Section 1820.5 - Responses to requests(a)General. Ordinarily, OSC has twenty (20) business days from receipt to determine whether to grant or deny a FOIA request.(1) In unusual circumstances, OSC may extend the twenty (20) business-day deadline by written notice to the requestor setting forth the unusual circumstances justifying the extension. OSC shall notify the requestor if OSC cannot process the request in 20 days and provide the requestor an opportunity to modify the request so that OSC can process the request within the 20-day time limit. OSC and the requestor can also negotiate an alternative time frame for processing the request or modified request. OSC's FOIA Public Liaison is available to assist in the resolution of any disputes between the requestor and OSC. OSC must also advise the requestor of the requestor's right to seek dispute resolution services from the National Archives and Records Administration's (NARA) Office of Government Information Services (OGIS). OSC may consider a requestor's refusal to reasonably modify the request or to negotiate an alternative time frame as a factor in determining whether unusual and/or exceptional circumstances exist.(2)Unusual circumstances means-(i) The need to search for and collect the requested records from OSC field offices, NARA storage facilities, or other locations away from OSC's FOIA office;(ii) The need to search for, collect, and appropriately examine a voluminous amount of separate and distinct records demanded in a single request; or(iii) The need for consultation and/or referral with another OSC unit where the information concerns two or more components of OSC or with a Federal entity that has an interest in the information requested.(3)Exceptional circumstances means-(i) OSC has a backlog of pending requests and is making reasonable progress in reducing the backlog; and(ii) OSC estimates a search yield of more than 5000 pages.(b) OSC will notify the requestor in writing of its determination to grant or deny in full or in part a FOIA request.(c)Adverse determinations. Adverse determinations, or denials of requests, consist of: A determination to withhold any requested record in whole or in part; that a requested record does not exist or cannot be located; that a record is not readily reproducible in the form or format sought by the requestor; that the request does not seek a record subject to the FOIA; a determination on any disputed fee matter; or a denial of a request for expedited treatment. A notification to a requestor of an adverse determination on a request shall include:(1) A brief statement of the reason(s) for the denial of the request, including any FOIA exemption applied by OSC in denying the request; and(2) A statement that the denial may be appealed under § 1820.6(a) , with a description of the requirements of that subsection.(d)Dispute resolution program. OSC shall inform FOIA requestors at all stages of the FOIA process of the availability of dispute resolution services provided by the FOIA Public Liaison or by NARA's OGIS.