For the reduction of toxic mercury vapor, HgX is an inexpensive, water soluble, non-hazardous, metallic-mercury/sulfide converting powder with a chelating compound and dispersing agent. It reacts rapidly, forming a film over the finely divided, nearly invisible beads of mercury and reacting to produce a non-vaporizing sulfide. Further, HgX keeps on working. Particles of HgX left on cleaned surfaces are reactivated during subsequent cleaning. HgX is not harmful. None of its components are classified as toxic. It leaves no odor. And no allergic reactions have ever been reported even after continuous use under various conditions. HgX is stable. It is supplied in a polyethylene jar and can be stored safely up to one year without any loss of activity.