601-D12-001
EPA EXTERNAL REVIEW DRAFT
Framework for Human Health Risk Assessment
to Inform Decision Making
July 12, 2012
U.S. Environmental Protection Agency
Office of the Science Advisor
Risk Assessment Forum
-------
This page is intentionally blank.
EPA RISK ASSESSMENT FORUM EXTERNAL REVIEW DRAFT
-------
Table of Contents
Disclaimer vi
Preface vii
List of Acronyms viii
List of Text Boxes ix
Executive Summary x
1 Introduction 1
1.1 Background and History 1
1.2 Overview of the Framework 3
1.2.1 Scope and Purpose 3
1.2.2 Description of the Framework 5
2 Planning 10
2.1 Planning and Scoping 10
2.1.1 Context, Purpose and Scope 14
2.1.2 Overarching Considerations 16
2.1.3 Responsibilities and Resources 21
2.1.4 Decision Points and Scientific Peer Review 22
2.1.5 Public, Stakeholder and Community Involvement 24
2.1.6 Past Experiences and Assessments 25
2.2 Problem Formulation 26
2.2.1 Conceptual Model 27
2.2.2 Analysis Plan 31
2.3 Fit for Purpose 38
3 Risk Assessment 40
3.1 Exposure Assessment 41
EPA RISK ASSESSMENT FORUM EXTERNAL REVIEW DRAFT
-------
3.2 Effects Assessment 42
3.2.1 Hazard Identification 43
3.2.2 Dose-Response Assessment 45
3.3 Risk Characterization 46
4 Public, Stakeholder and Community Involvement 50
4.1.1 Stakeholders 52
4.1.2 Community 53
4.2 Communication 54
5 Informing Decisions 56
5.1 Characterizing the Risks for Risk Management Options 56
5.2 Risk Management Factors Beyond the Risk Assessment and Characterization 57
6 Summary 59
References 61
Appendix I. Examples of EPA Program-Specific Resources and Guidance on Risk Assessment
Activities 73
EPA RISK ASSESSMENT FORUM EXTERNAL REVIEW DRAFT
iv
-------
Risk Assessment Forum Technical Panel
Rita Schoeny (Co-Chair)
Kathryn Gallagher (Co-Chair)
Julie Fitzpatrick (Science Coordinator)
Kacee Deener
Chris Dockins
Michael Firestone
William Jordan
Margaret McDonough
Deirdre Murphy
Marian Olsen
Kathleen Raffaele
Office of Water (on Detail to Office of Research and
Development)
Office of Water
Office of the Science Advisor/Risk Assessment
Forum
Office of Research and Development
Office of Policy
Office of Children's Health Protection
Office of Chemical Safety and Pollution Prevention
Region 1
Office of Air and Radiation
Region 2
Office of Solid Waste and Emergency Response
EPA RISK ASSESSMENT FORUM EXTERNAL REVIEW DRAFT
V
-------
Disclaimer
This document is a draft for peer review. It has not been adopted by the U.S.
Environmental Protection Agency and should not be construed to represent agency policy. It is
being circulated for comments on its technical merit and policy implications. Any mention of
trade names or commercial products does not constitute endorsement or recommendation for
use.
EPA RISK ASSESSMENT FORUM EXTERNAL REVIEW DRAFT
vi
-------
Preface
The purpose of this document is to describe a Framework for conducting human health
risk assessments that are responsive to the needs of decision-making processes in the U.S.
Environmental Protection Agency (EPA). This document does not present either a checklist or
compendium of requirements. Rather it includes issues to consider, provides suggested
questions to ask during risk assessment planning and execution, and identifies some useful
practices. The intended audience for this document includes those who assess risk, those who
use the information within and outside the EPA (e.g., risk managers), and those interested in
the process by which EPA conducts risk assessments. This document was produced by a
Technical Panel of the EPA Risk Assessment Forum.
EPA RISK ASSESSMENT FORUM EXTERNAL REVIEW DRAFT
vii
-------
List of Acronyms
AIEO American Indian Environmental Office
CAA Clean Air Act
CASAC Clean Air Scientific Advisory Committee
CERCLA Comprehensive Environmental Response, Compensation and Liability Act
CWA Clean Water Act
EJ Environmental Justice
EPA U.S. Environmental Protection Agency
FQPA Food Quality Protection Act
HPV High Production Volume
IRIS Integrated Risk Information System
IRP Integrated Review Plan
ISA Integrated Science Assessment
MOA Mode of Action
NAAQS National Ambient Air Quality Standards
NAS National Academy of Science
NRC National Research Council
OAQPS Office of Air Quality Planning and Standards
OMB Office of Management and Budget
OPPT Office of Pollution Prevention and Toxics
ORD Office of Research and Development
PA Policy Assessment
PCCRARM Presidential/Congressional Commission on Risk Assessment and Risk
Management
PMN Premanufacture Notice
REA Risk and Exposure Assessment
SAB Science Advisory Board
SDWA Safe Drinking Water Act
TCCR Transparency, Clarity, Consistency and Reasonableness
TSCA Toxic Substances Control Act
EPA RISK ASSESSMENT FORUM EXTERNAL REVIEW DRAFT
viii
-------
List of Text Boxes
Text Box 1-1: Examples of EPA Actions Informed by Risk Assessments 1
Text Box 1-2: Examples of Key EPA Documents Describing Risk Assessment Frameworks 3
Text Box 1-3: General Principles of Framework for Human Health Risk Assessment 4
Text Box 2-1: Key EPA References on Planning and Scoping 10
Text Box 2-2: Examples of Risk Assessment Planning and Scoping at EPA 12
Text Box 2-3: The Silver Book Statements on Utility 13
Text Box 2-4: Risk Assessment for Economic Benefits Analysis 17
Text Box 2-5: Key EPA Children's Health Guidance Documents 19
Text Box 2-6: Resources on Sustainability and Life Cycle Assessment 21
Text Box 2-7: Definitions of "Public," "Stakeholder" and "Community" 24
Text Box 2-8: EPA Resources on Conceptual Models 29
Text Box 2-9: Examples of Conceptual Models in EPA Risk Assessments 31
Text Box 2-10: Data Quality Resources 33
Text Box 2-11: EPA Exposure Assessment Resources for Human Health 33
Text Box 2-12: EPA Resources on Hazard Identification and Dose-Response Assessment 35
Text Box 2-13: Other Risk Analyses Resources 36
Text Box 2-14: Definitions of Uncertainty and Variability 37
Text Box 2-15: More Silver Book Statements on Utility 39
Text Box 3-1: Key Elements of an Exposure Characterization 43
Text Box 3-2: Example of a Consideration for Effects Characterization: Mode of Action 44
Text Box 3-3: Transparency—Clarity—Consistency—Reasonableness in the Risk Characterization
Handbook (U.S. EPA 2000b) 46
Text Box 3-4: Characterizing Cancer Risk from Early Life Exposure 47
Text Box 3-5: Considerations for Risk Characterization: Cumulative Risk Assessment 49
Text Box 4-1: EPA Resources for Public Involvement Efforts, Tools and Policies 52
Text Box 6-1: The Silver Book Recommendations for a Human Health Risk Assessment
Framework 59
EPA RISK ASSESSMENT FORUM EXTERNAL REVIEW DRAFT
ix
-------
Executive Summary
The Framework for Human Health Risk Assessment to Inform Decision Making
(Framework) is intended to facilitate implementation of existing U.S. Environmental Protection
Agency (EPA) guidance for conducting human health risk assessments and to improve the utility
of risk assessment in the decision-making process. The Framework takes into account
recommendations on risk assessment processes described in the National Research Council's
(NRC) 2009 report, Science and Decisions: Advancing Risk Assessment (NRC 2009). Particular
emphasis is given to recommendations on the design of risk assessment and on improving the
utility of risk assessment. This Framework highlights the important roles of planning and
scoping as well as problem formulation in designing a risk assessment that will serve a specific
and documented purpose. In accordance with longstanding agency policy, it also emphasizes
the importance of scientific review and public, stakeholder and community involvement. The
Framework will strengthen the EPA's emphasis on the importance of transparency of its human
health risk assessment and decision-making processes. This document is not intended to
supersede existing EPA guidance; rather, by citing and discussing existing guidance in the
context of the full framework, this document is intended to foster increased implementation of
agency guidance.
The key elements of the process for conducting a risk assessment are as follows:
• Planning and scoping: This step ensures that the risk assessment is sound and serves its
intended purpose. It also allows those interested in the risk assessment process to
determine the context of the risk assessment and the intended use of its results. A
broad range of technical experts working as a team may be involved in this stage.
• Problem formulation: This analytical phase identifies the major factors that must be
considered in a specific assessment, thus informing the technical approach. An
important outcome of problem formulation is a conceptual model that identifies the
stressor(s), the exposed population(s) and the endpoint(s) that will be addressed in the
risk assessment as well as the relationships among them.
• Exposure and effects assessment: Exposure assessment, a primary component of a risk
assessment, will reflect the considerations identified in problem formulation. Effects
assessment includes hazard identification and dose-response assessment. Susceptible
or more highly exposed populations may also be identified in these assessments.
EPA RISK ASSESSMENT FORUM EXTERNAL REVIEW DRAFT
X
-------
• Risk characterization: This final, integrative step provides risk managers with a useful,
synthesized, set of conclusions about the risk that has been assessed. It is judged by four
principles: transparency, clarity, consistency and reasonableness.
• Public, stakeholder and community involvement: Input from the public is sought and
considered. Such input is essential to the agency in fulfilling its mission to protect
human health and the environment.
• Informing decisions: The final step in the risk assessment process is connecting the
previously defined purpose and scope with the conclusions and strengths/limitations of
the risk assessment.
The Framework also reflects the NRC (2009) recommendations on assuring that risk
assessments are well tailored to the problems and decisions at hand, so that they can most
meaningfully inform the decision-making process. In describing these recommendations, the
NRC (2009) report uses the terms "fit for purpose" and "utility of risk assessment," among
others. The NRC (1983) four-step risk assessment paradigm is maintained in the current
Framework, but there is increased emphasis on assuring the utility of each risk assessment. The
utility of risk assessment is not something that is evaluated as a separate step in the process or
as a final check that occurs once the risk assessment is completed. Rather, an emphasis on
utility of the risk assessment for informing risk management decisions begins with planning and
scoping and continues throughout the process. The Framework stresses the practical nature of
risk assessment; it highlights the need for analysis in support of decision making and prompts
the risk assessor to consider areas of overarching concern to the agency, including children's
environmental health and environmental justice. The Framework encourages the consideration
of innovative technology and the still-developing area of sustainability concepts in
environmental decision making. This Framework supports enhanced dialogue between risk
assessors and risk managers while recognizing the distinction in their roles.
EPA RISK ASSESSMENT FORUM EXTERNAL REVIEW DRAFT
xi
-------
1 Introduction
1.1 Background and History
Since the agency's inception, risk
public health and the environment from
and methods employed for these
analyses have evolved. Risk
assessments performed by the agency
inform a broad range of regulatory
decisions (see Text Box 1-1). Thus, the
design, objectives and specific outputs
of risk assessments vary depending on
the purpose and governing statute.
Agency economic analyses also draw
on risk assessments to estimate the
value of health benefits associated
with regulatory options and actions.
assessment has informed actions taken to protect
a range of threats. Over time, the science, approaches
Text Box 1-1: Examples of EPA Actions Informed
by Risk Assessments
• Pesticide usage restrictions.
• Hazardous waste site remediation goals and
approaches.
• Regulation of hazardous materials usage.
• Ambient air quality standards.
• Emissions standards for hazardous air
pollutants.
This document provides a Framework for Human Health Risk Assessment to Inform
Decision Making (Framework) that draws on agency experience and takes into account the
recommendations on risk assessment process from the 'NRC's 2009 report, Science and
Decisions: Advancing Risk Assessment (NRC 2009)—also known as the "Silver Book." In
particular, this Framework seeks to address Silver Book recommendations on the design of and
improving the utility of risk assessments. This Framework also draws on a considerable body of
additional expert advice, beginning with the National Academy of Sciences' (NAS) NRC 1983
report, Risk Assessment in the Federal Government: Managing the Process (commonly referred
to as the "Red Book"), followed by the NRC's 1994 Report, Science and Judgment in Risk
Assessment (commonly referred to as the "Blue Book"), and incorporates principles from the
agency's extensive human health risk assessment guidance. Following publication of the Red
Book, the agency issued Risk Assessment and Management: Framework for Decision Making
(U.S. EPA 1984), which first articulated the EPA's risk assessment framework. In 1984, the
agency established what is now called the Risk Assessment Forum and in 1986 added the Risk
Assessment Council; in 1993, the Science Policy Council (now called the Science and Technology
Policy Council) replaced the Risk Assessment Council. Shortly after publication of the Red Book,
the EPA began issuing a series of guidelines for conducting risk assessments in a number of
areas (e.g., cancer, chemical mixtures, developmental toxicity, exposure assessment,
mutagenicity, neurotoxicity, and reproductive toxicity) (U.S. EPA 1986b, 1987, 2005a, 1986a,
EPA RISK ASSESSMENT FORUM EXTERNAL REVIEW DRAFT
1
-------
2000a, 1991b, 1992a, 1986c, 1998b, 1996, respectively). Many of these original agency-wide
risk assessment guidelines include frameworks that have been updated over time.
In its emphasis on the planning aspects of conducting risk assessments, this Framework
builds on principles found in the EPA's 1997 Guidance on Cumulative Risk Assessment. Part 1.
Planning and Scoping, which described an approach for integrated risk assessment and
management (U.S. EPA 1997a). The 1997 guidance was designed to help risk managers and risk
assessors plan and document the scope of risk assessments and consider appropriate
participants (that is, technical, advisory or stakeholder) and information sources to enrich the
risk assessment. Additionally, the 1997 guidance augmented the agency's February 1995
Guidance for Risk Characterization (U.S. EPA 1995d) by emphasizing the need for providing a
transparent, clear, consistent and reasonable basis for any assessment, and strongly
encouraged the undertaking of a formal problem formulation exercise for all risk assessments.
Prior to the 1997 Guidance on Cumulative Risk Assessment. Part 1. Planning and
Scoping, the agency published the Framework for Ecological Risk Assessment (U.S. EPA 1992b)
and subsequently released the Guidelines for Ecological Risk Assessment (U.S. EPA 1998a),
which incorporated planning and scoping into the ecological risk assessment process. In 2003,
the Framework for Cumulative Risk Assessment (U.S. EPA 2003a) further built on these
documents in formulating a flexible structure for conducting and evaluating cumulative risk
assessment (for human health or ecological risk). In 2006, the agency published A Framework
for Assessing Health Risk of Environmental Exposures to Children, which applied this general
structure (including problem formulation, analysis and risk characterization, the three critical
phases in the risk assessment process) in describing risk assessments focused on evaluating
potential risks arising as a result of early life exposure (U.S. EPA 2006a). In addition to these
more general agency documents, individual programs and offices have implemented risk
assessment frameworks specific to their missions. Examples of documents with risk assessment
frameworks are provided in Text Box 1-2. Finally, the agency has developed a Risk Assessment
Portal (U.S. EPA, 20121) that provides basic information about environmental risk assessments
and offers a comprehensive set of links to key EPA tools, guidance and guidelines.
EPA RISK ASSESSMENT FORUM EXTERNAL REVIEW DRAFT
2
-------
Text Box 1-2: Examples of Key EPA Documents Describing Risk Assessment Frameworks
• Risk Assessment Guidance for Superfund Part A (U.S. EPA 1989, 1991, 1998a, 1999a,
2001d,2004a, 2009)
• Framework for Ecological Risk Assessment (U.S. EPA 1992b)
• Guidance on Cumulative Risk Assessment:. Part 1. Planning and Scoping (U.S. EPA 1997a)
• Guidelines for Ecological Risk Assessment (U.S. EPA 1998a)
• Risk Characterization Handbook (U.S. EPA 2000b)
• Framework for Cumulative Risk Assessment (U.S. EPA 2003a)
• Office of Air Quality Planning and Standards Air Toxics Risk Assessment Library - General
Framework for Residual Risk Assessment (U.S. EPA 2004e)
• A Framework for Assessing Health Risk of Environmental Exposures to Children (U.S. EPA
2006a)
• Office of Pollution Prevention and Toxics Requirements for Submitting Electronic Pre-
manufacture Notices (PMNs) (U.S. EPA 2010d)
1.2 Overview of the Framework
1.2.1 Scope and Purpose
The purpose of this document is to describe a process for conducting human health risk
assessments that are responsive to the decision-making needs of the EPA. It provides an
organizing structure for implementing existing EPA guidance on human health risk assessment.
This Framework highlights the important role of planning and scoping in designing a risk
assessment so that it serves its intended purpose, as well as the importance of scientific review
and public, stakeholder and community involvement. This Framework is expected to promote
and increase the transparency of the human health risk assessment process at the agency. It is
consistent with the EPA Scientific Integrity Policy (U.S. EPA 2012b) and follows the general
principles laid out in Text Box 1-3.
EPA RISK ASSESSMENT FORUM EXTERNAL REVIEW DRAFT
3
-------
In building on the basic
components identified in the Red
Book (NRC 1983) and on
processes currently employed _ , . . . , .,, ,.., .. . . , ,
Each risk assessment should be fit for its intended
across the agency, this
Framework takes into account
key recommendations from the
Silver Book (NRC 2009), which ' Risk assessment should be based on exP°sure
scenarios, consistent with the purpose and context.
called for more interaction among
risk assessors and risk managers
during the course of a risk
roles (NRC 2009). Thus, this
Framework emphasizes the
Text Box 1-3: General Principles of Framework for
Human Health Risk Assessment
purpose.
Each risk assessment should state the purpose,
context and scope clearly.
As appropriate, it should include consideration of
susceptible population groups and lifestages.
The risk assessment should follow an acceptable,
assessment while recognizing and overtly logical path emP|oYing common sense and
sound judgment in applying relevant guidance.
keeping separate their different . A|| stepS; key assumptionS; |imitations and
decisions, along with associated rationale, should
be clearly conveyed.
importance of early identification ' There should be consideration of the role of
scientific peer and public consultation and review.
of risk management options so _, . . . , .,, ...
• The risk assessment should be presented in a
readily understandable and useful form.
that risk assessment can most
efficiently inform choices among
such options. Risk management
decisions are beyond the scope of the risk assessment proper; a risk assessment is one of the
sources of information that informs the particular decision at hand. As discussed in Section 5 of
this document, the risk assessment should not "make" the decision; it should characterize the
risk, including specifying who, what or how much is at risk. The Framework describes planning
to maximize the utility of the risk assessment for informing risk management decisions.
The Framework reflects the often iterative nature of risk assessment; that is, as some
scientific questions are answered, new ones may develop that require the generation of
additional data and/or analyses that better define the distribution of risk and/or address
uncertainty. Throughout the process, additional knowledge may result in further refinement of
the conceptual model and analysis plan.
Finally, this Framework incorporates areas of overarching agency interest, such as the
evaluation of risks to children (U.S. EPA 1995c) and environmental justice (EJ) (U.S. EPA 2012a),
and promotes the consideration of the concepts of sustainability and technology innovation in
risk management decision making. Executive orders that apply to these areas are Executive
Order 13045 (protection of children) and Executive Order 12898 (environmental justice).
EPA RISK ASSESSMENT FORUM EXTERNAL REVIEW DRAFT
4
-------
In summary, this Framework describes approaches for organizing and conducting
human health risk assessments; it complements but does not replace any existing guidance or
guidelines. Building from the agency's experience and NRC recommendations, the Framework is
intended to identify the critical aspects of the risk assessment process within a formal albeit
flexible structure. The Framework is not intended to be an exhaustive reference on all relevant
guidance; rather, the Framework is intended to clearly describe the overall process, with
attention to critical aspects of each component, giving relatively more attention to the
description of less technical (more process-associated) components of the process, while
identifying relevant references for the more technical components. It describes and discusses a
series of steps and considerations important to formulating and performing a risk assessment
to inform decisions. A major objective of the Framework is to improve the consistency and
transparency of risk assessments while enhancing harmonization of approaches across the
agency. The Framework aims to maximize the utility of the risk assessment for informing risk
management decisions as well as ensuring the most efficient use of resources by aligning the
nature and/or scope of the risk assessment with the decision to be made.
1.2.2 Description of the Framework
The Framework for Human Health Risk Assessment to Inform Decision Making, at its
most basic form, is illustrated in Figure 1-1. This figure reflects the main elements of the
Framework and their roles in the risk assessment process in a form that encompasses the broad
range of EPA risk assessment contexts. The figure conveys a path from planning and scoping to
informing decisions and illustrates that the process provides opportunities for feedback along
this path, which may vary among applications.
The main elements of the Framework are discussed in the subsequent four sections of
this document. The concept of "fit for purpose" is discussed in multiple sections in keeping with
the need for its consideration from planning through execution, to ensure that assessments
most meaningfully inform the decision-making process. Sections focused on the other elements
are as shown below.
• Planning and scoping and problem formulation are detailed in Section 2 (Planning).
• Exposure and effects assessment and risk characterization are discussed in Section 3
(Risk Assessment).
• Public, stakeholder and community involvement are addressed in Section 4 (Public,
Stakeholder and Community Involvement).
• Informing decisions is discussed in Section 5 (Informing Decisions).
EPA RISK ASSESSMENT FORUM EXTERNAL REVIEW DRAFT
5
-------
Public,
Stakeholder
and
Community
Involvement
Planning and Scoping
and Problem Formulation
Conceptual
Model
Analysis
Plan
Risk Assessment
Expos ure
Assessment
Effects Assessment
Hazard Identification
Dose Response
Risk Characterization
8
|
Q.
Informing Decisions
Figure 1-1. Framework for Human Health Risk Assessment to Inform Decision Making.
As described in the Silver Book (NRC 2009), the process begins with a decision to
conduct a risk assessment after what is described as a "signal" of potential harm is brought to
the EPA's attention. Generally, this would involve a set of existing or potential environmental
conditions that appear to pose a threat to human or environmental health. The process
outlined in the Framework initiates activities on the assessment of the risk potential of the
environmental conditions; that is, after the signal is received.
The initial stage in conducting any EPA risk assessment focuses on carefully
characterizing the task to be completed; it includes planning and scoping and problem
formulation components. The planning and scoping phase involves understanding the specific
environmental issue to be addressed; the legal framework under which any action will be
taken; the risk management options; and the public-, stakeholder- or community-specific
issues. Specific regulatory or programmatic requirements are considered throughout the
planning process. An essential question in this phase is what level of complexity is required
(e.g., screening, deterministic, or probabilistic risk assessment) to inform the necessary
decision; this consideration is termed here as "fit for purpose." Planning and scoping also
includes the identification of resources available to complete the assessment and the formation
of a risk assessment team capable of performing the technical analyses that may be needed.
The team members may include a project manager, risk assessor, and other staff with the
appropriate expertise necessary to address the specific question. Based on the information
developed during planning and scoping, the problem formulation is then conducted to develop
a conceptual model and incorporate the information into an analysis plan. The analysis plan
outlines how the exposure; hazard and dose-response; and risk characterization components of
EPA RISK ASSESSMENT FORUM EXTERNAL REVIEW DRAFT
6
-------
the risk assessment will be conducted, with consideration of data quality; uncertainty and
variability; and public, stakeholder and community involvement for each component as
appropriate.
The core risk assessment then is conducted based on the analysis plan developed during
problem formulation. The risk assessment phase includes developing the exposure and effects
characterizations and integrating those results for presentation as part of the risk
characterization. A key aspect of the Framework, "fit for purpose," is consideration of the
usefulness of the assessment for its intended purpose, to ensure that the assessment produced
is suitable and useful for informing the needed decisions. Attention to this concept is intended
to assure, through focused planning and problem formulation and periodic reconfirmation
during the process, that the informational needs of the risk managers will be met by the
information being generated by the assessment. Rather than a separate step or final check in
the process once the risk assessment is completed, an emphasis on the utility of the risk
assessment occurs throughout the process. This begins with planning and scoping and includes
evaluating the applicability of the risk assessment for informing risk management decisions;
these evaluations may take place in several points of the iterative risk assessment process. Thus
focus is maintained on the information needs for the risk management decisions by considering
such questions as: "Is the assessment achieving its objectives for informing risk management
decisions?" If the answer is negative, then the risk assessment team can make adjustments,
revisit steps or develop additional information as needed.
The risk assessment may be assessed via independent peer review and/or receiving
input from public, stakeholder and community involvement, recognizing that approaches for
addressing these different audiences will vary among assessments. Independent peer review
helps to ensure the integrity and quality of the scientific and technical aspects of the risk
assessment. Where there is a need for such review, it may involve internal or external technical
reviewers. Input from the public, internal and external stakeholders, and the affected
community(ies) can provide insights that may not otherwise be available to risk managers but
should in no way compromise the integrity or quality of the scientific and technical aspects of
the risk assessment.
In the risk management phase, risk managers will use the information in the assessment
report to evaluate the management options that are identified, thereby Informing Decisions as
to the selection of actions appropriate under statutory authority, relevant Executive Orders
(e.g., 12898, 13045) and Homeland Security Presidential Directives. Considerations in this phase
of the Framework include the risk assessment results for the various options, in light of all
appropriate factors. An outcome of this phase may be recognition of the need for additional
assessment, leading to iteration of previous steps. This phase also may include development of
EPA RISK ASSESSMENT FORUM EXTERNAL REVIEW DRAFT
7
-------
a strategy for communicating conclusions with the public, internal and external stakeholders,
and affected community(ies). In addition, plans may be made for evaluation of the outcome of
any actions taken.
The following case example describes the current process for conducting reviews of the
National Ambient Air Quality Standards (NAAQS) (U.S. EPA 2012f). This process includes explicit
phases for planning, assessment of currently available scientific evidence (including that on
hazard and dose response), risk and/or exposure assessment, and policy assessment and
rulemaking. In each phase there is consideration of the need for external peer review and/or
public comment. Although each component or step in this example may not rely on precisely
the same terms as those used in this Framework document, it illustrates one manner by which
the EPA implements the key aspects of this Framework for a program in which risk assessment
plays a role in informing regulatory decisions.
EPA RISK ASSESSMENT FORUM EXTERNAL REVIEW DRAFT
8
-------
Case Example: Reviews of National Ambient Air Quality Standards
EPA's current process for reviewing the National Ambient Air Quality Standards (NAAQS) has four major phases:
(1) planning, (2) science assessment, (3) risk/exposure assessment and (4) policy assessment and rulemaking. The
planning phase of the NAAQS review process begins with a science policy workshop to identify issues and questions to
frame the review. A draft Integrated Review Plan (IRP) for the review is prepared jointly by the EPA's National Center
for Environmental Assessment and the EPA's Office of Air Quality Planning and Standards (OAQPS). The draft IRP is
made available for consultation with the Clean Air Scientific Advisory Committee (CASAC) and for public comment. The
final IRP is prepared in consideration of CASAC and public comments, and it presents the current plan and specifies the
schedule for the entire review, the process for conducting the review and the key policy-relevant science issues that
will guide the review.
The second phase of the review, science assessment, involves the preparation of an Integrated Science Assessment
(ISA), which provides a concise review, synthesis and evaluation of the most policy-relevant science, including key
science judgments that are important to the design and scope of exposure and risk assessments. The ISA provides a
comprehensive assessment of the current scientific literature pertaining to known and anticipated effects on public
health and welfare associated with the presence of the pollutant in the ambient air, emphasizing information that has
become available since the last air quality criteria review to reflect the current state of knowledge. The ISA forms the
scientific foundation for the NAAQS review and is intended to provide information useful in forming judgments about
air quality indicator(s), form(s), averaging time(s) and level(s).
In the third phase, risk/exposure assessment, staff prepares planning documents that consider the extent to which
newly available scientific evidence and tools/methodologies warrant the conduct of quantitative risk and exposure
assessments. If warranted, these documents outline a general plan, including scope and methods, for conducting the
assessments. When an assessment is performed, one or more drafts of each risk and exposure assessment (REA)
document undergoes CASAC and public review prior to completion of final REA(s). The REA provides concise
presentations of methods, key results, observations, and related uncertainties.
The review process ends with a policy assessment and rulemaking phase. The Policy Assessment (PA) is a document
that provides a transparent OAQPS staff analysis and staff conclusions on the adequacy of the current standards and
potential alternatives that are appropriate to consider prior to the issuance of proposed and final rules. The PA
integrates and interprets the information from the ISA and REA(s) to frame policy options for consideration by the
Administrator. Such an evaluation of policy implications is intended to help "bridge the gap" between the agency's
scientific assessments, presented in the ISA and REA(s), and the judgments required of the EPA Administrator in
determining whether it is appropriate to retain or revise the NAAQS. The PA also is intended to facilitate the CASAC's
advice to the agency and recommendations to the Administrator on the adequacy of the existing standards or revisions
that may be appropriate to consider, as provided for in the Clean Air Act. In evaluating the adequacy of the current
standards and (as appropriate) a range of alternative standards, the PA considers the available scientific evidence and,
as available, quantitative risk-based analyses, together with related limitations and uncertainties. The PA focuses on
the information that is most pertinent to evaluating the basic elements of NAAQS: indicator, averaging time, form and
level. One or more drafts of a PA are released for CASAC review and public comment prior to completion of the final
PA. Following issuance of the final PA and consideration of conclusions presented therein, the agency develops and
publishes a notice of proposed rulemaking that communicates the Administrator's proposed decisions regarding the
standards review. A draft notice undergoes interagency review involving other federal agencies prior to publication.
Materials on which this decision is based, including the documents described above, are made available to the public in
the regulatory docket for the review. A public comment period, during which public hearings generally are held,
follows publication of the notice of proposed rulemaking. Taking into account comments received on the proposed
rule, the agency develops a final rule that undergoes interagency review prior to publication to complete the
rulemaking process. (Technology Transfer Network NAAQS U.S. EPA 2012p)
EPA RISK ASSESSMENT FORUM EXTERNAL REVIEW DRAFT
9
-------
2 Planning
There are multiple challenges and requirements that may arise in conducting a risk
assessment. For example, an assessment conducted as part of a regulatory action may have
various legal considerations, including the statute under which it is being conducted (e.g., CAA,
Clean Water Act [CWA]) and the regulatory program of which it is a part (e.g., 6-Year Review of
Drinking Water Contaminants under SDWA, Pesticide Registration Review, Risk and Technology
Review program). Such legal considerations may result in the selection of specific aspects of the
assessment.
There may also be technical challenges. For example, there may be a need to develop
appropriate analytical techniques or to use fate and transport models to estimate the range of
contaminant concentrations (and hence, potential exposure). An assessor also may be faced
with a lack of toxicity data for specific chemicals or routes of exposure. Information on sensitive
populations may be unavailable. Information on the likelihood or timing of combined exposures
to multiple chemicals may be difficult to obtain or estimate. Other challenges or considerations
may be related to resources, such as the need for access to specific expertise (e.g., modeling).
Time constraints associated with decision making and funding—or lack thereof—also may be an
issue and should be noted in the analysis plan.
2.1 Planning and Scoping
The planning and scoping phase
is an element of the EPA's data quality
objectives process and is critical to
producing a sound risk assessment that
serves its intended purpose (U.S. EPA
1997a, 1998a, 2000b, 2002a, 2003a,
2006f; Presidential/ Congressional
Commission on Risk Assessment and
Risk Management [PCCRARM] 1997a,
1997b; NRC 2009). EPA's guidance
related to the 2001 Data Quality Act
emphasizes the important role of
systematic planning and attention to
data quality objectives (U.S. EPA 2006f).
Text Box 2-1 provides a list of EPA
references on planning and scoping.
This phase may involve a team of
Text Box 2-1: Key EPA References on Planning
and Scoping
• Guidance on Cumulative Risk Assessment.
Part 1. Planning and Scoping (U.S. EPA
1997a)
• Guidelines for Ecological Risk Assessment
(U.S. EPA 1998a)
• Science Policy Council Handbook: Risk
Characterization (U.S. EPA 2000b)
• Lessons Learned on Planning and Scoping of
Environmental Risk Assessment (U.S. EPA
2002a)
• Framework for Cumulative Risk Assessment
(U.S. EPA2003a)
• Guidance on Systematic Planning Using the
Data Quality Objectives Process (U.S. EPA
2006f)
EPA RISK ASSESSMENT FORUM EXTERNAL REVIEW DRAFT
10
-------
technical experts, such as toxicologists, economists and engineers, as well as risk assessors and
risk managers. In some cases, other subject matter experts may include attorneys and
community outreach specialists. It also may be informed by external scientific or stakeholder
input. Questions addressed in the Planning and Scoping step (derived from U.S. EPA 1997a),
are as follows:
• What are the overall purposes and general scope of the risk assessment? Are there legal
limitations or other legal considerations? If so, what are they?
• What risk assessment products are needed by management for informed decision-
making? What is needed for other analyses (e.g., economic analysis)?
• What resources are required, available or pending? Resources could include data or
models, funding, personnel, expertise and/or coordination with other organizations.
• Who will be involved in conducting the risk assessment, and what are their roles (e.g.,
technical, legal or stakeholder advisors)?
• What schedule will be followed? This will include provision for timely and adequate
internal and independent external peer review where appropriate.
In general, planning and scoping provides the opportunity for the risk manager(s), risk
assessor(s) and others interested in the process to consider the context in which the risk
assessment is being conducted and the purpose(s) for which the results will be used. The risk
assessment team, in collaboration with the risk managers, also defines what is expected to be
covered, considering limitations or constraints (e.g., tools, resources or timing). Planning and
scoping is an important first step to ensure that each risk assessment has a clear purpose and
well-defined vision. Products from planning and scoping (e.g., the conceptual model and
analysis plan) reflect a common understanding and agreement on boundaries and conduct of
the assessment by those involved. Several examples of planning and scoping for EPA risk
assessments are summarized in Text Box-2-2.
EPA and external advisors have repeatedly recognized that an important part of
ensuring the usefulness of each risk assessment is the dialogue between the risk manager and
the risk assessment team on the nature of the decision to be informed by the risk assessment
(PCCRARM 1997a and b; NRC 2009; U.S. EPA 1998a, 2000b, 2002a, 2003a). This dialogue may
include discussion of many topics, for example:
EPA RISK ASSESSMENT FORUM EXTERNAL REVIEW DRAFT
11
-------
• Basis for the risk assessment (e.g., regulatory requirements, public concern, scientific
findings).
• How the information will be used.
• Risk management options.
• Areas of interest and applicable policies.
• Overarching considerations (e.g., environmental justice, children's health, cumulative
risk assessment and sustainability as presented in Section 2.1.2).
• Economics.
• Current knowledge.
• Level of effort.
• Plans for use and communication of the information.
Text Box 2-2: Examples of Risk Assessment Planning and Scoping at EPA
• In EPA's review of pesticide registrations, planning and scoping occurs for a series of risk
assessments, which although focused on different pesticides are designed to address a
common overarching regulatory purpose and assessment scope (Registration Review
Update. U.S. EPA 2004g).
• In the planning phase for reviews of NAAQS, an integrated review plan is developed that
describes all phases of the review, including the risk/exposure assessment. Additionally, a
risk and exposure (REA) planning document is developed as the first step in the REA phase
(for an example, planning documents for the particulate matter NAAQS review are
available at: Particulate Matter Standards—Documents From Current Review—Planning
Documents [U.S. EPA 2011n]).
• Planning and scoping are key components of human health risk assessments conducted
under the Comprehensive Environmental Response, Compensation and Liability Act
(CERCLA; also known as Superfund), and arediscussed in the following guidance
documents:
> Guidance for Conducting Remedial Investigations and Feasibility Studies Under
CERCLA (U.S. EPA 1988)
> Human Health: Planning and Scoping (U.S. EPA 2011o)
> Ecological: Planning and Scoping (U.S. EPA 2011p)
• In EPA's residual risk review of National Emissions Standards for Hazardous Air Pollutants,
the planning and scoping step encompasses a set of emissions source categories for which
risk assessments are of generally similar scope and basic design while differing in specific
aspects of the sources and the chemicals emitted. A general project is described at: Risk
and Technology Review (U.S. EPA 2011q), at which a case study risk assessment plan for
several source categories also is available.
EPA RISK ASSESSMENT FORUM EXTERNAL REVIEW DRAFT
12
-------
Figure 2-1 calls out the key elements of planning and scoping in the Framework, each of
which are discussed in further detail in subsequent sections. Text Box 2-3 provides context on
risk assessment from the Silver Book (NRC 2009).
Public,
Stakeholder
and
Community
Involvement
Planning and Scoping
and Problem Formulation
Conceptual
Model
Analysis
Plan
Risk Assessment
Exposure
Assessment
Effects Assessment
Hazard Identification
Dose Response
Risk Charactenzation
Informing Decisions
Key Considerations
for Planning and Scoping
• What decision is to be informed by risk
assessment and what are risk manage-
ment goals?
• What legal/statutory requirements
affect risk management options and
level/type of analysis?
What other considerations
(environmental justice, life stage,
cumulative risk, sustainability, etc.) may
influence risk management options and
analyses?
* What assessments (risk, economic,
etc.) are needed to address decision
making needs?
- What expertise, resources and timeline
are available to conduct the
assessment(s)?
Figure 2-1. Framework for Human Health Risk Assessment to Inform Decision Making: Key
considerations for Planning and Scoping.
Text Box 2-3: The Silver Book Statements on Utility
"Risk assessments should not be conducted unless it is clear that they are designed to answer specific
questions, and that the level of technical detail and uncertainty and variability analysis is appropriate
to the decision context" (NRC 2009, 247).
"The technical framework for risk assessment presented in the Red Book should remain intact but
should be embedded in a broader framework in which risk assessment is used principally to help to
discriminate among risk-management options" (NRC 2009, 256).
EPA RISK ASSESSMENT FORUM EXTERNAL REVIEW DRAFT
13
-------
• Section 2.1.1 focuses on the need to consider the purpose and context for the risk
assessment, noting that different processes may be employed depending on this
context and purpose.
• Section 2.1.2 describes important overarching considerations that may affect risk
management options.
• Section 2.1.3 discusses consideration of responsibilities, resources, participants and
timeline.
• Section 2.1.4 addresses planning for scientific review.
• Section 2.1.5 details public involvement.
• Section 2.1.6 discusses the incorporation of lessons learned from review of previous
assessments.
2.1.1 Context, Purpose and Scope
Each human health risk assessment is conducted within a particular context, which may
be specific to regulatory or programmatic needs or which may be responsive to environmental
events or newly identified circumstances of potential public health concern. Many EPA risk
assessments are performed to inform specific decisions that guide the development of
regulatory actions. For example, risk assessments commonly inform federal regulations
governing the establishment and review of NAAQS; the provision of public drinking water; and
the registration of pesticides for U.S. distribution, sale and use. For such risk assessments that
are routine and in which the type and level of effort needed is well-established, the degree of
additional planning and scoping that is warranted for each individual assessment may not be
intensive. In other cases, such as a response to a newly identified environmental concern,
careful planning and scoping is essential to the development of a risk assessment that provides
information needed to address the concern.
For risk assessments performed within a regulatory context, statutory language or
legislative history may impose requirements or restrictions that will need to be considered in
scoping the risk assessment; for example, the Food Quality Protection Act (FQPA) includes
directives on assessing risk that apply to pesticides in foods and water. In some regulatory
contexts, a risk assessment (or some quantitative aspect of it) may be a key input into benefit-
cost analyses of alternative regulatory options; these analyses may impose different or
additional requirements by comparison to regulatory contexts wherein costs are not
considered.
As stressed earlier, risk assessments are most useful when they are designed to answer
specific questions with a level of technical evaluation that is appropriate for the decision
context ("fit for purpose"). In situations that are perceived to be particularly complex, clear
articulation of the overall purpose or end use of an assessment may involve extensive
EPA RISK ASSESSMENT FORUM EXTERNAL REVIEW DRAFT
14
-------
interaction among the assessment team and the range of stakeholders to establish a common
understanding. Explicit consideration of the purpose and decision context in the planning phase
will help to ensure the most efficient use of resources in the development of a risk assessment
that fulfills its purpose. That is, the utility of and risk assessment is a function of how well it
informs the decision for which it is designed.
The planning phase includes explicit consideration of the nature of the assessment
question or the hypothesis that the assessment seeks to address, with the goal of developing or
clarifying the broad dimensions and elements of the assessment. In this step, the assessment
and management objectives are defined clearly.
The particular purpose for which an assessment will be used (e.g., site-specific versus
regional or national) often will have significant implications for the scope, level of detail and
approach of an assessment. The risk assessment scope can be defined, in a general sense, by
the scale of the environmental problem being considered (e.g., local scale vs. national scale)
and the regulatory context. One example is a risk assessment intended to investigate the health
risks associated with a hazardous waste site that falls under the CERCLA statute, while the
scope for this risk assessment may be site-specific, considering multiple receptors, multiple
chemicals and multiple pathways of exposure for on- and off-site receptors (depending on the
nature of the site). This will differ from the scope for a risk assessment on uses or exposure to a
particular chemical, which is conducted to inform a national regulation (such as a National
Primary Drinking Water Rule).
Scoping provides a foundation for the problem formulation step. Scope, in this context,
refers to the proposed boundaries of the assessment (e.g., what chemical[s] and exposure
pathway[s]). The scope is considered with other items (e.g., context, purpose, participants,
timeline, resources) in developing the detailed plan for the assessment. At this step, most EPA
assessment projects focus on identifying and considering information available in these areas:
• Sources of contaminants.
• Stressors, associated effects, susceptible populations and life stages.
• Routes and pathways.
• Stakeholder concerns.
• Any spatial or temporal aspects of exposure (U.S. EPA 1997a, 2001b).
Consideration of these elements during scoping helps to identify missing information
and potential assessment endpoints for the analysis plan. It also provides the basis for an early
conceptualization of the problem being assessed and the approaches for assessment. The
scoping discussion also should include regulatory context and any additional management or
programmatic needs or limitations. At this stage, consideration of the needs of related,
quantitative analyses (e.g., cost/benefit analysis or environmental impacts of associated policy
EPA RISK ASSESSMENT FORUM EXTERNAL REVIEW DRAFT
15
-------
decisions) can contribute to improved efficiency. It also will help to ensure the compatibility of
the quantitative analyses considered in the decision-making step described in Section 5. For
example, Text Box 2-4 notes considerations pertaining to risk assessment for economic benefits
analysis. Information considered and decisions made during the scoping step also shape the
development of the conceptual model and the analysis plan (as described in Section 2.2).
In the planning and scoping phase, it also is important to identify any subprocesses that
will feed into the risk assessment (e.g., Integrated Risk Information System [IRIS]). It also is
important to identify larger processes (e.g., rulemaking that occurs within the agency's Action
Development Process) (U.S. EPA 2011r). Furthermore, individual regulatory programs have a
formalized process detailing the risk assessment process (e.g., Superfund). These processes may
have specific information requirements and timelines, and these may impose additional
requirements on the risk assessment process. Depending on the nature of the risk assessment
and the importance of the decisions, it may be important to identify how the risk assessment
team will interact with other program offices affected by the ultimate decision. Interagency
coordination also may be needed.
2.1.2 Overarching Considerations
The purpose and scope of the assessment also should be considered in the context of
broad EPA priorities. The extent to which these affect any given risk assessment will depend on
many factors, including the risk assessment purpose, scope and regulatory context. These
overarching considerations, described below, may not affect all analyses; however, early
consideration and discussion of these issues can enhance the utility of the risk assessment.
Further, such considerations may receive particular attention in the risk management arena,
depending on the decision context. Several current examples of agency priorities that may be
important overarching considerations in human health risk assessments are described below.
Analysis of the following overarching considerations should involve consultation with experts
and offices that focus on them.
EPA RISK ASSESSMENT FORUM EXTERNAL REVIEW DRAFT
16
-------
Text Box 2-4: Risk Assessment for Economic Benefits Analysis
Although risk assessment and economic analysis often are considered very separate exercises, estimates
from or inputs to risk assessment sometimes may serve as inputs into models economists use for the
benefits side of benefit-cost analysis. Therefore, when benefit-cost analysis is needed to inform
decisions, early communication between the risk assessment and benefits analysis teams, including
consideration of the needs of both analyses, can contribute to efficiencies in the assessment designs.
Key considerations in economic benefits analyses include:
• Identifying a set of human health endpoints that are economically meaningful; that is,
endpoints that can be linked to human well-being and for which the risks can be monetized
using economic valuation methods. This may require the risk assessment to model additional
outcomes or different outcomes than it would otherwise. For example, benefits analysis
incorporates changes in all health effects across the relevant range of exposure, not just the
most sensitive. In this case, specific human health endpoints measured in laboratory or
epidemiological studies may need to be converted in the risk assessment to additional metrics
or normalized in such a manner that the effects can be valued in the economic analysis
• Estimating changes in the probabilities of human health outcomes rather than measures such
as reference doses and reference concentrations that do not estimate potential risk (as noted in
Chapter 5 of the Silver Book [NRC 2009]).
• Producing expected or central estimates of risk for a given population rather than conservative
estimates. The Science Advisory Board (SAB) Advisory on EPA's Superfund Benefits Analysis
highlights the issue of using conservative risk assessments in benefits analysis (U.S. EPA 2006b).
• Attempting to estimate the "cessation lag" associated with reductions in exposure. That is, the
analysis should characterize the time profile of changes in exposures and resulting changes in
risks. This concept is more fully described in the Arsenic Rule Benefits Analysis: An EPA SAB
Review (U.S. EPA2001a).
• Attempting to characterize the full uncertainty distribution associated with risk estimates. Not
only does this contribute to a better understanding of potential outcomes, it also enables
economists to incorporate risk assessment uncertainty into a broader analysis of uncertainty.
Formal probabilistic assessment of uncertainty in benefits and costs is required by the Office of
Management and Budget for some regulations.
Early communication between the teams can help to improve the analyses performed for both
purposes. For example, risk assessment estimates may be informative for benefit-cost analysis and also
can contribute information and insights into how behavioral changes may affect exposure and, thus,
change the risk. Even in cases in which the economists' contribution to the risk characterization is not
direct, communication between the teams will improve compatibility of the risk assessment and
economic analysis.
Additional information on economic analysis at can be found in Guidelines for Preparing Economic
Analyses (US EPA, 2010a).
EPA RISK ASSESSMENT FORUM EXTERNAL REVIEW DRAFT
17
-------
• En vironmental Justice
EPA defines Environmental Justice (EJ) 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 (U.S. EPA 2012q). Achieving EJ is an agency priority that is
factored into every decision (U.S. EPA 2010b). In the risk assessment process, the
potential for disproportionate environmental and public health impacts to minority or
low-income populations is an important consideration during the problem formulation
and planning and scoping stages. There has been discussion on addressing EJ concerns
in existing environmental and civil rights laws, their implementing regulations, Executive
Order 12898 and the EPA's EJ policies. More information can be found at EPA's EJ
website (U.S. EPA 2012a) and in the Interim Guidance on Considering Environmental
Justice During the Development of an Action (U.S. EPA 2010b). For example, EPA
priorities in this area include development of technical guidance and implementation
plans. EPA has established the American Indian Environmental Office (AIEO) to
coordinate the agency-wide effort to strengthen public health and environmental
protection in tribal lands, with a special emphasis on helping tribes administer their own
environmental programs. Information on the AIEO and related activities is available at
the American Indian Environmental Office website (U.S. EPA 2012g).
• Children's Health Protection
Protecting children's health from environmental pollutants has long been part of
the EPA's mission. Children may be proportionately more heavily exposed to some
environmental contaminants than adults based on their smaller size and increased
consumption per body weight of certain foods. Furthermore, their behavior patterns,
such as playing close to the ground and hand-to-mouth activity, also may increase their
exposure to contaminants. In addition, they may be more vulnerable to environmental
hazards because their organ systems still are developing and undergoing processes that
are specifically sensitive to certain chemicals, leading to potential windows of
susceptibility. Children also may be less able than adults to metabolize, detoxify and
excrete some chemicals.
In 1995, the EPA established its Policy on Evaluating Health Risk to Children to
ensure that environmental health risks to children explicitly and consistently are
evaluated as part of the EPA's risk assessments and that all standards set by the EPA are
protective of any heightened risks faced by children (U.S. EPA 1995c). In 1997, Executive
EPA RISK ASSESSMENT FORUM EXTERNAL REVIEW DRAFT
18
-------
Order 13045 on the Protection of Children from Environmental Health Risks and Safety
Risks was issued. This executive order requires all federal agencies to assign a high
priority to addressing health and safety risks to children, coordinate research priorities
on children's health, and ensure that their standards take into account special risks to
children (EO 13045).
Some public health statutes provide for the protection of sensitive populations,
population groups or subpopulations. For example, the 1996 Safe Drinking Water Act
(SDWA) amendments utilize the term "subpopulation" to describe groups with unique
attributes, including those defined by age or life stage. The EPA recognizes that these
terms, as used in such statutes, describe groups of people with common attributes,
including life stage, which may make them more sensitive or susceptible to the
stressor(s) being assessed. The EPA emphasizes the importance of recognizing that
childhood encompasses a sequence of life stages through which all members of a
population pass. A life stage approach to risk assessment considers the relevant periods
of exposure in developmental life stages and subsequent outcomes that may not be
expressed until later life stages (U.S. EPA 2005a). Accordingly, EPA's risk assessments
consider and take into account, using a variety of approaches, the potential for
differences across life stages that may affect risk. This encompasses a statute's use of
the term "subpopulation" and instead uses the term "life stage." Text Box 2-5 highlights
several guidance documents available to assist in considering of children's health.
Text Box 2-5: Key EPA Children's Health Guidance Documents
• Policy on Evaluating Health Risk to Children (U.S. EPA 1995c)
• Supplemental Guidance for Assessing Susceptibility from Early-Life Exposure to
Carcinogens (U.S. EPA 2005b)
• Guidance on Selecting Age Groups for Monitoring and Assessing Childhood
Exposures to Environmental Contaminants (U.S. EPA 2005c)
• A Framework for Assessing Health Risk of Environmental Exposures to Children
(U.S. EPA2006a)
• Guide to Considering Children's Health When Developing EPA Actions:
Implementing Executive Order 13045 and EPA's Policy on Evaluating Health Risks
to Children (U.S. EPA 2006e)
• Child-Specific Exposures Factors Handbook (U.S. EPA 2008a)
EPA RISK ASSESSMENT FORUM EXTERNAL REVIEW DRAFT
19
-------
• Cumulative Risk Assessment
In the EPA's 2003 Framework for Cumulative Risk Assessment (U.S. EPA 2003a),
cumulative risk is defined as the combined risks from aggregate exposures to multiple
agents or stressors. Several key points are made in this definition. First, cumulative risk
explicitly involves multiple agents or stressors. Second, the "agents or stressors" are not
limited to chemicals; stressors may, in some cases, also include biological or physical
agents as well as activities that, directly or indirectly, alter or cause the loss of a
necessity (such as habitat) or adversely influence health or increase susceptibility to
other stressors. Third, this definition requires that the risks from multiple agents or
stressors be combined.
This does not necessarily mean that the risks should be added; rather the term
"combining" may mean that some analysis is conducted to determine how the risks
from the various agents or stressors interact. An assessment that covers a number of
chemicals or other stressors but merely lists each chemical with a corresponding risk
without consideration of the other chemicals possibly present is not an assessment of
cumulative. Further, cumulative risk assessment is an analysis, characterization and
possible quantification of the combined risks to health or the environment from
multiple agents or stressors. One key aspect is that the specific characteristics of a given
cumulative risk assessment will vary depending on scientific and regulatory needs. For
example, a cumulative risk assessment need not necessarily be quantitative and is
frequently used in place-based assessments. The Office of Pesticide Programs'
cumulative assessments under the FQPA and those used by the Office of Water for
pesticides are legally defined in the Guidance on Cumulative Risk Assessment of
Pesticide Chemicals That Have a Common Mechanism ofToxicity as applying only to
chemicals with a common mechanism of action (U.S. EPA 2002d). Other environmental
statutes, such as the National Environmental Policy Act and Clean Air Act (CAA) (e.g.,
hazardous air pollutant aspects), also include various requirements for cumulative and
multiple pollutant analyses.
• Sustainability
Sustainability is defined in Executive Order 13514 as a process "to create and
maintain conditions, under which humans and nature can exist in productive harmony,
that permit fulfilling the social, economic, and other requirements of present and future
generations" (Executive Order 13514, 74 Federal Register 52126 [October 8, 2009]).
Sustainability is based on the simple principle that everything humans need for survival
and well-being depends, either directly or indirectly, on the natural environment. The
concept entails consideration of how we meet society's needs of today while ensuring
EPA RISK ASSESSMENT FORUM EXTERNAL REVIEW DRAFT
20
-------
future generations can meet their own. Sustainability is important to ensure that
humans have, and will continue to have, the water, materials and resources to protect
human health and the environment. EPA efforts in the area of sustainability practices
include approaches such as labeling green products, promoting green chemistry, and
engineering and managing materials rather than creating waste. Text Box 2-6 includes
EPA resources related to sustainability.
The planned risk assessment may
provide the risk manager with information
relevant to the sustainability of proposed
risk management options. Issues to
consider include the full life cycle impacts
of the agent, stressor or remedy under
review, as well as the potential unintended
consequences of decisions. Sustainability
and the U.S. EPA (NRC 2011) contains a
detailed discussion of how a framework
for sustainability relates to risk assessment
and risk management.
Text Box 2-6: Resources on
Sustainability and Life Cycle Assessment
• EPA/Office of Research and
Development (ORD) Sustainability
Program (U.S. EPA 2011e)
• EPA/ORD National Risk Management
Research Laboratory Life Cycle
Assessment Website (U.S. EPA 2011f)
• Susie/inability and the U.S. EPA (NRC
2011)
Thorough analysis of the above overarching considerations involves consultation with
experts and offices that focus on them. As appropriate, the risk assessment team should be
expanded to include individuals with the expertise needed for their full consideration.
2.1.3 Responsibilities and Resources
The planning process includes the initial allocation of responsibilities for members for
the assessment team as well as clarification of the interactions of the risk assessment team with
the risk managers and stakeholders. It is important that planning be a transparent effort so that
the basis for the final environmental decision (and the alternative options, limitations and
approaches considered but not selected) is clearly understood early in the process by the public
and regulated community. A team approach to planning risk assessments is essential (NRC
2009, U.S. EPA2002a).
The composition of the risk assessment team is dependent on the nature of the
problem. At a minimum, the team comprises individuals with the necessary scientific expertise,
as well as risk managers and other personnel as appropriate. Depending on the level of
complexity of a risk assessment and the context for its conduct, a multidisciplinary approach is
often necessary. Some disciplines that may be pertinent include: toxicology; epidemiology;
hydrogeology; fate and transport modeling (e.g., indoor and outdoor air, surface and drinking
EPA RISK ASSESSMENT FORUM EXTERNAL REVIEW DRAFT
21
-------
water); computer science (including geographic information systems [GIS], data management);
chemistry; biology; various engineering fields (e.g., chemical, environmental, mechanical,
industrial, civil); economics; sociology; statistics and communications. Lawyers and policy
makers also may be called on to contribute to risk assessment planning. Depending on the
context and process in which the risk assessment is conducted, specific expertise may be
needed to develop particular tools, data or analyses. Coordination with other federal, tribal and
state agencies and with other stakeholders also may be appropriate, depending on the type of
assessment being conducted.
Different members of the assessment team will provide expertise for specific elements
of the planning discussion. For example, the risk manager may identify the regulatory needs of
the assessment, time frames and quantity of funds available for the assessment. The site
assessment team would focus on evaluation of the current and future concentrations of the
contaminants in various media. An exposure assessor may help the team consider the nature,
fate and transport of the contaminants; sources, routes, timing and pathways; the extent of
contamination; and the availability of data, either at the national or local level. Other specialists
may provide information on topics such as funding levels and sources, contractor requirements
and relevant interagency agreements.
It also is important to describe or establish the resources in terms of staffing, budget
and time for the assessment as part of the planning phase. These aspects need to be
considered in the development of the analysis plan, as they can affect the scope and approach
for the assessment. The timeline for the assessment is developed, taking into account critical
legal and management time frames, as well as any need to meet external deadlines or
coordinate with the schedules of other organizations (including critical stakeholders or external
review bodies). When there is extensive stakeholder involvement, it is especially important that
this be reflected in the budget and schedule and understood by all participants (U.S. EPA
2003c). When evaluating the need for human data, bioethics should be considered (see the EPA
Office of the Science Advisor website on Ethics, Regulations, and Policies; U.S. EPA 2012h).
2.1.4 Decision Points and Scientific Peer Review
Various stages in the assessment process can provide decision points and opportunities
for scientific review and stakeholder involvement. For example, completion of a draft
conceptual model and analysis plan, or an iteration of the risk assessment, may be useful points
for focused discussion between the risk assessor and risk manager and/or for scientific review
and public, stakeholder and community involvement.
At such decision points, internal review and checks for quality of the assessment are
important. Other types of review also may be necessary, depending on the scope and purpose
EPA RISK ASSESSMENT FORUM EXTERNAL REVIEW DRAFT
22
-------
of the assessment. For example, an independent external peer review may be an important
element. Also some assessments (e.g., those developed for NAAQS, pesticide registration
decisions, or through the IRIS program) include a public review step, often coincident with the
scientific review step.
Scientific peer review is a process used to provide a critical evaluation of a specific
agency scientific and/or technical work product. The EPA has published a Peer Review
Handbook that describes the types and extent of reviews as well as the documentation needed
to fulfill EPA requirements (U.S. EPA 2006c). (The Peer Review Handbook incorporates the
guidance provided in the Office of Management and Budget's [OMB] 2004 Final Information
Quality Bulletin for Peer Review, [OMB 2004]). The Peer Review Handbook makes distinctions
among peer involvement, peer consultation and peer review. Peer review is a documented
process conducted to ensure that activities are technically supportable, competently
performed, properly documented and consistent with established quality criteria. Peer review
may be internal (to the EPA) or external. It is conducted by qualified individuals or organizations
that are independent of those who performed the work and who are collectively equivalent in
technical expertise (i.e., peers) to those who performed the original work. Peer review usually
involves a one-time interaction, or limited number of interactions, by the independent peer
reviewers with the authors of the work product. An assessment also may benefit from other
types of input (such as peer involvement and public comment) that differ from peer review
(U.S. EPA 2006c). Planning for the assessment includes discussion of whether and what types of
reviews will be included, in light of the context and constraints for the assessment, including
schedule and resources.
Consideration of the need for and timing of peer review steps is encouraged in the early
stages of the project or methods selection and/or as part of the culmination of the work
product, as appropriate (U.S. EPA 2006c). During the assessment planning and scoping process,
the team will need to determine whether any of the analyses or products of the assessment
need peer review and if so what level of peer review may be required and at what stage in the
process. Evaluating peer review requirements early will help ensure that adequate resources
are allocated. In addition, peer review considerations are an integral part of setting assessment
milestones and schedules. EPA's Peer Review Handbook (U.S. EPA 2006c) provides detailed
guidance for determining when peer review is required and how to plan and implement a peer
review. The principle underlying the agency's peer review policy is that "all influential scientific
and technical work products used in decision-making will be peer reviewed" (U.S. EPA 2006c,
30). The Peer Review Handbook stresses transparency in all parts of the peer review process,
and EPA supports systems (e.g., Science Inventory) for documentation and disclosure of peer
review plans and products (U.S. EPA 2012c).
EPA RISK ASSESSMENT FORUM EXTERNAL REVIEW DRAFT
23
-------
2.1.5 Public, Stakeholder and Community Involvement
The planning phase also includes consideration of opportunities for involvement and/or
review by the public and by specific stakeholders. EPA's public involvement policy (U.S. EPA
2003c), a framework for implementing it (U.S. EPA 2003d) and other references are available at
the EPA's Public Involvement Policy and Related Documents website (U.S. EPA 2012d): public,
stakeholder and community involvement are described at greater length in Section 4 of this
Framework document. Depending on the context for the risk assessment and overarching
process governing its conduct, risk assessment products also may be made available for public
comment, as required or practical under specific regulatory programs. Public, stakeholder and
community involvement may be initiated through a formal notice of availability of the risk
assessment and opportunity for public comment, and/or there may be a formal period for
public comment associated with a regulatory decision that was informed by the risk
assessment. Public commenters generally include a wide range of interested parties, both
experts and nonexperts, but they are not expected to provide the kind of independent, expert
information and in-depth analyses obtained from the peer-review process (U.S. EPA 2006c). The
involvement of public, stakeholders and communities (defined in Text Box 2-7) can help ensure
that the assessment process is transparent and that risk-informed decision-making proceeds
effectively, efficiently and credibly (NRC 2009). Such involvement also may facilitate
development of sustainable
solutions (NRC 2011).
The roles for
stakeholders are considered
• Public Involvement refers to the full range of activities
that the EPA uses to engage the American people in the
agency's decision-making process (U.S. EPA 2011g).
during the planning step.
Deciding how and when to
involve stakeholders will
•
Dr
organizations or interest groups that have a strong
depend on the context for w stakeholders are individuals or representatives from
and nature of an assessment. interest in the agency's work and policies (U.S. EPA
Depending on the project, a
discussions on purpose,
scope and approach, may be
defined (U.S. EPA 2003b).
from programs within EPA;
other federal agencies; state,
Text Box 2-7: Definitions of "Public," "Stakeholder" and
"Community"
2011g).
list of critical points for
. , , , , . . , > Internal Stakeholders include EPA program offices or
stakeholder input, such as ,»
regions (U.S. EPA 2007d).
External Stakeholders include the public, affected
industries, public health or environmental
organizations, other federal agencies, states, and
local and tribal governments (U.S. EPA 2007d).
Stakeholders may be
Community Involvement is the process of engaging in
dialogue and collaboration with community members
(U.S. EPA2011h).
EPA RISK ASSESSMENT FORUM EXTERNAL REVIEW DRAFT
24
-------
local and tribal governments; regulated industries; the regulated community; community
members affected by an environmental release; and members of the general public. PCCRARM
(1997a and b) suggests the following questions to identify potential stakeholders:
• Who might be affected by the assessment?
• Who has information and expertise that might be helpful?
• Who has been involved in similar risk situations before?
• Who has expressed interest in being involved in similar decisions before?
• Who might reasonably think that they should be included?
Assessments that require short-term, low-budget efforts or preliminary screening
assessments may not have the scope, time or resources for extensive public, stakeholder and
community involvement. Community involvement, however, is important to many community-
based or site-specific assessments; for a highly controversial location-specific assessment, early
and extensive public, stakeholder and/or community involvement can be essential to the
success of the risk assessment and the risk management options informed by the assessment.
The Framework for Implementing EPA's Public Involvement Policy (U.S. EPA 2003d)
provides general guidance for scoping a public involvement process and identifies the following
seven basic steps for conducting effective public involvement:
1. Plan and budget for public involvement activities.
2. Identify the interested and affected public.
3. Consider providing technical or financial assistance to the public to facilitate
involvement.
4. Provide information and outreach to the public.
5. Conduct public consultation and involvement activities.
6. Review and use input and provide feedback to the public.
7. Evaluate public involvement activities.
2.1.6 Past Experiences and Assessments
Review of past experiences and assessments is an important part of planning and can
contribute to the development of a more robust analysis plan and improve the usefulness of
the assessment. For example, in the review of existing national standards, consideration of
previous assessments and aspects of them where newly available information or tools may
impact risk estimates can inform the planning stages for a new risk assessment, including
conclusions regarding what new insights it might be able to provide. Further, such explicit
EPA RISK ASSESSMENT FORUM EXTERNAL REVIEW DRAFT
25
-------
consideration of the potential value added of a new assessment may improve the efficiency of
the associated risk-based decision making. Additionally, valuable lessons can be learned or
information obtained from assessments performed for conceptually similar situations (e.g.,
previous analyses for a similar industry, analog or chemical). Assessments by other agencies
(federal, state and international) also may be useful to study. Understanding past risk
assessment decisions and associated risk assumptions within a specific regulatory program is
important to assuring the usefulness of a given risk assessment in the decision making process.
Further, notable distinctions of the current assessment from previous assessments (e.g., new
health effects evidence or technical approaches) may be important to describe in the analysis
plan for the current assessment, as well as in the risk characterization.
2.2 Problem Formulation
Problem formulation is the part of the risk assessment planning process that
systematically identifies the major factors to be considered in a particular assessment. It draws
from the regulatory, decision-making and policy context of the assessment and informs the
technical approach of the assessment. EPA's Guidelines on Ecological Risk Assessment defines
problem formulation as the analytical phase of the assessment wherein "the purpose for the
assessment is articulated, the problem is defined, and a plan for analyzing and characterizing
risk is determined" (U.S. EPA 1998a, 2). The formalization of problem formulation in the current
Framework is a significant step in improving risk assessment processes.
An important outcome of the problem formulation step is a conceptual model that
identifies the stressor(s), the exposed population(s) and the endpoint(s) that will be addressed
in the risk assessment as well as the relationships among them. Assessment endpoints, as well
as the exposed population(s), are more limited in variety in human health risk assessment than
is the case in ecological risk assessment (U.S. EPA 1998a). Many agency regulatory programs
have established specific human health risk assessment endpoints, often linked to statutory
requirements. For example, risk assessments for the Superfund and Hazardous Air Pollutant
programs, among others, include among their assessment endpoints estimates of lifetime
individual cancer risk associated with the particular sources or sites assessed (U.S. EPA 1991a,
1999c). Alternatively, risk assessments performed for reviews of the NAAQS often focus on
population risk metrics particular to the health effects evidence for the air pollutant being
assessed. The analysis plan, the final product of problem formulation, is developed in light of
the conceptual model, any programmatically established assessment endpoints and other
planning considerations described in Section 2.1. Figure 2-2 highlights the problem formulation
steps within the Framework.
EPA RISK ASSESSMENT FORUM EXTERNAL REVIEW DRAFT
26
-------
Public,
Stakeholder
and
Community
Involvement
Planning and Scoping
andl
Problem Formulation
Conceptual
Model
Analysis
Plan
Risk Assessment
Exposure
Assessment
Effects Assessment
Hazard Identification
Dose Response
Risk Characterization
Informing Decisions
Key Considerations
for Problem Formulation
Conceptual Model
• What are the human health risk
pathways for this problem, including
the elements for each dimension
(e.g., populations/lifestages at risk)?
What factors and endpoints need to be
analyzed?
Analysis Plan
• What approaches, methods and
metrics will be used to assess expo-
sures, effects and risk, including the
associated uncertainty and variability?
What is the strategy for developing new
or using existing data?
Figure 2-2. Framework for Human Health Risk Assessment to Inform Decision Making: Key
Questions and Considerations for Problem Formulation.
2.2.1 Conceptual Model
A conceptual model includes both a written description and a visual representation of
actual or predicted relationships between humans (populations or population segments) and
the chemicals or other stressors to which they may be exposed. The complexity of the
conceptual model depends on the complexity of the problem; this may be related to the
number of stressors, exposure pathways or assessment endpoints; the nature of effects; and/or
the characteristics of the exposed population(s) or life stage(s). Generally, the conceptual
model identifies factors and endpoints that will be analyzed in the risk assessment. It also
addresses those items that may not be analyzed in the risk assessment, the recognition of
which may be important in the overall decision-making process. For example, although a risk
assessment for a particular stressor may focus on exposure pathways or media relevant to the
regulatory decision being faced (e.g., ingestion of drinking water), the conceptual model also
will describe the role of other pathways (e.g., consumption of fish), ensuring appropriate
characterization of and context for the assessment results.
The visual representation of the conceptual model and the associated narrative describe
the basic rationale for pursuing a particular course of action in the assessment. It can provide
documentation of decisions for future reference during risk assessment and can be useful in
characterization and communication of the risk management decision. The conceptual model
also is valuable as a risk communication tool both within the agency and in interactions with the
public. The conceptual model is a scientific or technical work product that can include the
following:
EPA RISK ASSESSMENT FORUM EXTERNAL REVIEW DRAFT
27
-------
• The rationale for selecting the sources, stressors, exposure pathways, receptors,
exposed populations, endpoints or risk metrics including effects.
• The basis for the model development.
• The scientific implications of additional data gathering.
A general conceptual model (visually represented in Figure 2-3) defines the key
elements for the problem to be assessed and shows pathways and routes of exposure between
the stressors and effects (endpoints) for human receptors. The visual representation of the
conceptual model is a diagram that may include the following types of elements:
• Source(s) of stressors of interest in the environment (e.g., releases from a leaking
storage tank, waste material poured on the ground).
• Types of stressor(s) that may be physical, chemical and/or biological.
• Exposure pathways, including fate and transport processes by which stressors may
move from the original point of release through the environment (e.g., a chemical in soil
might penetrate down into groundwater or might volatilize into air) and the interaction
by which populations or individuals are exposed (e.g., ingestion of contaminated water,
inhalation of chemicals in air, dermal contact with contaminated soil).
• Receptors, which may be groups of individuals or populations identified by common
characteristics, including life stage (e.g., general population, infants, local residents near
site of concern, adult workers, recreational visitors, populations/life stages with unique
exposures and/or susceptibilities to stressors).
• Types of endpoints to be considered (e.g., cancer, asthma, IQ decrement or
developmental effects).
• Risk metrics (e.g., cases of disease or disease incidence, hazard quotient, magnitude of
effect or margin of exposure).
EPA RISK ASSESSMENT FORUM EXTERNAL REVIEW DRAFT
28
-------
Sources
Risk Metrics
Exposure
Pathways/Routes
effects or biological
systems affected
(cancer, asthma,
IQ decrement)
Measure by which
risk is quantified
(cases of disease
or disease
incidence, hazard
quotient, magnitude
of effect, margin of
exposure)
Figure 2-3. Example of a Generalized Conceptual Model With Examples of Possible Dimensions
and Linkages (adapted from U.S. EPA 2002a, 2003a).
Conceptual models are used to plan the risk assessment and associated data collection
activities, and they may be periodically revised as data become available. Conceptual models
consist of two principal components: (1) a set of risk hypotheses that describe predicted
relationships among stressor, exposure and health endpoint/response, along with the rationale
for their selection; and (2) a diagram that illustrates the relationships presented in the risk
hypotheses. Text Box 2-8
identifies EPA guidance
documents with more
information about conceptual
models; references for
examples of conceptual
models from various EPA risk
assessments are in Text Box 2-
9.
Figure 2-4 presents a
diagram illustrating a detailed
conceptual model of multiple
exposure pathways and
receptors potentially affected
Text Box 2-8: EPA Resources on Conceptual Models
• Ecological Risk Assessment Guidelines (U.S. EPA
1998a, 40-41)
• Lessons Learned on Planning and Scoping for
Environmental Risk Assessments (U.S. EPA 2002a,
5-6)
• Science Policy Council Handbook: Risk
Characterization (U.S. EPA 2000b, 29-30, B-21, B-
23).
• Cumulative Risk Assessment Framework (U.S. EPA
2003a, 25-27)
• Framework for Assessing Health Risk of
Environmental Exposures to Children (U.S. EPA
2006a, 3-5 to 3-9)
EPA RISK ASSESSMENT FORUM EXTERNAL REVIEW DRAFT
29
-------
by multiple sources of chemical stressors; this model was designed by EPA Region 8 (U.S. EPA
2012e) for the analysis of Superfund sites contaminated with PCBs.
PCBSou
Gasification _^ „,,.,„,
Plant * DNAPL
Rally
1H1111H
USTs
Lagoons
Disposal, spills
ird ^^—
k^
•i
mrt
Sedin
4. j
" Surface
r i
•^ Ground
j
Leaching
On-Y
~r Subsurfa
1 Leaching
~* On-Y
*• Subsurfa
r
i i
«!.,.*.>
i
'L .
Soil Gas
ard
ce Soils
r+ Oust +•
ard
ce Soils *
Ingestion
Dermal
Ingestion
Dermal
Ingestion
Dermal
_k
Indoor Air -«> Inhalation _^.
Outdoor Air -^- Inhalation
Outdoor Air -> Inhalation
Ingestion
Dermal
Worker
Residential Recreational
•
X
•
•
X
•
•
•
X
O
X
X
X
X
•
X
•
I
On-Yard
Subsurface Soils
Ingestion
Dermal
in
1
_^
•
X
Legend
Pathway is not complete: no evaluation required
X fairway is w might be complete, but is judged to be minw; qualitatve evaluation
Q Palhway is « might be oomptelB jnd guild be significant, but data are lacking ID support quantitative evaluation; qualtelive evaluation
• Palhway is or might be complete and could be signif ;ant quanlilative evaluation
Figure 2-4. Example Conceptual Model of Exposure Pathways for Multiple Receptors to
Multiple Stressors for Superfund Site Assessment (Region 8 Site Conceptual Model; U.S. EPA
2012e).
EPA RISK ASSESSMENT FORUM EXTERNAL REVIEW DRAFT
30
-------
Text Box 2-9: Examples of Conceptual Models in EPA Risk Assessments
• Conceptual model to inform lead NAAQS risk assessment (U.S. EPA 2007c, 2-1 to 2-19)
• Case Study on Concentrated Animal Feeding Operations (U.S. EPA 2002b, Appendix B)
• Re-registration of Pentachlorophenol (U.S. EPA 2002c, Appendix C)
2.2.2 Analysis Plan
The analysis plan is the final stage of problem formulation (U.S. EPA 1989, 2000a, 2002a,
2003a). This is the implementation plan for performing the risk assessment and addressing the
agency's needs. It describes agreements made during the planning and scoping process and
provides details on technical aspects of the risk assessment, as described below. In some cases,
the plan will specify a phased or tiered risk assessment approach to facilitate management
consideration; scientific review; and/or public, stakeholder and community involvement.
During analysis planning, hypotheses about the relationships described in the
conceptual model are evaluated to determine how they will be assessed using available and
new data. Although the conceptual model may identify a larger set of pathways and
relationships, the analysis plan focuses on the pathways and relationships that will be pursued
during the analysis phase. The rationale for selecting or omitting pathways and relationships is
incorporated into the plan, as is acknowledgement of data gaps and uncertainties. The analysis
plan also may include a consideration of how the level of confidence (or precision) needed for
the management decision compares with that expected from available analytical approaches;
this is done to determine data needs and evaluate which analytic approach is best. When new
data are needed, the feasibility of obtaining them is evaluated. The analysis plan is most useful
when it contains explicit statements of how measures were selected, what the measures are
intended to evaluate, and which analyses they support.
The analysis plan may include these components:
• The assessment design and rationale for which relationships are addressed.
• Description of the data and information, methods and models to be used in the analyses
(including uncertainty analyses).
• The associated data gaps and limitations.
Analysis plans may be brief or extensive depending on the assessment and its level of
complexity. For assessments performed for some purposes (e.g., the EPA's new chemical
assessments under the Toxic Substances Control Act [TSCA]), a standard analysis plan is
EPA RISK ASSESSMENT FORUM EXTERNAL REVIEW DRAFT
31
-------
established for the set of assessments to be conducted for the same purpose and regulatory
context. The type or design of analyses to be conducted is influenced by statutory requirements
or programmatic objectives, data availability, resources and limitations, and the purpose and
scope of assessment. Thus, the risk assessment designs will vary, which will be reflected in the
development of the plan. For example, the EPA performs different types of risk assessments
that range from deterministic scenario-based assessments to more complex probabilistic
population modeling analyses. Assessments may be screening-level or more robust, depending
on various factors, including the specific resources available for the assessment. Further, the
organization of the analysis plan may vary with the purpose and context for the assessment. In
all cases, the plan addresses the quality of data to be used; assessments of exposure, hazard
and dose-response; and risk analyses, including analyses of uncertainty and variability. These
areas are described in the subsections below.
2.2.2.1 Data Quality
In developing and implementing the analysis plan, several aspects of the data and
information to be used in the assessment are evaluated, including the following (U.S. EPA
2003a):
• Soundness. The extent to which the scientific and technical procedures, measures,
methods or models employed to generate the information are reasonable and
consistent with the intended application.
• Applicability and utility. The extent to which the information is relevant for the
intended use.
• Clarity and completeness. The degree of clarity and completeness with which the data,
assumptions, methods, quality assurance, sponsoring organizations and analyses
employed to generate the information are documented.
• Uncertainty and variability. The extent to which the variability and uncertainty
(quantitative and qualitative) in the information or in the procedures, measures,
methods or models are evaluated and characterized.
• Evaluation and review. The extent of independent verification, validation, and peer
review of the information or of the procedures, measures, methods or models.
Evaluation of data quality requires context. Depending on how and for what purpose
the data will be used, the same data may be acceptable in one situation and unacceptable in
another. EPA has established a Quality System (U.S. EPA 20111) to ensure that environmental
programs and decisions are supported by data of the type and quality needed and expected for
their intended use. A critical aspect of this system involves the use of data quality objectives for
the development of new data and evaluation of existing data. Aspects of a risk assessment for
which data quality may be important to consider in the analysis plan include:
EPA RISK ASSESSMENT FORUM EXTERNAL REVIEW DRAFT
32
-------
The collection, evaluation and use of environmental data, including distributions of
contaminants, considerations of information on sources of variability, tolerance for
potential decision errors and/or precision requirements (U.S. EPA 20111).
Development, evaluation and use of
computer or mathematical models
including evaluation of uncertainty and
variability.
Use of secondary data collected for
purposes other than the planned
assessment.
Analysis plans also consider data quality guidance
specific to the program for which the assessment
is being conducted. Data quality resources are
given in Text Box 2-10.
Text Box 2-10: Data Quality Resources
• EPA Requirements for Quality
Assurance Project Plans (U.S. EPA
2001c)
• EPA's Quality System for
Environmental Data and
Technology (U.S. EPA 2011i)
• Superfund Quality
Assurance/Quality Control (U.S.
EPA 2011J)
• Resources for Planning New Data
Collections (U.S. EPA 2011k)
2.2.2.2 Exposure Assessment
The analysis plan describes the approach (quantitative or qualitative) to be employed
for characterizing exposure in the risk assessment. See Text Box 2-11 for EPA resources on
exposure assessment. This exposure assessment plan is developed by drawing on the
information, considerations and decisions represented by the conceptual model for human
health (as described in Section 2.2.1 above). Accordingly, the plan describes the exposure
assessment elements specified in the conceptual model, including the relevant routes and
pathways, frequency and
duration of exposures,
populations and life stages,
and assessment metrics. The
plan also defines the
methods, models and
information or data that will
be used, as well as the
environmental conditions or
scenarios (e.g., conditions
associated with alternative
standards or clean-up levels
for environmental
contaminants or different
Text Box 2-11: EPA Exposure Assessment Resources for
Human Health
• Guidelines for Exposure Assessment (U.S. EPA 1992a)
• Guidance on Selecting Age Groups for Monitoring and
Assessing Childhood Exposures to Environmental
Contaminants (U.S. EPA2005c)
• A Framework for Assessing Health Risk of
Environmental Exposures to Children (U.S. EPA 2006a)
• Highlights of the Child-Specific Exposure Factors
Handbook (U.S. EPA 2009)
• Exposure Factors Handbook (U.S. EPA 201 la)
EPA RISK ASSESSMENT FORUM EXTERNAL REVIEW DRAFT
33
-------
uses for a pesticide). Key limitations, assumptions and uncertainties associated with the tools
and approaches are recognized in the analysis plan.
The plan also identifies the approach for describing exposure variability. For example,
the approach might specify a deterministic scenario-based assessment to provide point
estimates for a particular population (e.g., long-term residents or high-end consumers of a
particular food such as fish) or life stage (e.g., very young children). In contrast, a more complex
probabilistic population modeling assessment might provide a distribution of estimates for the
specific population assessed; an example would be children living in three specific urban areas
under environmental conditions associated with a current standard or food consumption
patterns for specific age groups based on dietary survey information. The rationale for the
selected approach is described in the plan as well as the extent to which estimates will be
developed for the central and upper percentiles of the population being assessed. Further, the
plan generally delineates the approaches for assessing uncertainty and variability in the
exposure estimates.
2.2.2.3 Hazard Identification and Dose-Response
The analysis plan specifies the strategy for characterizing hazard and dose-response
relationships for the stressors being assessed. For example, the strategy may include use of
publicly available hazard identification and dose-response assessments that already have been
prepared (in accordance with agency guidance and methods), such as those in the EPA's IRIS
database. Alternatively, the strategy may specify a different approach for characterizing the
hazard of the identified stressors and describing the dose- or concentration-response
relationship that will be used in the risk assessment.
The EPA has established a variety of guidance documents for all components of risk
assessment (see Text Box 2-12). These documents address evaluation of particular types of
toxicity, dose-response assessment and endpoint selection; the consideration of information on
mode of action (MOA) or pathways of toxicity; the role of toxicokinetic information; and factors
influencing sensitivity and susceptibility (e.g., nutrition, life stage, exposure characteristics and
disease state). Rather than describing in detail the steps in effects assessment, the analysis plan
may refer to these or other published documents.
EPA RISK ASSESSMENT FORUM EXTERNAL REVIEW DRAFT
34
-------
Text Box 2-12: EPA Resources on Hazard Identification and Dose-Response Assessment
• Guidelines for the Health Risk Assessment of Chemical Mixtures and Supplementary
Guidance for Conducting Health Risk Assessment of Chemical Mixtures (U.S. EPA 1986a,
2000a)
• Guidelines for Developmental Toxicity Risk Assessment (U.S. EPA 1991)
• Methods for Derivation of Inhalation Reference Concentrations (RfCs) and Application of
Inhalation Dosimetry (U.S. EPA 1994)
• Guidelines for Reproductive Toxicity Risk Assessment (U.S. EPA 1996)
• Guidelines for Neurotoxicity Risk Assessment (U.S. EPA 1998b)
• A Review of the Reference Dose and Reference Concentration Processes (U.S. EPA 2002e)
• Guidelines for Carcinogen Risk Assessment (U.S. EPA 2005a)
• Supplemental Guidance for Assessing Susceptibility from Early-Life Exposure to Carcinogens
(U.S. EPA2005b)
• A Framework for Assessing Health Risk of Environmental Exposures to Children (U.S. EPA
2006a)
2.2.2.4 Risk Ch aracterization
The analysis plan identifies and describes the strategy or approach for combining
exposure information with hazard and dose-response information to generate risk estimates or
other measures for characterizing health risk. The approaches may vary widely, depending on
other considerations (described above for the planning phase), in the following manners:
purpose and context for the assessment, the available information, and resources and timeline
for the assessment. Risk analyses might range from deterministic scenario-based assessment to
a probabilistic population modeling assessment. Either of these approaches may yield estimates
for general population risk or for specific, defined groups within the general population. For
estimates of individual risk, calculations can consider central tendency and the upper end of
distribution. The upper end of the distribution used for risk characterization may vary
depending on the needs of the assessment (e.g., the 90th, 95th or 99th percentiles) (U.S. EPA
1992a).
Assessments may be screening-level or more robust depending on the purpose and
availability of data. Decisions on the type or design of the assessment are influenced by
statutory requirements or programmatic objectives, data or resource availability and
limitations, and purpose/scope of the assessment. Types of risk assessment metrics that might
be considered for the assessment include:
• Incidence of specific health outcomes.
• Risk of specific health outcomes.
EPA RISK ASSESSMENT FORUM EXTERNAL REVIEW DRAFT
35
-------
• Occurrences of exposures above health-based benchmarks or comparison points.
• Potential for occurrence of exposure above health-based benchmarks.
• Margins of exposure between a point of departure for an effect and a measured or
estimated environmental level.
• Hazard quotients for specific exposure scenarios (hazard quotients are measured or
estimated exposure levels divided by a reference value).
In defining the analyses to be performed, the plan also describes the associated limitations,
assumptions and plans for assessment of uncertainty and variability. Other EPA resources for
risk analysis are described in Text Box 2-13.
Text Box 2-13: Other Risk Analyses Resources
• Guidelines for the Health Risk Assessment of Chemical Mixtures and Supplementary
Guidance for Conducting Health Risk Assessment of Chemical Mixtures (U.S. EPA 1986a,
2000a)
• Risk Assessment Guidance for Superfund (U.S. EPA 1989, 1991, 1998a, 1999a, 2001d,
2004a, 2009)
• Science Policy Council Handbook: Risk Characterization (U.S. EPA 2000b)
• Methodology for Deriving Ambient Water Quality Criteria for the Protection of Human
Health (U.S. EPA2000d)
• Framework for Cumulative Risk Assessment (U.S. EPA 2003a)
• Air Toxics Risk Assessment Reference Library (U.S. EPA 2004b, 2004c, 2006d)
• A Framework for Assessing Health Risk of Environmental Exposures to Children (U.S. EPA
2006a)
EPA RISK ASSESSMENT FORUM EXTERNAL REVIEW DRAFT
36
-------
2.2.2.5 Uncertainty and Variability
Drawing from EPA guidance and experience, the analysis plan describes how uncertainty
and variability will be characterized in the risk assessment. The complexity of the approaches
will be influenced by considerations identified earlier in the planning phase, including purpose
and context for the assessment, as well as timeline and resources. Planning for this stage of the
assessment also will consider how elements of an uncertainty/variability evaluation can inform
different parts of the assessment approach, improving the overall plan as well as the utility of
the final product. The plan may consider the value of obtaining additional data or information
to reduce areas of uncertainty. More information about uncertainty and variability can be
found in Text Box 2-14.
Text Box 2-14: Definitions of Uncertainty and Variability
Uncertainty refers to imperfect knowledge or lack of precise knowledge of the real world, either for
specific values of interest or in the description of the system. Although numerous schemes for classifying
uncertainty have been proposed, most focus on two broad categories: parameter uncertainty and model
uncertainty. Descriptions of both areas are found in Risk Assessment Principles and Practices (U.S. EPA
2004d).
Variability refers to the inherent natural variation, diversity and heterogeneity across time and/or space
or individuals within a population. Although we can better describe and understand variability in the
world, or a particular system, it is unavoidable and cannot be reduced (U.S. EPA 2010c).
Resources for Characterizing Uncertainty/Variability
• Guiding Principles for Monte Carlo Analysis (U.S. EPA 1997c)
• Science Policy Council Handbook: Risk Characterization (U.S. EPA 2000b)
• Risk Assessment Guidance for Superfund Volume III—Part A: Process for Conducting Probabilistic
Risk Assessment ( U.S. EPA 2001d)
• Risk Assessment Principles and Practices (U.S. EPA 2004d)
• A Framework for Assessing Health Risk of Environmental Exposures to Children (U.S. EPA 2006a)
• Guidance Document on Characterizing and Communicating Uncertainty in Exposure Assessment
(World Health Organization, 2008)
• Using Probabilistic Methods to Enhance the Role of Risk Analysis in Decision-Making With Case
Study Examples (U.S. EPA 2010c)
EPA RISK ASSESSMENT FORUM EXTERNAL REVIEW DRAFT
37
-------
2.3 Fit for Purpose
Risk assessments at the EPA are performed to inform risk management decisions.
Accordingly, throughout the process of planning and performing the analyses it is important to
confirm that the assessment will address the information needs of risk managers. Periodic
confirmations may be part of the decision points or review steps described above or may be
done as they otherwise fit within the process of the assessment. In the Silver Book (NRC 2009),
the NRC recommended use of a framework that "maximizes the utility of risk assessment," with
a focus on assuring that risk assessments are well-tailored to the problems and decisions at
hand so that they can most meaningfully inform the decision-making process. In describing this
concept, the NRC (2009) report uses the terms "fit for purpose" and "utility of risk assessment,"
among others. Consistent with its usage as a key principle in quality assurance programs, "fit for
purpose" in this framework refers to the development of risk assessments and associated
products that are suitable and useful for their intended purpose(s) particularly that of informing
risk management decisions.
In the EPA's Framework described here, the utility of risk assessment is not an element
that is evaluated as a separate step in the process or a final check that occurs once the risk
assessment is completed. Rather, consistent with the NRC's emphasis on consideration of risk
management needs early in the process, the agency's Framework emphasizes attention to
utility throughout the process, beginning with planning and scoping, and including a specific
focus on the applicability of the risk assessment for informing risk management decisions.
Attention is given to this concept through focused planning and problem formulation and
confirmation during the process to ensure that the informational needs for the assessment are
being met by the information being generated by the assessment. Questions to consider in
evaluating the usefulness of the assessment design and its implementation include those listed
below:
• Does the assessment design meet the objectives and have the attributes identified in
the problem formulation step?
• Does the assessment, as implemented, meet the initial objectives? Or, if the initial
objectives have been modified (e.g., as a result of changed risk management options or
issues), does the assessment meet the modified objectives?
• Does the assessment have the attributes identified in planning?
• If the assessment requires peer review, has this been done appropriately and have the
issues raised during the peer review been adequately addressed?
EPA RISK ASSESSMENT FORUM EXTERNAL REVIEW DRAFT
38
-------
• How will the results of the risk assessment be communicated to the risk managers and
stakeholders?
• Does the assessment inform choices among risk management options? Are there any
additional risk assessment needs for discriminating between or implementing risk
management options?
Additional or revised analyses may be considered in the assessment, depending on the
answers to these and other questions that may reflect the specific risk management decision
being addressed.
The utility of the risk assessment is defined by the degree to which the assessment
informs choices among risk management options. Related to this, it is critical that there be
transparent dialogue between risk assessors and risk managers throughout the assessment
process, beginning with the planning stage. It is important to note, however, that the EPA
maintains the conceptual distinction between risk assessment and risk management, as
described in the Red Book (NRC 1983); the Framework does not allow for the manipulation of
the risk assessment to support predetermined policy choices. As articulated by the NRC in the
Silver Book, "the conduct of risk
assessments used to evaluate the risk-
management options [is] in no way to
be influenced by the preferences of
risk managers" (NRC 2009, 244). For
more information from the Silver Book
Text Box 2-15: More Silver Book Statements on
Utility
"Risk assessment in EPA is not an end in itself but a
means to develop policies that make the best use of
resources to protect the health of the public and of
ecosystems"(NRC 2009, 240).
"By focusing on early and careful problem
formulation and on the options for managing the
problem, implementation of the framework can do
much to improve the utility of risk assessment.
Indeed, without such a framework, risk assessments
may be addressing the wrong questions and yielding
results that fail to address the needs of risk
managers"(NRC 2009, 244).
see Text Box 2-15.
It is important to note that the
uses of any risk assessment will vary
with the environmental problem being
assessed; statutory mandates; and the
limitations of data, methods, time and
resources. Further, as recognized in
Section 5, risk assessments often are
just one of a variety of factors that are
considered in making a decision.
EPA RISK ASSESSMENT FORUM EXTERNAL REVIEW DRAFT
39
-------
3 Risk Assessment
Risk assessments conducted for the EPA range from relatively simple to complex
depending on needs of the risk management decision being made and the availability of
relevant data. The analyses that contribute to a risk assessment may range from those based on
default assumptions to more refined analyses that include site-specific information and
quantitative uncertainty assessment consistent with agency policies and guidances (U.S. EPA
1992a, 2005a, 2011a). Planning and scoping identifies the level of assessment appropriate for
the needs of the risk manager and the role that risk information plays in the decision. Problem
formulation uses this information to develop the conceptual model and analysis plan. The
assessment step builds on the conceptual model and implements the analysis plan. The steps in
risk assessment often are performed together, in an integrative fashion, rather than as a linear,
sequential process. As information is developed and preliminary conclusions drawn, it is not
uncommon to revisit data needs or to revise the conceptual model and analysis plan.
Communication among all members of the risk assessment team (and perhaps with
stakeholders) is needed to ensure that the purpose of the assessment remains the major
impetus for these revisions to plans and expectations.
The EPA has issued guidance on all four steps of the risk assessment paradigm (exposure
assessment, hazard identification, dose response and risk characterization); note that these
publications are highlighted in Section 2. This Framework document focuses on context, utility
and planning for the risk assessment itself, so it does not provide detail on the conduct of the
steps.
EPA risk assessments may focus on individual risk metrics or may include population-
level and/or life stage-specific assessments to inform characterization of risk. Different
categories of assessments may be conducted by the agency related to the specific types of
regulatory or programmatic decisions they are developed to inform. The agency's Risk
Assessment Portal (U.S. EPA 20121) provides basic information about environmental risk
assessments and offers a comprehensive set of links to key EPA tools, guidance and guidelines.
Figure 3-1 highlights the assessment phase in the Framework detailing several cross-
cutting areas for consideration in exposure or effects characterization. The risk assessor might
consider available data on metabolism; modeling; mode of action; toxicity; cumulative risk
(exposure and/or effects); the susceptibility of individuals based on factors such as life stage,
genetics and gender; specific population group factors including socio-economic considerations,
uncertainty and variability; and other factors relevant to characterization of risk (see Text Boxes
3-2 and 3-3 ). The landscape of risk assessment is changing with new advances in molecular
biology, computational toxicology and risk assessment methodology. The areas of consideration
EPA RISK ASSESSMENT FORUM EXTERNAL REVIEW DRAFT
40
-------
noted in Figure 3-1 are meant to be illustrative of today's practices, rather than definitive or
comprehensive, and they are likely to change as the science of risk assessment advances.
3.1 Exposure Assessment
Exposure characterization is one of the primary components of risk assessment. The
approaches employed for this component may vary across different risk assessments and will
reflect considerations described in the conceptual model and analysis plan.
Exposure is characterized, quantitatively or qualitatively, for several key aspects of the
assessment: relevant routes and pathways, frequency and duration, and populations and life
stages. The specific type of exposure estimation needed and the level of complexity employed
for this component of the assessment will vary depending on the assessment purpose, legal
authority and other factors considered in the planning and scoping step. For example, this step
may involve new data collection, implementation of simple or complex fate/
transport/exposure models and/or other data analysis. A key aspect of all exposure
characterizations is consideration of the potential for susceptible or more highly exposed
populations, life stages or groups. Based on considerations and decisions in the conceptual
model, quantitative exposure assessments may include the development of estimates specific
to these populations or life stages. The available toxicokinetic information may also be
characterized and internal doses calculated. The EPA's Exposure Factors Handbooks provide a
compendium of exposure factors for a number of parameters for adults and children, including
such metrics as ingestion of soil, time spent in residence, surveys of fish ingestion, ingestion of
homegrown products and inhalation rates (U.S. EPA 1997b, 2008a, 2011a). Available
toxicokinetic information also may be characterized and internal doses calculated. Some key
elements of exposure characterizations are listed in the Text Box 3-1.
EPA RISK ASSESSMENT FORUM EXTERNAL REVIEW DRAFT
41
-------
Public,
Stakeholder
and
Community
Involvement
Planning and Scoping
and Problem Formulation
Conceptual
Model
Analysis
Plan
Risk Assessment
Exposure
Assessment
Effects Assessment
Hazard Identification
Dose Response
Risk Characterization
T
Informing Decisions
Exposure Assessment
v How and to what range of
concentrations/doses are
populations/life stages of interest
exposed?
How do risk management options
affect existing/resulting conditions of
exposure?
Effects Assessment
Hazard ID: What adverse endpoints
are associated with agents of concern?
Are there data to identify susceptible
populations or to support a mode of
action for the agent?
Dose Response: What is the relation-
ship between exposure/dose and the
likelihood of each endpoint at the
exposure range of interest? How can
mode of action be used to inform
choices of low-dose extrapolation?
Risk Characterization
What is the nature and magnitude of
risk for existing conditions and for
options?
• What are the sources and magnitude of
uncertainty and variability in all steps of
the risk assessment?
Figure 3-1. Framework for Human Health Risk Assessment to Inform Decision Making: Key
Questions and Considerations for Assessment.
3.2 Effects Assessment
In human health risk assessment, the characterization of effects includes hazard
identification and dose-response assessment. The approaches employed for these components,
including, for example, the level of detail and complexity of quantitative aspects, may vary
across different risk assessments and will reflect considerations described in the conceptual
model and analysis plan.
EPA RISK ASSESSMENT FORUM EXTERNAL REVIEW DRAFT
42
-------
Text Box 3-1: Key Elements of an Exposure Characterization
• Assess sources, pathways and routes of exposure and determine approach for consideration
of multiple pathways, as relevant.
• Investigate patterns of exposure (e.g., frequency and duration).
• Assess populations and life stages (e.g., the general population, highly exposed/vulnerable
groups, highly susceptible groups) and determine basis for inclusion.
• Consider the rationale for the analysis approach, including any monitoring, modeling or other
analyses of exposure distributions such as Monte-Carlo or krieging.
• Establish descriptors of exposure, generally including estimates for "average" and "high-end"
exposures and susceptible populations or life stages.
• Determine data and methods used in developing the exposure estimates.
Drawn from EPA's Guidance for Risk Characterization (U.S. EPA 1995d) and Guidelines for Exposure
Assessment (U.S. EPA 1992a).
3.2.1 Hazard Identification
Hazard Identification is the process of identifying the type of hazard to human health
(e.g., cancer, birth defects) posed by the exposure of interest for a given risk assessment. In the
case of chemical stressors, the process examines the available scientific data for a given
chemical (or group of chemicals) and often develops a "weight of evidence" characterization of
hazard. This step requires identification, evaluation and synthesis of information to describe the
health effects of individual chemicals (or chemical mixtures). Studies evaluated may include
human clinical or epidemiological studies, in vivo or in vitro laboratory animal studies, or
mechanistic or kinetic studies in a variety of test systems. In recent years, risk assessors have
begun to consider additional types of data during hazard identification including those from
computational toxicology (quantitative structure-activity relationship, high-throughput assays)
and transcriptional or "omic" responses. Other data types may be identified in the future. Key
aspects of hazard identification include consideration of available information on toxicokinetics
(how the body absorbs, distributes, metabolizes and eliminates chemicals) and toxicodynamics
(effects that chemicals have on the body) as well as potential MOAs (or toxicity pathways)
related to the health effects identified. Text Box 3-2 describes some contexts in which MOA of
the adverse outcome pathway is considered.
In hazard identification, the strengths and limitations of the data and information used
to support the weight of evidence are described, including areas for which data may be
unavailable (data gaps). In situations where a quantitative risk assessment is to be performed, a
particular study or group of studies may be identified for use in dose-response assessment.
EPA RISK ASSESSMENT FORUM EXTERNAL REVIEW DRAFT
43
-------
Text Box 3-2: Example of a Consideration for Effects Characterization: Mode of Action
The Guidelines for Carcinogen Risk Assessment (U.S. EPA 2005a) emphasizes the important contribution that
understanding a chemical's MOA makes to informed risk assessment decisions. These can include:
• Relevance of data (e.g., animal, in vitro, in silica) for human health risk assessment.
• Harmonization of risk assessments for various health endpoints.
• Conditions under which an agent is likely to cause cancer (or some other health endpoint).
• Choice of low dose extrapolation (e.g., linear or nonlinear).
• In cancer assessments, applicability of default age-dependent adjustment factors for early life stage
exposure.
The carcinogen guidelines and supplemental guidance (U.S. EPA 2005a, 2005b) include a framework for assessing
available data to determine whether a hypothesized MOA is likely to be involved in induction of a specific tumor
type. This framework also is useful for assessment of other health endpoints. For an example of application of the
MOA framework to reproductive effects see the Office of Pesticide Program's work on the pesticide cacodylic acid
(U.S. EPA 20121).
Although the scientific community historically has been invested in understanding how chemicals cause biological
effects, the use of detailed information on MOA in human health risk assessment has been increasing as methods
are refined and more reliable information is generated. Recognizing the critical role in risk-based decision making
of understanding how a chemical causes effects, Toxicity Testing in the 21st Century (NRC 2007) proposed that
the next generation of toxicology studies be designed to focus on "toxicity pathways." These are normal
biological pathways that respond to chemicals or other stressors depending on the magnitude of the insult (dose,
timing, duration and frequency of perturbation). At low exposures, some systems will remain within their
homeostatic limits. At higher levels of stress, other adaptive biologic responses may occur, the adversity of which
may depend on physiological characteristics of those exposed; that is, groups of sensitive individuals may respond
adversely, whereas others may not. At greater magnitude of stress, the adaptive capacity may be overwhelmed
for all groups, increasing the likelihood of adverse effects. These and similar concepts may provide approaches for
applying greater scientific understanding of what a chemical does in causing an effect. This knowledge in turn will
support improved human health risk assessments.
The availability of data for these types of detailed assessments varies widely across chemicals. Accordingly the
EPA and the NRC continue to support the use of default methods and procedures to complete a risk assessment
when data are lacking.
Adverse Outcome Pathway: A description of plausible causal linkages that illustrates how a chemical interaction
with a biological system at the molecular level causes biological effects at the subcellular, cellular, tissue, organ
and whole animal levels of observation (Ankley et al. 2010).
Toxicity Pathways: Cellular response pathways that, when sufficiently perturbed, are expected to result in
adverse health effects (NRC 2007).
Mode of Action: The sequence of key events and cellular and biochemical events (measurable parameters),
starting with the interaction of an agent with the target cell or tissue, through functional and anatomical changes,
resulting in cancer or other adverse health effects (U.S. EPA 2005a, Boobis et al. 2008). Mode of action differs
from mechanism in that the latter implies a more detailed understanding of the molecular basis of
the toxic effect (Seed et al. 2005).
EPA RISK ASSESSMENT FORUM EXTERNAL REVIEW DRAFT
44
-------
Hazard identification may be focused on health risks of exposure to specific individual
chemicals or identification of groups of chemicals with common MOAs (e.g., pesticides). In
some cases, the specific chemicals for such focus are identified by statute (e.g., the CAA
hazardous air pollutants). Thus the chemical exposures to be evaluated in the risk assessment
may vary across programs depending on the legal authorities under which the assessment is
conducted. In all cases the conceptual model and analysis plan will specify the extent, content
and limits of the hazard identification.
3.2.2 Dose-Response Assessment
In this component of effects characterization, the relationship between exposure or
dose of a contaminant and the occurrence of particular health effects or outcomes is assessed.
Drawing from the conceptual model and analysis plan, the dose-response assessment (U.S. EPA
2012J) may be developed using a combination of data, science policy decisions and models. For
example, the response assessed may be incidence of some endpoint or health outcome (e.g.,
cancer incidence, incidence of a critical effect, hospital admission for a specific outcome or
death) or it may describe magnitude of response (e.g., magnitude of IQ loss). The assessment
also may include the derivation of an established metric such as EPA's reference doses and
reference concentrations (U.S. EPA 2002e).
In documentation of the dose-response assessment, aspects of the full database,
particularly the key studies, are described along with their strengths and weaknesses, including
the potential impact of those weaknesses on the reliability of the overall assessment.
Toxicokinetic information also is described; in data-rich situations, measured or modeled target
tissue dose may be used in the dose-response calculations. In some cases, multiple chemicals
may be included in a single dose-response assessment, with decisions made about the grouping
of chemicals, as well as the means by which the chemicals will be combined (e.g., common
MOA, common toxic effect, estimation of cancer potency factors, specific data for chemical
mixtures or likelihood of simultaneous exposure). Decisions on these issues are specific to the
individual risk assessment and may be influenced by the information gathered during problem
formulation. Details of the EPA practices and policies related to dose-response assessment can
be found in the various guidance documents noted in Section 2 of this document and at EPA's
Risk Assessment Guidance and Tools webpage (U.S. EPA 2012k).
EPA RISK ASSESSMENT FORUM EXTERNAL REVIEW DRAFT
45
-------
3.3 Risk Characterization
Risk characterization is the final, integrative step of risk assessment. The agency's
Science Policy Council Handbook: Risk Characterization (U.S. EPA 2000b) describes risk
characterization as the step that "integrates information from the preceding components of the
risk assessment and synthesizes an overall conclusion about the risk that is complete,
informative, and useful for decision makers" (U.S. EPA 2000b, 10). The handbook further notes
that a risk characterization is judged by the extent to which it achieves principles of
transparency, clarity, consistency and reasonableness (TCCR). (See Text Box 3-3 for descriptions
of TCCR.) The handbook recommends that these TCCR principles be applied in all stages of the
risk assessment, from planning and scoping through the conduct of the risk assessment, and in
all communication and documentation of the assessment.
Text Box 3-3: Transparency—Clarity—Consistency—Reasonableness in the Risk
Characterization Handbook (U.S. EPA 2000b]
• Transparency "provides explicitness in the risk assessment process. It ensures that any
reader understands all the steps, logic, key assumptions, limitations, and decisions in the
risk assessment, and comprehends the supporting rationale that led to the outcome."
• Clarity "refers to the risk assessment product(s). Making the product clear makes the
assessment free from obscurity and easy to understand by all readers inside and outside of
the risk assessment process."
• Consistency "provides a context for the reader and refers to the presentation of the
material in the risk assessment. For example, are the conclusions of the risk assessment
characterized in harmony with relevant policy, procedural guidance, and scientific
rationales and if not, why the conclusions differ. Also, does the assessment follow
precedent with other EPA actions or why not. Consistency, however, should not encourage
blindly following the guidance for risk assessment and characterization at the expense of
stifling innovation."
• Reasonableness "refers to the findings of the risk assessment in the context of the state-of-
the science, the default assumptions and the science policy choices made in the risk
assessment. It demonstrates that the risk assessment process followed an acceptable,
overt logic path and retained common sense in applying relevant guidance. The
assessment is based on sound judgment."
Risks can be expressed qualitatively or quantitatively for the exposure pathways of
interest. A risk characterization conveys the nature and presence or absence of risks in
qualitative or quantitative terms. In addition, it describes information on how the risks were
EPA RISK ASSESSMENT FORUM EXTERNAL REVIEW DRAFT
46
-------
assessed, where assumptions and uncertainties still exist and where policy choices will need to
be made.
In describing the nature and magnitude of risk for the assessed condition, the risk
characterization describes the universe of people who may be affected, including sensitive
and/or susceptible life stages or populations. These life stages and/or populations (e.g.,
potentially at-risk groups) are first considered in the planning and scoping phases and may be
explicitly evaluated in the risk assessment. Text Box 3-4 presents details on characterizing
cancer risk from early life exposures. Additionally, in consideration of highly exposed or
susceptible life stages and/or populations, risk characterizations generally present multiple risk
descriptors (e.g., high end and central tendency) and may include risk descriptors (e.g.,
maximum exposed individual, reasonable maximum exposure and central tendency) specific to
underlying legislative requirements (e.g., CERCLA, CAA, CWA) (U.S. EPA 1995d).
In risk characterization, information about uncertainty and variability (defined in Text
Box 2-14) from each step of the risk assessment (e.g., use of default parameters, choice of
models and data used for quantitative analysis) is integrated into an overall discussion/analysis
of the impact of the uncertainty
and variability on estimated risks.
The EPA endeavors to ensure that
risk is not underestimated when
data are missing by using several
techniques. The EPA may
characterize uncertainty using a
qualitative assessment of the
overall strength and limitations of
the data used in the assessment.
To estimate the effect of data
uncertainty on modeled pollutant
impacts, various modeling tools
may be employed. It should be
noted that even the
quantification of uncertainty and
variability in probabilistic risk
assessments itself includes an
element of additional
uncertainty. It is important that
the level and type of uncertainty
analysis be commensurate with
Text Box 3-4: Characterizing Cancer Risk from Early
Life Exposure
When assessing cancer risk resulting from early-life
exposures, the risk assessor considers life stage
differences in both exposure and dose-response. The
Guidelines for Carcinogen Risk Assessment (U.S. EPA
2005a) and EPA's Supplemental Guidance for Assessing
Susceptibility from Early-Life Exposure to Carcinogens
(U.S. EPA 2005b), provide guidance in this regard. The
preferred approach is the calculation of life-stage
specific slope factors and use of life-stage specific
exposure information when this is supported by data.
In the absence of sufficient data, age-dependent
adjustment factors (ADAFs) in dose response (i.e.,
slope factors) are combined with age-specific exposure
estimates when assessing cancer risks for chemicals
determined to act through a mutagenic MOA. This
integrative approach is used to assess total lifetime risk
resulting from lifetime or less-than-lifetime exposure
during a specific portion of a lifetime.
EPA RISK ASSESSMENT FORUM EXTERNAL REVIEW DRAFT
47
-------
the decision to be made, in the context of the resources needed to refine such estimations. For
example, highly detailed quantitative uncertainty analyses may not be warranted for some
decisions while they might be useful for others.
Communicating the results of probabilistic risk assessment requires particular attention.
Probabilistic risk assessments provide range and likelihood estimates for one or more aspects of
hazard, exposure or risk, rather than a single point estimate (U.S. EPA 2005e, 2010c). A goal of
probabilistic risk assessment is the quantitative characterization of the uncertainty and
variability in estimates of hazard, exposure, or risk (U.S. EPA 1997c). Risk assessors are
responsible for sharing information on probabilistic results so that risk managers have a clear
understanding of quantitative assessments of uncertainty and variability and how this
information will affect the risk management decision. A good dialogue between the risk
assessor and risk manager is key in aiding the risk manager's understanding and use of the
results from the probabilistic risk assessment.
Areas of uncertainty that may make a difference in the outcome of the assessment (and
thus on informing choices among risk management options) are highlighted in the risk
characterization. For example, the risk characterization document includes a discussion of any
issues associated with the data quality (e.g., reliability and availability) that may impact the
calculated risks or other metrics. This may include explicit discussions of the evaluation process
and description of issues that may impact the reliability or utility of the endpoints identified for
use. A key question addressed in the risk characterization is whether the risk assessment
outcome would change significantly if data were interpreted differently or if different models
were used. This kind of uncertainty is difficult or impossible to characterize probabilistically. It is
essential, however, to describe uncertainty and variability so that the impact will not be
overlooked or misinterpreted. It may be useful to revisit the analysis plan if it is concluded that
gathering additional information will have a substantive impact on reducing uncertainty in the
assessment.
The risk characterization step maintains and emphasizes the distinction between
scientific conclusions and policy judgments, which may include science policy choices such as
assumptions, default procedures and default values. In risk characterization, the assessor also
can usefully describe other policy considerations, such as calculating monetizable health
benefits under certain statutes or the lack of relevance of such calculations under other
statutes. Additional details on key information is presented in the agency's Science Policy
Council Handbook: Risk Characterization (U.S. EPA 2000b) and the Policy for Risk
Characterization (U.S. EPA 1995a). Figure 3-1 highlights the details of risk characterization in the
Framework.
EPA RISK ASSESSMENT FORUM EXTERNAL REVIEW DRAFT
48
-------
Text Box 3-5 describes cumulative risk assessment (an overarching EPA interest) as a
consideration for risk characterization.
Text Box 3-5: Considerations for Risk Characterization: Cumulative Risk Assessment
Cumulative risk assessments may differ in design and associated results. Examples of Cumulative risk
assessment at the EPA include:
Office of Pesticide Programs' evaluation of cumulative risk (U.S. EPA 2012m) according to the Food
Quality Protection Act of 1996. Some texts include:
• Guidance for Performing Aggregate Exposure and Risk Assessments (U.S. EPA 1999b)
• General Principles for Performing Aggregate Exposure and Risk Assessments. (U.S. EPA 2001b)
• Guidance on Cumulative Risk Assessment of Pesticide Chemicals That Have a Common
Mechanism ofToxicity (U.S. EPA 2002d)
The Office of Air and Radiation's assessment of hazardous air pollutant risks remaining after
implementation of technology-based emissions standards (U.S. EPA 20111)
The Office of Environmental Justice's Ensuring Risk Reduction in Communities with Multiple Stressors:
Environmental Justice and Cumulative Risks/Impacts (U.S. EPA 2004f)
Region 3's "Multi-criteria Integrated Resource Assessment (MIRA)" (U.S. EPA 2011m)
Additionally, two NRC publications, Science and Decisions: Advancing Risk Assessment (NRC 2009) and
Phthalates and Cumulative Risk Assessment: The Tasks Ahead (NRC 2008), describe approaches to
consider in the practice of cumulative risk assessment. For example, Phthalates and Cumulative Risk
Assessment discusses the advantages of focusing on physiologic consequences rather than structural or
mechanistic similarity in conducting cumulative risk assessment as this is more directly relevant to
relating chemical exposures to human diseases and disorders. Science and Decisions discusses the
importance of considering nonchemical stressors and background processes in cumulative risk
assessment.
EPA RISK ASSESSMENT FORUM EXTERNAL REVIEW DRAFT
49
-------
4 Public, Stakeholder and Community Involvement
As discussed in Planning and Scoping (Section 2.1), public, stakeholder and community
involvement are key elements of the Framework throughout all phases of the risk assessment.
Figure 4-1 highlights key questions and considerations for stakeholder involvement. As
indicated in the figure, public, stakeholder and community involvement are considered early
and often in the risk assessment and decision making process. Although the single term
"public" could be used to include the full range of external stakeholders, including community
members, this document specifically includes all three terms in recognition of differences in
what they each may convey to different readers and also in recognition of roles played by
internal stakeholders (see Text Box 2-7 for definitions).
Public,
Stakeholder
and
Community
Involvement
Planning and Scoping
and Problem Formulation
Conceptual
• > Model
Analysis
Plan
Risk Assessment
1 C ^
! Exposure
j Assessment
1 -^
f ~\
Effects Assessment
Hazard Identification
Dose Response
J
" ^ Risk Characterization
1
J
i
L
Fit for Purpose
i. Informing Decisions
Key Considerations for Public,
Stakeholder and Community
Involvement
# When are opportunities for public
involvement?
" Who are stakeholders or community
groups?
What communication products are
needed?
What mechanisms for community
and public involvement will be most
effective in actually involving the public
and community?
Figure 4-1. Framework for Human Health Risk Assessment to Inform Decision Making: Key
Questions and Considerations for Public, Stakeholder and Community Involvement.
Public participation is an essential aspect of the EPA's process for making decisions to
achieve the agency's mission of protecting human health and the environment. This provides
the EPA with the opportunity to obtain and consider a range of views on the issue being
assessed as well as on management options. Effective public involvement (including key
stakeholders and/or communities) can enhance the deliberative process and improve the
content of the agency's decisions (U.S. EPA 2003c), which is consistent with sustainability
principles. A critical feature of the Framework is the involvement of the public, stakeholders
and communities at key points in the process. The timing/frequency and level of community
EPA RISK ASSESSMENT FORUM EXTERNAL REVIEW DRAFT
50
-------
involvement will depend on a number of factors, including regulatory requirements, the nature
of the decision and community interest.
As discussed in Section 2.1.5, public involvement may begin when individuals and
organizations seek information from the EPA about a topic or issue or when the public receives
information from the EPA because the agency identifies them as a potentially affected party.
The EPA's outreach activities serve and engage these individuals and organizations (U.S. EPA
2003c).
Each decision or action by the agency may call for a different level of public
involvement, and certain members of the public, stakeholders or communities may need to be
involved at different steps in the risk assessment process. The EPA's Public Involvement Policy
(U.S. EPA 2003c, 1) states that, "EPA staff and managers should seek input reflecting all points
of view and should carefully consider this input when making decisions." In addition, the policy
(U.S. EPA 2003c, 1) states that, "EPA should not accept any recommendation or proposal
without careful, critical examination."
The overall goal of public involvement is to provide opportunities for people to
contribute at every point along the progression of the decision making process. Individuals and
groups decide for themselves whether, when and how to participate. It is recognized that not
everyone who is interested in the situation being assessed chooses to be an active participant
in providing input (e.g., facts, data and opinions) to policy or regulatory decisions of the agency.
The information provided through the public involvement process is considered by the agency's
officials in the decision making process.
4.1 Audiences for the Risk Assessment
If properly planned and executed, the technical risk characterization itself will be
consistent with the level of detail and complexity of the assessment conducted. The
information presented may vary by regulatory and audience needs, however. Co-regulators
such as states and tribal nations also are audiences for the risk assessments; these groups may
prefer a high level of technical detail in communication of an assessment. Several statutes and
executive orders affect the development of regulatory rules and other EPA decisions and may
define specific activities for public, stakeholder and community involvement. In addition,
several programs have developed specific guidance on public involvement (Dalton and Harter
2009) (variously termed public, stakeholder and community involvement), and these guidance
documents are listed in Text Box 4-1.
EPA RISK ASSESSMENT FORUM EXTERNAL REVIEW DRAFT
51
-------
Text Box 4-1: EPA Resources for Public Involvement Efforts, Tools and Policies
Public Involvement
• The Model Plan for Public Participation (U.S. EPA 2000c)
• EPA's Public Involvement Webpage (U.S. EPA 2011b)
• Pesticide Program Dialogue Committee: This Committee provides a forum for a
diverse group of stakeholders to provide feedback to the pesticide program on
various pesticide regulatory, policy and program implementation issues. (U.S. EPA
2011c)
Community Involvement
• EPA's Superfund Community Involvement Plans (U.S. EPA 2002f)
• EPA's Superfund Community Involvement Handbook (U.S. EPA 2005d)
• EPA's Superfund Community Involvement Publications Webpage (U.S. EPA 2011d)
Risk Communication
• EPA's Guidance for Assessing Chemical Contaminant Data for Use in Fish
Advisories, Volume IV: Risk Communication (U.S. EPA 1995b)
• Lessons Learned About Designing, Developing and Disseminating Environmental
Information Products (U.S. EPA 2000e)
• EPA's Risk Communication In Action: The Risk Communication Workbook (U.S. EPA
2007a)
• EPA's Risk Communication in Action: The Tools of Message Mapping (U.S. EPA
2007b)
• Susie/inability and the U.S. EPA (NRC 2011)
4.1.1 Stakeholders
The appropriate stakeholder involvement process will depend on the specifics of the
situation. Stakeholder involvement processes are highly adaptive and can be modified to take
changing circumstances into account. Additional details are found in Better Decisions Through
Consultation and Collaboration (Dalton and Harter 2009).
Staff and management of EPA offices are important internal stakeholders in the process
of drafting rules, policies, permits or plans. The planning process considers inclusion of internal
EPA RISK ASSESSMENT FORUM EXTERNAL REVIEW DRAFT
52
-------
stakeholders in establishing the project. Three key considerations include involving
stakeholders early, obtaining "buy-in" along the way and keeping stakeholders engaged.
Communication with stakeholders outside the agency may vary depending on
regulatory requirements. For example, regulatory and non-regulatory activities in the Office of
Chemical Safety and Pollution Prevention provide mechanisms to interact with stakeholders
while the EPA is developing the assessments. During the review of premanufacture notices
(PMNs) for new substances, the EPA Program Manager or other EPA personnel may contact the
submitter for additional information if the EPA identifies concerns or needs clarification of
technical information provided in the PMN. Rules issued under TSCA §5 (i.e., Significant New
Use Rules) and §6 (e.g., formaldehyde) provide a notice and comment period in the Federal
Register allowing public involvement in the Office of Pollution Prevention and Toxics' (OPPT)
rulemaking actions (e.g., Proposed Significant New Use Rule for Multiwalled Carbon Nanotubes
[U.S. EPA 2010e] and Formaldehyde Emissions From Pressed Wood Products [U.S. EPA 2008b).
Public meetings are scheduled in different parts of the United States to increase public
involvement in the rulemaking process. Under the High Production Volume (HPV) Challenge
Program, OPPT posts notice of and links to data summaries and test plans for HPV chemicals
(U.S. EPA 2012n) and provides a 120-day public comment period. The Office of Pesticide
Programs provides multiple opportunities for public comment and involvement in its
registration review program—at the opening of the process for a chemical on the Preliminary
Work Plan, on the draft risk assessment and on proposed regulatory actions.
Another example of stakeholder involvement is the IRIS process (U.S. EPA 2012o), which
provides multiple opportunities for stakeholder involvement. The process includes a call for
nominations that allows stakeholders to nominate chemicals for assessment through the IRIS
Program that includes a description why the chemical(s) should be considered for assessment.
Multiple opportunities for review and comment occur during the development of the health
hazard assessments. For example, the IRIS process includes a step that provides for review by
other offices within the EPA (agency review) and two opportunities for interagency science
consultation and discussion, which enable other federal agencies to comment on the
assessment. Finally, during the period of public review and comment, any interested member
of the public may comment on the assessment; there also is a public listening session in which
any stakeholder or member of the public has the opportunity to speak about the assessment.
4.1.2 Community
Community involvement may be a component of the stakeholder involvement process,
particularly in cases in which the issue assessed relates to a specific location
(e.g., decisions regarding contaminated waste sites or facilities with environmental releases).
Community involvement is the process of engaging in dialogue and collaboration with
EPA RISK ASSESSMENT FORUM EXTERNAL REVIEW DRAFT
53
-------
community members who may be directly impacted by the risk assessment. For example, in the
Superfund Program (U.S. EPA 2011h), the goal of community involvement is to advocate and
strengthen early and meaningful community participation during the investigation, while
conducting the risk assessment and during the decision making process (see EPA's Public
Involvement Webpage; U.S. EPA 2011b).
4.2 Communication
Successful communication begins early in the risk assessment process during planning
and scoping and problem formulation (see Section 2.1.5) and has a pivotal role throughout the
process. As the Silver Book (NRC 2009, 250) points out, "communication among those involved
in the policy and technical evaluations are [sic] difficult to achieve, but they are necessary for
success." Communication of risk may be challenging as a result of the complexity of the
information being conveyed, the inherent uncertainty in risk estimates and the varying needs of
the audiences (e.g., scientists, risk managers, various stakeholders, the media and the general
public). The Silver Book (NRC 2009, 66) recognized this issue, stating "... the critical final process
in risk assessment is ultimately communication."
Risk communication begins with understanding the risk characterization portion of the
risk assessment. Risk characterization is an integral part of a risk assessment and summarizes the
key findings and the strengths and weaknesses of the assessment for risk managers and others.
Although it provides information that may be useful for communicating with the public, risk
characterization is not synonymous with risk communication.
Risk communication emphasizes the process of providing information to the public,
including individuals, groups and other institutions, about levels of health or environmental risks.
Risk communication is used for such things as information and education, behavior change and
protective action, disaster warnings and emergency information, and joint problem solving.
Although the final risk assessment documentation (including the risk characterization) can be used
to communicate with the public, the risk communication process is probably better served by a
separate set of documents designed for particular audiences.
Risk communication tools are written, verbal or visual statements containing
information about risk. These tools put a particular risk in context, possibly adding comparisons
with other risks, often including advice about risk reduction behavior. Risk communications also
can encourage a dialogue between the sender and receiver of the message (U.S. EPA 2007a). In
general, the communication tools should be concise and provide adequate information for the
user but not at the level of detail provided in the risk characterization. In addition, care is
required to assure that the risk information is consistent with the data provided in the risk
characterization and includes risk assessment results, the strengths and limitations of the
analysis, and how they will be used by risk mangers.
EPA RISK ASSESSMENT FORUM EXTERNAL REVIEW DRAFT
54
-------
Risk communication documents need to consider the audience for the information. For
example, risk managers generally prefer not to receive the depth of detail found in the
technical risk characterization. The usual products prepared from the risk characterization for
risk managers often provide a summary and can take various forms depending on specific
needs (e.g., executive summary, bulleted list of key issues and conclusions, briefing packages)
(U.S. EPA 2000b). Risk characterization products prepared for the public, stakeholders and
communities can come in many forms. Generally, these communication pieces carry forward
the key issues and describe conclusions in a lay person's context rather than a technical one
written for a scientific presentation or paper; this can include plain language definitions,
translations into appropriate languages, use of graphics as appropriate to convey information
and so on. Communication products are developed to meet the needs of the intended audience
and may include products such as fact sheets for interested public, press releases, slide shows,
public relations notices, decision documents, and speeches and talks (U.S. EPA 2000b). Text Box
4-1 identifies resources helpful in developing a risk communication plan for various audiences.
EPA RISK ASSESSMENT FORUM EXTERNAL REVIEW DRAFT
55
-------
5 Informing Decisions
The final step in the risk assessment process is connecting the previously defined
purpose and scope with the conclusions and strengths/limitations of the risk assessment. The
assessments are conducted to provide a scientific characterization of risks based on analysis of
available information and knowledge that meets appropriate quality criteria. A description of
the human health risks, and characterization of the confidence in the information available to
describe the risks, supports risk management decisions. As discussed in Section 3.3, effective
risk characterization is based on transparency in conducting and explaining the risk assessment
combined with clarity, consistency and reasonableness in the preparation of the risk description
(U.S. EPA 2000b).The science supporting the risk assessment conclusions, as well as
consideration of important uncertainties, informs decisions among the risk management
options. As noted in Section 2.3, well planned, focused and conducted risk assessments will be
most useful and informative for decision making. Key questions and considerations for the
informing decisions step are shown in Figure 5-1.
5.1 Characterizing the Risks for Risk Management Options
It is the role of the risk assessor to provide a transparent description of all aspects of the
risk assessment (e.g., default assumptions, data selected and policy choices) to make clear the
range of plausible risk associated with each risk management option. Clear communication
between the risk assessors and risk managers is vital to assuring that risk information is
conveyed appropriately.
Whatever approach is used to estimate risk, it is important to be clear in describing the
range of possible risks (e.g., risks to highly exposed individuals, average exposed individuals or
groups). For example, the extent to which the assessment may underestimate or overestimate
risk for some populations should be highlighted to inform the decision making appropriately. As
discussed in Section 3.3, these uncertainties may be characterized quantitatively (e.g., using
probabilistic methods) or qualitatively (e.g., describing how the results would change if the data
were interpreted differently). The risk assessment characterizes the nature and magnitude of
risk and who is at risk under different risk management options (including a "status quo"
option). The EPA's policy is to describe the range of the risk and highlight susceptible
populations (U.S. EPA 1995a, 2000b).
EPA RISK ASSESSMENT FORUM EXTERNAL REVIEW DRAFT
56
-------
Public,
Stakeholder
and
Community
Involvement
Planning and Scoping
and Problem Formulation
Conceptual
Model
Analysis
Plan
Risk Assessment
Exposure
Assessment
Effects Assessment
Hazard Identification
Dose Response
Risk Characterization
Key Risk-Based Considerations
for Informing Decisions
What is the public health protection
level provided by each option?
What are the key limitations/
uncertainties associated with risk
estimates for each option?
• Does consideration of other factors
(technologies, costs, social consider-
ations, environmental justice, sustain-
ability, etc.) vary with each option?
Informing Decisions
Figure 5-1. Framework for Human Health Risk Assessment to Inform Decision Making: Key
Questions and Considerations for Informing Decisions.
The communication of the risk characterization will take different written and oral forms
to meet the needs of the intended audiences, including the risk managers. The level and
amount of detail in each product will vary according to the level and amount of detail of the risk
assessment that is being characterized by the product; thus, being fit for purpose. In addition, it
often will vary in format or detail for effective communication with the intended audience.
Summaries of the risk characterization may be provided to the risk managers depending on
their information needs. Key issues considered by risk managers include:
• Strengths of an assessment including the overall weight of evidence and the quality and
quantity of data supporting the hazard and/or exposure.
• Level of confidence or uncertainty in the assessment and the data underlying it.
• What are the life stages and/or populations at greatest risk?
• Information that would yield changes in the risk estimates under various candidate risk
management alternatives.
• Precedents that may inform the decision.
5.2 Risk Management Factors Beyond the Risk Assessment and
Characterization
EPA uses risk assessment as a key source of scientific information for making sound
decisions about managing risks to human health and the environment. Risk management
EPA RISK ASSESSMENT FORUM EXTERNAL REVIEW DRAFT
57
-------
decisions, however, may be informed by a range of factors, evidence and policy choices, such as
the following:
• Laws and Regulatory Requirements—legal mandates, flexibility and constraints.
• Economic Factors—costs, benefits and impacts of potential actions.
• Sustainability—life cycle, multimedia and long-term impacts.
• Technological Factors—feasibility, impact and range of risk management options.
• Political Factors—interactions with different branches and levels of government and the
citizens that they represent.
• Public and Social Factors—susceptible population groups, nonchemical stressors and
cumulative risk assessment considerations.
Statutory or regulatory requirements and restrictions, including those established by
states and tribal nations, may limit decision options as the discretionary power afforded to
agencies in making regulatory decisions varies greatly. The EPA faces regulatory, licensing and
other decisions covering a wide range of environmental issues and pollutants. These decisions
are made within a number of EPA program offices, each responding to a unique mixture of
statutes, precedents and stakeholders. In statutes, Congress establishes legal requirements that
generally describe the level of protectiveness that EPA regulations must achieve, and the
statute may impose specific risk assessment requirements. In addition, court precedents can
affect how the EPA considers assessments of risk. The statutory or regulatory requirements
often also specify other kinds of factors for consideration in the risk management decision.
EPA RISK ASSESSMENT FORUM EXTERNAL REVIEW DRAFT
58
-------
6 Summary
The Framework for Human Health Risk Assessment to Inform Decision Making is
intended to foster increased implementation of existing EPA guidance for conducting human
health risk assessments and to improve the utility of risk assessment in the decision making
process. This document lays out a Framework for conducting human health risk assessments in
support of decision making at the EPA. It draws on current EPA experience in applying both the
planning and scoping and problem formulation steps as well as on the advice of the NRC (2009)
and other advisory groups. For example, the Framework addresses recommendations in the
Silver Book (NRC 2009) on assuring the utility of risk assessment or the assessments fit for
purpose (Text Box 6-1). As indicated in the Framework diagram, Figure 6-1, the NRC 1983 four-
step risk assessment paradigm is maintained, but there is increased emphasis on interaction
between risk assessors and risk managers in planning the assessment to maximize utility.
Emphasis on utility is maintained throughout the process, beginning with planning and scoping
and during evaluation of the applicability of the risk assessment in informing risk management
choices. The Framework
highlights the practical
nature of risk
assessment. For
example, although the
agency is committed to
advancing risk
assessment science,
assessments are not
academic exercises.
Rather, they are
intended to support
decision making for the
protection of human
health. Application of
the Framework, with its
emphasis on problem
formulation and utility
of the risk assessment,
ultimately will result in
better, more
transparent choices
among risk
Text Box 6-1: The Silver Book Recommendations for a Human
Health Risk Assessment Framework
• The technical framework for risk assessment presented in the
Red Book should remain intact but should be embedded in a
broader framework in which risk assessment is used
principally to help to discriminate among risk-management
options (NRC 2009, 256).
• The framework for risk-based decision making (Figure 6-1)
should have as its core elements a problem-formulation and
scoping phase in which the available risk-management
options are identified, a planning and assessment phase in
which risk-assessment tools are used to determine risks under
existing conditions and with proposed options, and a
management phase in which risk and nonrisk information is
integrated to inform choices among options (NRC 2009, 256).
• EPA should phase in the use of the framework with a series of
demonstration projects that apply the framework and that
determine the degree to which the approach meets the needs
of the agency risk managers, and how risk-management
conclusions differ as a result of the revised orientation (NRC
2009, 256).
EPA RISK ASSESSMENT FORUM EXTERNAL REVIEW DRAFT
59
-------
management options. This Framework includes a foundation quite similar to that in Framework
for Ecological Risk Assessment (U.S. EPA 1992b), thus illustrating conceptual similarity between
the two types of risk assessment; however, it is not always advantageous to integrate human
health and ecological risk assessments. This Framework builds on agency policies and guidance,
and is directed at improving risk assessment products, but does not overturn or in any way
change existing science policy decisions.
«-
Public,
Stakeholder
and
Community
Involvement
•4-
•«-
^m m
^M •
^M •
r
Planning and Scoping
and Problem Formulation
Conceptual
k Model
Analysis
Plan
Risk Assessment
/• •>
Exposure
v y
Effects Assessment
Hazard Identification
Dose Response
v )
^ Risk Characterization
i
J
\
Fit for Purpose
^ Informing Decisions
Figure 6-1. Framework for Human Health Risk Assessment to Inform Decision Making
EPA programs routinely apply components of this Framework for Human Health Risk
Assessment to Inform Decision Making as evidenced by the examples cited in the preceding
sections. It is expected, however, that this document will facilitate the formal recognition of
these components in agency risk assessment activities. The Framework's explicit recognition of
the roles for planning, public, stakeholder and community involvement and consideration of
utility will assist in the development of risk assessments focused on informing risk management
decisions. Further, "institutionalization" of this Framework for Human Health Risk Assessment
to Inform Decision Making will contribute transparency to the agency's risk assessment process
and a level of consistency across assessments, across media and programs as well as between
human health and ecological outcomes.
The Framework is intended to be flexible. The structure will accommodate advances in
the technology and science; for example, development of life cycle analyses and use of data
from high throughput assays (those that generate data much more rapidly and for many more
chemicals than the standard toxicological assays of the 20th century). The Framework structure
is sufficiently adaptable to encompass needed changes in agency direction, developing needs
and newer revised legislative mandates.
EPA RISK ASSESSMENT FORUM EXTERNAL REVIEW DRAFT
60
-------
References
Ankley, Gerald T., Richard S. Bennett, Russell J. Erickson, Dale J. Hoff, Michael W. Hornung,
Rodney D. Johnson, David R. Mount, John W. Nichols, Christine L. Russom, Patricia K.
Schmieder, Jose A. Serrano, Joseph E. Tietge, and Daniel L. Villeneuve 2010. "Adverse
Outcome Pathways: A Conceptual Framework to Support Ecotoxicology Research and
Risk Assessment." Environmental Toxicology and Chemistry 29 (3): 730-741.
Boobis, Alan R., John E. Doe, Barbara Heinrich-Hirsch, M. E. (Bette) Meek, Sharon Munn,
Mathuros Ruchirawat, Josef Schlatter, Jennifer Seed, and Carolyn Vickers 2008. "IPCS
Framework for Analyzing the Relevance of a Noncancer Mode of Action for Humans."
Critical Reviews in Toxicology 38 (2): 87-96.
Clay, Donald 1991. Memorandum from Donald R. Clay, Assistant Administrator. Subject: Role of
the Baseline Risk Assessment in Superfund Remedy Selection Decisions. April 22.
http://www.epa.gov/oswer/riskassessment/pdf/baseline.pdf
Dalton, Deborah, and Philip J. Harter 2009. Better Decisions Through Consultation and
Collaboration. Prepared for the U.S. Environmental Protection Agency.
http://www.epa.gov/publicinvolvement/pdf/betterdecisions.pdf
Exec. Order No. 12898, 59 Fed. Reg. 7629 (Feb. 16,1994).
http://www.epa.gov/lawsregs/laws/eol2898.html
Exec. Order No. 13045, 62 Fed. Reg. 19885 (Apr. 23, 1997).
http://www.epa.gov/lawsregs/laws/eol3045.html
Exec. Order No. 13514, 74 Fed. Reg. 52117 (Oct. 8, 2009).
http://www.epa.gov/oaintrnt/practices/eol3514.htm
National Research Council (NRC) 1983. Risk Assessment in the Federal Government: Managing
the Process. (The "Red Book"). National Academy of Sciences, National Research
Council, Committee on the Institutional Means for Assessments of Risk to Public Health,
Commission on Life Sciences. Washington, DC: National Academy Press.
http://www.na p.edu/openbook.php?isbn=0309033497
NRC 1994. Science and Judgment in Risk Assessment (The "Blue Book"). National Academy of
Sciences, National Research Council, Committee on Risk Assessment of Hazardous Air
Pollutants, Board on Environmental Sciences and Technology, Commission on Life
Sciences. Washington, DC: National Academy Press.
http://www.nap.edu/catalog.php7record id=2125
EPA RISK ASSESSMENT FORUM EXTERNAL REVIEW DRAFT
61
-------
NRC 2007. Toxicity Testing in the 21st Century: A Vision and a Strategy. Committee on Toxicity
Testing and Assessment of Environmental Agents. Washington, DC: National Academy
Press, http://www.nap.edu/catalog.php7record id=11970
NRC 2008. Phthalates and Cumulative Risk Assessment: The Tasks Ahead. Committee on the
Health Risks of Phthalates. Washington, DC: National Academy press.
http://www.nap.edu/catalog.php7record id=12528
NRC 2009. Science and Decisions: Advancing Risk Assessment (The "Silver Book"). National
Academy of Sciences. Washington, DC: National Academy Press.
http://www.nap.edu/catalog.php7record id=12209
NRC 2011. Sustainability and the U.S. EPA. National Research Council, Committee on
Incorporating Sustainability in the U.S. Environmental Protection Agency. Washington,
DC: National Academy Press.
http://sites.nationalacademies.org/PGA/sustainability/EPA/index.htm
Office of Management and Budget 2004. Final Information Quality Bulletin for Peer Review.
Washington, DC. December 16.
http://www.whitehouse.gov/sites/default/files/omb/memoranda/fy2005/m05-03.pdf
Presidential/Congressional Commission on Risk Assessment and Risk Management (PCCRARM)
1997a. Framework for Environmental Health Risk Management. Final Report, Volume 1.
Washington, DC: The Presidential/Congressional Commission on Risk Assessment and
Risk Management, http://www.riskworld.com/riskcommission/default.html
PCCRARM 1997b. Risk Assessment and Risk Management in Regulatory Decision-Making. Final
Report, Volume 2. Washington, DC: The Presidential/Congressional Commission on Risk
Assessment and Risk Management.
http://www.riskworld.com/riskcommission/default.html
Seed, Jennifer, Edward W. Carney, Richard A. Corley, Kevin M. Crofton, John M. DeSesso, Paul
M. D. Foster, Robert Kavlock, Gary Kimmel, James Klaunig, M. E. Meek, R. Julian Preston,
William Slikker, Jr., Sonia Tabacova, Gary M. Williams, Jeanette Wiltse, R. Thomas
Zoeller, Penelope Fenner-Crisp, and Dorothy E. Patton 2005. "Overview: Using Mode of
Action and Life Stage Information to Evaluate the Human Relevance of Animal Toxicity
Data." Critical Reviews in Toxicology. 35 (8-9): 663-672.
U.S. Environmental Protection Agency (U.S. EPA) 1984. Risk Assessment and Management:
Framework for Decision Making. Washington, DC: Office of Policy, Planning and
Evaluation. EPA/600/985/002.
http://nepis.epa.gov/Exe/ZvPURL.cgi?Dockey=20008KTF.txt
EPA RISK ASSESSMENT FORUM EXTERNAL REVIEW DRAFT
62
-------
U.S. EPA 1986a. Guidelines for the Health Risk Assessment of Chemical Mixtures. Washington,
DC: Office of Research and Development. September. EPA/630/R-98/002.
http://www.epa.gov/raf/publications/pdfs/CHEMMIX 1986.PDF
U.S. EPA 1986b. Guidelines for Carcinogen Risk Assessment. Washington, DC: Risk Assessment
Forum. September. EPA/630/R-00/004.
http://www.epa.gov/raf/publications/pdfs/CA%20GUIDELINES 1986.PDF
U.S. EPA 1986c. Guidelines for Mutagenicity Risk Assessment. Washington, DC: Risk Assessment
Forum. September. EPA/630/R-98/003.
http://www.epa.gov/raf/publications/pdfs/MUTAGEN2.PDF
U.S. EPA 1987. The Risk Assessment Guidelines of 1986. Washington, DC: Office of Health and
Environmental Assessment. August. EPA/600/8-87/045.
http://cf pub. epa.gov/ncea/cfm/recordisplay.cfrn?deid=29777#Down load
U.S. EPA 1988. Guidance for Conducting Remedial Investigations and Feasibility Studies Under
CERCLA. Washington, DC: Office of Solid Waste and Emergency Response, Office of
Emergency and Remedial Response. October. EPA/540/G-89/004.
http://www.epa.gov/superfund/policv/remedy/pdfs/540g-89004-s.pdf
U.S. EPA 1989. Risk Assessment Guidance for Superfund: Volume 1, Human Health Evaluation
Manual (Part A). Washington, DC: Office of Emergency and Remedial Response.
December. EPA/540/1-89/002.
http://www.epa.gov/oswer/riskassessment/ragsa/pdf/rags a.pdf (Also see Parts B-D.)
U.S. EPA 1991a. Role of the Baseline Risk Assessment in Superfund Remedy Selection Decisions.
Memorandum from Agency Assistant Administrator for Solid Waste and Emergecny
Response, Donald R. Clay, Washington, DC. April 22.
U.S. EPA 1991b. Guidelines for DevelopmentalToxicity Risk Assessment. Washington, DC: Risk
Assessment Forum. EPJ\/600/Federal Register-91/001.
http://cfpub.epa.gov/ncea/cfm/recordisplay.cfm?deid=23162
U.S. EPA 1992a. Guidelines for Exposure Assessment. Washington, DC: Risk Assessment Forum.
EPA/600/Z-92/001. http://cfpub.epa.gov/ncea/cfm/recordisplay.cfm?deid=15263
U.S. EPA 1992b. Framework for Ecological Risk Assessment. Washington, DC: Risk Assessment
Forum. EPA/630/R-92/001. http://www.epa.gov/raf/publications/framework-eco-risk-
assessment.htm
U.S. EPA 1994. Methods for Derivation of Inhalation Reference Concentrations (RfCs) and
Application of Inhalation Dosimetry. Washington, DC: Office of Research and
EPA RISK ASSESSMENT FORUM EXTERNAL REVIEW DRAFT
63
-------
Development, Office of Health and Environmental Assessment. EPA/600/8-90/066F.
http://cfpub.epa.gov/ncea/cfm/recordisplay.cfm?deid=71993
U.S. EPA 1995a. Policy for Risk Characterization. Memorandum from Agency Administrator
Carol M. Browner, Washington, DC. March 21.
http://www.epa.gov/spc/pdfs/rccover.pdf
U.S. EPA 1995b. Guidance for Assessing Chemical Contaminant Data for Use in Fish Advisories,
Volume IV: Risk Communication. Washington, DC: Office of Water. March. EPA/823/R-
95/001.
http://water.epa.gov/scitech/swguidance/fishshellfish/techguidance/guidance.cfm
U.S. EPA 1995c. Policy on Evaluating Health Risks to Children. Memorandum from Agency
Administrator Carol M. Browner, Washington, DC. October 20.
http://www.epa.gov/spc/2poleval.htm
U.S. EPA 1995d. Guidance for Risk Characterization. Washington, DC: Science Policy Council.
http://www.epa.gov/spc/pdfs/rcguide.pdf
U.S. EPA 1996. Guidelines for Reproductive Toxicity Risk Assessment. Washington, DC: Risk
Assessment Forum. EPA/630/R-96/009.
http://www.epa.gov/raf/publications/guidelines-reproductive-tox-risk-assessment.htm
U.S. EPA 1997a. Guidance on Cumulative Risk Assessment, Part 1. Planning and Scoping.
Washington, DC: Science Policy Council. Attachment to memo dated July 3, 1997 from
the Administrator, Carol Browner, and Deputy Administrator, Fred Hansen, titled
"Cumulative Risk Assessment Guidance—Phase I Planning and Scoping."
http://www.epa.gov/OSA/spc/2cumrisk.htm
U.S. EPA 1997b. Exposure Factors Handbook (Final Report). Washington, DC: Office of Research
and Development, National Center for Environmental Assessment. August. EPA/600/P-
95/002Fa. http://www.epa.gov/ncea/pdfs/efh/front.pdf
U.S. EPA 1997c. Guiding Principles for Monte Carlo Analysis. Washington, DC: Risk Assessment
Forum. EPA/630/R-97/001. http://www.epa.gov/ncea/pdfs/montcarl.pdf
U.S. EPA 1998a. Guidelines for Ecological Risk Assessment. Washington, DC: Risk Assessment
Forum. EPA/630/R-95/002F. http://www.epa.gov/raf/publications/pdfs/ECOTXTBX.PDF
U.S. EPA 1998b. Guidelines for Neurotoxicity Risk Assessment. Washington, DC: Risk Assessment
Forum. EPA/630/R-95/001F. http://www.epa.gov/raf/publications/pdfs/NEUROTOX.PDF
U.S. EPA 1999a. Risk Assessment Guidance for Superfund (RAGS) Volume 3—Part A: Process for
Conducting Probabilistic Risk Assessment). Draft. Washington, DC: Office of Solid Waste
EPA RISK ASSESSMENT FORUM EXTERNAL REVIEW DRAFT
64
-------
and Emergency Response. December.
http://www.epa.gov/oswer/riskassessment/rags3adt/
U.S. EPA 1999b. Guidance for Performing Aggregate Exposure and Risk Assessments.
Washington, DC: Office of Pesticide Programs. November.
http://www.epa.gov/scipolv/sap/meetings/1999/february/guidance.pdf
U.S. EPA 1999c. Residual Risk Report to Congress. Research Triangle Park, NC: Office of Air
Quality Planning and Standards. March. EPA/453/R-99/001.
http://www.epa.gov/ttncaaal/t3/reports/risk rep.pdf
U.S. EPA 2000a. Supplementary Guidance for Conducting Health Risk Assessment of Chemical
Mixtures. Washington, DC: Risk Assessment Forum. August. EPA/630/R-00/002.
http://www.epa.gov/ncea/pdfs/chem mix/chem mix 08 2001.pdf
U.S. EPA 2000b. Science Policy Council Handbook: Risk Characterization. Washington, DC:
Science Policy Council. EPA/100/B-00/002. http://www.epa.gov/spc/pdfs/rchandbk.pdf
U.S. EPA 2000c. The Model Plan for Public Participation. Washington, DC: Office of Enforcement
and Compliance. February. EPA/300/K-00/001.
http://www.epa.gov/compliance/ei/resources/publications/neiac/model-public-part-
plan.pdf
U.S. EPA 2000d. Methodology for Deriving Ambient Water Quality Criteria for the Protection of
Human Health. Washington, DC: Office of Water. EPA/822/B-00/004.
http://water.epa.gov/scitech/swguidance/standards/criteria/health/methodology/inde
x.cfm
U.S. EPA 2000e. Lessons Learned About Designing, Developing, and Disseminating
Environmental Information Products. Washington, DC: Office of Environmental
Information. November. EPA/260/R-00/001.
http://nepis.epa.gov/Exe/ZvPURL.cgi?Dockey=P1005LPL.txt
U.S. EPA 2001a. Arsenic Rule Benefits Analysis: An SAB Review. EPA/SAB/EC-01/008.
http://www.epa.gov/ogwdwOOO/arsenic/pdfs/ec01008.pdf
U.S. EPA 2001b. General Principles for Performing Aggregate Exposure and Risk Assessments.
Washington, DC: Office of Pesticide Programs. Fax-On-Demand. Fax no. (202) 401-0527. Item
no. 6043. http://www.epa.gov/oppfeadl/trac/science/aggregate.pdf
U.S. EPA 2001c. EPA Requirements for Quality Assurance Project Plans. Washington, DC: Office
of Environmental Information. March. EPA/240/B-00/003.
http://www.epa.gov/quality/qs-docs/r5-final.pdf
EPA RISK ASSESSMENT FORUM EXTERNAL REVIEW DRAFT
65
-------
U.S. EPA 2001d. Risk Assessment Guidance for Superfund (RAGS) Volume III—Part A: Process for
Conducting Probabilistic Risk Assessment. Washington, DC: Office of Solid Waste and
Emergency Response. December. EPA/540/R-02/002.
http://www.epa.gov/oswer/riskassessment/rags3adt/pdf/rags3adt complete.pdf
U.S. EPA 2002a. Lessons Learned on Planning and Scoping of Environmental Risk Assessment.
Memorandum from the Science Policy Council. January.
http://www.epa.gov/spc/pdfs/llmemo.pdf
U.S. EPA 2002b. "Appendix B: Case Study on Concentrated Animal Feeding Operations." B. In
Lessons Learned on Planning and Scoping for Environmental Risk Assessments.
Washington, DC: Science Policy Council, http://www.epa.gov/spc/pdfs/handbook.pdf
U.S. EPA 2002c. "Appendix C: Re-registration of Pentachlorophenol." In Lessons Learned on
Planning and Scoping for Environmental Risk Assessments. Washington, DC: Science
Policy Council, http://www.epa.gov/spc/pdfs/handbook.pdf
U.S. EPA 2002d. Guidance on Cumulative Risk Assessment of Pesticide Chemicals That Have a
Common Mechanism ofToxicity. Washington, DC: Office of Pesticide Programs. January.
http://www.epa.gov/oppfeadl/trac/science/cumulative guidance.pdf
U.S. EPA 2002e. A Review of the Reference Dose and Reference Concentration Processes.
External review draft. Washington, DC: Risk Assessment Forum. May. EPA/630/P-
02/002F. http://www.epa.gov/raf/publications/pdfs/rfdrfcextrevdrft.pdf
U.S. EPA 2002f. "Superfund Community Involvement Plans." September.
http://www.epa.gov/superfund/community/pdfs/toolkit/7clplans.pdf
U.S. EPA 2002g. Guidance on Cumulative Risk Assessment of Pesticide Chemicals That Have a
Common Mechanism ofToxicity. Washington, DC: Office of Pesticide Programs.
http://www.epa.gov/scipolv/sap/meetings/2003/decemberll/cumulativeguidance2002
.pdf
U.S. EPA 2003a. Framework for Cumulative Risk Assessment. Washington, DC: Risk Assessment
Forum. May. EPA/630/P-02/001F.
http://www.epa.gov/raf/publications/pdfs/frmwrk cum risk assmnt.pdf
U.S. EPA 2003b. Considerations in Risk Communication: A Digest of Risk Communication as a
Risk Management Tool. Cincinnati, OH: Office of Research and Development, National
Risk Management Research Laboratory. March. EPA/625/R-02/004.
http://www.epa.gov/nrmrl/pubs/625r02004.html
U.S. EPA 2003c. Public Involvement Policy. May. EPA/233/B-03/002.
http://www.epa.gov/publicinvolvement/pdf/policy2003.pdf
EPA RISK ASSESSMENT FORUM EXTERNAL REVIEW DRAFT
66
-------
U.S. EPA 2003d. Framework for Implementing EPA's Public Involvement Policy. May. EPA/233/F-
03/001. http://www.epa.gov/publicinvolvement/policv2003/framework.pdf
U.S. EPA 2004a. Risk Assessment Guidance for Superfund Volume I: Human Health Evaluation
Manual (Part E, Supplemental Guidance for Dermal Risk Assessment). Washington, DC:
Office of Solid Waste and Emergency Response. EPA/540/R/99/005.
http://www.epa.gov/oswer/riskassessment/ragse/
U.S. EPA 2004b. Air Toxics Risk Assessment Reference Library, Volume 1. Technical Resource
Manual. Research Triangle Park, NC: Office of Air Quality Planning and Standards.
EPA/453/K-04/001A. http://www.epa.gov/ttn/fera/risk atra voll.html
U.S. EPA 2004c. Air Toxics Risk Assessment Reference Library, Volume 2. Facility-Specific
Assessment. Research Triangle Park, NC: Office of Air Quality Planning and Standards.
EPA/453/K-04/001B. http://www.epa.gov/ttn/fera/risk atra vol2.html
U.S. EPA 2004d. Risk Assessment Principles and Practices. Washington, DC: Office of the Science
Advisor, Risk Assessment Task Force. March. EPA/100/B-04/001.
http://www.epa.gov/osa/pdfs/ratf-final.pdf
U.S. EPA 2004e. Air Toxics Risk Assessment Library. Volume 1 Technical Resource Manual.
Washington, DC: Office of Air and Radiation. April. Residual Risk Framework described in
Part II—Human Health Risk Assessment: Inhalation.
http://www.epa.gov/ttn/fera/data/risk/vol I/chapter 05.pdf. All volumes available at:
http://www.epa.gov/ttn/fera/risk atra main.html
U.S. EPA 2004f. Ensuring Risk Reduction in Communities With Multiple Stressors: Environmental
Justice and Cumulative Risks/Impacts. Washington, DC: National Environmental Justice
Advisory Council, Cumulative Risks/Impacts Work Group. December.
http://www.epa.gov/environmentaliustice/resources/publications/neiac/neiac-cum-
risk-rpt-122104.pdf
U.S. EPA 2004g. Registration Review Update. Washington, DC: Office of Pesticide Programs,
Pesticide Program Dialogue Committee. October.
http://www.epa.gov/oppfeadl/cb/ppdc/regisreview/regreview-update.pdf
U.S. EPA 2005a. Guidelines for Carcinogen Risk Assessment. Washington, DC: Risk Assessment
Forum. March. EPA/630/P-03/001B.
http://www.epa.gov/raf/publications/pdfs/CANCER GUIDELINES FINAL 3-25-05.pdf
U.S. EPA 2005b. Supplemental Guidance for Assessing Susceptibility from Early-Life Exposure to
Carcinogens. Washington, DC: Risk Assessment Forum. March. EPA/630/R-03/003F.
http://www.epa.gov/ttn/atw/childrens supplement final.pdf
EPA RISK ASSESSMENT FORUM EXTERNAL REVIEW DRAFT
67
-------
U.S. EPA 2005c. Guidance on Selecting Age Groups for Monitoring and Assessing Childhood
Exposures to Environmental Contaminants (Final). Washington, DC: Risk Assessment
Forum. EPA/630/P-03/003F. http://www.epa.gov/raf/publications/guidance-on-
selecting-age-groups.htm
U.S. EPA 2005d. Superfund Community Involvement Handbook. Washington, DC: Office of Solid
Waste and Emergency Response. April. EPA/540/K-05/003.
http://www.epa.gov/superfund/community/cag/pdfs/ci handbook.pdf
U.S. EPA 2005e. A Probabilistic Exposure Assessment for children who Contact CCA-Treated
Playsets and Decks. Washington DC: U.S. Environmental Protection Agency. February.
http://www.epa.gov/heasd/sheds/CCA all.pdf
U.S. EPA 2006a. A Framework for Assessing Health Risk of Environmental Exposures to Children
(Final). Washington, DC: U.S. Environmental Protection Agency. EPA/600/R-05/093F.
http://cfpub.epa.gov/ncea/cfm/recordisplay.cfm?deid=158363
U.S. EPA 2006b. Advisory on EPA's Superfund Benefits Analysis. January 9.
http://yosemite.epa.gov/sab/sabproduct.nsf/58ADDDF28999BAC18525710100554AOF/
$File/superfund sab-adv-06-002.pdf
U.S. EPA 2006c. Peer Review Handbook, 3rd Edition. Washington, DC: Science Policy Council.
EPA/100/B-06/002.
http://www.epa.gov/peerreview/pdfs/peer review handbook 2006.pdf
U.S. EPA 2006d. Air Toxics Risk Assessment Reference Library, Volume 3. Community-Scale
Assessment. Research Triangle Park, NC: Office of Air Quality Planning and Standards.
EPA/452/K-06/001C. http://www.epa.gov/ttn/fera/risk atra vol3.html
U.S. EPA 2006e. EPA's Action Development Process. Guide to Considering Children's Health
When Developing EPA Actions: Implementing Executive Order 13045 and EPA's Policy on
Evaluating Health Risks to Children.
http://yosemite.epa.gov/ochp/ochpweb.nsf/content/ADPguide.htm/$File/EPA ADP Gu
ide 508.pdf
U.S. EPA 2006f. Guidance on Systematic Planning Using the Data Quality Objectives Process.
Washington, DC: Office of Environmental Information. EPA/QA/G-4.
http://www.epa.gov/quality/qs-docs/g4-final.pdf
U.S. EPA 2007a. Risk Communication in Action: The Risk Communication Workbook. Cincinnati,
OH: Office of Research and Development, National Risk Management Research
Laboratory. August. EPA/625/R-05/003.
http://nepis.epa.gov/Exe/ZyN ET.exe/60000l2U.TXT?ZvActionD=ZyDocument&Client=EP
A&lndex=2006+Thru+2010&Docs=&Query=&Time=&EndTime=&SearchMethod=l&Toc
EPA RISK ASSESSMENT FORUM EXTERNAL REVIEW DRAFT
68
-------
Restrict=n&Toc=&TocEntrv=&QField=&QFieldYear=&QFieldMonth=&QFieldDay=&lntQFi
eldOp=0&ExtQFieldOp=0&XmlQuerv=&File=D%3A%5Czyfiles%5Clndex%20Data%5C06th
rulO%5CTxt%5C00000001%5C60000l2U.txt&User=ANONYMOUS&Password=anonymou
s&SortMethod=h%7C-
&MaximumDocuments=l&FuzzvDegree=0&lmageQualitv=r75g8/r75g8/xl50yl50gl6/i4
25&Display=p%7Cf&DefSeekPage=x&SearchBack=ZvActionL&Back=ZyActionS&BackDesc
=Results%20page&MaximumPages=l&ZvEntrv=l&SeekPage=x&ZyPURL
U.S. EPA 2007b. Risk Communication in Action: The Tools of Message Mapping. Cincinnati, OH:
Office of Research and Development, National Risk Management Research Laboratory.
August. EPA/625/R-06/012. http://nepis.epa.gov/Exe/ZvPURL.cgi?Dockev=60000IOS.txt
U.S. EPA 2007c. Lead: Human Exposure and Health Risk Assessment for Selected Case Studies.
Volume 1. Human Exposure and Health Risk Assessments—Full-Scale. Research Triangle
Park, NC: Office of Air Quality Planning and Standards. July. EPA/452/R-07/014a.
http://www.epa.gov/ttn/naaqs/standards/pb/data/Pb-RA-Vol-l-073007.pdf
U.S. EPA 2007d. Better Decisions through Consultation and Collaboration. Washington, DC:
U.S. Environmental Protection Agency. Conflict Prevention and Resolution Center
http://www.epa.gov/adr/Better Decisions.pdf
U.S. EPA 2008a. Child-Specific Exposure Factors Handbook (Final Report) 2008. Washington, DC:
U.S. Environmental Protection Agency. EPA/600/R-06/096F.
http://cfpub.epa.gov/ncea/cfm/recordisplay.cfm?deid=199243
U.S. EPA 2008b. "Formaldehyde Emissions From Pressed Wood Products." Proposed
rulemaking. Federal Register 73 (233): 73620-43629. http://www.epa.gov/fedrgstr/EPA-
TOX/2008/December/Day-03/t28585.htm
U.S. EPA 2009. Highlights of the Child-Specific Exposure Factors Handbook (Final Report).
Washington, DC: Office of Research and Development, National Center for
Environmental Assessment. EPA/600/R-08/135.
http://cfpub.epa.gov/ncea/cfm/recordisplay.cfm?deid=200445
U.S. EPA 2010a. Guidelines for Preparing Economic Analysis. December 17. EPA/240/R-10/001.
http://yosemite.epa.gov/ee/epa/eerm.nsf/vwAN/EE-0568-50.pdf/$file/EE-0568-50.pdf
U.S. EPA 2010b. EPA's Action Development Process. Interim Guidance on Considering
Environmental Justice During the Development of an Action. Washington, DC. July.
http://www.epa.gov/environmentaljustice/resources/policv/considering-ej-in-
rulemaking-guide-07-2010.pdf
EPA RISK ASSESSMENT FORUM EXTERNAL REVIEW DRAFT
69
-------
U.S. EPA 2010c. Quantitative Health Risk Assessment for Particulate Matter. Research Triangle
Park, NC: Office of Air Quality Planning and Standards. EPA/452/R-10/005.
http://www.epa.gov/ttn/naaqs/standards/pm/data/PM RA FINAL June 2010.pdf
U.S. EPA 2010d. Requirements for Submitting Electronic P're-manufacture Notices (PMNs).
Washington, DC: Office of Chemical Safety and Pollution Prevention, Office of Pollution,
Prevention and Toxics. January, http://www.epa.gov/ncea/efh/pdfs/efh-complete.pdf
U.S. EPA 2010e. "Proposed Significant New Use Rule for Multi-walled Carbon Nanotubes."
Proposed rulemaking. Federal Register 75 (22): 5546-5551.
http://www.regulations.gov/#!documentDetail:D=EPA-HQ-OPPT-2009-0686-0001
U.S. EPA 2011a. Exposure Factors Handbook. Washington, DC: Office of Research and
Development. September. EPA/600/R-090/052F.
http://www.epa.gov/ncea/efh/pdfs/efh-complete.pdf
U.S. EPA 2011b. "EPA Public Involvement." Accessed November 11.
http://www.epa.gov/publicinvolvement/
U.S. EPA 2011c. "Pesticide Program Dialogue Committee." Accessed November 11.
http://www.epa.gov/oppfeadl/cb/ppdc/
U.S. EPA 2011d. "Superfund Community Involvement Publications." Accessed November 11.
http://www.epa.gov/superfund/community/publications.htm
U.S. EPA 2011e. "Sustainability." Accessed November 11. http://www.epa.gov/sustainability/
U.S. EPA 2011f. "Life-Cycle Assessment." Accessed November 11.
http://www.epa.gov/nrmrl/std/lca/lca.html
U.S. EPA 2011g. "Definitions of the Most Commonly Used Public Stakeholder Involvement
Terms." Accessed November 11. http://www.epa.gov/stakeholders/definit.htm
U.S. EPA 2011h. "Superfund Community Involvement." Accessed November 11.
http://www.epa.gov/superfund/community/
U.S. EPA 20111. "EPA's Quality System for Environmental Data and Technology." Accessed
November 11. http://www.epa.gov/quality/
U.S. EPA 2011J. "Superfund Quality Assurance/Quality Control." Accessed November 11.
http://www.epa.gov/superfund/programs/clp/qaqc.htm
U.S. EPA 2011k. "Resources for Planning New Data Collections." Accessed November 11.
http://www.epa.gov/quality/rnewdata.html
EPA RISK ASSESSMENT FORUM EXTERNAL REVIEW DRAFT
70
-------
U.S. EPA 20111. "Risk and Technology Review." Accessed November 11.
http://www.epa.gov/ttn/atw/rrisk/rtrpg.html
U.S. EPA 2011m. "Multi-criteria Integrated Resource Assessment (MIRA)." Accessed November
11. http://www.epa.gov/reg3esdl/data/mira.htm
U.S. EPA 2011n. "Particulate Matter Standards—Documents From Current Review—Planning
Documents." Accessed November 11.
http://www.epa.gOV/ttn/naaqs/standards/pm/s pm 2007 pd.html
U.S. EPA 2011o. "Human Health: Planning and Scoping." Accessed November 11.
http://www.epa.gov/oswer/riskassessment/human health plan.htm
U.S. EPA 2011p. "Ecological: Planning and Scoping." Accessed November 11.
http://www.epa.gov/oswer/riskassessment/eco plan.htm
U.S. EPA 2011q. "Risk and Technology Review." Accessed November 11.
http://www.epa.gov/ttn/atw/rrisk/rtrpg.html
U.S. EPA 2011r. EPA's Action Development Process. Guidance for EPA Staff on Developing Quality
Actions. Washington, DC. March.
http://vosemite.epa.gov/sab/SABPRODUCT.nsf/5088B3878A90053E8525788E005EC8D8/$File/a
dp03-00-ll.pdf
U.S. EPA 2012a. "Environmental Justice Policy and Guidance." Accessed May 24.
http://www.epa.gov/environmentaliustice/resources/policy/
U.S. EPA 2012b. "U.S. Environmental Protection Agency Scientific Integrity Policy." January 15.
http://www.epa.gov/research/htm/scientific-integrity.htm
U.S. EPA 2012c. "Science Inventory." Accessed May 24. http://cfpub.epa.gov/si/
U.S. EPA 2012d. "Public Involvement Policy and Related Documents." Accessed May 24.
http://www.epa.gov/publicinvolvement/public/
U.S. EPA 2012e. "Region 8 Site Conceptual Model." Accessed May 24.
http://www.epa.gov/region8/r8risk/hh_scm.html
U.S. EPA 2012f. "Process of Reviewing the National Ambient Air Quality Standards." Accessed May 24.
http://www.epa.gov/ttn/naaqs/review.html
U.S. EPA 2012g. "American Indian Environmental Office (AIEO)." Accessed May 24.
http://www.epa.gov/tribalportal/aieo/index.html
EPA RISK ASSESSMENT FORUM EXTERNAL REVIEW DRAFT
71
-------
U.S. EPA 2012h. "Office of the Science Advisor: Ethics, Regulations, and Policies." Accessed May 24.
http://www.epa.gov/phre/policv.htm
U.S. EPA 2012L "Risk Assessment Portal." Accessed May 28. http://www.epa.gov/risk/
U.S. EPA 2012J. "Dose-Response Assessment." Accessed May 28.
http://www.epa.gov/riskassessment/dose-response.htm
U.S. EPA 2012k. "Guidance & Tools." Accessed May 28.
http://www.epa.gov/risk assessment/guidance.htm
U.S. EPA 20121. "Cacodylic Acid." Accessed May 28.
http://www.epa.gov/opp00001/reregistration/cacodylic acid/
U.S. EPA 2012m. "Cumulative Risk Assessment Methods and Tools." Accessed May 28.
http://www.epa.gov/oppsrrdl/cumulative/methods tools.htm
U.S. EPA 2012n. "High Production Volume (HPV) Challenge: Robust Summaries and Test Plans."
Accessed May 28. http://www.epa.gov/hpv/pubs/summaries/viewsrch.htm
U.S. EPA 2012o. "IRIS Process." Accessed May 28. http://www.epa.gov/iris/process.htm
U.S. EPA 2012p. "Technology Transfer Network National Ambient Air Quality Standards (NAAQS)."
Accessed May 30. http://www.epa.gov/ttn/naaqs/
U.S. EPA 2012q. "Environmental Justice." Accessed May 30. http://www.epa.gov/environmentaliustice/
World Health Organization. 2008. Guidance Document on Characterizing and Communicating
Uncertainty in Exposure Assessment. Geneva, Switzerland.
http://www.who.int/ipcs/methods/harmonization/areas/uncertainty%20.pdf
EPA RISK ASSESSMENT FORUM EXTERNAL REVIEW DRAFT
72
-------
Appendix I. Examples of EPA Program-Specific Resources
and Guidance on Risk Assessment Activities
Air Toxics Program (Office of Air Quality Planning and Standards [OAQPS])
• Air Toxics Risk Assessment Reference Library for conducting air toxics analyses at the
facility and community-scale. The library provides information on the fundamental
principles of risk-based assessment for air toxics and how to apply those principles in
different settings as well as strategies for reducing risk at the local level.
o Volume 1: Technical Resource Manual
(http://www.epa.gov/ttn/fera/risk atra vol 1 .html)
o Volume 2: Facility-Specific Assessment
(http://www.epa.gov/ttn/fera/risk atra vo!2.html)
o Volume 3: Community-Scale Assessment
(http://www.epa.gov/ttn/fera/risk atra vol3.html)
• Residual Risk Report to Congress (http://www.epa.gov/ttn/oarpg/t3/reports/risk rep.pdf)
Hazardous Waste Program (Office of Solid Waste and Emergency Response [OSWER])
• Resource Conservation and Recovery Act Public Participation Manual
http ://www. epa. gov/wastes/hazard/tsd/permit/pubpart/manual. htm
National Ambient Air Quality Standards Program (NAAQS) (OAQPS)
• Process for NAAQS reviews, including role of risk assessment
(http://www.epa.gov/ttn/naaqs/review.html)
• Recent NAAQS risk assessments (http://www.epa.gov/ttn/fera/risk criteria.html)
• Current documents for NAAQS reviews (http://www.epa.gov/ttn/naaqs/)
Pesticides Program (Office of Pesticide Programs)
• Science Policy Issues and Guidance Documents
(http://www.epa.gov/oppfeadl/trac/science/)
• Public Participation in Registration Decisions. Washington, DC: Office of Pesticide
Programs, U.S .Environmental Protection Agency. 31 March 2010. -
http://www.epa.gov/pesticides/regulating/public-participation-process.html
• Models and Databases (http://www.epa.gov/pesticides/science/models db.htm)
• Public Participation Process for Registration Actions
(http://www.epa.gov/pesticides/regulating/public-participation-process.html)
EPA RISK ASSESSMENT FORUM EXTERNAL REVIEW DRAFT
73
-------
Safe Drinking Water Program (Office of Water)
• Public Access Information for the Safe Drinking Water Act
http://water.epa.gov/lawsregs/guidance/sdwa/upload/2009_08_28_sdwa_fs_30ann_public
involve web.pdf
Superfund Program (OSWER)
• Risk assessment resources and guidance
(http://www.epa.gov/oswer/riskassessment/risk superfund.htm)
• Supplement to RA GS Part A: Community Involvement in Superfund Risk Assessments
(1999)
(http://www.epa.gov/oswer/riskassessment/ragsa/pdf/ci_ra.pdf)
• Superfund Community Involvement Guidance and Publications
(http://www.epa.gov/superfund/community/involvement.htm)
EPA RISK ASSESSMENT FORUM EXTERNAL REVIEW DRAFT
74
------- |