The following exceptions apply to individual actions within categorical exclusions (CX). Environmental documents must be prepared for actions which may:

(a) Have significant adverse effects on public health or safety.

(b) Have adverse effects on such unique geographic characteristics as historic or cultural resources, parks, recreation or refuge lands, wilderness areas, wild or scenic rivers, sole or principal drinking water aquifers, prime farmlands, wetlands, floodplains, or ecologically significant or critical areas, including those listed on the Department of the Interior's National Register of Natural Landmarks.

(c) Have highly controversial environmental effects.

(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) Be directly related to other actions with individually insignificant but cumulatively significant environmental effects.

(g) Have adverse effects on properties listed or eligible for listing on the National Register of Historic Places.

(h) Have adverse effects on species listed or proposed to be listed on the List of Endangered or Threatened Species, or have adverse effects on designated Critical Habitat for these species.

(i) Require compliance with Executive Order 12988 (Floodplain Management), Executive Order 11990 (Protection of Wetlands), or the Fish and Wildlife Coordination Act. However, an action may be categorically excluded following applicable reviews if the action is found to be in conformance with the applicable law or executive order.

(j) Threaten to violate a Federal, State, local or tribal law or requirement imposed for the protection of the environment.