UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
WASHINGTON, D.C. 20460
MAR 1 7 2004
OFFICE OF THE
SCIENCE ADVISOR
MEMORANDUM
SUBJECT: EPA Risk Assessment Principles and Practices
FROM: Paul Oilman
EPA Science Advisor
TO: Assistant Administrators
General Counsel
Associate Administrators
Regional Administrators
The document entitled An Examination of EPA Risk Assessment Principles and Practices
represents an effort by EPA to examine how risk assessment is conducted at the Agency
(available at www.epa.gov/osa). The EPA Risk Assessment Task Force, a group of risk
assessment professionals from across the Agency, was assembled to perform this examination.
The document is an EPA Staff Paper which presents the perspectives of EPA risk assessors on
how they understand risk assessment to be conducted at the Agency. Further, it presents staff
recommendations for EPA and interested stakeholders to consider for how EPA can move
forward with strengthening and, where appropriate, improving its risk assessment practices.
This staff paper does not represent official EPA policy.
Stephen Johnson, Acting Deputy Administrator, Jessica Furey, AA Office of Policy,
Economics, and Innovation, and I requested this report to further the discussion and examination
of some broad questions about risk assessment. The contents of this staff paper are, in large part,
presented in response to public comments submitted to the Office of Manageme'nt and Budget
(OMB) on EPA's risk assessment practices'. Several comments highlighted concerns that EPA
risk assessments are overly conservative and lacking in transparency. Other comments suggested
that EPA's risk assessments are appropriately conservative - or in fact are insufficiently
protective of public health - and noted that conservative defaults provide an incentive for
generation of data to address uncertainties. While this report is not explicitly a "response to
In a February 3, 2003, Federal Register notice, the Office of Management and Budget requested public
comment on "ways in which 'precaution1 is embedded in current risk assessment procedures through 'conservative'
assumptions in estimation of risk" and "Examples of approaches in human and ecological risk assessment...which
appear unbalanced."
Internet Address (URL) • hltp://www.epa.gov
Recycled/Recyclable * Printed with Vegetable Oil Based Inks on 100% Postconsumer, Process Chlorine Free Recycled Paper
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comments" document, the comments to OMB were used to suggest practices that the staff paper
could address.
The Task Force's review is considered supplementary to other activities, such as revisions
to EPA's risk assessment guidelines. Instead of addressing the specific issues targeted in other
activities, the Task Force was charged with taking a broader look across EPA's risk assessment
principles and practices, and with considering several issues as they relate to EPA risk
assessment in general. Among the latter issues are questions such as:
a) Is science policy mixed into the risk assessment process or not?
b) Are EPA risk assessments sufficiently transparent in dealing with uncertainty and
variability as well as identifying default assumptions when used in risk
assessments?
c) When data are not available, are the utilized default assumptions applied in such a
way that the resulting risk estimates are reasonable and not unrealistic
overstatements of risk?
d) Are there characteristics of risk assessment that may result in risk, underestimation
that EPA should be addressing?
The Task Force has further developed a set of recommendations based on its review.
Some of the recommendations focus on increasing the certainty and confidence in EPA risk
assessments, including development of more specific data relevant to a decision and ensuring
that defaults that are invoked are themselves scientifically supported. Other recommendations
encourage greater transparency and clarity in EPA risk assessment practices and the risk
management process, such as greater use of planning and scoping and close attention to our
existing guidance (e.g., Risk Characterization Policy and Handbook). Some specific
recommendations include greater use of probabilistic analyses where appropriate (and
development of these techniques where EPA has not traditionally used them), greater cooperation
with EPA partners in risk assessment (e.g., states, foreign governments, affected stakeholders),
and a constant vigilance to our peer review efforts. These recommendations will be critical in
helping EPA update its agenda for further development of risk assessment practices. They will
also be critical in augmenting key current activities, such as finalization of the cancer risk
assessment guidelines revisions and the harmonization of human health risk assessment
approaches.
Most important for the near future, this staff paper will serve as a vehicle for opening up a
broader dialogue among EPA staff, EPA managers and external parties about the practice of risk
assessment at EPA. Several activities may take place as a part of this dialogue, including
possible workshops with EPA's Science Advisory Board or other external groups, such as the
National Academy of Sciences, on promising areas for further development of EPA risk
assessment practices. Also, meetings with states, non-governmental organizations, tribal groups,
professional societies and other interested parties to seek their input and suggestions can be
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sought. This staff paper represents the first step in a multi-step process geared towards
advancing risk assessment principles and practices at EPA. Newer and better approaches for risk
assessment may emerge as the dialogue proceeds.
cc: Stephen Johnson
Deputy Assistant Administrators
Deputy Regional Administrators
Science Policy Council
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