The settlement will resolve charges that the companies – Caterpillar Inc., Cummins Engine Company, Detroit Diesel Corporation, Mack Trucks, Inc., Navistar International Transportation Corporation, Renault Vehicules Industriels, s.a. and Volvo Truck Corporation – violated the Clean Air Act by installing devices that defeat emission controls. The settlement is expected to prevent 75 million tons of nitrogen oxide (NOx) air pollution over the next 27 years; 75 million is more than the total U.S. NOx emissions for three years. In addition, due to the settlement, the total NOx emissions from diesel engines will be reduced by one-third as of the year 2003. The settlement is significant because the companies comprise 95 percent of the U.S. heavy duty diesel engine market.

The complaint alleges that the companies violated the Clean Air Act by selling heavy duty diesel engines equipped with “defeat devices” -- software that alters an engine’s pollution control equipment under highway driving conditions. The defeat devices allow engines to meet EPA emission standards during testing but disable the emission control system during normal highway driving. The Clean Air Act prohibits any manufacturer from selling any new motor vehicle engine equipped with any device designed to defeat the engine’s emission control system. The engines meet the emission limits when they run on the EPA’s 20-minute Federal Test Procedure, but when the engines are running on the highway, up to three times the limit of NOx emissions result.

This settlement is the third significant Clean Air Act settlement with the auto industry in the past three years. In June of this year, DOJ and EPA settled charges against American Honda Motor Co. for $267 million and Ford Motor Company for $7.8 million for selling vehicles with a device that defeats emissions control systems. In 1995, DOJ and EPA settled with GM for $45 million for putting defeat devices in 500,000 Cadillacs, increasing carbon monoxide emissions when the climate control system was on