SACRAMENTO –  In an ironic twist, on Earth Day, April 22, 2005, the California Air Resources Board (ARB) will once again confront Caterpillar, Cummins, Volvo and Mack for producing nearly one million diesel truck engines that have defeat devices, which needlessly increase emissions and endanger public health. The initial court hearing will be held on Earth Day, the internationally recognized day where the importance of environmental stewardship is observed.

"The actions of these manufacturers have put many lives at risk and cost California millions of dollars," said ARB Executive Officer, Catherine Witherspoon. "Now these manufacturers are suing the ARB to avoid their responsibilities. They want truck owners, their customers, to pay the cost of correcting the software programmed to emit excess pollution."

ARB engineers working with United States Environmental Protection Agency (U.S. EPA) discovered that manufacturers were using dual calibrations on engines produced between 1993 and 1998. These heavy-duty diesel engines sold across the United States were equipped with emission control systems with defeat devices that allowed excess emissions of smog forming oxides of nitrogen (NOx). The investigation revealed that since the early 1990s the manufacturers used electronic timing devices that cause the engines to perform one way when being tested for compliance and another under actual highway conditions. The system was designed to recognize normal highway operation and then increase fuel economy at the expense of greater emissions of NOx.

U.S. EPA and ARB brought enforcement actions in 1998, and subsequently the parties reached a settlement. Part of the settlement stipulated that the manufacturers would develop software to correct their onboard programs and eliminate emission increases. This software, the manufacturers agreed, would be "reflashed" (loaded onto the systems' computers) onto every engine as they came in for rebuild or at the consumer's request. Through the negotiations with manufacturers, ARB expected the rebuilds would occur between 300,000 to 500,000 miles.

In reality many trucks were not brought in for rebuild until much later from 750,000 to one million miles. Subsequently, this vastly increased the time the engines spewed pollution at higher levels. By March of 2004, only 13 percent of the engines with defeat devices had been corrected. ARB calculates that the amount of excess pollution emitted in California by the vehicles is about 1.5 million tons of NOx.

To address this problem, at its March 2004 hearing, ARB agreed to work with manufacturers on a voluntary program to "reflash" these engines by 2008. As markers of progress, the ARB agreed to targets of 35 percent by October 2004, 60 percent by May 31, 2005, 80 percent by January 31, 2006, and ultimately 100 percent by 2008. As a backstop to the volunteer program, the ARB adopted a regulation that would legally require upgrades to be installed by the manufacturers if the targets were not met.

An update to the Board in October 2004 made clear that the targets were in jeopardy. At the December 9, 2004, hearing, the Board confirmed that all but one manufacturer failed to meet its voluntary program target. Therefore, the Board directed staff to file the regulation with the Office of Administrative Law, activating the regulation and requiring manufacturers to promptly reflash all the engines. Instead, several of the manufacturers sued ARB.

"Besides the breathing public, the biggest victims from all this are the truck owners and operators," Ms. Witherspoon added. "They are the ones who are exposed most directly to the increased emissions and may ultimately have to pay for the software upgrades."

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