As a part of routine plant operations, limited quantities of radioactive materials are released to the environment in liquid and airborne effluents. An effluent control program is implemented to ensure that the amount of radioactive materials released to the environment is minimal and does not exceed federal release limits. Effluent control is accomplished by plant components such as the ventilation system and filters, waste gas holdup tanks, demineralizers, and an evaporator system. In addition to minimizing the release of radioactive materials, the effluent control program includes all aspects of effluent and environmental monitoring. The Three Mile Island (TMI) radiological environmental program consists of taking radiation measurements and collecting samples from the environment, analyzing them for radioactivity content, and interpreting the results. With the emphasis on the critical pathways to humans, samples from the aquatic, atmospheric, and terrestrial environments are collected. Radiation doses to the public are estimated from the direct measurement of the dose rates from external sources and measurement of radionuclide concentrations in the environment that may contribute to an internal dose of radiation. Dose rates and radionuclide concentrations in the environment from normal plant operations are typically too small to be measured. As a result, the potential off-site doses are calculated using a computerized model that predicts concentrations of radioactive materials in the environment and estimates subsequent radiation doses. Radiological environmental monitoring performed by the TMI operator and independent agencies has confirmed the adequacy of engineering designs and effluent controls. Radiation doses to the public from normal operations have been far less than the U.S. Environmental Protection Agency environmental standards, the U.S. Nuclear Regulatory Commission dose limit guidelines, and the doses received from natural background radiation. Based on the results from years of effluent and environmental monitoring, which have been verified by independent monitoring, it is proper to conclude that radioactive releases from TMI have had no adverse effect on either the quality of the environment or the health and safety of the public.