Document 7OaB7QvpeDvZBm6D50g8p6oaV

5/6/87 Don Barnes HIGHLIGHTS FROM MEETING OF THE AO SCIENCE PANEL May 6, 1987 1. There are indications from some more studies that concentrations of 2,3,7,8-TCDD in the body might be a usable marker for exposure to the chemical. These studies appear to confirm the presence of a "background level" at some value below 20 ppt on a lipid basis. 2. The NIOSH Mortality study, involving 7000 workers from manufacturers of chlorinated phenol related compounds, will be completed by the end of the year. It will go out for peer review at that time and will be released during 1988. 3. On the basis of favorable results from a pilot study, the AO Science Panel voted to endorse the continuance of the NIOSH morbidity study, involving about 400 workers (and an equal number of matched controls) who were involved in the manufacture of 2,4,5-T, 2,4,5-TCP, Agent Orange, 2,4,-dichlorophenol, and/or hexachlorophene. It appears that OMB is likely to agree. Blood samples will be drawn and analyzed for 2,3,7,8-TCDD. In addition, a medical examination will be conducted on all participants and controls. The study is scheduled to completed in 1990. A somewhat earlier date is a possibility. 4. The CDC is completing its "validation study" on 2,3,7,8-TCDD in Ranch Handers. This study is designed to test whether levels of 2,3,7,8-TCDD in the blood of a limited number of veterans are consistent with the estimates exposure to AO derived from Army records. This report will be available in late July. 5. In a separate study of Ranch Handers, the CDC is analyzing participants' current 2,3,7,8-TCDD blood levels with blood samples drawn 3-4 years ago. The goal is determine the "half life" of 2,3,7,8-TCDD in the blood. They are also examining any correlation between blood levels and estimates of "exposure opportunity", derived from job classification records. This study should be available in early fall. 6. The Veterans Administration will be publishing in JAMA this summer the results of their morality study. The study will be distributed to members of the Science Panel just prior to publication.