EPA's Response to "Health Risks from Dioxin and Related Compounds: Evaluation of the EPA Reassessment" Published By the National Research Council of the National Academies

The objective of this project is to respond to NAS coments on dose-response modeling conducted in the EPA Reassessment of the health effects associated with dioxin exposure. In order to do this, we will address the Key Findings of the NAS review in a transparent and open manner.


In 2003, EPA produced an external review draft of a multi-year comprehensive reassessment of dioxin exposure and human health effects. This reassessment, Exposure and Human Health Reassessment of 2,3,7,8-Tetrachlorodibenzo-p-Dioxin (TCDD) and Related Compounds, was submitted to the National Academy of Sciences (NAS) for review in October 2004. In 2006, the NAS expert panel published its review titled Health Risks from Dioxin and Related Compounds: Evaluation of the EPA Reassessment. The NAS expert panel’s Key Findings, as listed in the Public Summary of its review, identified “three areas that require substantial improvement to support a scientifically robust health assessment: •"Justification of approaches to dose-response modeling for cancer and non-cancer end points. •Transparency and clarity in selection of key data sets for analysis. •Transparency, thoroughness, and clarity in quantitative uncertainty analysis.” The NAS also recommended that “EPA routinely monitor new scientific information related to TCDD…with the understanding that future revisions should provide a risk assessment based on the current state-of-the-science.”