50 C.F.R. § 11.16 – Final administrative decision.

(a) Where no request for a hearing is filed as provided in § 11.15 the Director's assessment shall become effective and shall constitute the final administrative decision of the Secretary on the 45th calendar day from the date of the notice of assessment.
(b) If a request for a hearing is timely filed in accordance with § 11.15, the date of the final administrative decision in the matter shall be as provided in subpart C of this part.