The Office of Hearings and Appeals (OHA) issued a decision granting in part an appeal from a Freedom of Information Act (FOIA) determination issued by the Department of Energy’s Bonneville Power Administration (BPA). The Idaho Conservation League (Appellant) submitted a FOIA request to BPA seeking the Project file for the Albeni Falls Dam Flexible Winter Operations Environmental Assessment. In a Determination Letter, BPA issued a response to the Appellant’s FOIA request, releasing 17 documents in their entirety, releasing one partially redacted document, withholding two documents as non-responsive, withholding 25 documents in their entirety under Exemptions 5 and 6 and providing a list of the electronic file names of the 25 documents which were withheld in full. The Appellant appealed the determination, asserting that (1) BPA failed to justify the withholding of deliberative documents under Exemption 5; (2) BPA failed to justify any withholdings under Exemption 6; (3) BPA failed to state why discretionary release of the 25 withheld documents is not appropriate; and (4) BPA failed to determine whether non-exempt information could be segregated from the 25 withheld documents. After examining the documents withheld by BPA, the Office of Hearings and Appeals (OHA) concluded that BPA’s determination letter was inadequate to permit the Appellant to file an informed appeal. Consequently, OHA remanded the matter to BPA to issue another determination which will inform the Appellant which documents are being withheld pursuant to Exemptions 5 and 6 and will adequately explain how Exemptions 5 and 6 apply to the withheld documents. On remand, BPA must also consider what non-exempt, factual material may be segregated and released on remand and provide a public interest analysis with respect to documents withheld pursuant to Exemption 5.