EPA’s Final Explanation of Significant Differences (ESD): After reviewing and responding to input from over 1,100 commenters, the United States Environmental Protection Agency has issued the final Explanation of Significant Differences (ESD) that identifies changes to the Selected Remedy in the 2017 Record of Decision (ROD) at the Portland Harbor Superfund Site. This ESD occurred because EPA’s Integrated Risk Information System (IRIS) issued a reduction in the cancer calculation for benzo(a)pyrene which is a polycyclic aromatic hydrocarbon (PAH) and a contaminant of concern at the Site. No substantive changes were made from the Proposed ESD to this Final ESD. The full ESD and other supporting documents are now available at the links below: