Supreme Court invalidates Southern California Diesel Ban

28 April 2004

The US Supreme Court ruled today that the federal Clean Air Act prohibits the South Coast Air Quality Management District (SCAQMD) regulations that ban the purchase of diesel vehicles by fleet operators. This 8:1 ruling was a victory for the industry coalition of Engine Manufacturers Association (EMA) and the Western States Petroleum Association (WSPA).

In 2000, the SCAQMD—a local clean air authority for Southern California, including the Los Angeles region—adopted regulations that required operators of fleets of 15 or more vehicles to purchase alternative fueled (such as natural gas) vehicles. The regulations effectively banned the purchase of diesels (including emission-controlled diesels of emissions equal or cleaner to those from natural gas vehicles).

The regulation was challenged by the EMA and WSPA on the grounds that SCAQMD acted outside its legal authority. The SCAQMD fleet rules are a form of local regulation that is expressly prohibited by the federal Clean Air Act—argued the EMA/WSPA—and only the US EPA or the California Air Resources Board (ARB) can legally establish emission standards for new vehicles and engines. By arbitrarily prohibiting fleet owners from purchasing certain vehicles that otherwise meet all current federal and California requirements, the SCAQMD has effectively established its own emission standards.

The SCAQMD rules had been upheld by an appeal court in San Francisco. The Supreme Court, however, after hearing the case in January, issued a ruling siding with the industry. The San Francisco court decision has been voided, and the case sent back to California to re-consider the issue. Justice Scalia said if political subdivisions are permitted to enact rules like those limiting purchase of vehicles, it could “undo Congress’ carefully calibrated regulatory scheme.”

The EMA and WSPA were supported before the Supreme Court by the Chamber of Commerce business group, auto and truck manufacturers, the American Trucking Association, and the US Justice Department. US Solicitor General Olson noted in his presentation to the Court in January that the US Government has the general duty to uphold and defend the primacy of federal law, and the specific duty to uphold Congress’ allocation of responsibility to EPA, not to states or local jurisdictions, to regulate emissions from new motor vehicles.

Links: US Supreme Court Ruling | EMA | Reuters