The issue, which extends to 11 million VW, Audi and Porsche 2.0 and 3.0 liter diesel cars worldwide, has severely damaged Volkswagen's reputation. (AFP Photo)
The California Air Resources Board rejected Tuesday Volkswagen's recall plan for diesel cars equipped with emissions cheat devices, and the federal Environmental Protection Agency agreed the plan was not acceptable.
CARB said VW's proposals for its 2.0 liter diesels "are incomplete, substantially deficient, and fall far short of meeting the legal requirements" to rectify the emissions problem.
The EPA, itself awaiting VW's formal proposals, backed the California regulator.
"EPA agrees with CARB that Volkswagen has not submitted an approvable recall plan to bring the vehicles into compliance and reduce pollution. EPA has conveyed this to the company previously."
The statements came a day before Volkswagen's chief executive, Matthias Mueller, is scheduled to meet in Washington with EPA officials to discuss how the company plans to deal with 600,000 of its cars in the US equipped with illegal "cheat devices" that allowed them to cover up excessive emissions.
The issue, which extends to 11 million VW, Audi and Porsche 2.0 and 3.0 liter diesel cars worldwide, has severely damaged Volkswagen's reputation and spawned a host of investigations in several countries.
In the United States alone the company is facing potentially tens of billions of dollars in fines over the scandal.
CARB also issued an official notice of violation to Volkswagen formally outlining the ways its cars broke California laws and listing some of the fines it could be facing.
"Volkswagen made a decision to cheat on emissions tests and then tried to cover it up," said CARB chair Mary Nichols in a statement.
"They continued and compounded the lie and when they were caught they tried to deny it. The result is thousands of tons of nitrogen oxide that have harmed the health of Californians."
In response, Volkswagen said in a statement that it was working with outside advisers "to develop a swift, fair and independent program, which will provide a comprehensive remedy for our customers."
"We are committed to working cooperatively with CARB and other regulators, and we plan to continue our discussions tomorrow when we meet with the EPA."