Heavy metal toxicity is a two-hit mechanism of disease. 1) Disrupt Immune System. 2. Toxic effects of the heavy metal, to generate an effective toxicity. The two critical features of a chelator are 1. high log stability constant with the metal, and 2. demonstration that the chelator can remove the heavy metal in vivo. Total body content of the heavy metal and the reservoirs that the heavy metal is deposited in are critical factors for treatment.