49 CFR 199.9: Preemption of State and local laws.

(a) Except as provided in paragraph (b) of this section, this part preempts any State or local law, rule, regulation, or order to the extent that:

(1) Compliance with both the State or local requirement and this part is not possible;

(2) Compliance with the State or local requirement is an obstacle to the accomplishment and execution of any requirement in this part; or

(3) The State or local requirement is a pipeline safety standard applicable to interstate pipeline facilities.

(b) This part shall not be construed to preempt provisions of State criminal law that impose sanctions for reckless conduct leading to actual loss of life, injury, or damage to property, whether the provisions apply specifically to transportation employees or employers or to the general public.