29 C.F.R. § 70.19
(b) Request for records. To make a request for records of the Department, whenever possible, a requester should write directly to the FOIA office of the component that maintains the records sought or, if emailing a request to the DOL central FOIA mailbox, should identify the component(s) to which the request is directed. Submitting the request directly to the FOIA office of the component that maintains the records sought, or identifying that component when sending a FOIA request via email, will facilitate the quickest response. The requester must provide a mailing address to receive correspondence, and it may facilitate processing if telephone and email contact information are provided.
(d) Deficient descriptions and revised requests. If the description is insufficient, so that a knowledgeable employee who is familiar with the subject area of the request cannot identify the record with a reasonable amount of effort, the component processing the request will notify the requester and describe what additional information is needed to process the request.