; (5) the proposed agency action is a rulemaking that is subject to section 553 of title 5, United States Code; or (6) the proposed agency action is an action for which such agency’s compliance with another statute’s requirements serve the same or similar function as the requirements of this Act with respect to such action. (b) Levels of review (1) Environmental impact statement An agency shall issue an environmental impact statement with respect to a proposed agency action that has a significant effect on the quality of the human environment. (2) Environmental assessment An agency shall prepare an environmental assessment with respect to a proposed agency action that is not likely to have a significant effect on the quality of the human environment, or if the significance of such effect is unknown, unless the agency finds that a categorical exclusion established by the agency, another Federal agency, or another provision of law applies. Such environmental assessment shall be a concise public document prepared by a Federal agency to set forth the basis of such agency’s finding of no significant impact. (3) Sources of information In making a determination under this subsection, an agency— (A) may make use of any reliable data source