43 C.F.R. § 46.100 : Public Lands: Interior — OFFICE OF THE SECRETARY OF THE INTERIOR — IMPLEMENTATION OF THE NATIONAL ENVIRONMENTAL POLICY ACT OF 1969 — PROTECTION AND ENHANCEMENT OF ENVIRONMENTAL QUALITY — Federal action subject to the procedural requirements of NEPA

(a) A bureau proposed action is subject to the procedural requirements of NEPA if it would cause effects on the human environment ( 40 CFR 1508.14 ), and is subject to bureau control and responsibility ( 40 CFR 1508.18 ). The determination of whether a proposed action is subject to the procedural requirements of NEPA depends on the extent to which bureaus exercise control and responsibility over the proposed action and whether Federal funding or approval are necessary to implement it. If Federal funding is provided with no Federal agency control as to the expenditure of such funds by the recipient, NEPA compliance is not necessary. The proposed action is not subject to the procedural requirements of NEPA if it is exempt from the requirements of section 102(2) of NEPA.
(b) A bureau shall apply the procedural requirements of NEPA when the proposal is developed to the point that:
(1) The bureau has a goal and is actively preparing to make a decision on one or more alternative means of accomplishing that goal; and
(2) The effects of the proposed action can be meaningfully evaluated ( 40 CFR 1508.23 ).

43 C.F.R. § 46.100