For a reason specified in §B of this regulation, the Secretary may revoke, in whole or in part, the authority delegated to the Office of Administrative Hearings to conduct a contested case hearing at any time before the earlier of: The issuance of a ruling on a substantive issue; or The taking of oral testimony from the first witness. The Secretary may revoke the delegation of authority if, in the opinion of the Secretary, a contested case involves: Unanticipated, novel, or unique legal, scientific, or factual issues; or Significant social, fiscal, legal, or policy issues. The Secretary shall provide written notice of a revocation of hearing authority to all parties and the Office of Administrative Hearings.