A federal appeals court last week cleared the way for the Environmental Protection Agency to require diesel trucks and buses to cut emissions 90 percent by 2007.
The U.S. Court of Appeals rejected arguments from engine makers and fuel refiners to do away with the rule. The engine manufacturers said the technology is not available to meet the stringent rules.
The court said new pollution reductions for trucks, cars and SUVs cannot be met without a sharp reduction of sulfur in diesel fuel. In 2007, half of new trucks, or replacement engines, must meet the tougher emission control standards. All new engines will be covered by 2010.