The growing scandal over Volkswagen’s emissions cheating widened further on Monday as U.S. officials added more models—including, for the first time, a Porsche—to the list of automobiles fitted with devices intended to thwart pollution controls.

The Environmental Protection Agency issued a second notice of violation to Volkswagen covering another 10,000 automobiles sold in North America under the VW, Audi and Porsche brands. That’s in addition to more than 11 million light diesel vehicles worldwide that have already been identified as having emissions-cheating software.

“Volkswagen has once again failed its obligation to comply with the law that protects clean air for all,” Cynthia Giles, the EPA’s assistant administrator for enforcement, said at a news conference.

The models added to the list were fitted with what EPA officials called a “defeat device”—in this case, software that could alter the vehicle’s emissions performance. When the car was undergoing emissions testing, the engine would shift to a cleaner mode that controlled emissions of nitrogen oxide, or NOx, a pollutant that contributes to urban smog.

Under normal driving conditions, the same vehicles would “emit up to nine times as much NOx as allowed” under U.S. environmental laws, Giles said.

Covered under Monday’s action were 2014 diesel versions of Volkswagen’s Touareg, as well as the 2015 Porsche Cayenne, and 2016 models of the Audi A6 Quattro, A7 Quattro, A8, A8L and Q5. The Porsche Cayenne uses many components of the VW Touareg and is assembled at a VW factory in Slovakia.

No formal recall notice has been issued for any of the affected vehicles, though U.S. officials said they expected that Volkswagen would correct the problems at no cost to consumers.

[VW scandal affects 11 million cars worldwide]

“The vehicles are safe and legal to drive at this time, and no action is required of consumers at this time,” said Janet McCabe, acting assistant administrator for the EPA’s Office of Air and Radiation.

Volkswagen has acknowledged using software to thwart pollution tests, and the company has set aside more than $7 billion to cover repairs and related costs. Still, the scandal has battered sales and tarnished the international reputation of the German automaker.

EPA officials would not say how, precisely, the agency discovered problems in the additional vehicles, or how VW officials responded, saying only that the investigation was continuing.

“We’re already making changes and upping our game on our testing program,” McCabe said.

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