B O S C
Board of Scientific Counselors
Report of the U.S. Environmental Protection agency
Board of Scientific Counselors
Human Health Risk Assessment (HHRA) Subcommittee
Responses to Charge Questions
Human Health Risk Assessment Subcommittee
Katrina Waters, Ph.D. (Chair)
Chris Gennings, Ph.D.
Jane Rose, Ph.D.
Pacific Northwest National Laboratory
Icahn School of Medicine at Mount Sinai
Procter & Gamble Co.
James Stevens, Ph.D. (Vice Chair)
Dale Johnson, Pharm.D., Ph.D., DABT
Gina Solomon, M.D., MPH
Paradox Found LLC
University of California, Berkeley;
Public Health Institute;

University of Michigan; Emiliem Inc.
University of California, San Francisco
Anthony Bahinski, Ph.D., MBA, FAHA
Daland Juberg, Ph.D., ATS
Ponisseril Somasundaran, Ph.D., MS
GlaxoSmithKline
Juberg Toxicology Consulting LLC
Columbia University; Somasundaran Inc.
Richard Becker, Ph.D., DABT
Juleen Lam, Ph.D., MHS, MS
Donna Vorhees, Sc.D.
American Chemistry Council
California State University, East Bay
Flealth Effects Institute; Boston University
Juan Colberg, Ph.D.
Timothy Malloy, J.D.
Clifford Weisel, Ph.D.
Pfizer Inc. Worldwide Research and
University of California, Los Angeles
Rutgers University
Development


Richard Di Giulio, Ph.D., MS
Jennifer McPartland, Ph.D.
MarkWiesner, Ph.D.
Duke University
Environmental Defense Fund
Duke University
EPA Contact
Tom Tracy, Designated Federal Officer
June 19, 2019
A Federal Advisory Committee for the U.S. Environmental Protection Agency's Office of Research and Development

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BOSC HHRA Subcommittee Report | June 19, 2019
Disclaimer Text. This report was written by the Human Health Risk Assessment (HHRA) Subcommittee of the Board of
Scientific Counselors, a public advisory committee chartered under the Federal Advisory Committee Act (FACA) that
provides external advice, information, and recommendations to the Office of Research and Development (ORD).This report
has not been reviewed for approval by the U.S. Environmental Protection Agency (EPA), and therefore, the report's
contents and recommendations do not necessarily represent the views and policies of EPA, or other agencies of the federal
government. Further, the content of this report does not represent information approved or disseminated by EPA, and,
consequently, it is not subject to EPA's Data Quality Guidelines. Mention of trade names or commercial products does not
constitute a recommendation for use. Reports of the Board of Scientific Counselors are posted on the Internet at
httpi//www, epa.gov/bosc.

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BOSC HHRA Subcommittee Report | June 19, 2019
Contents
List of Acronyms	iv
Background	5
StRAP Research Objectives	5
Charge Questions and Context	5
Subcommittee Responses to Charge Questions	6
Charge Question 1	7
Feedback	Error! Bookmark not defined.
Charge Question 2	8
Feedback	Error! Bookmark not defined.
Charge Question 3	8
Feedback	9
Charge Question 4	9
Feedback	10
Overall Suggestions/Other Considerations	Error! Bookmark not defined.
Conclusions	10
Appendix A: Meeting Agenda	11
Appendix B: Materials	12
Material Provided in Advance of the Meeting	12
Additional Material Provided During the Meeting	12

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BOSC HHRA Subcommittee Report | June 19, 2019
List of Acronyms
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BOSC HHRA Subcommittee Report | June 19, 2019
Background
The mission of the Environmental Protection Agency (EPA) Office of Research and Development (ORD) is
to provide the best available science and technology to inform and support public health environmental
decision-making at the Federal, state, tribal, and local levels, addressing critical environmental challenges
and anticipating future needs through leading-edge research. ORD prepares Strategic Research Action
Plans (StRAPs) to guide its research planning over the ensuing 4 years, and beyond. The EPA plays a central
role in evaluating potential impacts of chemicals on human health and the environment. EPA's objectives
are to provide efficient, transparent, and scientifically robust approaches to evaluating chemical safety
and to continually improve these approaches in response to scientific and technological advancements.
To achieve this, EPA applies advanced toxicological and exposure methods, data, tools, models, and
information access to make better informed and more timely decisions about the safety of chemicals,
many of which have not been thoroughly evaluated for potential risks to human health and the
environment. The Human Health Risk Assessment (HHRA) National Research Program advances the
scientific basis for risk assessments, including development of contemporary hazard identification and
dose-response evaluations, and evaluation of new data and science (such as those developed through the
CSS program) for advancing to risk assessment practice.
HHRA develops a portfolio of fit-for-purpose assessment products that meet the expressed needs and
priorities of customers, including EPA program offices and regions, states, and tribes. Assessment
priorities may be federally mandated by Congress (e.g., criteria air pollutants) or Agency programs and
regions (e.g., IRIS and PPRTV priorities), and are typically peer reviewed by other advisory committees,
such as the Science Advisory Board (SAB), the SAB Clean Air Scientific Advisory Committee (CASAC), and
the SAB Chemical Assessment Advisory Committee (CAAC). The focus of the BOSC CSS-HHRA
Subcommittee review is the foundational research described in the StRAP document, which underpins
HHRA's vision to advance the science and practice of risk assessment to support the EPA programs and
regions, states, and tribes.
The HHRA StRAP document is now in internal EPA development/review and will be transmitted to the
BOSC for review after the April 2019 Subcommittee meeting. During the April BOSC meeting, initial
feedback is requested on the overall strategic direction of HHRA, based on materials provided at the
meeting, including an overview of the program and posters/demonstrations showcasing the foci of
planned research. The BOSC review will be guided by the HHRA Charge Questions listed below. The BOSC
Subcommittee will complete its review of HHRA following transmittal of the StRAP, later this summer.
StRAP Research Objectives
Draft StRAP document was not provided.
Charge Questions and Context
The HHRA Subcommittee was charged with four questions as follows:
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BOSC HHRA Subcommittee Report | June 19, 2019
Q.1: Does the research outlined for the 2019-2022 timeframe support HHRA's ability to deliver
the range of assessments the Agency is requiring?
Q.2: Does the StRAP overview as presented, including the topics, research areas, and proposed
outputs, clearly describe the strategic vision of the program? Given the environmental problems
and research objectives articulated, please comment on the extent to which the StRAP provides
a coherent structure toward making progress on these objectives in the 2019-2022 timeframe.
Q.3: HHRA has been collaborating with CSS on laying the foundation for future risk assessments.
Please comment on the extent to which HHRA research is prepared to use novel data streams and
tools, such as those from CSS, to advance the future of assessment science.
Q.4: Recognizing ORD's focus on addressing identified partner research needs, are there any other
critical emerging assessment-related needs or fields of expertise and/or new research methods
where this program should consider investing resources?
Subcommittee Responses to Charge Questions
The value of HHRA expertise and products to EPA partners and stakeholders is tangibly evident to the
BOSC. For example, as described in the poster, HHRA Science Assessment Translation and Support, HHRA
manages two of ORD's Technical Support Centers (TSCs): Superfund Human Health Risk Technical
Support Center (STSC) and Ecological Risk Assessment Support Center (ERASC). Through STSC, HHRA is
able to provide critical technical support to regions, other federal agencies, and even international
entities. For example, in response to a request from Region 2, HHRA provided technical assistance in
developing relative potency factors, using expert driven-read across approaches, for chemicals of
interest lacking toxicity values. The same poster also described how HHRA provides key technical
support to program offices such as the Office of Water, Office of Air and Radiation, and Office of
Chemical Safety and Pollution Prevention.
HHRA's commitment to educating agency partners and other stakeholders on the application of
systematic review in environmental health is commendable and should be continued and further
strengthened. Systematic review is a tool for increasing transparency, rigor, and consistency of chemical
assessments and has been recommended by several National Research Council reports, Science and
Decisions (2009); Phthalates and Cumulative Risk (2008); and Review ofEPA's Integrated Risk
Information System (IRIS) Process (2014). In recent years, HHRA has been at the forefront of developing
and implementing systematic review methodology for chemical assessment. HHRA has established a
"Community of Practice" for systematic review within EPA that has also been recently extended to other
federal agencies. HHRA is also providing systematic review training to scientists in federal and state
agencies. These engagements provide valuable opportunities for HHRA to build the environmental
health systematic review community, and maintain a leadership position in advancing systematic review
methods for chemical assessment.
Based solely on HHRA presentations, posters, and demonstrations, the research areas and proposed
outputs appear to align well with the vision of the program. While the HHRA research outputs appear
relevant to the HHRA vision, specific research activities are not yet articulated so it is difficult to
determine if they will meet their objectives. The committee anticipates that HHRA will clearly articulate
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the research activities that will be undertaken in its StRAP during the next review meeting so that the
linkage between execution and output can be seen. One particular missing feature of the vision was
highlighted repeatedly regarding the importance of prioritizing and continuing research on chemical
mixtures in both CSS and HHRA subcommittee discussions. Such research is critical to assessing real-
world impacts of chemical exposures. The committee recommends that mixtures research and work on
cumulative risk assessment be an explicit component of both research programs.
Specific areas of strength as well as suggestions for the HHRA StRAP are described below.
Charge Question 1
Q.l. Does the research outlined for the 2019-2022 timeframe support HHRA's ability to deliver
the range of assessments the Agency is requiring?
Feedback
•	HHRA demonstrated impressive increased output and efficient use of time in generating work
products, for instance by employing literature search capabilities that capitalize on recent advances
in machine learning. The machine learning software employed prioritizes search results so that
screeners review studies that are most likely to be most relevant to the study question first, and
continually updates the prioritization order by learning as screeners review studies. During the
presentations, HHRA also highlighted potential interest in collaborations with external entities, such
as IBM Watson, to further enhance and integrate machine-learning capabilities into its workflows.
We encourage the continued use of machine learning to streamline the identification of relevant
literature and data in systematic review to the greatest extent possible.
•	HHRA research to advance approaches for the derivation of risk-specific doses for noncancer effects
is impressive and directly responsive to two National Research Council reports, Science and
Decisions (2009) and Review of the IRIS Program (2014). Specifically, HHRA is developing case
examples using the APROBA methodology developed by the World Health Organization (WHO)
International Program on Chemical Safety (IPCS)—a methodology for calculating probabilistic RfD
estimates (see poster: Quantitative Noncancer Risk: IPCS Approach to Uncertainty). Furthermore,
plans to integrate the APROBA methodology into the EPA's BMDS software in future versions will
increase the accessibility and ease of use of this novel approach for the Agency as well as external
users.
•	Another strength of HHRA research efforts is the use of freely available software programs with data
sharing capabilities such as SWIFT-Review and HAWCthat can be used both by agency partners and
external stakeholders for chemical assessment work, as well as the creation of open databases like
HERO for literature searching, reference tracking and organization, and tagging. Use of free and
open chemical assessment tools such as these increases the transparency, reproducibility, and
efficient updating of HHRA assessments products and also increases their accessibility and utility to
partners and stakeholders.
•	Development of improved uncertainty methods is an important advance that will contribute to
analysis of future issues dealing with multiple exposures and sensitive populations.
•	The BOSC notes that HHRA has been developing and institutionalizing work flows that are problem
formulation-driven and fit-for-purpose so that there is strong alignment of HHRA applied research
projects with the specific decision contexts of the programs they serve. This will enable
identification and selection of case-specific tools and methods that will help to optimize HHRA's
investment of resources to achieve the applied research objectives in a timely manner.
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•	So far in fiscal year 2019, HHRA staff have reported over 4,000 hours of support, on a broad array of
issues, to program and regional offices. The availability of concrete, on-demand, hands-on support
from HHRA to agency partners is a strength and to be commended.
Charge Question 2
Q.2. Does the StRAP overview as presented, including the topics, research areas, and proposed
outputs, clearly describe the strategic vision of the program? Given the environmental problems
and research objectives articulated, please comment on the extent to which the StRAP provides
a coherent structure toward making progress on these objectives in the 2019-2022 timeframe.
Feedback
•	The BOSC notes that the previous HHRA StRAP included objectives to evaluate mixtures, including
chemical and non-chemical stressors, to support cumulative risk assessment. The 2016 report of the
BOSC particularly commended these efforts. The presentations at this meeting did not clearly reflect
that HHRA is continuing to prioritize research on methods that could apply to mixtures or
cumulative exposure and toxicity assessments. The potential risk from what is known as the 'cocktail
effect', caused by mixtures of chemicals at low levels, needs to be investigated and the risk to
human health better understood. For example, the NAS recommended use of cumulative risk
assessment for phthalates, but the poster presentations appeared to be evaluating phthalates
individually. Moreover, the BOSC was advised that work on phthalates had been stopped despite
clear guidance to pursue such analyses by the National Academies. At a minimum, the StRAP for
HHRA (and other programs) needs to anticipate that such policy shifts will occur and explain how
the agency will maximize the benefit of work completed to date.
•	The HHRA StRAP should clearly specify what falls within and outside of its scope of work as it relates
to risk assessment and the exposure and toxicity data that informs such assessments. This clarity will
allow the BOSC to provide guidance better targeted to HHRA's charge. For example, HHRA's poster
presentations focused more on toxicity than exposure. The 2016-2019 StRAP emphasizes exposure
assessment with "Science Challenge 2" to [bjroaden exposure assessment technology with exposure
factors for translation of exposure, bioavailability, and dose estimates (both human and ecological)
to flexibly address different exposure scenarios." It would be helpful to clarify the extent to which
exposure considerations are within the purview of the HHRA research program.
•	The BOSC supports the integration of human health risk assessment with ecological assessment, but
it will be important to describe in the StRAP how such integration will occur.
•	HHRA has invested in educating and training agency partners and other stakeholders on the
application of systematic review for chemical assessment. In the HHRA StRAP, the committee would
like to see these efforts further developed in a way that clearly supports the HHRA vision.
Specifically, we recommend that the StRAP include concrete examples of how training will be
developed and deployed into the future.
•	The BOSC commends the documentation of requests for technical assistance. HHRA should consider
analyzing the requests that come in from the regional offices and other partners and stakeholders to
identify areas of need in furtherance of science challenges specified in the 2016-2019 StRAP: (1)
"Enhance data access and management systems to support transparency and efficiency" and (2)
"Develop and apply effective methods for stakeholder engagement and risk assessment training to
varied audiences." HHRA could then develop action plans in the StRAP to more systematically
address the identified areas of need, which would ideally be summarized in an appendix to the
StRAP.
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Charge Question 3
Q.3. HHRA has been collaborating with CSS on laying the foundation for future risk assessments.
Please comment on the extent to which HHRA research and program deliverables are prepared
to use novel data streams and tools, such as those from CSS, to advance the future of assessment
science.
Feedback
•	Overall, the BOSC was very impressed with the vision for some coordinated development of
products with CSS (e.g., RapidTox). The decision context will inform the complexity of the analyses
and the degree to which HHRA needs to depend on or utilize the variety of tools/approaches offered
by CSS research (i.e., there is no requirement for HHRA to utilize or overlay its assessment sciences
approaches on all available research initiatives currently developed or being developed by CSS).
•	HHRA is making strides outlining the use of CSS tools, such as BMD software improvements to
incorporate ToxCast data for chemicals with good animal toxicology data, as well as application of
read-across methods, transcriptomics, and other tools to identify appropriate surrogate toxicity
information. These efforts should be continued and expanded, with greater interaction among staff
in the two programs defined through specific use cases. Conversely, CSS could benefit by using some
of the technology being successfully leveraged by HHRA, such as machine learning software,
something that has apparently resulted in a 60% increase on productivity for selected HHRA
activities.
•	HHRA should also look beyond CSS and be prepared to evaluate the scientific confidence of other
novel data streams and tools, and, as appropriate, use these to meet the specific design needs of
HHRA assessments. Examples include NTP initiatives, models or methods developed by academics,
other scientific experts and research institutions, etc.
•	HHRA's proposed Research Area 3, Emerging and Innovative Assessment Methodologies, includes
three research outputs that are directly oriented around advancing the incorporation of new
approach methodologies (NAMs) into chemical assessment. The committee views such effort as a
valuable and important component of HHRA's research agenda. Already, there are clear efforts by
HHRA to integrate CSS products into the practice of chemical assessment as conveyed through
posters, demos, and the presentation by the HHRA national program director. For example, the
poster, New Approach Methodologies in Human Health Risk Assessment, illustrated how HHRA is
exploring the use of three different types of NAMs—read across, transcriptomics, and high-
throughput in vitro testing—in chemical assessment for purposes ranging from analogue selection to
AOP development and BMD modeling of dose-response gene expression data.
•	Acknowledging that HHRA is already taking steps to include use of NAMs into its chemical
assessment work and research, the committee suggests that HHRA identify specific case studies that
it will pursue to examine different applications of NAMs in chemical assessment. For example, HHRA
could pursue case studies that showcase how NAMs may be used to build confidence in chemical
assessments, the extent to which NAMs can or cannot be used as stand-alone for decision-making,
and how NAMs may be employed in the assessment of chemical mixtures. A specific research
activity discussed at the in-person meeting involved taking an existing set of PPRTV values and
comparing such values with those derived solely using NAMs. In general, research and case study
development around the use of NAMs in chemical assessment should explicitly include exploration
of the application of CCS products. Case studies would help to build collaborations and lines of
communication between HHRA and CSS.
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Charge Question 4
Q.4: Recognizing ORD's focus on addressing identified partner research needs, are there any other
critical emerging assessment-related needs or fields of expertise and/or new research methods
where this program should consider investing resources?
Feedback
•	The previous 2016-2019 HHRA StRAP included a research focus on epigenetic and other
susceptibility factors in risk assessment. Specifically, it described "Science Challenge 8: to [e]xpand
CRA [cumulative risk assessment] methods to advance "place-based" community risk
characterizations, apportion multimedia exposures and risk to various receptors, incorporate
multiple stressors, consider epigenetics and susceptibility, and support multi-criteria decision
analysis and sustainability." The BOSC previously commended this area of research, and it remains
important for improving the toxicity evaluations that support risk assessments, especially those
involving children and other vulnerable subpopulations. An epigenomic risk assessment approach
should be addressed by the new HHRA StRAP.
•	Under the funding Programme Horizon 2020, the EU has started to address the issue of mixtures. As
reported by Bopp et al (Environment International 120 (2018) 544-562), there are several projects
working on "developing methodologies to better assess chemical mixtures, by generating and
making available internal and external exposure data, developing models for exposure assessment,
developing tools for in silico and in vitro effect assessment". Projects like EDC-MixRisk, EuroMix,
EUToxRisk, HBM4EU and SOLUTIONS are already working on this and their model could be a way for
the EPA to address developing solutions to this issue under reduced resources and funding. The
BOSC suggestion is for the EPA to evaluate the feasibility of collaborating with the EU on this project.
•	Progress to date on developing systematic review methods is impressive, and the BOSC strongly
supports continuation of this work with strong processes for assessing risk of bias. HHRA should
focus some effort on the development of improved methods to incorporate mechanistic studies into
systematic reviews (including grading such studies at the evidence integration phase).
•	CSS and other ORD programs are evaluating some important emerging issues (e.g., 3-D printers,
algal blooms, microplastics) that could benefit from HHRA research that is conducted in coordinated
fashion with the other efforts, if resources permit.
•	Important to public health is inter-agency coordination (CPSC, FDA, EPA) focused on risk evaluation
of compounds that fall across intra-agency purviews. For example, phthalates are present in
consumer products, enteric coating in oral medication, and cosmetics. HHRA should work with
other agencies to coordinate assessments based on human relevant exposure and risk estimates.
Perhaps biomonitoring data (e.g., NHANES) can be used to demonstrate population level exposure
estimates to single compounds and mixtures. Further, the HHRA should work with international
groups focusing on grouping chemicals in hazard and risk assessments (e.g., policies on EDCs in the
EU; the mixtures mandate in the HBM4EU).
Conclusions
Consensus conclusions will be completed after the formal review of the StRAP document.
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Appendix A: Meeting Agenda
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BOSC HHRA Subcommittee Report | June 19, 2019
Appendix B: Materials
Material Provided in Advance of the Meeting
Materials to Support the Charge Questions
•	Bulleted list
Informational Materials
•	Bulleted list
Additional Material Provided During the Meeting
•	Bulleted list
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