43 CFR § 46.215 - Categorical exclusions: Extraordinary circumstances.
Extraordinary circumstances (see paragraph 46.205(c)) exist for individual actions within categorical exclusions that may meet any of the criteria listed in paragraphs (a) through (l) of this section. Applicability of extraordinary circumstances to categorical exclusions is determined by the Responsible Official.
(a) Have significant impacts on public health or safety.
(b) Have significant impacts on such natural resources and unique geographic characteristics as historic or cultural resources; park, recreation or refuge lands; wilderness areas; wild or scenic rivers; national natural landmarks; sole or principal drinking water aquifers; prime farmlands; wetlands (EO 11990); floodplains (EO 11988); national monuments; migratory birds; and other ecologically significant or critical areas.
(c) Have highly controversial environmental effects or involve unresolved conflicts concerning alternative uses of available resources [NEPA section 102(2)(E)].
(d) Have highly uncertain and potentially significant environmental effects or involve unique or unknown environmental risks.
(e) Establish a precedent for future action or represent a decision in principle about future actions with potentially significant environmental effects.
(f) Have a direct relationship to other actions with individually insignificant but cumulatively significant environmental effects.
(g) Have significant impacts on properties listed, or eligible for listing, on the National Register of Historic Places as determined by the bureau.
(h) Have significant impacts on species listed, or proposed to be listed, on the List of Endangered or Threatened Species or have significant impacts on designated Critical Habitat for these species.
(i) Violate a Federal law, or a State, local, or tribal law or requirement imposed for the protection of the environment.
(j) Have a disproportionately high and adverse effect on low income or minority populations (EO 12898).
(k) Limit access to and ceremonial use of Indian sacred sites on Federal lands by Indian religious practitioners or significantly adversely affect the physical integrity of such sacred sites (EO 13007).
(l) Contribute to the introduction, continued existence, or spread of noxious weeds or non-native invasive species known to occur in the area or actions that may promote the introduction, growth, or expansion of the range of such species (Federal Noxious Weed Control Act and EO 13112).