The US Environmental Protection Agency (EPA) said late Monday that the German automaker Volkswagen used devices to cheat on emissions tests in its 3.0-liter diesel engines, found mostly in Audis and Porsches, which are part of the company's portfolio of automobile brands.
The latest notice of violation follows the agency's September announcement that Europe's biggest automaker had used the so-called "defeat devices" in its 2.0-liter diesel engines in certain VW and Audi cars between 2009 and 2015.
The EPA said the company's latest violations of the Clean Air Act covered vehicles from model years 2014 to 2016.
"VW has once again failed its obligation to comply with the law that protects clean air for all Americans," said Cynthia Giles, Assistant Administrator for the EPA's enforcement division. "All companies should be playing by the same rules. EPA, with our state, and federal partners, will continue to investigate these serious matters, to secure the benefits of the Clean Air Act, ensure a level playing field for responsible businesses, and to ensure consumers get the environmental performance they expect."
Without the defeat devices activated, VW's vehicles would emit up to nine times the allowable limits of nitrous oxides (NOx) under EPA Clean Air Act regulations.
NOx contributes to the creation of ground-level ozone and fine particulate matter. Exposure to these pollutants has been linked to a wide range of serious health effects, including asthma attacks and premature death due to heart and lung disease.
The company has admitted to using the cheating software in 11 million vehicles worldwide, including 500,000 in the United States. The EPA said its latest notice of violation covered an estimated 10,000 vehicles.
The company said in a statement that it planned to cooperate fully with the EPA, but denied the agency's allegations.
"Volkswagen AG wishes to emphasize that no software has been installed in the 3-liter V6 diesel power units to alter emissions characteristics in a forbidden manner," the company said.
Arndt Ellinghorst, an analyst at banking advisory firm Evercore ISI, told Reuters the latest allegations were worrying because they had emerged more than six weeks after the initial scandal broke.
"It appears that it is the EPA that has discovered this violation and not VW, raising concerns around reporting, transparency, and integrity within VW," he said.
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