In analyzing CaF/sub 2/:Dy (TLD-200) data from the environmental monitoring program at the Lawrence Livermore Laboratory, a quantity of significance is the dose to the thermoluminescence dosimeters during shielded storage. This paper describes a method for determining this shield dose, which can then be related to the dose from cosmic radiation. Data, based on quarterly TLD exposure periods, show a range of 43-56 ..mu..rads per day in a 75 mm thick lead shield. Observed variations in the shield dose have led to studies of prolonged exposure of TLDs to elevated and reduced temperatures typical of those in the Livermore Valley.