N

E

P

A

National

Environmental

Policy

Act

Recommendations

for the Preparation of

Environmental Assessments

and Environmental Impact

Statements

Second Edition

December 2004

U.S. Department of Energy

Environment, Safety and Health

Office of NEPA Policy and Compliance

Recommendations 

for the Preparation of 

Environmental Assessments and 

Environmental Impact Statements 

Second Edition 

December 2004 

U.S. Department of Energy 

Environment, Safety and Health 

Office of NEPA Policy and Compliance 

printed on recycled paper 

Recommendations for the Preparation of Environmental Assessments 

and Environmental Impact Statements, Second Edition 

Preface 

This document provides recommendations for the Department of Energy’s (DOE’s) preparation of 

environmental assessments and environmental impact statements under the National Environmental 

Policy Act of 1969 (NEPA). The Office of NEPA Policy and Compliance prepared these 

recommendations in consultation with the Office of the Assistant General Counsel for Environment 

and following coordination with the DOE NEPA Community. The recommendations should materially 

aid those responsible for preparing and reviewing NEPA documents to focus on significant 

environmental issues, adequately analyze environmental impacts, and effectively present the 

analysis to decisionmakers and the public. The recommendations are not all-encompassing, 

however; preparers must apply independent judgment to determine the appropriate scope and 

analytical requirements of NEPA for each proposal. These recommendations do not constitute legal 

requirements, but are intended to enhance compliance with existing NEPA regulations 

(40 CFR Parts 1500−1508, 10 CFR Part 1021). 

This second edition revises the original document issued in 1993. The revisions include new 

sections addressing biological impacts, endangered species protection requirements, environmental 

justice, cumulative impacts, Clean Air Act conformity, Floodplain and Wetland Environmental Review 

Requirements, historic preservation requirements, mitigation, responses to comments, and the 

glossary. Recommendations have been added regarding the use of distribution lists and an index, 

and the discussions of accident analysis and other topics have been updated to reflect topic-specific 

guidance issued by the NEPA Office and recent DOE experience. Some sections of the original 

document have been reorganized or reworded. The NEPA Office may revise this document further 

from time to time to address additional issues and, as necessary, to reflect new policies, regulations, 

and judicial determinations. The NEPA Office welcomes suggestions for improvement. 

This guidance document and related NEPA requirements and guidance are available on the DOE 

NEPA Web site at www.eh.doe.gov/nepa. 

Recommendations for the Preparation of Environmental Assessments 

and Environmental Impact Statements, Second Edition 

Contents

 1. How to Apply These Recommendations .............................................................................1

2. Document Summary............................................................................................................4

3. Purpose and Need for Action ..............................................................................................5

4. Description of Alternatives, Including the Proposed Action.................................................7

4.1 Proposed Action..........................................................................................................7

4.2 Range of Reasonable Alternatives..............................................................................9

4.3 No Action Alternative.................................................................................................11

4.4 Describing Alternatives..............................................................................................12

5. Affected Environment ........................................................................................................14

6. Environmental Impacts (Effects)........................................................................................16

6.1 Impact Identification and Quantification ....................................................................19

6.2 Human Health Effects ...............................................................................................20

6.3 Biological Impacts .....................................................................................................25

6.4 Transportation Impacts..............................................................................................26

6.5 Accident Analysis ......................................................................................................27

6.6 Environmental Justice ...............................................................................................29

6.7 Cumulative Impacts...................................................................................................29

6.8 Compliance with Other Requirements.......................................................................31

6.8.1 Endangered Species Act ................................................................................31

6.8.2 Clean Air Conformity Requirements................................................................32

6.8.3 Floodplain and Wetland Environmental Review Requirements ......................33

6.8.4 National Historic Preservation Act ..................................................................33

6.9 Mitigation...................................................................................................................34

6.10 Comparison of Impacts .............................................................................................34

6.11 Conclusions in EAs and EISs....................................................................................35

7. List of Preparers, List of Agencies and Persons Consulted, and Distribution List.............36

8. Appendices, References, and Index..................................................................................37

9. Responses to Comments ..................................................................................................39

10. General Document Quality and Readability ......................................................................41

10.1 Objectivity..................................................................................................................41

10.2 Writing Quality...........................................................................................................41

10.3 Graphics and Data Treatment (Units, Statistics).......................................................43

10.4 Glossary ....................................................................................................................45

U.S. Department of Energy, Office of NEPA Policy and Compliance, December 2004 1

1. How to Apply These Recommendations 

Introduction 

This document provides background information and recommendations to improve the quality of 

environmental assessments (EAs) and environmental impact statements (EISs) that the 

U.S. Department of Energy (DOE) prepares under the National Environmental Policy Act of 

1969 (NEPA) and to thereby expedite the review and approval of EAs and EISs. The NEPA 

process is intended to inform the public and decisionmakers about the potential environmental 

impacts of proposed actions and alternatives and ultimately foster better decisions. 

Sections 2 through 9 generally parallel the format for EISs described in the Council on 

Environmental Quality’s (CEQ’s) regulations for implementing NEPA (40 CFR 1502.10), though 

much of this document applies to the preparation of EAs as well as EISs. The discussions 

highlight any distinctions to be drawn between EAs and EISs in the application of the 

recommendations in this document. Section 10 covers general principles to improve the 

readability of any NEPA document. Clear writing makes it easier to review the EA or EIS and 

understand the analysis presented, which enhances public participation and decisionmaking. 

This document focuses on the content of an EA or EIS, rather than the NEPA process itself. For 

example, section 4.1 includes recommendations for how to describe the proposed action but not 

recommendations on when a proposal becomes a proposed action subject to review under 

NEPA. Most sections begin with a background discussion, which summarizes applicable 

requirements. The recommendations highlight approaches that should be considered, as 

appropriate, when implementing the requirements. Many sections conclude with references to 

more detailed, related guidance. 

Throughout this document, the term analyzed alternative refers to an alternative for which the 

potential environmental impacts are assessed in detail. (See section 4.) An alternative 

considered but dismissed from detailed evaluation is not an “analyzed alternative” for purposes 

of this document. The terms impact and effect are synonymous and used interchangeably, 

consistent with 40 CFR 1508.8. One term, however, may be favored in a particular context 

(e.g., health effects, transportation impacts). 

Because each DOE proposed program or project presents a unique set of circumstances and 

potential impacts, the preparation of EAs or EISs does not reduce to a simple formula or 

cookbook. Therefore, the recommendations in this document should be adapted to the 

particular circumstances presented by each proposal, often by using a “sliding-scale” 

approach. 

Sliding-Scale Approach 

The sliding-scale approach to NEPA analysis applies generally to all of the recommendations in 

this document. This approach recognizes that agency proposals can be characterized as falling 

somewhere on a continuum with respect to environmental impacts. This approach implements 

CEQ’s instruction that in EISs agencies “focus on significant environmental issues and 

alternatives” (40 CFR 1502.1) and discuss impacts “in proportion to their significance” 

(40 CFR 1502.2(b)). (Note that under CEQ’s regulations and judicial rulings the degree to which 

environmental effects are likely to be controversial with respect to technical issues is a factor in 

determining significance. See 40 CFR 1508.27 for guidance on determining significance in the 

NEPA context.) The sliding-scale approach also makes good sense for EAs and other NEPA 

documents. 
2 U.S. Department of Energy, Office of NEPA Policy and Compliance, December 2004

When applying the sliding-scale approach to NEPA analysis, the preparer should analyze 

issues and impacts with the amount of detail commensurate with their importance. The term 

“scale” refers to the spectrum of significance of environmental impacts. Proposals with clearly 

small environmental impacts usually will require less depth and breadth of analysis either in 

identifying alternatives or analyzing their impacts (though the analysis still must satisfy all NEPA 

requirements). Conversely, as proposals fall increasingly closer to the high end of the 

continuum of potential environmental impacts, the depth and breadth of analysis will increase. 

Application of the sliding-scale approach is not, however, a rationale for preparing an EA (even 

a complex EA) rather than an EIS for a proposal with potentially significant environmental 

impacts. While some EAs need to be more complex than others, proposed actions with the 

potential for significant environmental impacts normally require an EIS. (DOE’s NEPA 

regulations at 10 CFR 1021 Subpart D, Appendices C and D identify proposed actions that 

normally require EAs and EISs.) 

Consistency in EAs and EISs 

When preparing EAs and EISs, sometimes information from existing NEPA documents can be 

used. For example, descriptions of the affected environment may be used directly or updated as 

required. Analysis of impacts may be used or refined in a new NEPA document if the existing 

analysis adequately describes the impacts from an analyzed alternative. Using parts of 

approved EAs and EISs can help reduce document preparation time and foster consistency. 

Similarly, information from other DOE (or other agency) documents, such as documented safety 

analyses, may be summarized and expressly incorporated by reference into EAs and EISs. 

NEPA document managers should review assumptions and methodologies employed in the 

existing documents to ensure the analysis is applicable to the new EA or EIS. 

Care also should be taken when preparing EAs and EISs to ensure that consistent and 

appropriate statements are made with regard to facility status and DOE programs and policies 

that affect the entire DOE complex. For example, an EA or EIS that describes and analyzes the 

generation and management of nuclear waste must describe and analyze waste disposition 

activities in a manner consistent with facility status and DOE’s programs and policies for the 

waste. An EA or EIS that is consistent with other NEPA documents, facility status, and DOE 

programs and policies will more accurately reflect choices among alternatives and provide more 

useful information for the public and the decisionmaker. 

Recommendations 

• Apply the advice in this document thoughtfully and sensibly in light of the specific 

circumstances that each proposed action presents. 

• Use this document as one tool among many (for example, use it in conjunction with DOE’s 

EA and EIS checklists). These recommendations do not provide comprehensive guidance 

on the preparation of EAs or EISs, or a replacement for good judgment. 

• Provide a level of detail and analysis commensurate with the importance of the issue or 

potential impact. Focus EAs and EISs on issues with potential for significant environmental 

impacts. Bear in mind that CEQ guidance defines an EA as a concise document that should 

not contain long descriptions or detailed data (Question 36a, “Forty Most Asked Questions 

Concerning CEQ’s NEPA Regulations,” as amended, 51 FR 15618, April 25, 1986; hereafter 

“CEQ’s 40 Questions”). 
U.S. Department of Energy, Office of NEPA Policy and Compliance, December 2004 3

• Identify trivial issues and impacts as such. Include only enough discussion to show why

more study is not warranted. 

• Provide information that a concerned citizen might want, keeping in mind that concerned 

citizens may need evidence for conclusions that seem obvious to the preparers. 

• Where substantial deviation from this general guidance appears necessary, arrange 

discussions, through the NEPA Compliance Officers, among cognizant program and field 

offices and the Office of NEPA Policy and Compliance, and Counsel, as appropriate, on the 

approach to the EA or EIS. 

Related Guidance 

• Environmental Assessment Checklist, 1994 

• Environmental Impact Statement Checklist, 1997

Available on the DOE NEPA Web site (www.eh.doe.gov/nepa) under Guidance. 
4 U.S. Department of Energy, Office of NEPA Policy and Compliance, December 2004

2. Document Summary 

Background 

A document summary facilitates the review of an EIS. For many readers, the summary forms 

their first and lasting impression of an EIS. The summary also highlights the major findings and 

conclusions of the environmental analyses for the public and the decisionmaker. Although not 

required, a brief summary similarly may be useful in an EA. 

CEQ NEPA regulations require that: “Each environmental impact statement shall contain a 

summary which adequately and accurately summarizes the statement. The summary shall 

stress the major conclusions, areas of controversy (including issues raised by agencies and the 

public), and the issues to be resolved (including the choice among alternatives). The summary 

will normally not exceed 15 pages” (40 CFR 1502.12). 

Recommendations 

• Ensure the summary is concise, informative, and easy to read. 

• Focus the summary on a comparison of analyzed alternatives. Describe each alternative, 

identifying the preferred alternative(s) if one or more exists (40 CFR 1502.14 (e)). Highlight 

key differences among alternatives, emphasizing the environmental implications of choosing 

among them. Include a table of comparison of impacts. 

• Emphasize issues and impacts in proportion to their importance. 

• Describe areas of controversy (including those raised in comments). 

• State the issues to be resolved, including the decision to be made and its relationship to the 

purpose and need for agency action. 

• Prepare the summary to read as a “stand-alone” document. It may be bound with the rest of 

the EA or EIS, or printed separately. 

Explanation: Address key elements of the entire EIS (or EA) such that the reader will 

understand the analysis without referring to the main body of the EIS. The summary 

should include information essential to a reasoned choice among alternatives, but 

may refer to EIS sections where subjects are treated in greater depth. 

• Be consistent with the main body of the EA or EIS. Do not introduce ideas, information, or 

conclusions in the summary that are not otherwise in the EA or EIS. 

• In a draft EIS, briefly describe the scoping process, summarize major issues raised in 

scoping comments, and identify major changes made to the scope of the EIS in response to 

comments. In a final EIS, briefly describe the public comment process, summarize major 

issues raised in comments and DOE’s response, and identify major changes from the draft 

to final EIS. 

Related Guidance 

• Environmental Impact Statement Summary, 1998 

Available on the DOE NEPA Web site (www.eh.doe.gov/nepa) under Guidance.
U.S. Department of Energy, Office of NEPA Policy and Compliance, December 2004 5

3. Purpose and Need for Action 

Background 

An EIS must “briefly specify the underlying purpose and need to which the agency is responding 

in proposing the alternatives including the proposed action” (40 CFR 1502.13). Similarly, an EA 

must include a brief discussion of the need for the proposal (40 CFR 1508.9(b)). (CEQ 

regulations do not distinguish between “purpose” and “need,” and use the terms together and 

separately.) 

In general, the statement of purpose and need should reflect the goals to be achieved by the 

statutory authority or programmatic mission under which DOE is proposing to act (i.e., an 

explanation of why agency action is needed). The statement of purpose and need is not a 

justification of what DOE proposes to do (i.e., it is not a rationale for a proposed action or 

preferred alternative) nor is it an explanation why DOE is preparing an EA or EIS (i.e., it is not to 

comply with NEPA).

The statement of the agency’s underlying purpose and need is critical to identifying the range of 

reasonable alternatives. If the purpose and need is defined too broadly, the number of 

alternatives that might require analysis would be virtually limitless. It is inappropriate in most 

situations, however, to define purpose and need so narrowly that only a single alternative could 

be identified for analysis. The proposed action is generally only one means of meeting the 

agency’s underlying purpose and need for action. 

Recommendations 

• Relate the statement of purpose and need to the broad requirement or goal for agency 

action – not to the need for a specific proposal. 

Example: An appropriate statement of purpose and need for agency action could be 

that a site needs to perform laboratory analysis within 24 hours of water sampling to 

comply with quality assurance procedures. An inappropriate statement of purpose 

and need under these circumstances would be that the agency needs to construct a 

new on-site laboratory; a new on-site laboratory, however, could be the proposed 

action. 

• Do not include requirements (e.g., conceptual design specifications) in the statement of 

purpose and need that unreasonably narrow or bias the range of reasonable alternatives. 

Example: Do not specify a particular technology in the statement of purpose and 

need if other technologies could be used to fulfill quality assurance procedures. An 

appropriate statement of purpose and need would allow different technologies to be 

included as reasonable alternatives. 

• Write the statement of purpose and need to identify the problem or opportunity to which the 

agency is responding. Recognize that the statement will determine the range of reasonable 

alternatives. 

Example: If the purpose and need for agency action is a requirement to perform 

laboratory analysis within 24 hours of sampling to comply with quality assurance 

procedures, the range of reasonable alternatives could be limited to on-site 
6 U.S. Department of Energy, Office of NEPA Policy and Compliance, December 2004

laboratory construction and expansion, and use of off-site laboratories, if any, that 

could reasonably be expected to provide 24-hour turnaround consistently. 

However, if the purpose and need for agency action is to increase laboratory 

analysis capability (i.e., without a 24-hour turnaround restriction), the range of 

reasonable alternatives also would likely include using DOE and commercial 

laboratories nationwide. 
U.S. Department of Energy, Office of NEPA Policy and Compliance, December 2004 7

4. Description of Alternatives, Including the Proposed Action 

Background 

In defining the scope of an EA or EIS, it is important to clearly describe the proposed action and 

identify the range of reasonable alternatives. In general, the range of reasonable alternatives is 

broader and the number of alternatives appropriately subjected to an analysis of impacts is 

greater in an EIS than in an EA. (In this document, “analyzed alternative” means an alternative, 

including any proposed action and no action, for which potential environmental impacts are 

assessed in detail. It does not include those alternatives considered but dismissed from detailed 

evaluation.) The following sections address how to define the proposed action, determine the 

range of reasonable alternatives, define the no action alternative, and describe all analyzed 

alternatives. The depth of analysis required for assessing and comparing the potential impacts 

of the alternatives is addressed in section 6. 

CEQ’s regulations direct all agencies to use the NEPA process to identify and assess the 

reasonable alternatives to proposed actions that will avoid or minimize adverse effects of these 

actions upon the quality of the human environment (40 CFR 1500.2(e)). 

From among the analyzed alternatives, an agency is to identify a preferred alternative. CEQ’s 

regulations require that an EIS “[i]dentify the agency’s preferred alternative or alternatives, if one 

or more exists, in the draft statement and identify such alternative in the final statement unless 

another law prohibits the expression of such a preference” (40 CFR 1502.14(e)). CEQ’s 

guidance indicates that the preferred alternative is the alternative that “the agency believes 

would fulfill its statutory mission and responsibilities, giving consideration to economic, 

environmental, technical and other factors.” It is identified to inform the public of the agency’s 

“orientation” (Question 4a, “CEQ’s Forty Questions”). CEQ’s guidance further states that the 

preferred alternative could be, but is not necessarily, the proposed action (Question 5a, “CEQ’s 

Forty Questions”). 

CEQ’s regulations require that EISs identify those alternatives that have been eliminated from 

detailed study (i.e., impacts analysis) because they are unreasonable and briefly discuss why 

they have been eliminated (40 CFR 1502.14(a)). This is also good practice for EAs, particularly 

when parties who are questioning the action have suggested alternatives that DOE believes do 

not respond to the purpose and need, or are unreasonable in other respects. If all or nearly all 

prospective alternatives are found to be unreasonable, the purpose and need may be too 

narrowly defined. (See section 3.) 

4.1 Proposed Action 

Background 

Sometimes the proposed action is stated in the form of a specific alternative (e.g., to build and 

operate a specific waste treatment facility with other treatment alternatives). Sometimes the 

proposed action is a broad proposal to fulfill the underlying purpose and need through one or 

more alternatives. As an example of the latter case, DOE may have a purpose and need to 

safely store or dispose of an inventory of waste that must first be treated to enhance its stability. 

The proposed action might be to select one or more waste treatment technologies described in 

the range of reasonable alternatives. 

With regard to EISs, CEQ’s regulations state that an agency should analyze “connected 

actions” and “cumulative actions” in one EIS. An agency also should analyze its “similar actions” 
8 U.S. Department of Energy, Office of NEPA Policy and Compliance, December 2004

in one EIS when that is the best way to adequately assess the combined impacts of the similar 

actions or reasonable alternatives (40 CFR 1508.25). 

Agency “connected actions” are those actions that automatically trigger other actions that may 

require EISs, cannot or will not proceed unless other actions are taken previously or 

simultaneously, or are interdependent parts of a larger action and depend on the larger action 

for justification. “Cumulative actions” are those that when viewed with other actions proposed by 

the agency have cumulatively significant impacts and therefore should be discussed in the 

same EIS. “Similar actions” are those that when viewed with other reasonably foreseeable or 

proposed agency actions have similarities that provide a basis for evaluating their 

environmental impacts together, such as common timing or geography. 

CEQ’s regulations are directed at avoiding segmentation, wherein the significance of the 

environmental impacts of an action as a whole would not be evident if the action were to be 

broken into component parts and the impact of those parts analyzed separately. Although 

CEQ’s regulations do not specifically direct agencies to consider their connected actions, 

cumulative actions, and similar actions in defining the scope of an EA, the impacts from such 

actions should be considered together in a single EA. 

Cumulative, connected, or similar actions should not be confused with cumulative impacts, 

which result from the past, present, or reasonably foreseeable actions of any Federal or 

non-Federal agency. (See section 6.7.) 

Recommendations 

• Think of a proposed action expansively and aim to include rather than exclude activities 

from the scope of a proposed action. 

Example: If a proposed action involves construction of a new facility, the EA or EIS 

should acknowledge that the facility eventually will be shut down and, as appropriate, 

require decontamination and decommissioning and other post-operational activities. 

These post-operational activities should be described to the fullest extent possible in 

the EA or EIS and their environmental impacts analyzed. 

If, however, the post-operational activities are sufficiently distant and DOE has no 

proposal yet for what activities would be undertaken, the post-operational activities 

may be treated as a connected action with indirect effects. (See section 6.) (The 

impacts of the proposed action and the connected action must both be described, 

but consideration of alternatives for the connected action may be deferred until the 

connected action is proposed.) 

• Consider relationships between a proposed action and other actions DOE proposes to take 

that may affect the same environmental resources. 

• Describe private and other Federal agency proposed actions that would be “enabled” by 

DOE’s proposed action (such as issuing a grant or contract, participating in a cooperative 

agreement, approving a request for an interconnection with a transmission system, or 

performing “work for others”). 

Explanation: An EA or EIS should not represent a private action that has been 

federalized by DOE funding as a DOE action. For example, the EA or EIS should 

state that “the proposed action is a DOE grant to State University for construction 
U.S. Department of Energy, Office of NEPA Policy and Compliance, December 2004 9

and operation of a new undergraduate chemistry laboratory,” rather than stating that 

DOE proposes to construct and operate a chemistry laboratory at the University. 

Note that actions by DOE’s contractors on DOE’s behalf are not “private” actions. 

• Include transportation activities as part of the proposed action when the transportation 

activities would be necessary to make the action happen or are an essential follow-on to the 

primary action. 

• Arrange consultations, through the NEPA Compliance Officers, among cognizant program 

and field offices, the Office of NEPA Policy and Compliance, and Counsel, as appropriate, 

when there is a substantive question about the scope of a proposed action. 

4.2 Range of Reasonable Alternatives 

Background 

CEQ’s regulations require agencies to use “the NEPA process to identify and assess the 

reasonable alternatives to proposed actions that will avoid or minimize adverse effects” 

(40 CFR 1500.2(e)). 

Environmental Impact Statements

CEQ’s regulations state that the comparative analysis of alternatives, including the proposed 

action, is the heart of an EIS (40 CFR 1502.14). The regulations require a rigorous exploration 

and objective evaluation of reasonable alternatives and that the EIS include the no action 

alternative (discussed separately in section 4.3). 

An EIS need not discuss every unique alternative when an unmanageably large number is 

involved. CEQ’s guidance states that for EISs, reasonable alternatives include those that are 

practical or feasible from a common sense, technical, and economic standpoint. “When there 

are potentially a very large number of alternatives, only a reasonable number of examples, 

covering the full spectrum of alternatives, must be analyzed and compared in the EIS” 

(Questions 1 and 2, “CEQ’s Forty Questions”). 

Environmental Assessments

CEQ’s regulations require that an EA include a brief discussion of alternatives to a proposed 

action that involves unresolved conflicts concerning alternative uses of available resources 

(40 CFR 1508.9(b)). Although this requirement (which stems from section 102(2)(E) of NEPA) 

has had varying interpretations, courts are increasingly requiring discussion of alternatives in 

EAs. In addition, DOE’s NEPA regulations (but not CEQ’s regulations) require that EAs include 

a no action alternative (10 CFR 1021.321(c)). Thus, an EA is used to satisfy requirements for 

analyzing alternatives, as well as to determine whether to prepare an EIS. 

EAs that address proposals where there is heightened technical controversy surrounding 

potential impacts or where there is otherwise greater potential for significant environmental 

impacts from the proposed action may need to identify and analyze more alternatives than other 

EAs. (See section 6, Background.) Conversely, the smaller the impacts of the proposed action, 

the less need there is to consider alternatives. In other words, where a proposed action falls on 

the sliding scale will affect the alternatives analysis. All DOE EAs, however, must satisfy 

minimum requirements as reflected in 40 CFR 1508.9 and 10 CFR 1021.321. Alternatives that 
10 U.S. Department of Energy, Office of NEPA Policy and Compliance, December 2004

might have fewer or smaller impacts than the proposed action should be considered. The 

addition of alternatives to an EA is not a substitute for preparing an EIS when one is required. 

Recommendations 

• Identify the range of reasonable alternatives that satisfies the agency’s purpose and need. 

Include alternatives that would respond to the underlying purpose and need under a variety 

of reasonably foreseeable circumstances. Alternatives should be defined broadly enough to 

allow small changes in the way DOE implements the selected alternative, but not so broadly 

to preclude meaningful analysis. 

• Analyze alternatives that seem impractical only because of current programmatic 

assumptions, but otherwise would be reasonable. Also, consider whether it is foreseeable 

that technical or economic factors might change such that an apparently infeasible but 

otherwise reasonable alternative would become feasible. 

Example: The proposed action is management of a legacy material that has no 

current programmatic use, but is not authorized to be sold and is not classified as a 

waste. Consider whether it is possible that the material could be reclassified as 

government surplus or as a waste (depending on its characteristics) and include 

alternatives that would prepare it for commercial sale or disposal. 

Example: The proposed action is development of a new processing facility. The site 

has extensive experience with a particular processing technology and expects to use 

that technology in the new facility. Other technologies might be applicable, but they 

have received less research and development and no funding for further 

development. In the NEPA document, include alternatives that use other 

technologies, particularly those that might have environmental, safety, or cost 

advantages. 

• Do not overlook reasonable technology, transportation, or siting alternatives, including 

off-site alternatives. 

• Address reasonable alternatives that are outside DOE’s jurisdiction, even if they conflict 

with lawfully established requirements (e.g., an alternative that could be reasonable if an 

existing law could be amended or if a regulatory agency granted a waiver). 

• Identify and briefly discuss alternatives considered but dismissed from detailed evaluation, 

particularly any such alternatives raised during the public scoping or comment process. 

Explain why an alternative is not reasonable (e.g., that the cost or time to implement would 

be impractical, technical implementation would be infeasible). Make the method for 

screening alternatives clear to readers. The failure to consider alternatives that seem

reasonable to others would affect the credibility of an otherwise adequate NEPA review. 

• Note that infeasible alternatives are certainly unreasonable; feasible alternatives also may 

be unreasonable. 

Example: It might be feasible to build a new facility at a given site without regard to 

infrastructure because all necessary infrastructure already exists. It might not be a 

reasonable alternative, however, to build the same facility at another site because 

the required infrastructure is not in place and could not be provided at reasonable 

time or expense. 
U.S. Department of Energy, Office of NEPA Policy and Compliance, December 2004 11

• As a general guide for EAs (for which requirements are less specific than for EISs), use the 

sliding-scale approach when determining how many alternatives to identify and analyze in 

an EA and the depth of analysis to provide for each alternative. Consider adding alternatives 

if they might have fewer or smaller impacts than the proposed action. 

4.3 No Action Alternative 

Background 

The no action alternative must be considered in all DOE EAs and EISs. The no action 

alternative may or may not be a reasonable alternative. 

The no action alternative provides a baseline against which impacts of the other analyzed 

alternatives can be compared. No action does not necessarily mean doing nothing. Rather, the 

no action alternative often involves maintaining or continuing the “status quo” (e.g., a 

management plan or activity covered by an existing NEPA review). For proposed new 

projects, "no action" means that the proposed activity would not take place. For proposed 

changes to an ongoing activity, "no action" can mean continuing with present plans. It also 

can mean discontinuing the present course of action by phasing-out operations (Question 3, 

“CEQ’s Forty Questions”). 

Recommendations 

• In some situations, no action taken by DOE may constitute the only alternative to the 

proposed action. 

Example: DOE may be involved with a private applicant and faced with a go/no-go 

decision (e.g., fund or not fund, approve or not approve). In such a case, the no 

action alternative may include several sub-alternatives consisting of those 

reasonably foreseeable courses of action that would be available to the applicant if 

DOE denies its application. DOE should describe such sub-alternatives and analyze 

their impacts to the extent they are reasonably foreseeable. 

• Consider the no action alternative even if DOE is under a court order or legislative command 

to act. (Note that if DOE clearly has no discretion regarding its action, then the action is not 

subject to NEPA review. See definition of Action at 10 CFR 1021.104(b).) Include discussion 

of the legal ramifications of no action, if appropriate. 

• When a NEPA document addresses ongoing activities, it may be useful to consider more 

than one version of “no action.” 

Example: A site-wide EIS might analyze the continuation of the present course of 

action as one no action alternative and discontinuation of present operations as a 

second no action alternative. In such cases, it is important to carefully name the no 

action alternatives to avoid confusion. 
12 U.S. Department of Energy, Office of NEPA Policy and Compliance, December 2004

4.4 Describing Alternatives 

Recommendations 

• Describe each analyzed alternative, including no action, in sufficient detail so that its scope 

is clear and its potential impacts can be identified. 

Explanation: As appropriate, include the following elements in the description of each 

alternative – 

(1) general project progression – information on construction milestones, projected 

operating cycle, and any aspects of the alternative that could result in impacts that 

vary over time (for example, with time of day or season of the year); 

(2) pre-operational activities – information on construction, including pre-construction 

site surveys, site clearing and preparation (e.g., excavating, construction lay-down or 

staging areas), access road construction, and other activities that would be 

necessary to support construction; 

(3) operational activities – description of project and related support operations or 

facilities on-site and off-site, including identification of roads, parking lots, utility hookups, borrow sites, and maintenance and transportation activities. Identify waste 

streams in general (including emissions) and state how they would be treated and/or 

disposed of; and 

(4) post-operational requirements – description of reasonably foreseeable future 

requirements including site close-out and site restoration. Describe any related 

decontamination and decommissioning activities, including associated waste 

streams, to the extent practicable. Where only limited discussion of decontamination 

and decommissioning or other such distant future post-operational activities is 

possible, include a statement that a separate NEPA review may be needed before 

such future activities occur. (See section 4.1.) 

• Describe alternatives objectively by focusing on clear explanations of the elements or 

activities that define each alternative and avoiding any appearance of bias. 

• When identifying releases, include rate and duration. Provide an explanation when it is not 

possible to quantify releases that may result in significant impact (40 CFR 1502.22). 

Example: Rather than stating that the discharge rate would be “1.0 mg/hr,” state that 

the estimated rate would be “1.0 mg/hr for 8 hours per day, 5 days per week during 

the lifetime of the operation.” The impact of the latter is more readily determined. 

• Use the same time span to assess the impacts of all alternatives, including no action. 

• Encompass reasonably foreseeable modifications and circumstances that can change over 

time when describing an alternative. Aim to include rather than exclude activities from the 

scope of the alternative. Account for the possibility that the time estimated to implement an 

alternative may change. 
U.S. Department of Energy, Office of NEPA Policy and Compliance, December 2004 13

Example: Identify a realistic maximum volume of chemical to be used in a process 

per unit time or over the entire length of the project, rather than, or in addition to, 

specifying the expected volume. 

• Describe each analyzed alternative in a manner that makes clear to readers what the 

differences between alternatives would be (e.g., alternate location, technology). 

• Consider structuring alternatives to allow a decision to be based on a combination of 

alternatives or elements of alternatives, as appropriate. 

Explanation: Sometimes DOE can fulfill its purpose and need by combining elements 

of two or more alternatives. DOE can choose this approach while the EIS is being 

prepared or in a record of decision. While the EIS is being prepared, if DOE identifies 

a preferred alternative that is a combination of elements of other alternatives, this 

combination should be presented in the EIS as a discrete alternative (i.e., present a 

cohesive description of the preferred alternative and its impacts rather than merely 

direct readers to the descriptions of its various elements). 

Otherwise, the EIS should state clearly that DOE may combine elements of 

alternatives in its record of decision, as appropriate. (Note that the analysis of 

potential impacts should provide sufficient information to allow the reader to 

determine the impacts of reasonable combinations of alternatives. This does not 

necessarily mean that the impacts of every conceivable combination of alternatives 

must be presented.) 

• In defining an alternative, consider what measures are available to reduce environmental 

impacts and include these measures in the detailed description of the alternative. 

Explanation: Some measures may be inherent in any alternative (e.g., standard 

construction practices, standard operating procedures, implementation of resource 

protection policies, DOE-required procedures, pollution prevention activities). Other 

measures may be necessary for a particular alternative to be likely to proceed 

(e.g., scheduling construction or operation not to occur when an endangered 

migratory species is in seasonal residence on-site). 

• Where discrete, major mitigation options are available, consider presenting them as 

separate alternatives or sub-alternatives so that their impacts can be compared. (See 

section 6.9.) 

Example: Sub-alternatives based on major mitigation strategies to reduce air impacts 

from a power plant might include a credit trading strategy or investment in regional 

road construction projects. 
14 U.S. Department of Energy, Office of NEPA Policy and Compliance, December 2004

5. Affected Environment 

Background 

CEQ’s regulations require a succinct description of the affected environment (with respect to the 

proposed action and all analyzed alternatives) in a discrete section of an EIS unless an agency 

has a compelling reason to use a different format (40 CFR 1502.10 and 1502.15). An EA should 

provide a brief description of the environment to be affected by a proposed action (and by any 

other analyzed alternative). 

The extent of the “affected environment” may not be the same for all potentially affected 

resource areas. For example, traffic may increase within four miles of a site from which waste 

would be removed to a nearby landfill (the extent of the affected environment with respect to 

transportation impacts). In contrast, groundwater extending two miles from the site may be 

affected (the extent of the affected environment with respect to groundwater impacts). 

Recommendations 

• In describing the affected environment, lay the foundation for evaluating the potential 

environmental impacts of the analyzed alternatives. 

Explanation: Provide appropriate (i.e., sufficient, but not excessive) detail concerning 

environmental resources (such as air quality) that may be affected by the 

alternatives to adequately support the impact analysis, including cumulative impact 

analysis. 

• Use affected environment descriptions from existing DOE NEPA documents, where 

appropriate and to the extent possible. Use the most current data available (e.g., latest 

census). 

Explanation: The description should not be reinvented when the description in 

existing NEPA documents could be used directly or updated. This can help reduce 

document preparation time and foster consistency among DOE NEPA documents. 

However, the description of the affected environment should be appropriate to the 

alternatives and, thus, may vary among DOE NEPA documents for a particular site. 

• Limit the description of the existing environment to information that directly relates to the 

scope of the analyzed alternatives (i.e., provide the information that is necessary to assess 

or understand the impacts). Where appropriate, summarize and incorporate by reference 

more detailed descriptions of the affected environment. 

Example: Provide information on hydrogeology or water resources only if one or 

more alternatives would consume water or could result in discharges to surface or 

ground water. 

• Incorporate in the EA or EIS descriptions of the affected environment relevant to the 

discussion of compliance with requirements other than NEPA. (See section 6.8.) 

Example: Environmentally-sensitive resources (e.g., floodplains and wetlands, 

threatened and endangered species, and property of historic, archeological, or 

architectural significance) may be present in the area and affected by the analyzed 

alternatives. If such resources are present, be sure to satisfy requirements for 

environmental review under applicable laws, regulations, and Executive Orders and, 
U.S. Department of Energy, Office of NEPA Policy and Compliance, December 2004 15

to the extent possible, integrate such review with the EA or EIS. When appropriate, 

state that environmentally-sensitive resources are not present. Append consultation 

letters, as appropriate. 

• Present information on the potentially impacted minority and low-income populations. 

Consider whether these populations may interact with the environment in ways that create 

unique exposure pathways. Distribution of these populations may be diffuse and not 

captured by census data alone. Supplement census data with other relevant information. 

Explanation: Minority and low-income populations should be identified for the 

geographic region relevant to each resource area or impact type. Consider, for 

example, whether minority or low-income populations uniquely rely on certain natural 

resources for food or natural areas for cultural, religious, or economic reasons. If no 

such populations are present, then document this finding; explain that there is no 

need for further environmental justice analysis for that resource area. 
16 U.S. Department of Energy, Office of NEPA Policy and Compliance, December 2004

6. Environmental Impacts (Effects) 

This section provides recommended approaches for analyzing impacts. The general 

recommendations provided in this section apply to impact analysis for all resource areas, as do 

the recommendations regarding impact identification and quantification in section 6.1. 

Sections 6.2 through 6.7 provide recommendations for analyzing certain impacts that are 

routinely encountered in DOE NEPA documents. Sections 6.8 through 6.11 discuss other 

aspects of impact analysis. 

Two concepts used in discussing environmental impacts are risk and bounding analysis. The 

term risk has a wide variety of meanings. Frequently in EAs and EISs, risk is expressed 

quantitatively as the probability of an adverse event occurring multiplied by the consequence of 

that event (i.e., the product of these two factors). Risk also can refer to a general statement of 

concern, hazard, or danger, or it can denote uncertainty or chance. Thus, it is important to 

define clearly the context in which the term is used. 

A bounding analysis is an analysis designed to identify the range of potential impacts or risks, 

both upper and lower. Such an approach might be used in an EA or EIS, for example, to simplify 

assumptions, address uncertainty, or because expected values are unknown. As a practical 

matter, a bounding analysis most often is used to provide conservatism in the face of 

uncertainty. 

Background 

Section 102(2)(C) of NEPA requires evaluation of: 

• unavoidable impacts 

• the relationship between short-term uses of the environment and the maintenance and 

enhancement of long-term productivity 

• any irreversible or irretrievable commitments of resources. 

In addition, CEQ regulations (40 CFR 1502.16) state that an EIS should discuss: 

• direct and indirect effects 

• possible conflicts between the proposed action and the objectives of Federal, regional, 

state, local, and tribal land use plans, policies, and controls 

• energy and natural or depletable resource requirements and conservation potential of 

alternatives and mitigation measures 

• urban quality, historic and cultural resources, and the design of the built environment. 

CEQ regulations also require consideration of cumulative impacts (40 CFR 1508.25(c); 

cumulative impacts are discussed in section 6.7). 

An impact may be adverse or beneficial, and the overall impacts of an alternative may be 

significant even if on balance the impacts would be beneficial (40 CFR 1508.8 and 

1508.27(b)(1)). In addition to characterizing impacts, an EA or EIS should discuss means to 

mitigate impacts. (See section 6.9.) 

Direct effects are caused by an action and occur at the same time and place as the action. 

Indirect effects are reasonably foreseeable effects caused by the action that occur later in time 

or farther in distance (40 CFR 1508.8). Irreversible and irretrievable commitments of resources 

include resource loss (such as the burning of fossil fuel) and forgone resources (i.e., resources 
U.S. Department of Energy, Office of NEPA Policy and Compliance, December 2004 17

that would remain but would be inaccessible or could not be used, such as land and 

ecosystems inundated by dam construction). 

In general, impacts (beneficial and adverse) will be more thoroughly analyzed in an EIS than in 

an EA because an EIS deals with actions that admittedly may have significant impacts. An EIS 

must devote substantial treatment to all reasonable alternatives analyzed to enable a 

comparison among those alternatives. Also, an EIS must identify the methodology used for the 

impacts analysis (often discussed in an appendix) and make explicit reference to scientific or 

other resources relied upon (40 CFR 1502.24). All NEPA documents must rely on high quality 

information, including accurate scientific analysis (40 CFR 1500.1(b)). 

When confronted with incomplete or unavailable information for an analysis of reasonably 

foreseeable, significant adverse environmental effects, CEQ’s regulations require agencies to 

indicate that such information is lacking and to obtain the information when doing so does not 

entail an exorbitant cost and the information is essential to a reasoned choice among 

alternatives (40 CFR 1502.22). Otherwise, agencies are to discuss the implications for the 

analysis. 

An EA may focus the impacts analysis on the proposed action in order to provide the basis for a 

significance determination. The CEQ regulations (40 CFR 1508.9(b)), however, require an EA 

also to include brief discussions of the impacts of alternatives to a proposed action that involves 

unresolved conflicts concerning alternative uses of available resources. As with the choice of 

alternatives (section 4.2), the analysis of impacts of alternatives should be more detailed in an 

EA where there is heightened technical controversy surrounding potential impacts or where 

there is otherwise greater potential for significant impacts. That is, the sliding-scale approach 

applies to impacts analysis in much the same way as it applies to the choice of alternatives. An 

unusually complex and lengthy EA, however, may indicate the need for an EIS (Question 36b, 

“CEQ’s Forty Questions”). 

CEQ distinguishes between the “environmental consequences section” of an EIS, which should 

be devoted largely to a scientific analysis of the impacts of the analyzed alternatives, and the 

“alternatives section,” which should present a concise comparison of alternatives (based on and 

summarizing information developed in the “environmental consequences section”) (Question 7, 

“CEQ’s Forty Questions”). In both cases, DOE normally presents the impacts of each analyzed 

alternative by resource area. In some cases impacts may be presented by alternative. 

Section 6.10 provides some general approaches to alternatives comparisons in both EAs and 

EISs. 

Recommendations 

• Address environmental impacts in proportion to their potential significance. That is, focus the 

impacts analysis and discussion on project attributes that have significant impacts or 

potential for significant impacts. 

• Identify, but do not address, clearly insignificant impacts in detail. Indicate how all relevant 

environmental attributes were considered, and provide enough information to show why 

greater consideration is not needed. 

• Identify all potential nontrivial impacts from all elements of an alternative, including those 

that may not be the primary focus of the alternative. 

Example: For proposed waste treatment and disposal, the EA or EIS should assess 

any adverse environmental effects of transport, storage, and handling on worker and 
18 U.S. Department of Energy, Office of NEPA Policy and Compliance, December 2004

public health and environmental resources, in addition to the more obvious effects 

from treatment and disposal operations. 

• Identify possible indirect impacts, and indicate the degree to which these impacts are 

uncertain. 

Example: The classic example of an indirect impact is growth and development that 

follows the construction of a road or the extension of utility lines. Another example is 

the installation of a flood control or hydroelectric power dam that might directly 

interrupt salmon migration and spawning; over time, bald eagles (which feed on 

salmon) might indirectly suffer from a loss of food supply. 

• Analyze environmental impacts for as long as they are reasonably foreseeable, not 

speculative, including foreseeable long-term as well as short-term effects. 

Example: Waste disposal impacts may occur hundreds or thousands of years from 

the time the actual disposal activity took place. 

• It may be helpful to present the impacts by resource area (rather than by alternative) to 

allow for direct comparison among alternatives. 

• Consider environmental impacts within geographic boundaries appropriate for each 

resource reviewed. 

• Separately address the impacts from all elements or activities encompassed within each 

alternative (e.g., construction, operation, waste management, transportation, 

decontamination and decommissioning). 

Explanation: This approach allows a comparison of elements of alternatives, which 

can allow decisionmakers to assess whether to combine elements of two or more 

alternatives. This approach also allows a comparison of mitigation options. 

• Where requirements (e.g., standards) are directly relevant to limiting environmental impacts, 

identify the requirements, briefly state their conditions (e.g., release limits), and indicate 

whether the alternative threatens a violation of any applicable environmental protection 

requirement. Note that compliance with requirements does not mean there is no potential for 

significant impacts, and demonstrating compliance does not substitute for analyzing 

impacts. 

• Consider the quality of the affected environment. An alternative that would contaminate a 

pristine area or that would increase pollutant levels close to applicable limits (e.g., an 

alternative that could cause “significant deterioration”) may have significant impacts. 

• Do not confuse the description of impacts from the no action alternative with the description 

of the affected environment. 

Example: The affected environment’s air quality discussion might describe the 

general climate, wind, temperature, rainfall, ambient concentrations of air pollutants 

at the site, and current site emissions and emission rates. Also, this discussion 

would identify, as appropriate, existing air quality permits and specify the attainment 

status for criteria pollutants. In contrast, impact assessment for the no action 
U.S. Department of Energy, Office of NEPA Policy and Compliance, December 2004 19

alternative would include projections of future site emissions and emission rates 

without the proposed action. 

• Identify any responsible opposing views regarding how to conduct impacts analysis or 

interpret conclusions. 

Explanation: DOE’s approach may not be the only credible way to analyze potential 

impacts and interpret the results of the analysis. Different means may be identified 

through comments on the EA or EIS or through other information. The EA or EIS 

should (1) acknowledge the controversy (i.e., the differences of opinion or fact) and 

(2) explain the basis for DOE’s choice of methodology in a manner that 

demonstrates that the analysis in the EA or EIS is technically sound and provides a 

sufficient basis for decisionmaking. Also, consider explaining how use of the different 

methodology would affect the conclusions, as this different perspective might be 

useful to the decisionmaking process. In some cases, it may be prudent and useful 

to present the results of using the alternative data, assumptions, or methodologies. 

6.1 Impact Identification and Quantification 

Recommendations 

• Quantify impacts to the extent practicable, consistent with the sliding-scale approach and 

taking into account available project information and design data. Acknowledge uncertainty 

and incompleteness in the data. Where the uncertainty is significant or a major factor in 

understanding the impacts, explain how the uncertainty affects the analysis. 

Explanation: In some cases, it is appropriate to explain uncertainty qualitatively 

(e.g., by discussing the factors that make the estimate uncertain and considering that 

uncertainty when comparing impact estimates). In other cases, a more detailed 

analysis might be necessary. One tool for such cases is sensitivity analysis, which 

identifies the factors that most affect the estimate and provides insight into the range 

of potential impacts. 

• Provide sufficient data and references to allow review of the validity of analytical methods 

and results. 

• Present impact estimates so as to avoid inappropriate comparisons or summing (don’t add 

apples and oranges). 

Explanation: EAs and EISs evaluate numerous and varied impacts (e.g., health 

effects, transportation impacts) for each alternative. In comparing alternatives, any 

quantitative impact estimates should be presented separately. Any attempt to 

combine them should recognize differences and uncertainties in methodology or 

calculation. 

• Do not attempt to quantify impacts on environmental resources when it is clear from the 

context that impacts would be virtually absent. Provide a brief negative declaration, such as, 

“The project would not affect threatened or endangered species or their habitats,” and 

provide appropriate references, consultation letters, or explanation. 
20 U.S. Department of Energy, Office of NEPA Policy and Compliance, December 2004

• Compare environmental impacts in their appropriate context. Do not use regional, national, 

or global comparisons that might trivialize the significance of a local impact. 

Example: Local comparisons may sometimes appropriately provide a context for 

assessing impact (e.g., withdrawing 10 hectares of agricultural land from use in a 

county with 10,000 hectares in production of the same crop). However, it would be 

inappropriate to say, “Five traffic fatalities would be expected locally as a result of the 

alternative’s shipping campaign, but this is small compared to the approximately 

200,000 traffic fatalities that would be expected to occur nationally during the same 

five-year period.” 

• In addition to identifying pollutants that would be released and wastes that would be 

produced, identify potential effects from these substances (e.g., human diseases, and 

effects on plant and animal populations and ecosystem functions). A quantified release rate 

should not be the endpoint in impact analysis. 

Example: Releases into fresh water streams may affect humans who drink the water, 

alter aquatic invertebrate populations, or accumulate in sediment and ultimately have 

adverse impacts on benthic invertebrates. 

• Recognize that relative comparisons do not provide absolute information, and both relative 

and absolute information generally are needed. 

Example: The statement “routine emissions would increase by 0.05 percent” does 

not describe an impact (although it is a valuable part of the description of the 

alternative). The statement provides neither the absolute value of emissions nor the 

basis for determining their environmental impacts. Further, relative comparisons, 

particularly those given without a baseline of absolute magnitude, may be misleading 

(e.g., “99.9% pure water” could describe raw sewage). 

• Describe the likelihood of potential impacts whenever possible. 

Explanation: Both the estimated frequency and the magnitude of impacts inform 

readers about the nature of the impact and mitigation options. Often, the most 

significant impacts arise from scenarios that are unlikely to occur, whereas less 

significant impacts may occur frequently. 

• In general, use available data for an EA. If data needed to quantify impacts are not 

available, qualitatively describe the most relevant impacts. Be aware that inability to 

satisfactorily characterize an important impact in an EA likely will render it inadequate to 

support a finding of no significant impact. 

6.2 Human Health Effects 

Background 

The principal potential human health effect from exposure to low doses of radiation is cancer. 

Human health effects from exposure to chemicals may be both toxic effects (such as nervous 

system disorders) and cancer. Exposure and dose are neither health effects nor environmental 

impacts. Rather, they cause the health effects. A common problem in estimating effects from 

human exposure to chemicals or radiation is the failure (or inability in some cases) to carry the 
U.S. Department of Energy, Office of NEPA Policy and Compliance, December 2004 21

analysis to completion; that is, to identify, and quantify when appropriate, potentially significant 

health effects (e.g., number of deaths). Also, consider the potential for non-radiological and 

non-chemical human health effects (e.g. physical injury). 

It is appropriate, but not at all sufficient for purposes of analysis, to state that DOE facilities and 

operators would have to comply with all applicable requirements, that exposure to workers and 

the public would be minimized by using appropriate and approved safeguards and procedures, 

or that exposure to workers and the public would be maintained as low as reasonably 

achievable below applicable dose limits. 

Recommendations: Human health effects generally 

• Apply the sliding-scale approach when characterizing human health effects. 

• Determine the period of estimated exposure by how long an alternative would expose 

workers or the general public. In general, impacts should be analyzed for as long as they 

are reasonably expected to occur. 

Explanation: Typically use 30 years for workers and the public unless the alternative 

specifies a different period of potential exposure (e.g., the operating life of the facility 

is assumed to be 10 years). If there is a potential for lifelong exposure to the public 

(e.g., from long-lived contaminants that are permanently at a site, such as from 

waste disposal or residual radioactivity or contaminants that persist in soils or 

groundwater), use 70 years for the period of estimated exposure. Impacts related to 

decommissioning may need to be considered beyond the operational lifetime of a 

facility, and waste disposal impacts may occur hundreds or thousands of years from 

the time that the disposal activity takes place. 

• Analyses generally should be based on realistic exposure conditions. Where conservative 

assumptions (i.e., those that tend to overstate the impact) are made, describe the degree of 

conservatism, and characterize the “average” or “probable” exposure conditions if possible. 

• Consider all potential routes of exposure, not just the most obvious route. 

Example: Where the proposed activities might result in the air suspension of 

contaminated soils, consider the downwind exposure of the public to suspended 

particles. 

• Aim to provide estimates of potential health effects from chemical or radiological exposure 

for three subsets of populations and maximally exposed individuals in those populations: 

(1) involved workers (participants at the location of the action), 

(2) noninvolved workers (workers that would be on the site of the alternative but not 

involved in the action), and 

(3) members of the general public. 

Provide these estimates for both routine operations and accident scenarios. (Accidents are 

discussed in section 6.5.) 
22 U.S. Department of Energy, Office of NEPA Policy and Compliance, December 2004

• Provide the basis for health effects calculations, as it may be misleading to present only the 

resulting estimates. As appropriate, present the dose, or dose-to-risk (health effects) 

conversion factor, potential health effects calculated for the year of maximum dose and for 

the total period of estimated exposure, and any other germane information (further 

discussion below). 

Recommendations: Carcinogenic effects from radiation exposure 

• When providing quantitative estimates of carcinogenic effects of radiation exposure, express 

population (or collective) effects as an estimated number of excess fatal cancers and 

express maximum individual effects as the estimated maximum probability of the premature 

death of an individual. Excess fatal cancers refers to those latent cancer fatalities beyond 

what would be expected to occur in the population absent the radiation exposure. 

• Evaluate effects for involved workers, noninvolved workers, and the general public under 

both routine operations and accident scenarios. Discuss uncertainty associated with 

estimates, as appropriate. 

• When providing quantitative estimates of radiation impacts, always use current dose-to-risk 

conversion factors that have been adopted by cognizant health and environmental 

protection agencies, such as the Nuclear Regulatory Commission and the Environmental 

Protection Agency (EPA). Specify the conversion factors being used and provide a 

reference to their source. Be aware that conversion factors are occasionally revised to 

incorporate new experimental and epidemiological information. 

Example: Analyses are frequently conducted using models and codes that project 

Total Effective Dose Equivalent (TEDE) estimates rather than exposure or intake 

estimates and, in such cases, it is normally appropriate to use TEDE dose-to-risk 

factors. As of this writing, the dose-to-risk conversion factor that should be used for 

estimating excess cancer deaths from exposure to low dose rates of ionizing 

radiation is 600 cancer deaths (latent cancer fatalities) per million person-rem TEDE 

(6 × 10−4

 deaths per rem). This conversion factor may be applied to the general 

population (which includes children) and the worker population. In general, estimates 

of cancer mortality derived from these conversion factors should not be stated using 

more than one significant digit. As of this writing, the dose-to-risk factor 

recommended for morbidity (cancer incidence) is 800 cancers per million person-rem 

(8 × 10−4

 cancers per rem). (“Estimating Radiation Risk from Total Effective Dose 

Equivalent (TEDE), ISCORS Technical Report No. 1,” DOE/EH-412/0015/0802 

rev. 1, January 2003.) 

Use of the dose-to-risk conversion factors described above is acceptable for most 

comparative analyses. Such use, however, will tend to result in more conservative 

estimates than use of more detailed, radionuclide-specific methods for assessing 

risk. More detailed methods may be used when doing so would produce a more 

useful estimate based on project-specific information. One method to prepare such 

detailed analyses is to use the appropriate exposure-to-risk factors from Federal 

Guidance Report #13 (“Cancer Risk Coefficients for Environmental Exposure to 

Radionuclides,” EPA 402-R-99-001, September 1999). 

• Use statements about background or natural sources of radiation and about relevant dose 

limits judiciously to help explain the impacts but not to suggest that the impacts are 

acceptable. Do not assert that the average annual effective dose equivalent caused by a 
U.S. Department of Energy, Office of NEPA Policy and Compliance, December 2004 23

project translates to an insignificant increase in risk simply because it constitutes only a 

small increase above background or because it complies with applicable requirements. 

Present information and allow readers to make their own judgments. 

Example: The average annual effective dose equivalent that individuals receive from 

naturally occurring radiation, or some other point of reference (e.g., airplane travel), 

might provide readers perspective on doses estimated for the analyzed alternative. 

Impacts from the alternatives would occur independently of impacts from natural 

background radiation, however, and the text should not imply that background 

radiation provides a basis for judging the significance of the impacts of the analyzed 

alternative. 

Example: While compliance with applicable requirements is necessary for the 

alternative to be permitted or approved, the discussion must describe the impact of 

the alternative as well as state whether DOE would be in compliance. The fact that 

exposures are subject to limits and must be maintained as low as reasonably 

achievable (under DOE Order 5400.5) does not in itself demonstrate that the effects 

on workers’ health (from the project or cumulatively with other exposures) are 

insignificant. EAs and EISs should fully disclose impacts and present sufficient 

information to allow a comparison among the alternatives. 

• Always define “risk” when using the term and provide the context for its use. If “risk” or 

“probability” is used in describing potential effects, be certain to state the effect the 

probability describes (e.g., the probability of cancer death, probability of high dose rate, 

probability of a particular accident scenario). Present the probability and potential effect in 

addition to any risk estimate. (See section 6, introduction.) 

• Consistent with the sliding-scale approach, the assessment of health effects from 

occupational radiation exposures in EAs usually need not be as extensive as the 

assessment in EISs. When estimated occupational dose rates are substantially below 1 rem 

per year for each individual and 1,000 person-rem per year for the worker population, the 

following may serve as a model description of the health effects from occupational radiation 

exposure from normal operations:

Worker exposures to radiation under normal operations would be controlled under 

established procedures that require doses to be kept as low as reasonably 

achievable and that limit any individual’s dose to less than 5 rem per year. Based on 

relevant experience with _____ [reference similar projects for which worker exposure 

data is available], DOE expects the average annual dose rate from this alternative to 

be maintained below ___ rem per year [e.g., 0.1 rem per year]. The collective worker 

dose would not exceed ___ person-rem. [Obtain the result by multiplying: average 

dose rate (rem/year, from the previous sentence) times the average number of 

workers being exposed times the operational life of the project (years).] Based on 

the currently recommended dose-to-risk conversion factor of 6 × 10−4

 excess fatal 

cancers per person-rem [cite current Federal guidance], workers engaged in this 

alternative would not be expected to incur any harmful health effects from radiation 

exposures they receive during normal operations. 

Example: Assuming that an average worker population of 50 people each receive an 

average exposure of 0.1 rem per year for the project lifetime of 30 years, the 

workers’ collective dose would be 50 × 0.1 rem/year × 30 years = 150 person-rem. 

Multiply the estimated person-rem by the dose-to-risk conversion factor to calculate 
24 U.S. Department of Energy, Office of NEPA Policy and Compliance, December 2004

the estimated number of excess fatal cancers among the worker population for the 

life of the project (150 person-rem × 0.0006 fatal cancers/person-rem = 0.09 fatal 

cancers). A fatal cancer would not be expected among this population. It would not 

be appropriate, however, to interpret this result as indicating that there is zero risk of 

harm to workers from the radiation exposure. 

The above model description may be used when exposures are confidently projected to be 

below the levels indicated – the farther below, the more appropriate the simple approach 

becomes – and when there are no substantial counterindications to its use. Two examples 

of such counterindications are: (1) the exposure estimates are unusually uncertain, such as 

when workers would be operating under conditions for which there is little relevant 

experience; or (2) there is a high level of interest regarding the alternative in which 

occupational radiation risk might be an issue. 

• For EISs, or for EAs for which counterindications exist (as discussed above), include more 

complete statements of health effects, such as in the following example for involved 

workers. 

Example: [Discuss any counterindication, e.g., why is the exposure estimate 

uncertain and how is that uncertainty factored into the dose estimate. Then provide a 

more detailed discussion of the estimated health effects than in the preceding 

example, adding information such as the estimate for the maximally exposed 

worker.] Based on a dose-to-risk conversion factor of 6 × 10−4

 latent cancer fatalities 

per person-rem, the maximally exposed worker (dose rate of 1 rem per year) would 

have an estimated annual probability of a fatal cancer induced by the radiation of 

6 × 10−4

 [cite current Federal guidance]. The estimated probability of the worker 

dying from cancer induced by such radiation doses over the worker’s projected 

exposure period (30 years) is approximately 2 × 10−2

 (or 1 chance in 50). 

The group of 200 workers are estimated to be exposed at an average dose rate of 

50 mrem/year. Assuming the group is exposed at this rate for 30 years, the 

estimated number of excess fatal cancers induced among the workers would be 

about 0.2. It is likely there would be no fatal cancers attributable to this exposure. 

Recommendations: Effects from chemical exposure 

• As appropriate, and as discussed generally above, evaluate toxic and carcinogenic health 

effects from exposure to hazardous chemicals for involved and noninvolved workers and the 

general public. For toxic effects, compare dose estimates with appropriate reference doses. 

For carcinogenic effects, calculate values for potential carcinogenic effects from exposure or 

dose estimates using appropriate exposure-effect or dose-effect relationships. 

• As appropriate data permit, evaluate acute and chronic health effects (including cancer and 

occurrence of inheritable mutations) and address cumulative or synergistic health effects 

from exposure to multiple chemicals. 

• If reference doses, exposures, or exposure- or dose-effect relationships are not available, 

use reference concentrations, Occupational Safety and Health Administration permissible 

exposure limits, or other criteria that may be available in such sources as EPA’s Integrated 

Risk Information System database or the National Library of Medicine’s MEDLAR database. 
U.S. Department of Energy, Office of NEPA Policy and Compliance, December 2004 25

6.3 Biological Impacts 

Background 

DOE activities may expose populations of plants and animals (biota) to radioactive and 

chemically hazardous materials in environmental media or to materials released in waste 

streams. DOE Order 450.1, Environmental Protection Program, requires a biota protection 

program, including environmental monitoring, that may provide data for evaluating potential 

impacts in an EA or EIS. 

Physical, chemical, or radiological stressors – individually or in any combination – can impact 

animal and plant life. A variety of dose and risk assessment tools are available for conducting 

screening evaluations to identify potential impacts to biota, and for conducting evaluations of 

dose and risk, as needed. Screening, followed by detailed assessment, where appropriate, can 

ensure that the magnitude of the assessment effort is scaled to the likelihood and severity of 

environmental impacts. 

The principal biological impacts of concern in most circumstances are assessed at the 

population level, with a focus on the potential decrease in local species population size and a 

decline in suitable habitat. When threatened or endangered species, or commercially- or 

culturally-valuable species, may be affected, however, consideration of impacts to individuals 

may be appropriate. 

Recommendations 

• Analyze the impact of each alternative on aquatic and terrestrial biota, as appropriate. In 

addition to chemical and radiological stressors, consider physical stressors individually and 

cumulatively, when assessing potential biological impacts. 

Examples: A physical stressor might be a new fence that would have no effect on a 

sensitive bird species, while severely impeding a major migratory route for mule 

deer. A second example might be the physical impact a wind farm could have on 

migratory birds. 

• Note that routes of exposure for biota and people may differ. 

Example: Human access to certain areas of a DOE site might be restricted, but the 

restrictions might not prevent exposure to animal and plant life. Exposure pathways 

from contaminated soil or sediment for a burrowing terrestrial animal and benthic 

aquatic animal, respectively, could be much greater than for humans. 

• When conducting biota dose and risk assessments, identify the appropriate dose or risk 

standards, criteria, or benchmarks. When conducting assessments, use principal indicator 

species in the analysis. 

Explanation: The species should have a comparably high degree of sensitivity to the 

stressor(s) being evaluated, and should be important to the structure and function of 

the biological community. In general, if a more sensitive species is not significantly 

impacted, other species likely will not be significantly impacted either. 

• Indicate whether implementation of each alternative would comply with applicable dose 

limits for protection of biota. 
26 U.S. Department of Energy, Office of NEPA Policy and Compliance, December 2004

Explanation: DOE currently uses radiation dose limits of 1 rad/day for the protection 

of aquatic organisms (DOE O 5400.5), and guidelines of 1 rad/day for terrestrial 

plants and 0.1 rad/day for terrestrial animals (A Graded Approach for Evaluating 

Radiation Doses to Aquatic and Terrestrial Biota, DOE-STD-1153-2002, July 2002). 

The DOE Technical Standard provides guidance and examples of representative 

species that could serve as indicators of radiological impact in assessments. 

• Identify impacts on threatened or endangered species and their critical habitat. 

(See section 6.8.1.) 

6.4 Transportation Impacts 

Background 

When transport of waste or materials of a hazardous or radioactive nature is part of an analyzed 

alternative, or, more generally, when transport is in any respect a major factor 

(e.g., transportation of construction materials for a proposed major project), the environmental 

impacts of such transport should be analyzed, even when DOE is not responsible for the 

transportation. Transportation impacts include those from transport to and from a site, as well 

as impacts from on-site transport, when such activities are needed to accomplish the 

analyzed alternative. Include loading or unloading activities in the transportation impacts 

analysis. 

Recommendations 

• As with the choice of alternatives, apply a sliding-scale approach to the transportation 

analysis. The nature of the alternatives determines whether to describe the transportation 

impacts qualitatively or to analyze them quantitatively. 

• Analyze all transportation links that are reasonably foreseeable parts of the analyzed 

alternative, such as overland transport, port transfer, and marine transport. If the action 

contains links that traverse the global commons (e.g., the oceans or outer space), then 

impacts from such transport should be included in the NEPA analysis; state that the global 

commons analysis is provided pursuant to Executive Order 12114. 

• Do not base conclusions about significance of transportation impacts exclusively on 

statements that transportation would be conducted in accordance with all applicable 

regulations or requirements of the U.S. Department of Transportation, the Environmental 

Protection Agency, the Nuclear Regulatory Commission, or state authorities. 

• Evaluate both routine (i.e., incident-free) transport and accidents. (Accident analysis is 

discussed in section 6.5.) Evaluate potential public and worker health impacts from 

exposure to chemicals or radiation. Also, be sure to consider non-radiological and nonchemical transportation impacts, such as fatalities from collision that do not result in any 

cargo release. In many cases, such impacts would exceed estimated radiological and 

chemical impacts. 

• Estimate the annual and total impact of all transportation associated with the analyzed 

alternative, by the use of specific routes (if known and appropriate), to represent the 

expected environmental impacts over the term of the analyzed alternative, including, for 

chemical and radiological exposure, the impact on a maximally exposed individual. Impacts 

related to transportation must be totaled over the duration of the project (e.g., 48 trips per 
U.S. Department of Energy, Office of NEPA Policy and Compliance, December 2004 27

year for 5 years). (Note: This total is not the cumulative impact of transportation impacts 

from an analyzed alternative and other transportation activities over the same time period in 

the area.) 

• Be sure to use current, technically sound estimation methods and data for assessing the 

impacts of transportation (e.g., the most current version of RADTRAN, when quantification is 

appropriate). 

6.5 Accident Analysis 

This section summarizes key points from “Recommendations for Analyzing Accidents Under the 

National Environmental Policy Act” (2002), which provides more detailed guidance. 

Background 

An accident is an unplanned event or sequence of events that results in undesirable 

consequences. Accidents may be caused by equipment malfunction, human error, or natural 

phenomena. NEPA documents should inform the decisionmaker and the public about the 

chances that reasonably foreseeable accidents associated with proposed actions and 

alternatives could occur, and about their potential adverse consequences. 

The key to informative accident analyses is to develop realistic scenarios that address the range 

of reasonably foreseeable event probabilities and consequences, including low probability/high 

consequence accidents and higher probability/(usually) lower consequence accidents. The 

environmental consequences of accidents are impacts (effects) on human health and the 

environment. Accident analyses in NEPA documents should estimate the magnitude of risk (for 

accidents, risk is normally defined as the probability of the accident occurring multiplied by the 

consequence of the accident) that each analyzed alternative would present and provide 

comparisons of risks among alternatives, providing information necessary for a reasoned choice 

among alternatives and appropriate consideration of mitigation measures. 

It may be appropriate in certain cases to address potential environmental impacts that could 

result from intentional destructive acts. Analysis of such acts, which are not accidents, poses a 

challenge because the potential number of scenarios is limitless and the likelihood of attack is 

unknowable. Consequences of destructive acts, however, may be compared to consequences 

of severe accidents, because the forces resulting in releases of hazardous or radioactive 

materials could be similar. 

Recommendations 

• Develop realistic scenarios that represent the spectrum of reasonably foreseeable 

accidents. Analyze maximum reasonably foreseeable accidents for a given alternative to 

represent potential accidents at the high consequence end of the spectrum. Also analyze 

other accidents in the “spectrum” if they may contribute importantly to, or even dominate, 

accident risks. 

Explanation: A maximum reasonably foreseeable accident is an accident with the 

most severe consequences that can be reasonably expected to occur for a given 

proposal. It is not the same as a worst-case accident. A worst-case accident is one 

whose probability is so remote or speculative as to render it not reasonably 

foreseeable and therefore not helpful to the decisionmaker. Analysis of worst-case 

accidents is not required under NEPA. 
28 U.S. Department of Energy, Office of NEPA Policy and Compliance, December 2004

• Consider scenarios with frequencies of 10−6 to 10−7 per year if the consequences may be 

very large. Scenarios with frequencies less than 10−7

 per year rarely need to be examined. 

• Because one purpose of NEPA analysis is to inform the public, consider analyzing an 

accident scenario in which the public has expressed a keen interest, even when the 

scenario is not reasonably foreseeable. Do not, however, analyze physically impossible 

accidents or scenarios that are based on pure conjecture (consistent with 40 CFR 1502.22). 

Always explain why a scenario of interest to the public was excluded from analysis. 

• Use a bounding approach when many uncertainties prevent a more realistic approach 

(i.e., one based on expected values), but be aware that bounding analyses may mask 

differences among alternatives. 

• Evaluate accident impacts on the public, involved workers, and non-involved workers. For 

each of these population groups, evaluate impacts on the maximally exposed individuals 

and the collective impact to the group. 

• Identify and quantify potential health effects (e.g., latent cancer fatalities). Do not report only 

dose estimates. Always use current dose-to-risk conversion factors that have been adopted 

by cognizant health and environmental protection agencies. (See section 6.2.) 

• Present both the probability of occurrence (i.e., the probability that adverse consequences 

would occur) and the consequences of the accident. Risk (which often is defined as the 

product of probability and consequence) also can be presented, but it should augment, not 

substitute for, the separate presentation of probability and consequence. 

• Consider non-radiological impacts that could result from an accident (e.g., impacts from 

releases of toxic chemicals). Also consider injuries and fatalities from construction and 

physical hazards that are often greater than those from radiological and chemical 

exposures. 

• Evaluate (at least qualitatively) indirect impacts to the environment that would result from 

contamination resulting from an accident, such as economic issues (e.g., the cost of 

cleanup), water quality, and impacts to biota. 

• Discuss factors contributing to uncertainties in the accident analysis. Decisionmakers need 

to understand the nature and extent of uncertainty in choosing among alternatives and 

considering potential mitigation measures. In circumstances where substantial uncertainty 

exists regarding an estimate, a qualitative estimate may be used.

• In many cases, existing safety documents may be summarized and incorporated by 

reference in NEPA accident analyses. Make sure such safety documents are appropriate for 

the NEPA review. Ensure that accident risk comparisons among alternatives are fair by 

using a consistent set of assumptions or clearly noting any differences. 

Related Guidance 

• Recommendations for Analyzing Accidents Under the National Environmental Policy Act, 

2002 

Available on the DOE NEPA Web site (www.eh.doe.gov/nepa) under Guidance. 
U.S. Department of Energy, Office of NEPA Policy and Compliance, December 2004 29

6.6 Environmental Justice 

Background 

Each Federal agency is to “make achieving environmental justice part of its mission by 

identifying and addressing, as appropriate, disproportionately high and adverse human 

health or environmental effects of its programs, policies, and activities on minority populations 

and low-income populations” (Executive Order 12898, Federal Actions to Address 

Environmental Justice in Minority Populations and Low-Income Populations, February 1994, 

59 FR 7629; emphasis added). 

The Presidential Memorandum accompanying the Executive Order directs Federal agencies to 

“analyze the environmental effects, including human health, economic and social effects, of 

Federal actions, including effects on minority communities and low-income communities, when 

such analysis is required by the National Environmental Policy Act.” 

EPA defines environmental justice as: “The fair treatment and meaningful involvement of all 

people regardless of race, color, national origin, or income with respect to the development, 

implementation, and enforcement of environmental laws, regulations, and policies. Fair 

treatment means that no group of people, including racial, ethnic, or socioeconomic group 

should bear a disproportionate share of the negative environmental consequences resulting 

from industrial, municipal, and commercial operations or the execution of federal, state, local, 

and tribal programs and policies.” 

Recommendations 

• For each alternative, consider whether there are any significant adverse impacts to minority 

and low income populations (see section 5) that would appreciably exceed impacts to the 

general population or other appropriate comparison group. Consider all potential impacts 

(e.g., health effects, air quality, water quality, cultural resources, cumulative impacts). 

• Consider whether minority and low-income populations would have different ways than the 

general population of being affected by an alternative. Examples include unique exposure 

pathways or rates of exposure (e.g., from subsistence fishing), special sensitivities (e.g., to 

air pollution because of less access to health care and poorer control of asthma), or different 

uses of natural resources (e.g., for cultural, religious, or economic practices). 

Related Guidance 

• CEQ, Environmental Justice Guidance under the National Environmental Policy Act, 1997 

Available on the DOE NEPA Web site (www.eh.doe.gov/nepa) under Guidance.

6.7 Cumulative Impacts 

Background 

Cumulative impacts (or “cumulative effects” as they also are known) are defined in the CEQ 

regulations as follows: 

“Cumulative impact” is the impact on the environment which results from the 

incremental impact of the action when added to other past, present, and 

reasonably foreseeable future actions regardless of what agency (Federal or 
30 U.S. Department of Energy, Office of NEPA Policy and Compliance, December 2004

non-Federal) or person undertakes such other actions. Cumulative impacts 

can result from individually minor but collectively significant actions taking 

place over a period of time (40 CFR 1508.7). 

Recommendations 

• Describe cumulative impacts for each analyzed alternative. Understanding the cumulative 

impacts for each alternative may help distinguish among alternatives. 

Explanation: When two alternatives would affect the same resource(s) in the same, 

or a very similar, way for the same period of time, it would not be necessary to 

analyze or describe the cumulative impacts separately for both alternatives. In such 

cases, clearly explain the basis for concluding that the cumulative impacts are the 

same or very similar. 

• Evaluate potential cumulative impacts for all impact areas. 

Example: The importance of considering cumulative impacts is demonstrated by the 

markedly different effects of adding a small amount of liquid to a full glass as 

opposed to a nearly empty one. Similarly, the cumulative impact of taking an action 

that would increase traffic by a few trucks per day at an already overcrowded 

intersection is different from the impacts of adding the same traffic to a little-used 

rural crossing. Also, a small loss of wildlife habitat from one alternative, combined 

with losses from other projects, may produce an overall significant loss of wildlife 

habitat and materially affect the regional biodiversity. 

• Consider impacts from relevant past, present, and reasonably foreseeable future actions 

that occur within defined geographic boundaries for as long as they are reasonably 

foreseeable for the alternative. 

Explanation: The availability of information tends to determine how far into the past 

actions can be examined. Certain types of data, such as land use at DOE sites, may 

be available over several decades, while others, such as water quality data, may 

only be available for relatively short periods. Present actions tend to be easier to 

identify than past or future actions. Coordination with Federal, state, and local 

agencies and other relevant organizations often is helpful in collecting available data. 

• Identify pathways and potential impacts appropriate for the cumulative impacts analysis. The 

sources of impacts on a resource may be more diverse when analyzing cumulative impacts 

than project-specific impacts, and the nature of impacts may differ. 

Example: The cumulative impacts on fish might be affected by effluent released from 

the alternative plus non-DOE sources, such as agricultural runoff, erosion from 

construction activities, or effluent from other facilities, including some yet to be built. 

• Consider cumulative impacts when developing mitigation. 

Related Guidance 

• CEQ, Considering Cumulative Effects Under the National Environmental Policy Act, 1997 

Available on the DOE NEPA Web site (www.eh.doe.gov/nepa) under Guidance.
U.S. Department of Energy, Office of NEPA Policy and Compliance, December 2004 31

6.8 Compliance with Other Requirements 

Background 

CEQ’s and DOE’s regulations require integration of NEPA with other environmental review and 

consultation requirements to the fullest extent possible and combining environmental 

documents to reduce duplication and paperwork (40 CFR 1500.4(k) and (o), 1502.25, 1506.4; 

10 CFR 1021.341). In addition, CEQ’s regulations require that an EIS identify all Federal 

permits, licenses, and other entitlements that must be obtained in implementing the proposal 

(40 CFR 1502.25(b)). Note that agency obligations under these other requirements are 

independent from NEPA and must be complied with even when an EA or EIS is not required. 

A statement that the proposed action or analyzed alternatives would be in compliance with 

applicable environmental regulations, DOE Orders, or licenses does not substitute for a 

discussion of potential environmental impacts. As a practical matter, all alternatives must 

comply with applicable requirements, yet some actions may nevertheless have significant 

environmental impacts (e.g., a new nuclear power reactor). 

Recommendations 

• Explain whether and how each alternative would be in compliance with applicable 

requirements. Do not rely, however, on compliance with applicable requirements (e.g., 

waste disposal permits, water or air emissions permits) as evidence that an analyzed 

alternative does not have potential for significant impact. 

Example: Rather than just stating that “all wastes would be disposed of in 

accordance with applicable regulatory requirements and DOE Orders,” address 

(e.g., document by reference) whether each alternative provides adequate disposal 

capacity in a facility that is permitted to receive the waste type. 

• Conduct a single analysis that satisfies the requirements of NEPA and other applicable 

requirements. In general, include this analysis in an appendix or separate section of the EA 

or EIS. Include a summary of pertinent parts in the impacts section of the EA or EIS, and 

reference rather than repeat analysis from the more detailed appendix or separate section 

devoted to the discussion of compliance with other applicable requirements. 

6.8.1 Endangered Species Act 

Background 

Section 7 of the Endangered Species Act (ESA) directs all Federal agencies to use their 

existing authorities to conserve threatened and endangered species and, in consultation with 

the Fish and Wildlife Service (FWS) or the National Marine Fisheries Service (NMFS), to ensure 

that their actions do not jeopardize listed species or destroy or adversely modify critical habitat. 

Section 7 applies to management of Federal lands, as well as other Federal actions that may 

affect listed species, such as Federal approval of private activities through the issuance of 

Federal permits, licenses, or other actions. 

Pursuant to Section 7(c) of the ESA, DOE must prepare a biological assessment whenever an 

endangered or threatened species or its critical habitat may be affected by a proposed action. 

Such an assessment should be undertaken during the NEPA process, if possible, so that the 

results of the assessment can be included in the consideration of potential environmental 

impacts. 
32 U.S. Department of Energy, Office of NEPA Policy and Compliance, December 2004

Recommendations 

• When a listed species or designated critical habitat may be affected by an alternative, 

initiate early informal consultation under Section 7 with FWS or NMFS. 

• Include a description of Section 7 consultation activities (both formal and informal) in the EA 

or EIS. Include any correspondence from FWS or NMFS, as well as any biological 

assessment or biological opinion, in an appendix. 

Related Guidance 

• Endangered Species Act Consultation Handbook: Procedures for Conducting Section 7 

Consultations and Conferences, 1998 

Available on the FWS Web site at endangered.fws.gov/consultations/s7hndbk/s7hndbk.htm. 

6.8.2 Clean Air Conformity Requirements 

Background 

Federal agencies must ensure that their actions conform to applicable Federal, state, or tribal 

implementation plans for achieving National Ambient Air Quality Standards (NAAQS: 

40 CFR Part 50). To conform, Federal actions must not contribute to new violations of the 

standards, increase the frequency or severity of existing violations, or delay timely attainment of 

standards in the area of concern (e.g., a state or a smaller air quality region such as a cluster of 

counties). The conformity analysis (40 CFR Part 93) and NEPA process should be conducted in 

parallel and integrated to the extent practicable. 

The conformity analysis may involve two phases. First is the conformity review process to 

determine whether the conformity regulations would apply to an alternative (i.e., whether a 

conformity determination is needed). Second is the conformity determination process to 

demonstrate how an alternative would conform to the applicable implementation plan. 

Recommendations 

• Complete the conformity review process for all analyzed alternatives in EAs and EISs to 

facilitate the comparison of alternatives with respect to air quality issues. A conformity 

review normally is not needed for the no action alternative; a conformity review may be 

needed, however, if activities associated with the no action alternative have pollutant air 

emissions that have not been subject to a prior conformity review. 

• Conduct the conformity determination process (if needed) for only the preferred alternative. 

Consider preparing a draft conformity determination for each analyzed alternative in cases 

where doing so would increase flexibility in making a final decision subsequent to the EA or 

EIS or allow comparison of the full cost requirements of each alternative. 

Explanation: The extent of analysis needed for a conformity determination coupled 

with the potential need to negotiate binding mitigation measures or offsets with 

non-DOE entities normally makes it impractical to complete the conformity 

determination process for all alternatives. Moreover, the conformity regulations do 

not require that conformity determinations be conducted for all alternatives. 
U.S. Department of Energy, Office of NEPA Policy and Compliance, December 2004 33

Related Guidance 

• Clean Air Act General Conformity Requirements and the National Environmental Policy Act 

Process, 2000 

Available on the DOE NEPA Web site (www.eh.doe.gov/nepa) under Guidance. 

• Compliance with the General Conformity Regulations, 2003 

Available on DOE’s Environmental Policy and Guidance Web site at 

www.eh.doe.gov/oepa/guidance/caa/conformbrf.pdf. 

6.8.3 Floodplain and Wetland Environmental Review Requirements 

Background 

Executive Orders 11988 Floodplain Management (May 24, 1977) and 11990 Protection of 

Wetlands (May 24, 1977) direct Federal agencies to undertake various actions to protect 

floodplains and wetlands, including preparing a floodplain or wetland assessment for any action 

proposed in a floodplain and new construction proposed in a wetland. DOE’s regulations 

implementing these Executive Orders, Floodplain and Wetland Environmental Review 

Requirements (10 CFR Part 1022), require that any floodplain or wetland assessment normally 

be included in an EA or EIS, if one is being prepared (10 CFR 1022.13(b)). 

A floodplain or wetland assessment includes a description of the alternatives, a discussion of its 

potential effects on the floodplain or wetland (including a discussion of floodplain or wetland 

values), and consideration of alternatives (10 CFR 1022.4). The outcome of a floodplain 

assessment is documented in a floodplain statement of findings, which may be incorporated into 

a finding of no significant impact, final EIS, or record of decision, as appropriate 

(10 CFR 1022.14). A wetland statement of findings may be similarly prepared for a wetland 

assessment but is not required. 

Recommendation 

• Identify the need for a floodplain or wetland assessment when determining the required level 

of NEPA documentation. 

6.8.4 National Historic Preservation Act 

Background 

Section 106 of the National Historic Preservation Act of 1966 (NHPA) requires Federal agencies 

to “take into account” the effect of their projects on historical and archeological resources and to 

give the Advisory Council on Historic Preservation the opportunity to comment on such effects. 

Where both NEPA and the NHPA are applicable, draft EAs and EISs must integrate NHPA 

considerations along with other environmental impact analyses and studies (40 CFR 1502.25). 

Additional requirements regarding consultation with external parties and other aspects of 

integrating NHPA and NEPA are found in regulations implementing Section 106 

(36 CFR Part 800, Subpart B). 
34 U.S. Department of Energy, Office of NEPA Policy and Compliance, December 2004

Recommendation 

• Identify early in the NEPA planning process whether to request comments on an EA or EIS 

by the Advisory Council on Historic Preservation or other parties, such as the State or Tribal 

Historic Preservation Officer. 

6.9 Mitigation 

Background 

Mitigation involves taking steps to avoid, minimize, rectify, reduce, eliminate, or compensate for 

the impact of an analyzed alternative (40 CFR 1508.20). Examples of mitigation include “design 

alternatives that would decrease pollution emissions, construction impacts, aesthetic intrusion, 

as well as relocation assistance, possible land use controls that could be enacted, and other 

possible efforts.” Mitigation measures discussed in an EIS must cover the range of impacts of 

the analyzed alternatives, and such measures should be considered even for impacts that by 

themselves would not be considered “significant” (Question 19a, “CEQ’s Forty Questions”). 

Recommendations 

• Consider mitigation for all impact areas, emphasizing steps to address those impacts with 

the greatest potential for significance. 

• Evaluate pollution prevention strategies and technologies beyond those inherent in the 

alternative. 

• Indicate whether the implementation of a mitigation measure is within DOE’s jurisdiction. 

Identify any external parties (e.g., state, local, or tribal government agencies; land owners) 

who must be involved in establishing or implementing the mitigation. 

• Consider involving affected communities in the development of mitigation measures. 

6.10 Comparison of Impacts 

Recommendations 

• Present the impacts of alternatives in comparative form to sharply define the issues and 

provide a clear basis for choice (40 CFR 1502.14). The use of tables to show comparisons 

is recommended, along with text to explain or emphasize major issues. 

• Conduct analysis to discriminate among alternatives. Do not present bounding impact 

estimates that obscure differences among alternatives. 

• Present enough information to allow readers to evaluate the differences among alternatives. 

Avoid bias for or against alternatives. 

• Where DOE may wish to choose from among elements of more than one alternative, 

present impacts in a manner that permits appropriate comparisons of various combinations. 

Explanation: For some proposals, DOE may select a combination of elements from 

more than one alternative rather than a single alternative analyzed in an EA or EIS. 
U.S. Department of Energy, Office of NEPA Policy and Compliance, December 2004 35

For example, an EIS might analyze several treatment technologies as discrete 

alternatives, but DOE might choose to implement more than one technology to 

manage a diverse waste stream. Recognize that the impacts of a combination might 

not be simply the sum of the parts. (See section 4.4.) 

• Consider using analytic tools such as a sensitivity analysis to focus the comparison on the 

most important factors affecting impact estimates. 

Explanation: A sensitivity analysis identifies the factors that most strongly influence 

an estimate. This can aid the comparison, for example, by highlighting that 

transportation distance (i.e., miles driven) is a relatively greater contributor to the 

likelihood of accidents than the number of shipping and receiving locations. 

6.11 Conclusions in EAs and EISs 

Recommendations 

• Make clear how conclusions follow from the analysis contained in the EA or EIS. Do not 

present unsubstantiated conclusions. 

• Provide sufficient information to support a technical review of the analysis and conclusions. 

This often can be accomplished by citing appropriate references or providing detailed 

technical information in an appendix. (See section 8.) 

• Explain the cause-and-effect relationship between an action and its impacts; do not simply 

provide the end result. 

Example: Do not simply state that the construction of a fence would reduce the mule 

deer population on a site. Rather, explain how the fence could prevent mule deer 

migration, for example, between high elevation summer ranges on the DOE site and 

off-site lower elevation winter ranges. Then explain that, because both winter and 

summer habitat are essential for the survival of this mule deer population, the fence 

would cause a reduction of ___ percent or elimination of the mule deer population on 

the site. Provide sufficient information for a reader of the EA or EIS to confirm the 

conclusion. 
36 U.S. Department of Energy, Office of NEPA Policy and Compliance, December 2004

7. List of Preparers, List of Agencies and Persons Consulted, 

and Distribution List 

Background 

An EIS (but not an EA) is required to list the names and qualifications (expertise, experience, 

and professional disciplines) of persons who were primarily responsible for preparing the EIS or 

significant background papers (40 CFR 1502.17). An EA must contain a list of outside agencies 

and persons consulted (i.e., those outside DOE and its contractors) during preparation of the 

document (40 CFR 1508.9(b)). An EIS must include a list of agencies, organizations, and 

individuals to whom copies of the EIS are sent (40 CFR 1502.10). 

CEQ and DOE conflict-of-interest considerations at 40 CFR 1506.5(c) and 10 CFR 1021.310 

apply to preparation of an EIS but not to preparation of an EA. DOE’s regulations require that a 

draft or final EIS include “a disclosure statement executed by any contractor (or subcontractor) 

under contract with DOE to prepare the EIS” that the contractor (or subcontractor) has no 

conflicts of interest (10 CFR 1021.310). 

Recommendations 

• Indicate DOE (not a contractor) as the preparer on the title page of an EA or EIS because 

DOE is responsible for complying with NEPA; the contractor’s role is to assist DOE. 

• Do not list DOE or DOE-contractor personnel who prepare an EA or who are consulted 

during its preparation in the list of outside agencies and persons consulted. 

• For an EIS prepared by a contractor or subcontractor, confirm the absence of conflict of 

interest early in the process. 

• Include a distribution list in both the draft and final EIS. 
U.S. Department of Energy, Office of NEPA Policy and Compliance, December 2004 37

8. Appendices, References, and Index 

Background 

CEQ’s regulations state that, if prepared, an appendix to an EIS shall: (a) consist of material 

prepared in connection with the EIS, (b) consist of material that substantiates analysis 

fundamental to the EIS, (c) normally be analytic and relevant to the decision to be made, and 

(d) be circulated with the EIS or be readily available upon request (40 CFR 1502.18). In general, 

there will be less need for and use of appendices in EAs than in EISs because EAs address 

less significant impacts and are more concise documents. In addition, CEQ guidance states: 

Lengthy technical discussions of modeling methodology, baseline studies, or 

other work are best reserved for the appendix... a plain language summary of 

the analysis and conclusions of that technical discussion should go in the text 

of the EIS.... Material that is not directly related to preparation of the EIS 

should be incorporated by reference (Question 25a, “CEQ’s Forty Questions”). 

Material incorporated by reference shall be cited and briefly described in the EIS and must be 

reasonably available for public inspection (40 CFR 1502.21). Applying the same procedure to 

EAs makes good sense. 

CEQ regulations also require that an index be included in EISs (40 CFR 1502.10). CEQ advises 

that: 

The EIS index should have a level of detail sufficient to focus on areas of the 

EIS of reasonable interest to any reader. It cannot be restricted to the most 

important topics. On the other hand, it need not identify every conceivable 

term or phrase in the EIS. If an agency believes that the reader is reasonably 

likely to be interested in a topic, it should be included (Question 26a, “CEQ’s 

Forty Questions”). 

An index also may be useful in an EA. 

Recommendations 

• Ensure that information in the main body of the EA or EIS is consistent with any relevant 

appendix. Similarly, limit appendices to information that supports discussions in the main 

body. 

• Provide supporting information that reviewers may want to examine, such as details of the 

modeling methodology, in an appendix. As a general rule, do not put raw data in an 

appendix, unless the data are critical for analytical validation. 

• Provide analyses prepared under related environmental review requirements (e.g., a 

biological assessment prepared for endangered species consultation requirements of 

Section 7 of the Endangered Species Act) in an appendix (and include a brief summary in 

the affected environment and impacts sections of the EA or EIS). The main body of the EIS 

may reference, rather than repeat, analysis from the appendix. Also include official 

communications related to environmentally-sensitive resources in appendices. (See 

section 6.8.) 
38 U.S. Department of Energy, Office of NEPA Policy and Compliance, December 2004

• Segregate information that is exempt from disclosure requirements, such as classified 

information or nonclassified security-sensitive information (e.g., official use only information), 

into an appendix to allow public review of the remainder of the NEPA document 

(10 CFR 1021.340(b)). 

• If a reference document is not available for public review (e.g., a classified document), 

present as much information as possible in the EA or EIS to verify the relevant conclusions 

from the reference document. 

• Cite personal communications or “unpublished file data” only as sources of information, not 

as support for conclusions regarding the significance of impacts. 

Example: A personal communication with a local official may be cited as the source 

of information for traffic volume on a particular highway but could not be cited for an 

analysis of increased fatalities expected per increased volume of traffic. 

• Cite a draft document only if it is the best available source of relevant information, has 

attained sufficiently high review or approval within the issuing organization, and is available 

to the public. 

• Do not rely upon the table of contents as an index. 

• Consider using an index specialist. Do not rely solely on computer software to generate an 

adequate index; apply a quality control process. 
U.S. Department of Energy, Office of NEPA Policy and Compliance, December 2004 39

9. Responses to Comments 

This section summarizes key points from “The EIS Comment-Response Process” (2004), which 

provides more detailed guidance. 

Background 

CEQ’s regulations require that, in preparing a final EIS, agencies “assess and consider 

comments [received on a draft EIS] both individually and collectively” and respond to comments 

by modifying alternatives; developing and evaluating alternatives not previously given serious 

consideration; supplementing, improving, or modifying analyses; making factual corrections; or 

explaining why comments do not warrant further agency response (40 CFR 1503.4(a)). 

Recommendations 

• Provide a response to each comment, and tell whether (and if so where) the comment 

resulted in changes to the EIS. 

Explanation: Give equal weight to oral and written comments. Address all 

substantive elements of a comment. 

If changes were made in response to a comment, briefly describe the changes and 

identify the sections of the EIS that were changed. 

Acknowledge comments that are out of scope, and explain in the response why they 

are; if prudent, respond anyway to answer a question or to set the record straight. 

• Apply the sliding-scale concept. 

Explanation: Respond to comments commensurate with their substance. Tailor the 

approach for responses to the circumstances of the EIS, taking into account the 

complexity of the issues presented and the number of comments received. 

Example: Provide a brief response to a focused brief comment; a more 

comprehensive response to a detailed, well-supported comment. 

One approach could be to use responses to well-developed, thorough comments as 

a foundation for responses to similar but less-detailed comments. Another approach 

could be to prepare a summary comment and a consolidated response for similar 

comments. Ensure any cross-referenced response is fully responsive to a specific 

comment. 

• For identical or very similar comment documents received in high volume (e.g., multiple 

faxes, e-mails, or postcards), reprint and respond to one as a sample comment document, 

but provide the names of all commentors alphabetically. 

Explanation: Respond to a comment’s substance without regard to how many 

commentors express a similar view. 

• Integrate the comment-response process with other aspects of final EIS preparation. Use 

the process of responding to comments to focus final EIS preparation. 
40 U.S. Department of Energy, Office of NEPA Policy and Compliance, December 2004

• Describe the overall comment-response process, including areas of controversy in issues 

raised by commentors and a summary of EIS changes made in response to comments. 

• Explain the comment-response format so that all commentors can find responses to their 

and others’ comments. Attach all comments (or summaries of voluminous comments). 

Related Guidance 

• The EIS Comment-Response Process, 2004 

Available on the DOE NEPA Web site (www.eh.doe.gov/nepa) under Guidance. 
U.S. Department of Energy, Office of NEPA Policy and Compliance, December 2004 41

10. General Document Quality and Readability 

Background 

A key challenge in preparing readable NEPA documents is to present technical material in 

language that a lay person can understand. CEQ’s regulations require that EISs be written in 

plain language and recommend using appropriate graphics to enhance understanding by 

decisionmakers and the public (40 CFR 1502.8). The same editorial principles should be 

applied to EAs. 

This effort to produce a quality, readable document enhances the entire NEPA process. 

Reviewers are more likely to focus on the most significant issues when presented with clear and 

accurate information. Decisionmakers can better compare alternatives when the analysis is 

presented clearly and without an abundance of agency or technical jargon. 

10.1 Objectivity 

Recommendations 

• Remember that while EAs and EISs support decisions, they are pre-decisional documents 

and should not indicate that a decision has been made. 

Example: Use conditional wording and verb tense, such as “would” rather than “will,” 

in action descriptions. 

• Use language that is objective and descriptive, not judgmental, particularly with regard to the 

significance of impacts. Present impact data and any applicable or relevant requirements or 

standards for the reader to form judgments. 

Example: Do not characterize impacts as “acceptable.” Use quantitative 

comparisons or words such as “very small” or “substantial,” if necessary, to describe 

impacts. 

• In EAs, do not use the word “significant” or “insignificant” in conclusory statements. 

Conclusions of overall insignificance or significance will be made in a finding of no 

significant impact or a determination to prepare an EIS. 

• Avoid tone and nuance that are not objective. 

Explanation: When responding to public comments and in discussing responsible 

opposing views, do not subtly play down alternatives that DOE does not prefer. 

Provide professional, authoritative, and dispassionate responses, not casual or flip 

responses. 

10.2 Writing Quality 

Recommendations 

• Write documents to inform, not intimidate, the interested public. Write precisely and 

concisely in plain language and active voice. Avoid jargon. 
42 U.S. Department of Energy, Office of NEPA Policy and Compliance, December 2004

Example: Stating that “The waste would be repackaged and transported to the new 

storage facility” (passive voice) does not tell the reader who would take the action. 

“DOE would repackage and transport the waste to the new storage facility” (active 

voice) clearly identifies the party proposing to take the action. In this way, active 

voice communicates more information and gives the reader a clearer understanding 

of what is proposed. 

• Avoid unnecessary repetition. 

Example: A detailed description of an activity that is part of more than one alternative 

need not be repeated for each alternative. 

• Use technical writers and editors to help identify unclear passages, undefined terms, and 

unsupported conclusions, and generally to improve the presentation of material. 

• Present plain language descriptions that accurately portray the technical complexity of 

issues. 

• Define technical terms that may be unfamiliar to a lay person. Use existing authoritative 

definitions as much as possible. Provide a glossary when many specialized terms are used. 

(See section 10.4.) 

Example: Terms such as “risk” may have a different meaning in a technical sense 

than in a colloquial sense. 

• Use regulatory terms consistent with their regulatory definitions. 

Example: Terms involving “toxic” and “hazardous” (such as hazardous material, 

hazardous substance, extremely hazardous substance, hazardous chemical, 

hazardous waste, toxic substances, and toxic waste) are frequently misused. 

• Provide scientific names, as well as common names, for biota; to avoid confusion and 

ambiguity, include the subspecies or variety name if appropriate (particularly for 

endangered, threatened, or protected species). 

• Do not rely solely on the “spell check” function of word processing programs to check for 

spelling errors. Correctly spelled words are often used incorrectly. 

• When in doubt about the proper use of a word, grammar, or spelling, use the Government 

Printing Office Style Manual, which also provides guidance on document format, 

organization, and references. 

Related Guidance 

• Government Printing Office Style Manual 

Available at www.gpoaccess.gov/stylemanual. 
U.S. Department of Energy, Office of NEPA Policy and Compliance, December 2004 43

10.3 Graphics and Data Treatment (Units, Statistics) 

Recommendations: Graphics and tables 

• Use easy-to-follow graphics and tables to summarize data, show correlations, and facilitate 

readers’ access to information. Take care that graphics and tables inform and do not 

confuse the reader. In the text, highlight the key data and findings presented in the graphics 

and tables. 

• Select axes for graphs to avoid misleading representations. 

Explanation: Do not use an enlarged scale to minimize the visual impact of a 

parameter value. The default graphing scales of various computer graphics software 

packages might result in inappropriate choices. 

Example: Plotting values that are all less than 0.1 on a chart with a scale of 0−1 

makes it difficult to gauge any particular value and makes comparison of values 

more difficult. (See sample chart below.) 

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

12345

Series1

Series2

Series3

Presenting the same data on a chart with a more appropriate scale (0−0.08) makes it 

easy to identify each value and better interpret the relationship between values. (See 

sample chart below.) 

0

0.01

0.02

0.03

0.04

0.05

0.06

0.07

0.08

12345

Series1

Series2

Series3
44 U.S. Department of Energy, Office of NEPA Policy and Compliance, December 2004

• Plot graphs that may be compared to one another on the same axes and scales whenever 

possible. 

• Avoid data graphs with axes that begin at a value other than zero, or construct such graphs 

carefully so as to avoid misleading the reader. 

Example: In the sample chart below, the values for items 4 and 5 appear, at first 

glance, to be zero. The values are not zero, but they are below 0.01 (refer to the 

sample charts above, which are based on the same data set). If presenting data in 

this manner, clearly note on the chart and in accompanying text that some values fall 

outside the scale presented in the chart. 

0.01

0.02

0.03

0.04

0.05

0.06

0.07

0.08

12345

Series1

Series2

Series3

• Use maps and drawings to depict all features that are needed to understand the project and 

its impacts; provide directional arrows and scale indicators. 

• Do not include extraneous information, such as irrelevant contour lines on maps. 

• Make maps and other figures consistent with the text. 

Recommendations: Units 

• Use consistent, relevant, and conventional units in tables, graphics, and text. 

• Use the metric system to the extent possible. When the metric system is used, also include 

conventional (English) units to facilitate public understanding. When conventional units are 

used, also include metric conversions. (See DOE Guide 241.1-1A, Guide to the 

Management of Scientific and Technical Information, November 23, 2001.) 

• Use authoritative sources for conversion factors, such as a recent edition of the Handbook 

of Chemistry and Physics (CRC Press).

• Avoid misplaced decimal points. 

• Use units that facilitate comparisons and understanding. 
U.S. Department of Energy, Office of NEPA Policy and Compliance, December 2004 45

Example: In comparing emissions to requirements, display both emissions and 

requirements in the same units. Use 5 parts per billion, not 0.000005 parts per 

thousand. 

• If scientific notation is used, explain how to convert values to more traditional numbers. 

• Use appropriate significant figures. 

Examples: “Three feet” is more correctly converted to “about one meter” than to 

“0.914 meters.” Use 0.5 person-rem rather than 0.478 person-rem when the dose is 

known or estimated to only one significant figure, which is usually the case in NEPA 

assessments. 

• Use consistent units throughout a document and appendices whenever possible. 

Recommendations: Statistics 

• Avoid misleading use of statistics, mixing cause and effect, and implying causation from 

correlation. 

• Avoid use of an inappropriate statistic. 

Explanation: In some cases, using a range of values, the maximum or minimum 

value, or even all the data (e.g., presented graphically) may be more meaningful than 

using the arithmetic mean. For example, if a contaminant concentration has been 

measured twice with values of 10 and 1,000, the arithmetic mean value does not 

adequately characterize the situation, and it would be better to report both 

measurements. For some data (such as aquifer permeability, atmospheric pollutant 

concentration, coliform bacteria counts, or other data that span orders of magnitude), 

geometric means are more representative than arithmetic means. 

10.4 Glossary 

Background 

Technical and regulatory terms used in NEPA documents should be defined to aid readers’ 

understanding. 

Recommendations 

• Thoughtfully define terms to adequately describe how they are used in a particular 

document. Modify terms in the DOE NEPA glossary, as appropriate. Wholesale reinvention 

of definitions is unwarranted and wasteful. 

• Mark in bold or italics the first occurrence of terms that are defined in the glossary to signal 

the reader to consult the glossary, as needed. Explain this system in a footnote or text box 

at the beginning of the NEPA document and the glossary. 

Related Guidance 

• Glossary of Terms Used in DOE NEPA Documents, 1998 

Available on the DOE NEPA Web site (www.eh.doe.gov/nepa) under Guidance.