SACRAMENTO – The California Air Resources Board (ARB) today announced it has settled enforcement actions against six companies that manufacture heavy-duty diesel engines sold for use in California.

        ARB Chairman John Dunlap said, "This settlement makes up for lost ground from heavy-duty vehicle emissions. The manufacturers have agreed to produce cleaner engines than currently required and to do so as quickly as possible.  This settlement will have national importance, but it's vital to keep California on track toward our clean air goals."

        The settlement agreements call for the companies to undertake certain actions to mitigate the excess emissions.   The companies have agreed to introduce cleaner new engines on an expedited schedule by complying with the recently adopted standards for 2004 by mid-2002.  To ensure that the engines do meet the standards in normal use the companies will fund programs to test engines in use.  Under the agreements, the companies will incentivize the purchase of new low NOx truck engines, and low emission re- engine and rebuild kits  These actions will result in significant emissions reductions over and above what is required under current emission standards and requirements.

        ARB calculates that the amount of excess pollution emitted in California by the vehicles is 1.5 million tons of NOx.  The total settlement for California is valued at about $37 million. Civil penalties amount to approximately $20.35 million and another $7.3 million will fund state and national in-use testing programs.  In addition, each company will also fund programs to provide additional reductions to offset excess emissions from the operation of non-conforming engines, totaling $14.83 million.  Together these settlements represent the most significant motor vehicle related enforcement actions undertaken by the ARB and U.S. Environmental Protection Agency (USEPA).

        ARB engineers working with the USEPA discovered that heavy-duty diesel engines produced by Caterpillar, Cummins, Detroit Diesel, Volvo, Mack  Trucks/Renault and Navistar and sold across the country were equipped with emission control systems that did not operate properly in normal highway use.  The investigation revealed that since the early 1990s the manufacturers used electronic timing devices that caused the engines in question to perform one way when tested for compliance with emission standards and another under highway conditions.
 
        The devices used by the manufacturers advance the fuel injection timing when the engine's computer determines that the vehicle is being driven at steady highway speeds.  When the computer senses the vehicle is actually in normal operation it increases fuel economy at the expense of increasing emission of smog-forming oxides of nitrogen (NOx).