In all cases, agency NEPA procedures must consider the "extraordinary circumstances" which are set out in the agency NEPA implementing procedures, and can preclude the use of a Categorical Exclusion. Extraordinary circumstances include potential effects to environmentally sensitive areas or resources, and public controversy over the environmental effects of the agency's proposed action. If a review of the extraordinary circumstances disclose no potential environmental impacts, the agency may apply the Categorical Exclusion and proceed with their action.