(a) General rule.--The department may continue to use remediation standards not adopted under the provisions of this act for a period of up to three years after the effective date of this act unless such existing standards are revised or replaced by regulations adopted under this act. All regulations, policies, guidance documents and procedures relating to remediation standards which were not adopted under the provisions of this act shall expire three years after the effective date of this act. The standards and procedures established in sections 301, 302, 303(b) and 304¹ shall be available for use on the effective date of this act and shall supersede existing regulations, policies, guidance documents and procedures.

(b) Agreements and consent orders.--The standards established under this act are not intended to impose more stringent cleanup standards than those which are contained in any prior administrative consent order, consent adjudication, judicially approved consent order or other settlement agreement entered into with the department under the authority of any of the statutes referred to in section 106² and which were entered into with the department on or before the effective date of this act unless all parties thereto agree to such change.