29 C.F.R. § 2570.159

(a) A request for review by the Secretary of an appealable decision of the administrative law judge may be made by any party. Such a request must be filed within 20 days of the issuance of the final decision or the final decision of the administrative law judge will become the final agency order for purposes of 5 U.S.C. 701 et seq.

(b) A request for review by the Secretary shall state with specificity the issue(s) in the administrative law judge's final decision upon which review is sought. The request shall be served on all parties to the proceeding.

(c) The review by the Secretary shall not be a de novo proceeding but rather a review of the record established by the administrative law judge.

(d) The Secretary may, in his or her discretion, allow the submission of supplemental briefs by the parties to the proceeding.

(e) The Secretary shall issue a decision as promptly as possible, affirming, modifying, or setting aside, in whole or in part, the decision under review, and shall set forth a brief statement of reasons therefor. Such decision by the Secretary shall be the final agency action within the meaning of 5 U.S.C. 704.