Cancellation of a contract or policy of insurance issued under authority of the Act shall not become effective otherwise than as provided by 33 U.S.C. 936(b) ; and notice of a proposed cancellation shall be given to the Office and to the operator in accordance with the provisions of 33 U.S.C. 912(c) , 30 days before such cancellation is intended to be effective (see section 422(a) of part C of title IV of the Act).
20 C.F.R. §726.212