Additives for suppressing tungsten leachability

The leachability of tungsten in an aqueous medium may be suppressed by combining tungsten metal with a metal oxide or metal salt that will form an insoluble tungsten-containing compound when the mixture is brought into contact with an aqueous medium. The additive is preferably present in an amount from about 1 weight percent (wt.%) to about 10 weight percent of the tungsten. Preferred additives are lead oxide and calcium sulfate. The method can be used in processing tungsten powder to pressed powder compacts.