This invention relates to a process for standardized preparation of thermoplastic polyurethane elastomers by deactivating metal traces during the reaction, at an NCO:OH ratio of between about 0.85 and about 1.2:1, of(a) substantially linear hydroxyl-terminated polyols;(b) organic diisocyanates;(c) optional diol chain extenders; and(d) optional catalysts or other auxiliaries and/or additives, in the presence of(e) 0.000001 to 0.3% by weight, based on the total weight of the other components, of certain phosphorus compounds, wherein the phosphorus compounds are added to one or more of the other components before or during preparation of the thermoplastic polyurethane elastomers.