In December 1983, the Administrator of the EPA formed a Science Advisory Board Subcommittee to review the methodology used by the Office of Radiation Programs in assessing health risks from airborne release of radionuclides. In addition, new technical data was gathered which included the results of radionuclide emission testing at calciners at three elemental phosphorus plants. New information also became available on the cost and effectiveness of methods for reducing radon emissions from underground uranium mines. Because the Agency intended to consider this new information in the ongoing rulemaking, public comment was requested on the new information, (49 FR 33695, August 24, 1984). This document summarizes public comment on the new information and EPA's response to them. In addition, Section 2 of the document contains EPA's response to the Science Advisory Board Subcommittee's comments.