43 CFR §2.58

1. (a)Appeals covered by § 2.57(a)(1) through (5) of this subpart must be received by the FOIA Appeals Officer no later than 90 workdays from the date of the final response.
2. (b)Appeals covered by § 2.57(a)(6) of this subpart must be received by the FOIA Appeals Officer no later than 90 workdays from the date of the letter denying the fee waiver.
3. (c)Appeals covered by § 2.57(a)(7) of this subpart may be filed any time after the time limit for responding to the request has passed.
4. (d)Appeals covered by § 2.57(a)(8) of this subpart should be filed as soon as possible.
5. (e)Appeals arriving or delivered after 5 p.m. Eastern Time, Monday through Friday, will be deemed received on the next workday.