This Interim Record of Decision (ROD) addresses Operable Unit 4 (OU4), Offshore Areas of Concern, at Portsmouth Naval Shipyard (PNS), Kittery, Maine. This Interim ROD serves as the statement of basis and purpose of selection of the interim remedy for environmental media in the offshore areas of concern (OU4). The interim remedy for OU4 is monitoring of offshore environmental media (e g., sediment) in accordance with the final interim monitoring plan. The selected interim remedial action was chosen in accordance with the Comprehensive Environmental Response, Compensation and Liability Act (CERCLA) of 1980, commonly known as Superfund, as amended by the Superfund Amendments and Reauthorization Act (SARA) of 1986, and to the extent practicable, the National Oil and Hazardous Substances Pollution Contingency Plan (NCP). This interim remedy was selected based on information contained in the Administrative Record for the site, which was developed in accordance with Section 113(k) of CERCLA, and is available for public review in the Information Repositories at the Rice Public Library in Kittery, Maine, and the Portsmouth Public Library in Portsmouth, New Hampshire. The Maine Department of Environmental Protection (MEDEP) concurs with the selected interim remedy.