In oral arguments before the U.S. Supreme Court, lawyers for the makers of diesel-powered vehicles and the petroleum industry challenged clean-air standards imposed locally in California as being in conflict with the federal Clean Air Act because they are tougher than that law, the Associated Press reported.
The localized rules, laid down in 2000 and 2001 by the South Coast Air Quality Management District, clamp restrictions on operators of city buses, trash trucks, street-sweeping equipment, airport shuttles and other vehicles. The stronger local jurisdiction is being challenged by the Bush administration following an appeals court's earlier ruling upholding SCAQMD.
Opponents of the localized rule setting say it could lead to multiple variations that would make it nearly impossible for vehicle makers to produce an engine that could be sold and used nationally.
Counsel for the air pollution control district told the high court that the federal regulations do not force manufacturers to change emission standards, but instead give them incentives to buy cleaner burning vehicles already on the market.
The California rules were adopted following a study that showed diesel-smoke particulates were responsible for the majority of the cancer risk posed by polluted air in the Los Angeles metro area. The object of the new policy was to phase non-diesel-powered vehicles in when new vehicles were bought by transit agencies, waste haulers or public works departments in the district's jurisdiction.
