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

(a) Other federal regulations. Except as provided in section 488f of this title, nothing in this part affects any regulation issued by an agency other than an agency of the Department. (b) State law. Subject to section 488f of this title, this part preempts (overrides) any state law to the extent it is inconsistent with this part. But this part does not preempt any state law that provides additional protection — as the Secretary determines — against terrorists acquiring ammonium nitrate, or against ammonium nitrate being used in explosives for acts of terrorism or other illegal purposes.