{"data":{"id":"us/1-cfr-601.17","jurisdiction":"us","citation":"1 CFR 601.17","heading":"Supplemental Environmental Assessments.","body":"(a) The NCPC shall prepare a supplemental EA if five or more years have elapsed since adoption of the EA and:\n(1) There are substantial changes to the proposed action that are relevant to environmental concerns; or\n(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.\n(b) The NCPC may supplement a Draft or Final EA at any time to further the purposes of NEPA.\n(c) The NCPC shall prepare, circulate, and file a supplement to a Draft or Final EA, and adopt a FONSI in accordance with the requirements of §§ 601.15 and 601.16. If NCPC is not the Lead Agency, it shall proceed as outlined in § 601.16(b) and (c).","path":["Title 1—General Provisions","CHAPTER VI—NATIONAL CAPITAL PLANNING COMMISSION","PART 601—IMPLEMENTATION OF THE NATIONAL ENVIRONMENTAL POLICY ACT","Subpart E—Environmental Assessments"],"source_url":"https://www.ecfr.gov/api/versioner/v1/full/2026-08-25/title-1.xml","current_through":"2026-08-25","vintage":"","retrieved_at":"2026-08-27T02:23:37Z","sha256":"2c337f9b52f2a9b2e732aaa1faa7568e76865ec9c7a9e5252df47c682c00ce88","source_id":"us-cfr","stale":true,"prev":"us/1-cfr-601.16","next":"us/1-cfr-601.18"},"notice":"GroundRules: Original legal text. Not legal advice."}