U.S. EPA OFFICE OF THE ADMINISTRATOR
MEMORANDUM
SUBJECT: Cumulative Risk Assessment Guidance --
Phase 1 Planning and Scoping
Copies of this document and other guidance-oriented
information are available via the Internet on the
Brownfields Home Page at:
http://www.epa.gov/brownfields/gdc.htm#risk
As you are aware, the processes that EPA and others
follow to assess environmental risk are of great
interest to environmental professionals and to the
public, and growing attention is being given to the
combined effects of multiple environmental stressors.
Consistent with this, EPA and others are asking more
questions about the wider and more complex issues that
define a cumulative approach to risk assessment.
Today, we are providing guidance for all EPA offices
on cumulative risk assessment. This guidance directs
each office to take into account cumulative risk
issues in scoping and planning major risk
assessments and to consider a broader scope that
integrates multiple sources, effects, pathways,
stressors and populations for cumulative risk analyses
in all cases for which relevant data are available.
This assures a more consistent and scientifically
complete Agency-wide approach to cumulative risk
assessments in order to better protect public health
and the environment.
This approach provides a platform for significant
advances in our scientific approach to assessing
environmental risks. For most of our history, EPA has
assessed risks and made environmental protection
decisions based on individual contaminants, such as
lead, chlordane, and DDT, with risk assessments for
these chemicals often focused on one source, pathway
or adverse effect. Today, better methods and data
often allow us to describe and quantify the risks that
Americans face from many sources of pollution, rather
than by one pollutant at a time. We are increasingly
able to assess not simply whether a population is at
risk, but how that risk presents itself. In addition,
we are better able in many cases to analyze risks
by considering any unique impacts the risks may elicit
due to the gender, ethnicity, geographic origin, or
age of the affected populations. Where data are
available, therefore, we may be able to determine more
precisely whether environmental threats pose a greater
risk to women, children, the elderly, and other
specific populations, and whether a cumulative
exposure to many contaminants, in combination, poses a
greater risk to the public.
Of particular importance are the right-to-know
implications of this guidance, which requires that we
build opportunities for citizens and other
stakeholders to understand our ongoing risk
assessments, and to provide us with their comments.
Our goal is to ensure that citizens and other
stakeholders have an opportunity to help define the
way in which an environmental or public health problem
is assessed, to understand how the available data are
used in the risk assessment, and to see how the data
affect decisions about risk management.
Some Regions and Programs within the Agency are
already making significant efforts to use integrated
or cumulative risk assessment techniques, and this
guidance both reflects those practices and makes them
consistent across the Agency. The scope of integrated
risk assessments often involves coordination across
many program offices and statutory mandates for risk
analysis; for example, those called for under the new
safe drinking water and food safety laws. Therefore,
this guidance calls for ongoing communication among
risk assessors, risk managers, economists, engineers,
and other technical experts within the Agency.
While we can more consistently take into account many
new factors in this approach to risk assessment, many
other potentially important factors are more difficult
to include in our analyses, particularly the social,
economic, behavioral or psychological factors that
also may contribute to adverse health effects. These
include, among others, such factors as existing health
conditions, anxiety, nutritional status, crime and
congestion. Assessment of these factors is often
hampered by a lack of data to establish plausible
cause-and-effect relationships; difficulties in
measuring exposure, incidence and susceptibilities
related to these risks; and few methods for assessing
or managing these risks. This guidance does not
address these factors. We expect, nonetheless, that
this guidance will be updated as our understanding and
experience develop; and, the Agency is focusing its
research to improve our ability to incorporate these
broader concerns into our cumulative risk assessments
as new data and methods are brought forward.
For more information via the Internet, please
visit the EPA Brownfields Home Page at:
http://www.epa.gov/brownfields/