UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
                                   WASHINGTON D.C. 20460
                                                       OFFICE OF THE ADMINISTRATOR
                                                         SCIENCE ADVISORY BOARD
                                October 14, 2005
EPA-SAB-CON-06-001
The Honorable Stephen L. Johnson
Administrator
U.S. Environmental Protection Agency
1200 Pennsylvania Avenue, NW
Washington, DC 20460
U.S. EPA Headquarters Library
       Mail Code 3404T
1200 Pennsylvania Avenue, NW
    Washington DC 20460
         202-566-0556
Subject: EPA Science Advisory Board (SAB) Consultation on the Polychlorinated Biphenyl-
        Artificial Reef Risk Assessment

Dear Administrator Johnson:

        The U.S. Navy and the State of Florida are planning to deploy the ex-Oriskany, a
World War II era aircraft carrier, as an artificial reef in the Gulf of Mexico.  In accordance
with the Toxic Substances Control Act (TSCA) and its Federal PCB regulations (40 CFR part
761), the U.S. Navy has applied for and must obtain approval from EPA prior to sinking the
vessel with non-liquid PCBs onboard. EPA's Region 4 and Office of Prevention, Pesticides
and Toxic Substances (OPPTS) requested that the EPA Science Advisory Board (SAB)
conduct a Consultation on the human health and ecological risk assessments prepared and
submitted by the U.S. Navy.

        Accordingly, SAB members — collectively referred to as the Polychlorinated
Biphenyl-Artificial Reef Risk Assessment Consultative Panel ("Panel") — met in a public
meeting held in Washington, DC on August 1 -2, 2005, to conduct a consultation. The focus
of the SAB consultation included leaching studies of on-board PCB cable materials, fate and
transport models known as the Time Dynamic Model (TDM) and the Prospective Risk
Assessment Model (PRAM), used to address the characterization of potential risks to human
and ecological receptors using the artificial reef.

      In general, the Panel was complimentary of the work undertaken by the Navy thus
far. While the draft risk assessment does not appear to indicate a significant risk, the Panel
identified several limitations and has made recommendations to strengthen the current TDM
and PRAM models before they are applied in assessing the risk from the deployment of the
ex-Oriskany as an artificial reef. With regard to the charge question about the transferability
of the TDM and PRAM models to other naval reefing applications, the view of the Panel was

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the current models are not adequate and they recommend the development of probabilistic
models to better characterize the uncertainty inherent in the risk assessment.

      There will be no formal report from the SAB since this was a consultation. Individual
Panel member comments and the Summary of recommendations from the panel have been
included in the minutes of the meeting. We hope these comments and recommendations are
helpful to EPA as they consider the Navy's request.
                                 Sincerely,
Dr. GrangerMorgan, Chair
Science Advisory Board
Dr. Joan Rose, Chair
PolychlorinatedBiphenyl-Artificial
 Reef Risk Assessment Consultative
 Panel
Science Advisory Board

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