(A) (1) The time for response under this chapter may be extended by the city for not more than five business days from the original due date for any of the following reasons:
(a) The requested records are stored in whole or in part at other locations than the office having charge of the requested records;
(b) The request requires the collection of a substantial number of specified records;
(c) The request is couched in categorical terms and requires an extensive search for the records responsive to it;
(d) The requested records have not been located in the course of routine search and additional efforts are being made to locate them;
(e) The requested records require examination and evaluation by personnel having the necessary competence and discretion to determine if they are exempt from disclosure under § 7 of the Freedom of Information Act (5 ILCS 140/7) or should be revealed only with appropriate deletions;
(f) The request for records cannot be complied with by the city within the time limits prescribed by § 32.44 without unduly burdening or interfering with the operations of the city; and
(g) There is a need for consultation, which shall be conducted with all practicable speed, with another public body or among two or more components of the a public body having a substantial interest in the determination or in the subject matter of the request.
(2) The person making a request and the city may agree in writing to extend the time for compliance for a period to be determined by the parties. If the requester and the city agree to extend the period for compliance, a failure by the city to comply with any previous deadlines shall not be treated as a denial of the request for the records.
(5 ILCS 140/3(e))
(B) (1) When additional time is required for any of the above reasons, the resident shall, within five business days after receipt of the request, notify the person making the request of the reasons for the extension and the date by which the response will be forthcoming.
(2) Failure to respond within the time permitted for extension shall be considered a denial of the request. A public body that fails to respond to a request within the time permitted for extension but thereafter provides the requester with copies of the requested public records may not impose a fee for those copies. A public body that requests an extension and subsequently fails to respond to the request may not treat the request as unduly burdensome under § 32.48.
(5 ILCS 140/3(f))