1 CFR 601.26: Supplemental Environmental Impact Statement.

(a) The NCPC shall prepare a supplemental EIS if five or more years has elapsed since adoption of the EIS and:

(1) There are substantial changes to the proposed action that are relevant to environmental concerns; or

(2) There are significant new circumstances or information that are relevant to environmental concerns and have a bearing on the proposed action or its impacts.

(b) The NCPC may supplement a Draft or Final EIS at any time, to further the purposes of NEPA.

(c) The NCPC shall prepare, circulate, and file a supplement to a Draft or Final EIS in in accordance with the requirements of §§ 601.22 through 601.24 except that Public Scoping is optional for a supplemental EIS.

(d) The NCPC shall prepare a ROD for a Supplemental EIS. The ROD's contents, the procedure for public review, and the manner in which it shall be adopted shall be as set forth in § 601.25.