Oxidation-sensitive, low-peroxide polymer contained in a sealed, protective-gas-filled packaging form, comprising, per kilogram of polymer solid, at least one inorganic phosphorus compound in amounts such that the total phosphorus content is 2*10−5 to 0.02 mol, and methods for stabilizing oxidation-sensitive polymer against peroxide formation, wherein, during or after the polymerization, at least one inorganic phosphorus compound is added in one or more portions in amounts such that the total phosphorus content per kilogram of polymer solid content of the finished polymer is 2*10−5 to 0.02 mol, and the polymer treated in such a way is placed into a protective-gas filled, sealed packaging form, and also use of these polymers.