@ Non-blooming fire retardant compositions are disclosed comprising an ammonium phosphate-containing fire retardant and an effective amount of boric acid or an alkali metal borate. The ammonium phosphate-containing fire retardant preferably comprises the reaction mixture of aqueous phosphoric acid and an alkylene oxide. Preferably, the boric acid or alkali metal borate is present in an amount of from about 2.5% to about 12% by weight of solids in the phosphate-containing fire retardant. Such compositions are less susceptible to exudation of the fire retardant from treated wood panels during drying of the panels at elevated temperatures, and are particularly suitable for use in continuous treatment processes.