Summary: GAO discussed federal agencies' efforts to deal with radon contamination in housing. GAO noted that: (1) the Environmental Protection Agency's (EPA) radon activities include a legislatively mandated national radon assessment, which an EPA advisory committee's concerns has delayed; (2) EPA provides assistance to states in identifying high-risk areas; (3) the Department of Housing and Urban Development (HUD) provides radon disclosure notices to certain mortgage applicants, but its overall response to radon issues has been limited and sporadic; (4) HUD has not developed a comprehensive radon policy because it believes that it has no direct statutory mandate to deal with radon issues, except for a required cooperative effort with EPA to identify radon assessment methods; (5) while neither the Veterans Administration (VA) nor the Farmers' Home Administration (FmHA) have radon policies, FmHA is developing an indoor air pollution policy that will include radon; (6) VA believes that radon should be a state and local government issue; (7) the National Park Service has tested a number of its buildings and plans to perform radon mitigation work on about 350 buildings; and (8) legal issues concerning government liability for radon contamination have yet to be resolved.