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5
How Risk Assessment and
Risk Management Relate to the
Sustainability Framework
As described in Chapter 4, risk assessment is an important analytic tool
used to evaluate the effects of environmental stressors on ecosystem and human
health. This tool has been applied over the past 25 years to facilitate manage-
ment of environmental threats and remains a key analytic method in support of
sustainability decision making, as envisioned by the Committee on Incorporating
Sustainability in the U.S. EPA.
The formal risk assessment and risk management framework derives from
a 1983 NRC report Risk Assessment in the Federal Government: Managing the
Process, now known as the Red Book (NRC 1983). The goal was to help federal
agencies, including EPA, make informed decisions about chemical agents in the
setting of a growing understanding and public concern about the link between
exposures to toxins and adverse effects, including cancer and birth defects. This
setting of growing understanding and growing concern is similar to that faced
by EPA in dealing with the challenges posed by the need for decision-making
processes that fully support sustainability goals.
The NRC Red Book considered risk assessment to be an input into risk man-
agement. Building on work done in the United States and around the world, the
four-step risk assessment paradigm was described as hazard identification, dose-
response assessment, exposure assessment, and risk characterization. Risk manage-
ment decisions were fully acknowledged to be based not only on risk assessment
but also on economic, legal, and other policy-based evaluations. The risk manage-
ment process involved development of regulatory options, and “evaluation of public
health, economic, social, and political consequences of regulatory options.” Those
evaluations plus the “risk characterization,” the fourth step of the risk assessment,
are weighed for agency decision and actions, as illustrated in Figure 5-1.
79
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80
FIGURE 5-1 Elements of risk assessment and risk management in the Red Book.
SOURCE: NRC 1983.
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HOW RISK ASSESSMENT AND RISK MANAGEMENT RELATE
EPA was over a decade old and had achieved many of its original objectives
before the formal risk assessment paradigm was proposed in the NRC Red Book.
EPA also needed the risk assessment paradigm to deal with risks that were below
what was readily observable—particularly cancer risks, which were and are of
great public concern (NRC 1983). EPA had already promulgated National Ambi -
ent Air Quality Standards for major air pollutants under the Clean Air Act based
on non-cancer health effects. This involved direct observations of epidemiologic
associations without inferring the existence of effects at air concentrations much
lower than ambient levels. Risk assessment enabled effective and defensible
decisions at more stringent levels corresponding to small but significant risks
and was a valuable adjunct to EPA’s existing “command and control” approach
to regulating overt pollution of air, water, and soil.
The elements of risk assessment were already in place and being used in
the United States and elsewhere, particularly for food and occupational health
issues related to chemicals, before the publication of the Red Book. The NRC
committee gathered ideas and did a superb job formulating a coherent approach.
The Red Book committee was particularly effective in articulating the strengths
and limitations of the various parts of the paradigm.
The NRC Red Book committee also had a major role in clearly defining key
terms, such as “risk” and “hazard.” The terms had been subject to various defini -
tions or were used interchangeably, complicating communication and develop -
ment of an agreed upon approach to risk issues. Also of note, the 1983 Red Book
was not immediately adopted within EPA or elsewhere. It required several years
for its general acceptance at EPA and its diffusion to state and local agencies.
INFERENCE GUIDELINES AND OPERATIONAL PROCEDURES
The Red Book (NRC 1983) stated that regulatory agencies had difficulty
making decisions about a chemical agent because of the “inherent limitations,”
particularly uncertainties, in the science and limited analytic capacity. To bridge
gaps in knowledge, the Red Book recommended that uncertainties be addressed
through default inference guidelines— “an explicit statement of a predetermined
choice among the options that arise in inferring human risk from data that are
not fully adequate or not drawn directly from human experience” (p.51). It ac -
knowledged the impossibility of distinguishing among such options based purely
on scientific observations. These inference guidelines were seen as a way to pro-
mote consistency in analyses and avoid manipulation of outcomes. A system of
guidelines, default options, and practice has developed over the years to support
assessment, and a recent NRC (2009) review of EPA’s risk assessment practice
endorsed and emphasized the need for a clear system of defaults to support
agency decision making.
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82 SUSTAINABILILTY AND THE U.S. EPA
LIMITATIONS OF THE RISK ASSESSMENT
AND RISK MANAGEMENT PARADIGM
EPA has had many successes in addressing the environmental problems of
significant concern in the 1980s when the risk paradigm was developed. Major
improvements in air and water are evident; wastes are being handled in ways less
likely to pollute soil and other media; substantially lower levels of dioxins and
polychlorinated biphenyls (PCBs) are present in the environment and in humans
(EPA 2008).
Yet it is evident that standard risk-based regulatory approaches have limita-
tions, including difficulty in dealing with complex problems that are not readily
addressed by analyses that seek to “simplify the multidimensionality of the risk
or make sense of the uncertainty” (NRC 1996) or require a volume of information
and analyses that far outstrip the resources available to provide them (NRC 2006).
Examples include global climate change (WHO 2003), environmental justice
(NRC 1996, 2009), green chemistry (NRC 2006), nanotechnology (GAO 2010),
and species loss. Recognition of the limitations in approaching these complex
issues has led to approaches to widen the risk paradigm, to include the context
in which the analysis is performed, the early consideration of a broad range of
decision options, and the cumulative threats of multiple social, environmental,
and economic stressors to health and the environment. These recent approaches
can be considered to be attempts to widen the risk paradigm so as to more readily
confront concerns that are central to sustainability.
Risk assessment as an analytic tool is limited in part because it works
best for those chemical and physical agents that have already been emitted, in
part because the nature and degree of exposure is better understood and can be
monitored. In terms used in public health, risk assessment is pertinent mostly to
secondary prevention (there already is a problem) rather than primary prevention
(the problem never occurs) which arguably is included within the Sustainability
Framework. Other issues include the inability to scientifically verify low-level
risks; significant delays in risk assessment, particularly at the national level
(NRC 2009); challenges to the toxicologic basis underlying risk assessment pre -
sented by agents such as nanoparticles (Tsuji et al. 2006) or endocrine disruptors
(Welshons et al. 2003); and the absence of data on hazard or exposure for quanti -
tative risk assessment (NRC 2009). Default assumptions developed or used in the
Sustainability Assessment and Management approach need to be evidence-based
and used according to current EPA policy.
EVOLUTION OF THE RISK ASSESSMENT AND
RISK MANAGEMENT PARADIGM
Risk assessment has been used by the agency as the main means for translat-
ing various types of biologic information about health effects of chemicals into
measures of harmfulness to people. The growing understanding from biomedical
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HOW RISK ASSESSMENT AND RISK MANAGEMENT RELATE
and toxicologic research on how chemicals contribute to disease, coupled with
better technologies and analytic tools for characterizing exposures, has resulted
in continuing calls for refinement in risk assessment.
The increasing understanding of how people might differ in their responses
to chemicals has led to calls for explicit treatment of human variability (NRC
1994, 2009) and vulnerable populations in risk assessment. The NRC’s (1993,
p. 3) finding that children are not little adults in terms of sensitivity and require
consideration in risk assessment resulted in changes in practice, some through
legislation. Along with genetics, preexisting health conditions also can drive
individual differences in response to chemicals. Psychosocial stress may also
influence risk (e.g., those exposed to violence have increased asthma in response
to traffic-related air pollution). Environmental chemicals can add to endogenous
exposures to agents that affect the same disease processes. All the above factors
have raised concerns about some of the underlying default assumptions used in
dose-response assessment and overall approaches to risk assessment (NRC 2009).
There has been tension over taking these factors into account because defaults
developed to address them may ultimately translate to greater stringency in risk
management, and there is uncertainty over how these factors translate to risk.
Coincident with calls for a fuller incorporation of variability in risk as -
sessment has been a push toward more sophisticated approaches toward uncer-
tainty assessment. Cautionary notes have been given regarding the “unknown
unknowns” and the limits of uncertainty analysis (NRC 1996). Approaches to
such limitations and to scale the analysis to the decision at hand (NRC 1996,
2007, 2009) have been advanced.
At the same time, the scope of assessment has expanded. Multiple, related
chemical exposures (NRC 2008), multiple environmental sources, psychosocial
stressors in underserved communities, and other aspects of vulnerability has led
to calls for cumulative risk assessment (NRC 2009). There is an explicit recog -
nition that the current quantitative risk assessment system of defaults and tech -
niques cannot address problems of such complexity adequately and that simpler
approaches are needed (Callahan and Sexton 2007; NRC 2009). Over time, ap -
proaches to formally assess ecologic risk conditions that take a systems perspec -
tive have emerged. Finally, the great number of chemicals of potential concern is
always increasing. The vast array of chemicals that are potential environmental
contaminants include synthetic chemistry products, industrial chemicals, off
releases from consumer products, combustion by-products, and environmental
transformation by-products following chemical release—an array too vast to ad -
dress by the chemical-by-chemical approach of toxicity testing in animals of each
health effect of concern and then predicting human risk (NRC 2006).
Nanomaterials share many of these same characteristics. A recognition of the
limited capacity to generate toxicity data to make evidentiary decisions about risk
led a 2007 NRC committee to recommend initiating a 10-20 year national effort
of developing new approaches for establishing the evidence base that would rely
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84 SUSTAINABILILTY AND THE U.S. EPA
to a large extent on toxicogenomic screens. To reduce the costs and facilitate the
development of new toxicity-testing approaches, interagency collaborations have
been established within the United States, and the United States has also been a
major supporter of, and contributor to, the OECD Chemicals Programme and its
work on the “Mutual Acceptance of Data” and “Code of Good Laboratory Prac -
tices” (Ruffing 2010). As a result of recent chemical registration requirement, it
is now apparent that over 100,000 chemical substances are in use in the European
Union (EC 2011), a number far greater than expected, albeit some are used in low
volumes. This finding provides further indication of the extremely limited capac -
ity of the current risk-based system to deal with chemical management needs.
Thus, although risk assessment provides a useful tool for looking at health effects
for a circumscribed problem in a systematic way, it may not be up to the task of
addressing many of the complex problems facing the agency.
The framework for risk-based decision making has been confused with risk
assessment. For some sectors in the nongovernmental and business communi-
ties, the term “risk assessment” is of concern. For environmentalists the term
can sometimes be code for license to pollute up to levels just below those that
would be labeled a de minimis risk under traditional risk assessment methodology
(Long et al. 2002). Further, the methodology may not account for all chemicals
of concern to the community (NRC 1996), for environmental hazards from other
facilities in the community, for community vulnerability (Morello-Frosch et al.
2011). Ultimately, risk assessment can be taken by the community as emblematic
of their powerlessness (Freeman and Godsil 1993). From the business community
perspective, risks just over a preset de minimis “bright line” can be characterized
harmful and result in costly mitigation measures (Long et al. 2002). The identifi -
cation of hazards even with vanishingly low exposures and risks can sometimes
be felt as stigmatizing and a liability for the business community. In implementa -
tion of some environmental programs, a bright line can translate directly to a risk
management response without consideration of other concerns (Goldstein 1993).
These experiences can lead to challenges of the risk assessment and the science
underlying it as a means to delay the possibility of costly actions.
Further the separation of risk assessment and risk management without
consideration of the specifics of the regulatory decision to be made has resulted
in protracted analyses that are not focused on the specific decision to be made.
To address these issues, the NRC (2009) recently altered the risk assessment and
risk management framework. As shown in Figure 5-2, risk assessment and other
analytic tools are used as approaches to discriminate among potential alternatives
or options for risk mitigation, identified early in the process.
The risk assessment and risk management paradigm forms the basis for
risk-based decision making within EPA programs, such as the legacy cleanup
programs Comprehensive Environmental Response, Compensation, and Liability
Act (CERCLA) and Resource Conservation and Recovery Act (RCRA) and in
standard setting programs, for example, NAAQS and maximum contaminant
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FIGURE 5-2 Framework for risk-based decision making.
85
SOURCE: NRC 2009
Figure 5-2
R01984 Sustainability in EPA, Green Book
bitmapped
scaled for landscape
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86 SUSTAINABILILTY AND THE U.S. EPA
levels (MCLs) set under the Safe Drinking Water Act. In these programs, factors
other than risk are also considered and are consistent with the risk management
framework in the Red Book (NRC 1983) and Science and Decisions (NRC 2009).
However, with risk reduction as the primary objective, full consideration has
generally not been given to all three sustainability pillars.
Here are two examples showing how factors other than risk are taken into
account in risk management—one from setting drinking-water standards and the
other from the legacy cleanup programs. In these programs, EPA often defines
an ideal goal. An analogue in the legacy cleanup programs is the setting of pre-
liminary remediation goals (PRGs)—starting points for setting cleanup levels in
soil. In this situation, the risk management decision may involve an assessment
of the technical feasibility of achieving a given goal. In comparing alternative
risk management options in the legacy cleanup programs, numerous factors can
be considered under the EPA National Contingency Plan. More explicit consid -
eration of sustainability factors is now being considered by EPA under its green
remediation strategy and is applied in some cases. Efforts have been accelerated
to perform cleanups in the most environmentally sustainable manner (e.g., renew-
able energy use, minimum waste generation, and reduction of life-cycle green-
house gas emissions) and to address environmental justice inequities. Analyses
to characterize risks to the community, costs, community improvements, and
trade-offs can provide the basis for choosing practicable management options
that mitigate significant risks while providing benefits for the surrounding com -
munity, and meeting other sustainability goals. Thus, elements of sustainability
assessment and thinking are increasingly being incorporated into environmental
remediation decision making.
As required by the Safe Drinking Water Act, a maximum contaminant level
goal (MCLG) of zero is specified for chemicals suspected of being carcinogens
and having linear dose response relationships. Zero is clearly an unattainable
goal. The actual enforceable standard, however, is based on a small number of
technical factors, such as analytic detection limits and cost, resulting in a regula -
tory standard—a Maximum Contaminant Level (MCL)—that is greater than zero.
For example, the MCLG for trichloroethylene is zero, but the MCL is currently
5 ppb.
THE INTERFACE BETWEEN THE RISK ASSESSMENT AND
RISK MANAGEMENT PARADIGM AND SUSTAINABILITY
The committee’s Statement of Task includes the question, “How can the
EPA decision-making process rooted in the risk assessment/risk management
paradigm be integrated into this new sustainability framework?” To respond to
this charge, the committee has separated risk assessment from risk management.
The four-step risk assessment paradigm will continue to be valuable in identify -
ing and managing risks, quantitatively or qualitatively. The conceptual approach
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HOW RISK ASSESSMENT AND RISK MANAGEMENT RELATE
to identifying an intrinsic hazard, understanding the link between the hazard and
an unwanted effect, calculating the extent to which humans or ecosystems are
exposed to that hazard, and characterizing the resultant risk in a manner pertinent
to policy makers and the public can be extended beyond the risk of chemical and
physical agents in the environment. It can also incorporate qualitative approaches
and other approaches to express risk or cumulative risks to address a wider
range of issues, but tools will be needed to make that a reality. Accordingly, the
committee reaffirms the value of risk assessment, finds it to be a useful tool for
sustainability, and encourages the further development of risk assessment tools,
such as to address cumulative risks, to improve its usefulness.
The committee notes that the term “risk management” is used in two ways:
as a formal description of EPA’s policies related to control of environmental
risks and as an informal term denoting any EPA approach to management of cur-
rent or potential threats. Sustainability goes beyond risk management in being
primarily concerned with maximizing benefit, while addressing risks of concern,
rather than being an exercise focused mainly on achieving de minimis risk. The
focus on de minimis risk sometimes includes risk-risk and risk-benefit trade-offs
in management decisions, but does not necessarily or typically encompass the
social (including health), environmental, and economic pillars of sustainability.
Risk management in either the formal or informal use of the term does not fully
encompass the sustainability paradigm in which the management of risk is per-
ceived as an opportunity to maximize benefits while controlling environmental
harm. Table 5-1 presents the committee’s comparison of key features of risk
assessment/risk management framework with sustainability.
The Sustainability Framework can include each of the basic elements of the
Red Book and recent (NRC 2009) risk assessment and risk management para -
digms. In some cases, however, a formal four-step risk assessment will not help
to discriminate among potential decision options and should not be performed.
For example, the time frame for the decision may not permit the type of data
gathering needed to support risk assessment, or the nature of the problem is
such that a risk assessment would be noninformative. For decision processes in
which four-step risk assessment is included, the Sustainability Framework can
be viewed as representing the risk paradigm expanded and adapted to address
sustainability goals, as illustrated in Figure 5-3, where the first two steps are
dealt with in Phase I.
Under the Sustainability Framework, in addition to considering possible
technology options to minimize risk, consideration of opportunities and options
for improvements along social, environmental, and economic dimensions would
also be elements corresponding to the risk assessment and risk management (RA/
RM) framework’s phase I, the problem formulation and scoping phase. Phase I
would also include identifying possible state, local, and other federal collabora -
tors that may participate in the project. Stakeholders—interested parties affected
by the decision—could help identify options.
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88 SUSTAINABILILTY AND THE U.S. EPA
TABLE 5-1 Differences Between Features of Risk Assessment and Risk
Management and Sustainable Development
Risk Assessment and
Feature Risk Management Sustainability
Relation to EPA Typically required An exercise of discretion in
statutes implementation of statutes
Driver Statutes and implementing Opportunity to reduce costs; increase
regulations; need to defend social, environmental, and economic
ultimate decision publicly and in benefits while meeting statutory
court requirements to mitigate risk
Questions to be What is the risk? What action How little harm is possible? How can
answered to take in face of risk? At times, we maximize social, environmental,
what is the result of cost–benefit and economic benefits?
analysis?
Number of decisions Typically fewer Could be coordinated suite of
to be made at one decisions affecting, e.g., a particular
time place
Number of agencies Less More
involved
Subject matter Pollutants and chemicals Social, environmental, and economic
factors (including not only pollutants
and chemicals but also, e.g.,
community, jobs, and quality of life)
Focal points Ecologic and health risks from Social (including but not limited to
chemicals public health), environmental, and
economic impacts
Metrics Typically quantitative (for human Quantitative and qualitative
health)
Formal assessment Typically yes No, but formal processes can be used
process required?
Who does it in EPA? Primarily risk assessors (e.g., Multidisciplinary and potentially
toxicologists, epidemiologists, multi-program teams; more
exposure assessors and sometimes collaboration with outside federal,
economists); program risk state, and local agencies
managers; limited collaboration
with external agencies
Stakeholders Beyond scientific peer review Generally more inclusive and
involved? and formal public notice and broader due to the questions
comment requirements, depends
on program
Nature of stakeholder Often part of routine public Discussion at many different levels;
involvement? comment and review more “outside the box”
Relationship among Often adversarial Potentially more collaborative
stakeholders
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HOW RISK ASSESSMENT AND RISK MANAGEMENT RELATE
FIGURE 5-3 Correspondence between sustainability assessment and management ele -
ments and risk assessment and risk management (RA/RM) framework.
5-3 new
Bitmapped
Corresponding to an RA/RM phase II under the Sustainability Framework in
addition to planning and conducting the risk assessment, other assessments would
be included to help discriminate among policy options. Analysis would address
critical social, environmental, and economic features associated with the differ-
ent options. Analyses of trade-offs between different features associated with the
different policy options would also be conducted. All analyses would be sized
in terms of intensity and scope to provide outcomes that enable selection across
options. It is in this phase that analyses would, if required or desirable, receive
technical peer review and stakeholder comment.
Corresponding to an RA/RM phase III under the Sustainability Framework,
the decision makers would deliberate on the results of these assessments, struggle
with trade-offs, and make decisions. The implementation of the decision would
be followed by an evaluation of its effectiveness.
FINDINGS AND RECOMMENDATIONS
5.1. Key Finding: The risk assessment and risk management frameworks
articulated by the NRC (1983-2009) are analogous with the committee’s
proposed Sustainability Assessment and Management approach. However,
differences in their overall goals how greater complexity in the Sustainability
Framework components of scoping, analysis, deliberation, and decision
making. The four-step risk assessment process, as envisioned by the NRC
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(1983) Red Book, is an important component and tool used to inform deci -
sions in the Sustainability Assessment and Management approach (p.86-89).
5.1. Key Recommendation: EPA should include risk assessment as a tool,
when appropriate, as a key input into its sustainability decision making.
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