Concerned Citizens for Nuclear Safety (“Concerned Citizens”) filed an Informal Appeal with the Environmental Appeals Board (“Board”) under 40 C.F.R. § 124.5(b) seeking review of the U.S. Environmental Protection Agency Region 6’s (“Region”) denial of Concerned Citizens’ request to terminate as to one outfall – referred to as Outfall 051 – a National Pollutant Discharge Elimination System (“NPDES”) permit issued for operations at the Los Alamos National Laboratory in New Mexico (“Los Alamos Laboratory”).