SACRAMENTO (Reuters) -- California is preparing a major enforcement action against Volkswagen AG over its admitted cheating on tailpipe emissions tests, the state's top air official said on Thursday.
Mary Nichols, chair of the California Air Resources Board, said it was too soon to say what penalties would be levied against the company, which admitted duping the tests earlier this month.
The state is also preparing to oversee a recall of vehicles in California equipped with the device that allowed it to pass laboratory tests measuring their output of the air pollutant NOx, which contributes to smog, Nichols said.
"Our top priority is to make sure these cars are in compliance," said Stanley Young, spokesman for the Air Board.
"That will obviously involve at some point a recall. But first VW has to demonstrate to us what they are going to do and that it will be effective," he said.
Volkswagen has said that 11 million vehicles worldwide could be affected by the diesel-emissions scandal, including 500,000 in the United States. Californians own 14 percent of affected U.S. vehicles.
The EPA is also looking at options.
EPA agency spokeswoman Julia Valentine said it is considering all appropriate remedies in an email to Reuters, when asked if federal regulators were contemplating mandatory action.
Nichols said the international scandal could lead regulators to harmonize their emissions testing protocols.
"For years that has been a discussion about aligning the testing and procedures of the U.S. and Europe, and the emerging markets in China and India," she said. "The U.S. and Europe are not even in complete agreement with each other."
Air Resources Board member Alex Sherriffs said the state's carbon market, which puts a price on emissions of heat-trapping greenhouse gases, will make it relatively easy for the state to quantify how much Volkswagen owes for violating emissions testing.
"We're looking at the damage to the environment and that can be measured," he said. "We've developed a price for carbon and we've developed what we understand to be the cost of reducing emissions. That looks like the easy piece in terms of putting a price on that," he said.