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HUMAN HEALTH
RISK ASSESSMENT
Background
Every day, the U.S. Environmental
Protection Agency (EPA) must make
decisions about environmental pollutants
that impact human health and the
environment. These decisions span a
complex regulatory landscape. The
Human Health Risk Assessment (HHRA)
program informs Agency decisions by
providing state-of-the-science products in
support of risk assessment., Examples of
HHRA products include independently
peer reviewed human health
assessments for individual chemicals and
chemical mixtures; integrated science
assessments for criteria air pollutants;
rapid risk assessments and technical
support to meet partner and stakeholder
needs; and tools to modernize human
health risk assessment,
The HHRA program is comprised of four
integrated topics, which provide a critical
part of the scientific foundation for much
of EPA's decision-making (e.g. site
specific cleanups, regulations), enabling
the Agency to better predict and prevent
risk, The work conducted by the HHRA
program responds directly to the needs of
EPA's program and regional offices, as
well as to issues of shared concern
among the broader risk assessment
community,
Topic 1: Integrated Risk Information
System (IRIS)
The Integrated Risk Information System
(IRIS) topic develops peer- reviewed,
qualitative and quantitative health hazard
and dose-response assessments on
environmental pollutants of relevance to
U.S. Environmental Protection Agency
Office of Research and Development
EPA's regulatory mandates, IRIS
assessments, which are publicly
available atwww.epa.gov/iris. are widely
used by EPA's programs and regions, as
well as by states, international
organizations, and the public, to support
decision-making.
EPA and the risk assessment/risk
management community consider IRIS
the premier source of hazard and dose-
response information for environmental
pollutants, IRIS assessments receive
public comment and are subject to
rigorous independent peer review.
In May 2009, EPA revised the IRIS
process to streamline and accelerate
completion of critical assessments.
Additional improvements to ensure the
continued use of the best and most
transparent science were announced in
July 2011. In July 2013, in response to
recommendations made by the National
Research Council, EPA announced
additional changes to the IRIS Program to
improve the science of assessments,
improve the productivity of the Program,
and increase transparency so issues are
identified and debated early in the
process,
Other key components of this topic
include continued improvements to the
IRIS Program and database and updating
old or outdated IRIS assessments to
ensure they reflect the most currently
available peer-reviewed science.
Scientists in the HHRA program also
provide critical technical support to EPA's
program and regional offices in the areas
of statistics, pharmacokinetic modeling,
and mode- or mechanism-of-action.
Topic 2: Integrated Science
Assessments (ISAs)
Understanding the current science about
the health and welfare effects of air
pollutants is a critical Agency need to
support decisions about the National
Ambient Air Quality Standards (NAAQS).
To meet this need, scientists in the
HHRA program develop Integrated
Science Assessments (ISAs) that
synthesize the latest available, relevant
science on the health and welfare effects
of the six criteria air pollutants—ozone,
particulate matter, sulfur dioxide, nitrogen
oxides, carbon monoxide, and lead.
ISAs are major assessments that
undergo rigorous external peer review by
the Clean Air Scientific Advisory

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Committee (CASAC) and provide the
scientific-basis for the Administrator's
decisions for the NAAQS. Statutory
requirements mandate the development
of ISAs on a five-year cycle.
This topic area also includes the
development of Multipollutant Science
Documents (MSDs) that are an important
step in understanding and characterizing
the health and welfare impacts of
exposure to mixtures of air pollutants.
The MSDs are being developed with
scientists in EPA's Air, Climate, and
Energy research program and EPA's
program office partners.
In May 2009, EPA revised the NAAQS
process to speed development of these
assessments and supporting documents
(www.epa.gov/naaqs). The Office of
Management and Budget (OMB) and
EPA estimate that attainment of the
NAAQS offers significant health and
environmental benefits to the public, such
as fewer adverse health effects,
improved visibility, and less damage to
agriculture and vegetation.
Topic 3: Community and Site-Specific
Risk
Communities are often faced with an
urgent need for coordinated assistance to
assess and address issues of chemical
and other environmental contamination.
EPA's HHRA program, in collaboration
with the Homeland Security research
program, is often called upon to assist in
these situations to provide the science to
support decision-making at cleanup sites,
develop tools to help understand risks to
impacted communities, or supply rapid
responses to ensure that decision-
makers have the tools they need to
address evolving community concerns
about environmental chemicals.
For example, after the BP oil spill,
Hurricane Katrina, and the Freedom
Industries chemical spill in West Virginia,
HHRA scientists provided rapid risk and
exposure assessment support to help
EPA better understand the potential risk
of these environmental emergencies.
The routine development of Provisional
Peer Reviewed Toxicity Values (PPRTV)
provide EPA's Office of Land and
Emergency Management (OLEM) with
needed toxicity values that provide a
scientific basis for decision-making in
communities, such as clean up decisions
at contaminated Superfund sites.
HHRA scientists are also working to
better understand how nonchemical
stressors - such as socioeconomic status
- may impact health effects resulting
from exposure to environmental
chemicals. This effort will better position
the Agency to respond to community
environmental justice concerns.
Taken together, work under this topic
area helps ensure that EPA has the tools
and information they need to make timely
decisions and address community
concerns. Ultimately, projects conducted
under this theme will help EPA meet its
mission to protect human health and
clean up contaminated communities,
including reducing risks for sensitive
populations.
Topic 4: Advancing Analyses and
Applications
Advances in molecular and systems
biology are changing the landscape of
human health and ecological risk
assessment. Additionally, several recent
and important reports from the National
Research Council highlighted unmet risk
assessment needs and suggested
developing new approaches to advance
risk assessment using alternative
technologies and data emerging from
various programs in the United States
and internationally.
Work under this topic focuses on
translating new research in molecular
biology and computational sciences, such
as that being conducted under EPA's
Chemical Safety for Sustainability
Program, into practical applications for
developing hazard and dose-response
assessments - a critically important step
for advancing risk assessment. This work
impacts not only the development of
IRIS, ISA, and PPRTV assessments, but
also helps the Agency to rapidly assess
and address emerging problems.
Key elements of this work also include
designing and implementing tools to
make developing hazard and dose-
response assessments more efficient;
providing support and training for risk
assessment through the Health and
Environmental Research Online (HERO)
database (http://hero.epa.gov/) and the
Risk Assessment Training and
Experience (RATE) program; and the
implementation of workshops and public
meetings to discuss and evaluate specific
scientific issues. Collectively, work in this
topic will allow EPA to develop hazard
and dose-response assessments more
effectively and transparently.
CONTACT:
Tina Bahadori, Sc.D.
National Program Director
(202) 564-7903, bahadori.tina@epa.gov
Samantha Jones, Ph.D.
Interim Deputy National Program Director
(202) 564-6794, iones.samantha@epa.gov
Lou D'Amico, Ph.D.
Acting Associate Director for Policy and
Communications
(202) 564-4605, damico.louis@epa.gov
Kirkley Cain
Program Analyst
(202) 564-4131, cain.kirklev@epa.gov
Anna Champlin
Science Communication and Coordination Lead
(202) 564-8074, champlin.anna@epa.gov
Web site: https://www.epa.gov/aboutepa/about-
human-health-risk-assessment-program
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U.S. Environmental Protection Agency
Office of Research and Development

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