We link atomic-scale defects called E′ centers to radiation-induced leakage current (RILC). We present evidence that strongly suggests that RILC tolerance is processing dependent and that this tolerance appears to be correlated with lower E′ center generation. We furthermore note that in oxides subjected to quite high irradiation levels, the density of (generally electrically neutral) E′ centers is far greater than would be expected for the hole trap E′ centers involved in the radiation-induced positive charge buildup observed in thicker oxides.