40 CFR § 1501.4 - Whether to prepare an environmental impact statement.
In determining whether to prepare an environmental impact statement the Federal agency shall:
(a) Determine under its procedures supplementing these regulations (described in § 1507.3) whether the proposal is one which:
(1) Normally requires an environmental impact statement, or
(2) Normally does not require either an environmental impact statement or an environmental assessment (categorical exclusion).
(b) If the proposed action is not covered by paragraph (a) of this section, prepare an environmental assessment (§ 1508.9). The agency shall involve environmental agencies, applicants, and the public, to the extent practicable, in preparing assessments required by § 1508.9(a)(1).
(c) Based on the environmental assessment make its determination whether to prepare an environmental impact statement.
(d) Commence the scoping process (§ 1501.7), if the agency will prepare an environmental impact statement.
(e) Prepare a finding of no significant impact (§ 1508.13), if the agency determines on the basis of the environmental assessment not to prepare a statement.
(1) The agency shall make the finding of no significant impact available to the affected public as specified in § 1506.6.
(2) In certain limited circumstances, which the agency may cover in its procedures under § 1507.3, the agency shall make the finding of no significant impact available for public review (including State and areawide clearinghouses) for 30 days before the agency makes its final determination whether to prepare an environmental impact statement and before the action may begin. The circumstances are:
(i) The proposed action is, or is closely similar to, one which normally requires the preparation of an environmental impact statement under the procedures adopted by the agency pursuant to § 1507.3, or
(ii) The nature of the proposed action is one without precedent.