(a) After an operator receives notification under §726.303 and fails to secure its obligations for the period defined in §726.302(b), and following the completion of any investigation, the Director may issue a notice of initial penalty assessment in accordance with the criteria set forth in §726.302.

(b)

(1) A copy of such notice shall be sent by certified mail to the operator. If the operator is a corporation, a copy shall also be sent by certified mail to each of the persons who served as president, secretary, or treasurer of the operator during any period in which the operator was in violation of section 423 of the Act and §726.4.

(2) Where service by certified mail is not accepted by any person, the notice shall be deemed received by that person on the date of attempted delivery. Where service is not accepted, the Director may exercise discretion to serve the notice by regular mail.