A National Academy of Sciences (NAS) is the National Academy of Sciences/National Research Council (NRC) performs level 2 peer review to determine if EMAP projects have overall scientific merit and integrate both internally and with other government-sponsored monitoring programs. Two commissions of the NRC--the Commission on Geosciences, Environment, and Resources (specifically, its Water Science and Technology Board) and the Commission on Life Sciences-jointly organized the Committee to Review EPA's Environmental Monitoring and Assessment Program in 1991.