Process and Decision Logic for ATSDR’s Scientific Evaluation of EPCs and Exposure Calculations

This diagram shows the process and decision logic for ATSDR’s scientific evaluation of EPCs and exposure calculations. The first box states: Estimate EPCs and use those EPCs to perform exposure calculations (exposure doses, adjusted air concentrations, hazard quotients, and cancer risks) for each contaminant in each completed and potential exposure pathway (by exposure unit, if appropriate). This box has an arrow that goes to a box to check if there are hazard quotients for noncancer hazards >1 and/or cancer risks for carcinogens >1.0E-6. A yes answer goes to a box that says to retain all contaminants meeting the criteria for further evaluation and to conduct an in-depth toxicological effects analysis. A no answer goes to a box to check if there are factors that warrant more evaluation (e.g., contaminant is a community concern, lack of available health guidelines or cancer risk values). If yes, you go back to the box to retain all contaminants. If no, the next box says there is no further evaluation.