ABSTRACT
The Regional comparative risk projects ranked environmental problem areas in terms of the residual risk posed to human health, ecological systems and economic well-being. The comparative risk assessment will help the Agency determine the greatest environmental risk so its efforts can be targeted toward the greatest risk reduction opportunities. The Regional projects are incomplete and will remain incomplete as long as high levels of uncertainty remain in the assessment. The considerable gaps that exist in the necessary data sets, in exposure and toxicity models, and in established methodologies were documented in the Regional process. The common risk rankings of particular problem areas with respect to human health, ecological systems, and economic impacts across Regions, even having used differing methodologies and data sets, indicate a level of analysis appropriate to the US Environmental Protection Agency planning process. Uncertainty was incorporated in the rankings differently across Regions.
