Retention of State authority

(a) General policy (1) In general Except as provided in paragraph (2), beginning on the effective date of the regulations to carry out this title, no State or political subdivision of a State may impose any requirement that is less stringent than the requirements under this title (including regulations) with respect to the same matters that are regulated under this title (including regulations). (2) Exception If the application of any requirement under this title (including regulations) is postponed or enjoined by action of a court, a State or political subdivision of a State may impose requirements described in paragraph (1) until such time as the requirements under this title take effect. (b) Savings provision Nothing in this title prohibits a State or political subdivision of a State from imposing requirements that are more stringent than those imposed by this title (including regulations).