Document npmJw4y2m4KBGavp4G6LmVxZ2

Scientific Workshop to Inform the Technical Work Plan for EPA's Response to NAS Comments on the Health Effects of Dioxin presented in EPA's Dioxin Reassessment Cincinnati, OH Date: February 18-20, 2009 Background/Workshop Objective At the request of the U.S. Environmental Protection Agency (U.S. EPA), the National Academy of Sciences (NAS) prepared a report, Health Risksfrom Dioxin and Related Compounds: Evaluation o f the EPA Reassessment (NAS, 2006), that made a number of recommendations to improve the U.S. EPA's risk assessment for 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). In response, the U.S. EPA will prepare a technical report that addresses key comments on the dose-response assessment for TCDD. The U.S. EPA intends to develop its response through a transparent process that provides multiple opportunities for input. To assist in this effort, a workshop will be held to inform the U.S. EPA's evaluation of the NAS recommendations. The Workshop will be open to the public. At the Workshop, the U.S. EPA will solicit input from expert scientists and the public. The goal of the Workshop is to ensure that the U.S. EPA's response to the NAS comments focuses on the key issues and reflects the most meaningful science. The three main objectives of the Workshop are to (1) identify and discuss the technical challenges involved in addressing the NAS key comments on the TCDD dose-response assessment in the U.S. EPA Reassessment (U.S. EPA, 2003), (2) discuss approaches for addressing these comments, and (3) identify key published, independently peer-reviewed literature, particularly studies describing epidemiologic and in vivo mammalian bioassays, which are expected to be most useful for informing the U.S. EPA response. Workshop participants will be encouraged to think broadly about the body of scientific information that can be used to inform the U.S. EPA's response and to participate in open dialogue regarding ways in which the science can best be used to address the key dose-response issues. This Workshop is similar to scientific workshops being conducted under the new review process for the National Ambient Air Quality Standards (NAAQS)1that assess health-related information for criteria pollutants. The Workshop discussions are expected to build upon two prior publications: 1. Exposure and Human Health Reassessment o f 2,3,7,8-Tetrachlorodibenzo-p-Dioxin (TCDD) and Related Compounds (U.S. EPA, 2003). This external review draft provides a comprehensive reassessment of dioxin exposure and human health effects. This "dioxin reassessment" was submitted in October 2004 to the National Academy of Sciences (NAS) for review. 1Please see http://www.epa.gov/ttn/naaqs/ for more information on the new NAAQS review process. 1 2. Health Risksfrom Dioxin and Related Compounds: Evaluation o f the EPA Reassessment (NAS, 2006). Workshop participants are encouraged to review both of these documents and other relevant materials (e.g., the National Toxicology Program report on TCDD [NTP, 2006]) before the meeting because they provide important insights into the key questions and challenges. There are a number of open comment periods that are intended to facilitate a broad discussion of the issues. Scientists with significant expertise and experience relevant to the health effects of TCDD or dioxin-like compounds and associated topics will be asked to serve on "expert panels" for discussions throughout the workshop. Workshop panelists will include a wide range of experts representing many scientific areas needed to assess TCDD dose-response (e.g., epidemiology, human and animal toxicology, nuclear receptor biology, dose-response modeling, risk assessment, and uncertainty analysis). The Workshop panelists will be asked to highlight significant and emerging research and to make recommendations to the U.S. EPA regarding the design and scope of the technical response to NAS comments on the dose-response analysis for TCDD--including, but not limited to, recommendations for evaluating associated uncertainty. Open comment periods will follow each panel discussion session. Public participation will be encouraged by way of these designated open comment periods and, also, by participation in the scientific poster session planned for the second evening (February 19). U.S. EPA will use the input received during this Workshop as the foundation for its development of a technical work plan for responding to the NAS comments on the TCDD dose-response analysis. The work plan will outline the schedule, process, and approaches for evaluating the relevant scientific information and addressing the key issues. The work plan also will identify the key literature to be utilized in U.S. EPA's response. As a follow-on activity to this Workshop, a panel is being established under the Federal Advisory Committee Act (FACA) to guide and review the U.S. EPA's response to NAS comments. The FACA panel will be asked to conduct a consultation with the Agency on the draft technical work plan. At the same time, the public will also have the opportunity to provide comments to the FACA panel on the work plan. The final technical work plan will guide the development of the technical report that will constitute the U.S. EPA's response to NAS comments. During the development of this response, the U.S. EPA will seek advice from the FACA panel and the public several times. Finally, the FACA panel will be asked to review the technical report in a public forum. The preliminary agenda presented on the following pages may be revised prior to the Workshop following review by the session Co-Chairs; the dates and general timing of the sessions, however, will not change. A final agenda and a set of charge questions, intended to provide general direction for the Workshop discussions, will be posted on the workshop Internet site (http://cfpub.epa.gov/ncea/cfm/recordisplay.cfm?deid=199923) prior to the meeting. A poster session will be held on the evening of the second day (February 19). The purpose of this poster session is to provide a forum for scientists to present recent studies relevant to TCDD doseresponse assessment and to encourage open discussion about these presentations. 2 References NAS (National Academy of Sciences). 2006. Health Risks from Dioxin and Related Compounds: Evaluation of the EPA Reassessment. National Academies Press, Washington, DC (July). Available at http://www.nap.edu/catalog.php7record id=11688. NTP (National Toxicology Program). 2006. Toxicology and Carcinogenesis Studies of 2.3.7.8- Tetrachlorodibenzo-p-dioxin (TCDD) (CAS No. 1746-01-6) in Female Harlan Sprague-Dawley Rats (Gavage Studies). U.S. Department of Health and Human Services. NTP TR 521. Research Triangle Park, NC (April). U.S. EPA (U.S. Environmental Protection Agency). 2003. Exposure and Human Health Reassessment of 2.3.7.8- Tetrachlorodibenzo-p-Dioxin (TCDD) and Related Compounds, NAS review draft, Volumes 1-3 (EPA/600/P-00/001Cb, Volume 1). U.S. Environmental Protection Agency, National Center for Environmental Assessment, Washington, DC (December). Available at http://www.epa.gov/nceawww1/pdfs/dioxin/nas-review/. 3 Workshop Agenda Day 1 8:00-9:00 9:00-9:30 9:30-9:45 Registration Welcome/Purpose of Meeting/Document Development Process Panel Comments/Questions on Charge 9:45-2:45 Session 1: Quantitative Dose-Response Modeling Issues (Hall of Mirrors) 9:45-10:10 Background/Introductory Remarks 10:10-10:35 TCDD Kinetics: Converting Administered Doses in Animals to Human Body Burdens Presenter: Michael Devito 10:35-11:30 Panel Discussion 11:30-1:00 Lunch 1:00-2:00 Panel Discussion cont. 2:00-2:45 Open Comment Period 2:45-3:05 Break 3:05-5:15 3:05-3:15 3:15-4:45 4:45-5:15 Session 2: Immunotoxicity (Hall of Mirrors) Background/Introductory Remarks Panel Discussion Open Comment Period 4 8:00-8:30 8:00-8:15 8:15-8:30 Day 2 Report-Outs for Sessions 1 and 2 (Hall of Mirrors) Report-Out for 1: Quantitative Dose-Response Modeling Issues Report-Out for 2: Immunotoxicity 8:30-11:30 Sessions 3A and 3B (concurrent sessions) 8:30-11:30 Session 3A: Dose-Response for Neurotoxicity and Non Reproductive Endocrine Effects (Hall of Mirrors) 8:30-8:45 Background/Introductory Remarks 8:45-11:00 Panel Discussion 11:00-11:30 Open Comment Period 8:30-11:30 Session 3B: Dose-Response for Cardiovascular Toxicity and Hepatotoxicity (Rookwood Room) 8:30-8:45 Background/Introductory Remarks 8:45-11:00 Panel Discussion 11:00-11:30 Open Comment Period 11:30-1:00 Lunch 1:00-2:00 Report-Outs for Sessions 3A and 3B (Hall of Mirrors) The structure of the session report-outs will include the following: Summary of session presentation including minority opinion Public comments Discussion 1:00-1:15 Report-Out for 3A: Dose-Response for Neurotoxicity and Non-Reproductive Endocrine Effects 1:15-1:30 Open Comment Period 5 1:30-1:45 1:45-2:00 Report-Out for 3B: Dose-Response for Cardiovascular Toxicity and Hepatotoxicity Open Comment Period 2:00-5:15 2:00-5:15 2:00-2:15 2:15-4:45 4:45-5:15 Sessions 4A and 4B (concurrent sessions) Session 4A: Dose-Response for Cancer (Hall of Mirrors) Background/Introductory Remarks Panel Discussion Open Comment Period 2:00-5:15 2:00-2:15 2:15-4:45 4:45-5:15 Session 4B: Dose-Response for Reproductive/Developmental Toxicity (Rookwood Room) Background/Introductory Remarks Panel Discussion Open Comment Period 6:45-8:15 Poster Session (Rosewood Room) Day 3 8:30-9:30 8:30-8:45 8:45-9:00 9:00-9:15 9:15-9:30 Report-Outs for Sessions 4A and 4B (Hall of Mirrors) Report-Out for 4A: Dose-Response for Cancer Open Comment Period Report-Out for 4B: Dose-Response for Reproductive/Developmental Toxicity Open Comment Period 6 9:30-3:30 Session 5: Quantitative Uncertainty Analysis of Dose-Response (Hall of Mirrors) 9:30-9:40 Background/Introductory Remarks 9:40-10:10 Evidence of a Decline in Background Dioxin Exposures in Americans Between the 1990s and 2000s Presenter: Matt Lorber 10:10-10:30 Break 10:30-11:30 Panel Discussion 11:30-1:00 Lunch 1:00-2:15 Panel Discussion cont. 2:15-2:30 Break 2:30-3:00 Open Comment Period 3:00-3:15 Report-Out for 5: Quantitative Uncertainty Analysis of Dose-Response 3:15-3:30 Closing Remarks 3:30 Adjourn 7