ammonium nitrate
(1) Ammonium nitrate The term “ammonium nitrate” means— (A) solid ammonium nitrate that is chiefly the ammonium salt of nitric acid and contains not less than 33 percent nitrogen by weight; and (B) any mixture containing a percentage of ammonium nitrate that is equal to or greater than the percentage determined by the Secretary under section 488a(b) of this title .