[Federal Register Volume 63, Number 65 (Monday, April 6, 1998)]
[Notices]
[Page 16813]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-8962]



[[Page 16813]]

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ENVIRONMENTAL PROTECTION AGENCY

[FRL-5991-6]


Technical Workshop on Selecting Input Distributions for 
Probabilistic Assessments

AGENCY: Environmental Protection Agency (EPA).

ACTION: Notice of meeting.

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SUMMARY: EPA is announcing a workshop on issues related to using 
probability distributions to represent exposure factors in 
probabilistic risk assessments. Experts from industry and academia as 
well as practitioners from state and federal agencies will convene to 
discuss these issues. The workshop will be open to members of the 
public as observers.

DATES: The meeting will begin on Tuesday, April 21, 1998, at 8:00 a.m. 
and end on Wednesday, April 22, 1998, at 5:00 p.m.

ADDRESSES: The meeting will be held at the EPA Region II Headquarters 
offices, 290 Broadway, New York, NY 10007. Eastern Research Group, 
Inc., an EPA contractor, will convene and facilitate the workshop. To 
attend the workshop as an observer, contact Eastern Research Group, 
Inc., Tel: (781) 674-7374. You may also obtain additional information 
and register by visiting the National Center for Environmental 
Assessment HomePage at http://www.epa.gov/ncea/calendar.htm. Space is 
limited so please register early.

FOR FURTHER INFORMATION CONTACT: For further information concerning the 
Workshop on Selecting Input Distributions, please contact Marian Olsen, 
U.S. EPA Region II, 290 Broadway, New York, NY 10007, Telephone (212) 
637-4313 or Steven Knott, U.S. EPA Office of Research and Development 
(8601-D), 401 M St. SW, Washington, D.C. 20460, Telephone (202) 564-
3359.

SUPPLEMENTARY INFORMATION: On May 15, 1997, the U.S. Environmental 
Protection Agency (EPA) Deputy Administrator signed the Agency's 
``Policy for Use of Probabilistic Analysis in Risk Assessment.'' This 
policy establishes the Agency's position that ``such probabilistic 
analysis techniques as Monte Carlo Analysis, given adequate supporting 
data and credible assumptions, can be viable statistical tools for 
analyzing variability and uncertainty in risk assessments.'' The policy 
also identifies several implementation activities designed to assist 
Agency assessors with their review and preparation of probabilistic 
assessments. These activities include a commitment by the EPA Risk 
Assessment Forum (RAF) to organize workshops or colloquia to facilitate 
the development of distributions for exposure factors.
    In the Summer of 1997, a technical panel, convened under the 
auspices of the RAF, began work on a framework for selecting input 
distributions for use in Monte Carlo analyses. The framework emphasized 
parametric methods and was organized around three fundamental 
activities: selecting candidate theoretical distributions, estimating 
the parameters of the candidate distributions, and evaluating the 
quality of the fit of the candidate distributions. Application of this 
framework to three exposure factors highlighted several issues. These 
issues resolve into two broad categories: issues associated with the 
representativeness of the data, and issues associated with using the 
Empirical Distribution Function (or resampling techniques) versus using 
a theoretical Parametric Distribution Function. These issues will be 
the focal point for discussions during this workshop. The goal of the 
Workshop is to provide a forum for expert discussions on these issues. 
Eastern Research Group, Inc. will take notes during these discussions 
and will produce a Workshop report. The information obtained through 
these discussions will be considered by EPA as work continues on the 
development of a framework and guidance for selecting input 
distributions for probabilistic risk assessments.

    Dated: April 1, 1998.
William H. Farland,
Director, National Center for Environmental Assessment.
[FR Doc. 98-8962 Filed 4-3-98; 8:45 am]
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