1 CFR § 601.26 - Supplemental Environmental Impact Statement.

---
identifier: "/us/cfr/t1/s601.26"
source: "ecfr"
legal_status: "authoritative_unofficial"
title: "1 CFR § 601.26 - Supplemental Environmental Impact Statement."
title_number: 1
title_name: "General Provisions"
section_number: "601.26"
section_name: "Supplemental Environmental Impact Statement."
chapter_name: "NATIONAL CAPITAL PLANNING COMMISSION"
part_number: "601"
part_name: "IMPLEMENTATION OF THE NATIONAL ENVIRONMENTAL POLICY ACT"
positive_law: false
currency: "2026-03-24"
last_updated: "2026-03-24"
format_version: "1.1.0"
generator: "[email protected]"
authority: "42 U.S.C. 4371; 40 CFR 1507.3"
regulatory_source: "82 FR 45424, Sept. 29, 2017; 82 FR 48609, Oct. 19, 2017, unless otherwise noted."
cfr_part: "601"
---


# 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.