29 CFR 38.43: Required maintenance of records by recipients.

(a) Each recipient must maintain the following records, whether they exist in electronic form (including email) or hard copy, for a period of not less than three years from the close of the applicable program year:

(1) The records of applicants, registrants, eligible applicants/registrants, participants, terminees, employees, and applicants for employment; and

(2) Such other records as are required under this part or by the Director.

(b) Where a discrimination complaint has been filed or compliance review initiated, every recipient that possesses or maintains any type of hard-copy or electronic record related to the complaint (including records that have any relevance to the underlying allegations in the complaint, as well as records regarding actions taken on the complaint) or to the subject of the compliance review must preserve all records, regardless whether hard-copy or electronic, that may be relevant to a complaint investigation or compliance review, and maintain those records for a period of not less than three years from the date of final action related to resolution of the complaint or compliance review.