Neutron attenuation in the old pile shields is dependent more and more on the slowing down characteristics of the iron as the hydrogen is baked out of the masonite. For neutrons above 1 or 2 Mev, iron does a good job by inelastic scattering. However, below this energy attenuation can be done only by the gradual moderation by elastic scattering to thermal energies with subsequent capture in the iron. Since iron is heavy and thus a poor moderator, there is a good possibility that many neutrons of intermediate energy will leak out of a burned out shield. Also, iron has a large dip in its cross section at 25 Kev which might allow a large burst of neutrons at this energy to leak out. Measurements using a lucite moderator with gold foil detectors indicate a large leakage of neutrons of intermediate energy, but interpretation of these measurements is difficult. These considerations prompted an attempt to get a rough idea of the energy distribution of the leakage neutrons through pure iron using a simple qualitative theory.