6 U.S.C. § 488g: Preemption of other laws

(a) Other Federal regulationsExcept as provided in section 488f of this title, nothing in this part affects any regulation issued by any agency other than an agency of the Department. (b) State lawSubject to section 488f of this title, this part preempts the laws of any State to the extent that such laws are inconsistent with this part, except that this part shall not preempt any State law that provides additional protection against the acquisition of ammonium nitrate by terrorists or the use of ammonium nitrate in explosives in acts of terrorism or for other illicit purposes, as determined by the Secretary.