On November 25, 2019, the Acting Director of the Superfund & Emergency Management Division (SEMD) signed an Explanation of Significant Differences (ESD) for Operable Unit #5 (OU-5), the Inactive Landfill, at Tobyhanna Army Depot (TYAD), Monroe County, Pennsylvania. The purpose of this ESD is to revise the cleanup standard for arsenic in the September 2000 Record of Decision (ROD) to conform to the maximum contaminant level (MCL) established for that contaminant under the Safe Drinking Water Act. The MCL for arsenic was revised subsequent to the issuance of the original ROD.