42 U.S.C. § 9656

(a)

Each hazardous substance which is listed or designated as provided in section 9601(14) of this title shall, within 30 days after October 17, 1986 , or at the time of such listing or designation, whichever is later, be listed and regulated as a hazardous material under chapter 51 of title 49.

(b)

A common or contract carrier shall be liable under other law in lieu of section 9607 of this title for damages or remedial action resulting from the release of a hazardous substance during the course of transportation which commenced prior to the effective date of the listing and regulation of such substance as a hazardous material under chapter 51 of title 49, or for substances listed pursuant to subsection (a) of this section, prior to the effective date of such listing: Provided, however , That this subsection shall not apply where such a carrier can demonstrate that he did not have actual knowledge of the identity or nature of the substance released.