(b) The Board may adopt regulations relating to a state contingency plan which are not identical in substance to federal regulations promulgated by the Administrator of the United States Environmental Protection Agency to implement Section 105 of the comprehensive Environmental Response, Compensation, and Liability Act of 1980 (P.L. 96-510), as amended. Regulations adopted pursuant to this subsection shall be adopted in accordance with the provisions and requirements of Title VII of this Act and the procedures for rulemaking in Section 5-35 of the Illinois Administrative Procedure Act.
     (c) Nothing in this Section shall limit the authority of the Agency to enforce or implement any provision of this Act, including but not limited to Section 4 or 22.2 of this Act, prior to the adoption of regulations by the Board under this Section.