RAC is well-versed in reviewing and estimating releases of chemical and radioactive materials to the environment (source terms). Source term estimates are an essential part of the risk assessment process to determine health impacts to the surrounding population. Our source term analysis capabilities can address historical, present day, or future releases. We have conducted a number of historical dose reconstructions of nuclear facilities, and as part of those studies, we have estimated historical releases from facilities that began operation many decades ago. We use these release estimates, coupled with transport modeling and contemporary environmental measurements, to understand the effects of the operations on environmental concentrations and to evaluate whether other nearby sources or natural processes may also contribute to those concentrations. RAC also assists facilities in assessing future emissions, whether from new facilities or as a result of process or effluent treatment modifications to existing plants. Careful analyses of releases and their movement in the environment can provide a sound basis for determining historic, current, and future public exposures.