Section 601.21 - Programmatic Environmental Impact Statements and tiering(a) The NCPC shall prepare a programmatic Environmental Document (Programmatic EA or PEA or Programmatic EIS or PEIS) to assess the impacts of proposed projects and plans when there is uncertainty regarding the timing, location and environmental impacts of subsequent implementing actions. At the time NCPC undertakes a site or project specific action within the parameters of the PEA or PEIS, NCPC shall tier its Environmental Document by summarizing information in the PEIS or PEA, as applicable, and concentrate on the issues applicable to the specific action.(b) A PEIS or PEA prepared by NCPC shall be governed by the CEQ regulations and the rules of this part.