Since the discovery of x rays, the public has shown increasing concern about exposure to radiation. In the mid-1980s, with the dissemination of information about the ubiquitous nature of radon, this concern about radiation exposure has taken on a new perspective. As the general public realizes that exposure to radiation is on unavoidable part of life, questions arise as to how much exposure is acceptable when weighed against the costs of reducing the exposure. Because limited resources are available to protect the public's health and the environment, these resources need to be used wisely. The cost-effectiveness of the various options to lessen the potential adverse health effects from radon must be considered.