony-free" applications, particularly in the electronics industry. Flamtard S works extremely effectively in PVC systems for cable sheating, epoxy resins for printed circuit boards, polyamides and surface coatings.