UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
WASHINGTON D.C. 20460
OFFICE OF THE ADMINISTRATOR
SCIENCE ADVISORY BOARD
October 26, 2004
EPA-SAB-COM-05-001
The Honorable Michael O. Leavitt
Administrator
U.S. Environmental Protection Agency
1200 Pennsylvania Avenue, N.W.
Washington, D.C. 20460
Dear Administrator Leavitt:
On July 26, 2004, EPA offices provided a series of informative presentations to the
Environmental Health (EHC) and Integrated Human Exposure (IHEC) Committees of the
Science Advisory Board (SAB). The focus of the presentations was on the human health aspects
of the staff paper titled, "Examination of EPA Risk Assessment Principles and Practices." The
SAB would like to express its sincerest thanks to the presenters for their expertise, perspectives
and insights. Their contributions greatly increased our understanding of the Agency's risk
assessment policies, methods, current practices and future directions. We hope to continue
working with the Agency to explore ways by which the SAB can assist in enhancing its risk
assessment methods.
From these presentations and discussions, two key messages were conveyed that the SAB
believes are worthy of its explicit support. The first is the Agency's stated paradigm shift that
would require the use of available and relevant data instead of default assumptions; only in the
absence of such data would default assumptions be invoked. This is expected to reduce the
current primary reliance on default models and assumptions as the basis of decision-making.
This new approach will have the benefit of encouraging data generation by the scientific
community, thereby, broadening the knowledge base and potentially reducing uncertainty in risk
assessment. As pointed out by EPA representatives, this shift is already articulated in the 2003
Draft Final Guidelines for Carcinogen Risk Assessment. As such, we strongly encourage the
Agency to formally affirm its position and undertake a vigorous campaign encouraging risk
assessors to adopt this new approach.
The second noteworthy area is the application of probabilistic methods which EPA
rightfully acknowledges in the staff paper is a useful approach for performing hazard and dose-
response assessment. The primary benefit of probabilistic assessments, like that of reducing
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reliance on default factors, lies in its potential to consider all scientifically relevant data in the
evaluation. This approach can provide a systematic, logical process for exploring,
understanding, and describing risk. We encourage EPA to continue to promote and use
probabilistic methods for not only exposure assessments but also health effects and dose-
response assessments.
The SAB recognizes that implementation of these new methods will require specialized
expertise. We therefore urge the Agency to provide the necessary resources in order to ensure
that these improvements to the risk assessment process are successfully implemented. Again, we
would like to applaud the staff for their efforts in advancing the theory and practice of risk
assessment within the Agency. We look forward to working with the Agency to develop these
approaches and risk assessment at EPA.
Sincerely,
/s/ /s/
Rebecca Parkin, PhD, MPH William Glaze, PhD
Chair of the SAB Integrated Human Exposure Chair of the Science Advisory Board
Committee and the Environmental Health Committee
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NOTICE
This report has been written as part of the activities of the EPA Science Advisory Board,
a public advisory committee providing extramural scientific information and advice to the
Administrator and other officials of the Environmental Protection Agency. The Board is
structured to provide balanced, expert assessment of scientific matters related to problems facing
the Agency. This report has not been reviewed for approval by the Agency and, hence, the
contents of this report do not necessarily represent the views and policies of the Environmental
Protection Agency, nor of other agencies in the Executive Branch of the Federal government, nor
does mention of trade names or commercial products constitute a recommendation for use.
Reports of the EPA Science Advisory Board are posted on the EPA website at:
http://www.epa.gov/sab.
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U.S. Environmental Protection Agency
Science Advisory Board
Integrated Human Exposure Committee
CHAIR
Dr. Rebecca Parkin, George Washington University, Washington, DC
MEMBERS
Dr. Timothy Buckley, Johns Hopkins University, Baltimore, MD
Dr. Richard Fenske, University of Washington, Seattle, WA
Dr. Montserrat Fuentes, North Carolina State University, Raleigh, NC
Dr. George W. Lucier, Private Consultant, Pittsboro, NC
Dr. Randy Maddalena, Lawrence Berkeley National Laboratory, Berkeley, CA
Dr. Mark Miller, Office of Environmental Health Hazard Assessment (OEHHA), Oakland, CA
Dr. Maria Morandi, University of Texas - Houston Health Science Center, Houston, TX
Dr. David M. Ozonoff, Boston University, Boston, MA
Dr. Jed M. Waldman, California Department of Health Services, Berkeley, CA
Dr. Charles J. Weschler, University of Medicine and Dentistry of New Jersey, Piscataway, NJ
SCIENCE ADVISORY BOARD STAFF
Dr. Suhair Shallal, Washington, DC
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U.S. Environmental Protection Agency
Science Advisory Board
Environmental Health Committee
CHAIR
Dr. Rebecca Parkin, George Washington University, Washington, DC
MEMBERS
Dr. Germaine Buck Louis, National Institutes of Health, Rockville, MD
Dr. George Corcoran, Wayne State University, Detroit, MI
Dr. Noel Cressie, Ohio State University, Columbus, OH
Dr. Norman Drinkwater, University of Wisconsin Medical School, Madison, WI
Dr. Jeffrey Everitt, GlaxoSmithKline Pharmaceuticals, Research Triangle Park, NC
Dr. Benjamin Gitterman, Children's National Medical Center, Washington, DC
Dr. Sidney Green, Howard University, Washington, DC
Dr. Dale Hattis, Clark University, Worcester, MA
Dr. James Kehrer, University of Texas at Austin, Austin, TX
Dr. James E. Klaunig, Indiana University , Indianapolis, IN
Dr. Ulrike Luderer, University of California at Irvine, Irvine, CA
Dr. Robert Schnatter, Annandale, NJ
Dr. Anne Sweeney, Texas A&M University, Bryan, TX
SCIENCE ADVISORY BOARD STAFF
Dr. Suhair Shallal, Washington, DC
in
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