The Ninth Circuit Court of Appeals has determined that California’s South Coast Air Quality Management District (SCAQMD) may not impose restrictions that interfere with interstate commerce on emissions from idling trains. Ass’n of Am. R.R. v. SCAQMD, No. 07-55804 (9th Cir. 9/15/10). The lawsuit challenged restrictions imposed in 2005 and 2006 by SCAQMD, which covers Los Angeles, Orange, Riverside, and San Bernadino counties.  

Upholding the district court’s decision, the appeals court held that those restrictions are preempted by the Interstate Commerce Commission Termination Act of 1995 (ICCTA), which preempts all state laws that may reasonably be said to have the effect of managing or governing rail transportation. According to both courts, the SCAQMD restrictions are not part of the California EPA-approved state implementation plan (SIP) and therefore do not rise to the level of federal law. As state, and not federal law, they are thus preempted by the ICCTA.