EPA reviews all draft Environmental Impact Statements (EIS) prepared by other federal agencies, as well as other certain federal actions, as required by Section 309 of the Clean Air Act. Section 309 also requires that EPA make these reviews public, and EPA does this by posting EPA comment letters on EISs in the EIS database.

EPA's reviews are primarily concerned with identifying and recommending appropriate measures to avoid and mitigate significant environmental impacts associated with the proposal. EPA also evaluates the adequacy of the information presented in the EIS. As part of EPA's review, EPA rates all draft EISs submitted using a two-prong rating system:

• A rating for the environmental impacts of the proposed action and
• A rating for the adequacy of the information presented in the EIS.

Learn more about EPA's Rating System Criteria.

EPA also conducts reviews of final EISs to ensure that the lead agency has taken EPA's comments into account. If the project remains environmentally unsatisfactory, EPA may refer the matter to the Council on Environmental Quality (CEQ). Learn more about CEQ's referral process (PDF) (4 pp, 40 K, About PDF).

EPA has prepared a detailed manual that explains the policies and procedures for carrying out its review responsibilities under the National Environmental Policy Act and Section 309 of the Clean Air Act.

• Read more about EPA's Policy and Procedures for 309 Reviews.