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Environmental Impact Statement Rating System Criteria

EPA has developed a set of criteria for rating a draft Environmental Impact Statement (EIS). EPA rates the draft EIS on an alpha-numeric system and includes the designated rating in EPA's comment letter. In general, the rating is based on the lead agency's preferred alternative. The rating system provides a basis upon which EPA makes recommendations to the lead agency for improving the draft EIS.

The alphabetical categories listed below signify EPA's evaluation of the environmental impacts of the proposal: 

The numerical categories listed below signify an evaluation of the adequacy of the draft EIS: 

The rating of the draft EIS consists of one of the category combinations shown below:

  • LO
  • EC-1, EC-2
  • EO-1, EO-2, EO-3
  • EU-1, EU-2, EU-3, or 3

Rating the Environmental Impact of the Action

LO (Lack of Objections)

The review has not identified any potential environmental impacts requiring substantive changes to the preferred alternative. The review may have disclosed opportunities for application of mitigation measures that could be accomplished with no more than minor changes to the proposed action.

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EC (Environmental Concerns)

The review has identified environmental impacts that should be avoided in order to fully protect the environment. Corrective measures may require changes to the preferred alternative or application of mitigation measures that can reduce the environmental impact.

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EO (Environmental Objections)

The review has identified significant environmental impacts that should be avoided in order to adequately protect the environment. Corrective measures may require substantial changes to the preferred alternative or consideration of some other project alternative (including the no action alternative or a new alternative). The basis for environmental Objections can include situations:

  • Where an action might violate or be inconsistent with achievement or maintenance of a national environmental standard;

  • Where the federal agency violates its own substantive environmental requirements that relate to EPA's areas of jurisdiction or expertise;

  • Where there is a violation of an EPA policy declaration;

  • Where there are no applicable standards or where applicable standards will not be violated but there is potential for significant environmental degradation that could be corrected by project modification or other feasible alternatives; or

  • Where proceeding with the proposed action would set a precedent for future actions that collectively could result in significant environmental impacts.

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EU (Environmentally Unsatisfactory)

The review has identified adverse environmental impacts that are of sufficient magnitude that EPA believes the proposed action must not proceed as proposed. The basis for an environmentally unsatisfactory determination consists of identification of environmentally objectionable impacts as defined above and one or more of the following conditions:

  • The potential violation of, or inconsistency with, a national environmental standard is substantive and/or will occur on a long-term basis;

  • There are no applicable standards but the severity, duration, or geographical scope of the impacts associated with the proposed action warrant special attention; or

  • The potential environmental impacts resulting from the proposed action are of national importance because of the threat to national environmental resources or to environmental policies.

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Rating the Adequacy of the Draft Environmental Impact Statement (EIS)

Category 1 - Adequate

The draft EIS adequately sets forth the environmental impact(s) of the preferred alternative and those of the alternatives reasonably available to the project or action. No further analysis or data collection is necessary, but the reviewer may suggest the addition of clarifying language or information.

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Category 2 - Insufficient Information

The draft EIS does not contain sufficient information to fully assess environmental impacts that should be avoided in order to fully protect the environment, or the reviewer has identified new reasonably available alternatives that are within the spectrum of alternatives analyzed in the draft EIS, which could reduce the environmental impacts of the proposal. The identified additional information, data, analyses, or discussion should be included in the final EIS.

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Category 3 - Inadequate

The draft EIS does not adequately assess the potentially significant environmental impacts of the proposal, or the reviewer has identified new, reasonably available, alternatives, that are outside of the spectrum of alternatives analyzed in the draft EIS, which should be analyzed in order to reduce the potentially significant environmental impacts. The identified additional information, data, analyses, or discussions are of such a magnitude that they should have full public review at a draft stage. This rating indicates EPA's belief that the draft EIS does not meet the purposes of NEPA and/or the Section 309 review, and thus should be formally revised and made available for public comment in a supplemental or revised draft EIS.

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