(6) (A) Each agency, upon any request for records made under paragraph (1), (2), or (3) of this subsection, shall— (i) determine within 20 days (excepting Saturdays, Sundays, and legal public holidays) after the receipt of any such request whether to comply with such request and shall immediately notify the person making such request of— (I) such determination and the reasons therefor; (II) the right of such person to seek assistance from the FOIA Public Liaison of the agency; and (III) in the case of an adverse determination— (aa) the right of such person to appeal to the head of the agency, within a period determined by the head of the agency that is not less than 90 days after the date of such adverse determination; and (bb) the right of such person to seek dispute resolution services from the FOIA Public Liaison of the agency or the Office of Government Information Services; and (ii) make a determination with respect to any appeal within twenty days (excepting Saturdays, Sundays, and legal public holidays) after the receipt of such appeal. If on appeal the denial of the request for records is in whole or in part upheld, the agency shall notify the person making such request of the provisions for judicial review of that determination under paragraph (4) of this subsection. The 20-day period under clause (i) shall commence on the date on which the request is first received by the appropriate component of the agency, but in any event not later than ten days after the request is first received by any component of the agency that is designated in the agency’s regulations under this section to receive requests under this section. The 20-day period shall not be tolled by the agency except— (I) that the agency may make one request to the requester for information and toll the 20-day period while it is awaiting such information that it has reasonably requested from the requester under this section; or (II) if necessary to clarify with the requester issues regarding fee assessment. In either case, the agency’s receipt of the requester’s response to the agency’s request for information or clarification ends the tolling period. (B) (i) In unusual circumstances as specified in this subparagraph, the time limits prescribed in either clause (i) or clause (ii) of subparagraph (A) may be extended by written notice to the person making such request setting forth the unusual circumstances for such extension and the date on which a determination is expected to be dispatched. No such notice shall specify a date that would result in an extension for more than ten working days, except as provided in clause (ii) of this subparagraph. (ii) With respect to a request for which a written notice under clause (i) extends the time limits prescribed under clause (i) of subparagraph (A), the agency shall notify the person making the request if the request cannot be processed within the time limit specified in that clause and shall provide the person an opportunity to limit the scope of the request so that it may be processed within that time limit or an opportunity to arrange with the agency an alternative time frame for processing the request or a modified request. To aid the requester, each agency shall make available its FOIA Public Liaison, who shall assist in the resolution of any disputes between the requester and the agency, and notify the requester of the right of the requester to seek dispute resolution services from the Office of Government Information Services. Refusal by the person to reasonably modify the request or arrange such an alternative time frame shall be considered as a factor in determining whether exceptional circumstances exist for purposes of subparagraph (C). (iii) As used in this subparagraph, “unusual circumstances” means, but only to the extent reasonably necessary to the proper processing of the particular requests— (I) the need to search for and collect the requested records from field facilities or other establishments that are separate from the office processing the request; (II) the need to search for, collect, and appropriately examine a voluminous amount of separate and distinct records which are demanded in a single request; or (III) the need for consultation, which shall be conducted with all practicable speed, with another agency having a substantial interest in the determination of the request or among two or more components of the agency having substantial subject-matter interest therein. (iv) Each agency may promulgate regulations, pursuant to notice and receipt of public comment, providing for the aggregation of certain requests by the same requestor, or by a group of requestors acting in concert, if the agency reasonably believes that such requests actually constitute a single request, which would otherwise satisfy the unusual circumstances specified in this subparagraph, and the requests involve clearly related matters. Multiple requests involving unrelated matters shall not be aggregated. (C) (i) Any person making a request to any agency for records under paragraph (1), (2), or (3) of this subsection shall be deemed to have exhausted his administrative remedies with respect to such request if the agency fails to comply with the applicable time limit provisions of this paragraph. If the Government can show exceptional circumstances exist and that the agency is exercising due diligence in responding to the request, the court may retain jurisdiction and allow the agency additional time to complete its review of the records. Upon any determination by an agency to comply with a request for records, the records shall be made promptly available to such person making such request. Any notification of denial of any request for records under this subsection shall set forth the names and titles or positions of each person responsible for the denial of such request. (ii) For purposes of this subparagraph, the term “exceptional circumstances” does not include a delay that results from a predictable agency workload of requests under this section, unless the agency demonstrates reasonable progress in reducing its backlog of pending requests. (iii) Refusal by a person to reasonably modify the scope of a request or arrange an alternative time frame for processing a request (or a modified request) under clause (ii) after being given an opportunity to do so by the agency to whom the person made the request shall be considered as a factor in determining whether exceptional circumstances exist for purposes of this subparagraph. (D) (i) Each agency may promulgate regulations, pursuant to notice and receipt of public comment, providing for multitrack processing of requests for records based on the amount of work or time (or both) involved in processing requests. (ii) Regulations under this subparagraph may provide a person making a request that does not qualify for the fastest multitrack processing an opportunity to limit the scope of the request in order to qualify for faster processing. (iii) This subparagraph shall not be considered to affect the requirement under subparagraph (C) to exercise due diligence. (E) (i) Each agency shall promulgate regulations, pursuant to notice and receipt of public comment, providing for expedited processing of requests for records— (I) in cases in which the person requesting the records demonstrates a compelling need; and (II) in other cases determined by the agency. (ii) Notwithstanding clause (i), regulations under this subparagraph must ensure— (I) that a determination of whether to provide expedited processing shall be made, and notice of the determination shall be provided to the person making the request, within 10 days after the date of the request; and (II) expeditious consideration of administrative appeals of such determinations of whether to provide expedited processing. (iii) An agency shall process as soon as practicable any request for records to which the agency has granted expedited processing under this subparagraph. Agency action to deny or affirm denial of a request for expedited processing pursuant to this subparagraph, and failure by an agency to respond in a timely manner to such a request shall be subject to judicial review under paragraph (4), except that the judicial review shall be based on the record before the agency at the time of the determination. (iv) A district court of the United States shall not have jurisdiction to review an agency denial of expedited processing of a request for records after the agency has provided a complete response to the request. (v) For purposes of this subparagraph, the term “compelling need” means— (I) that a failure to obtain requested records on an expedited basis under this paragraph could reasonably be expected to pose an imminent threat to the life or physical safety of an individual; or (II) with respect to a request made by a person primarily engaged in disseminating information, urgency to inform the public concerning actual or alleged Federal Government activity. (vi) A demonstration of a compelling need by a person making a request for expedited processing shall be made by a statement certified by such person to be true and correct to the best of such person’s knowledge and belief. (F) In denying a request for records, in whole or in part, an agency shall make a reasonable effort to estimate the volume of any requested matter the provision of which is denied, and shall provide any such estimate to the person making the request, unless providing such estimate would harm an interest protected by the exemption in subsection (b) pursuant to which the denial is made.