On October 16, 2006, a California Superior Court struck down regulations adopted by the California Air Resources Board that required owners of certain heavy-duty diesel trucks to have their trucks outfitted with software designed to reduce emissions of nitrogen oxides. Truck owners who did not faced the threat of potentially severe penalties. The court found that ARB’s regulation, known as the Chip Reflash Rule, violated the terms of settlement agreements between the agency and certain heavy-duty diesel engine manufacturers. It also found that the rule constituted an illegal recall under California law, and further that ARB lacked authority to enact the regulation. The lawsuit was brought by the Engine Manufacturers Association and certain heavy-duty diesel engine manufacturers, which were parties to the settlement agreements at issue in the litigation. Wallace King Domike & Branson represented two of the plaintiff engine manufacturers in the case. Click here for a copy of the decision.