Federal prosecutors on Monday filed a civil lawsuit against Volkswagen over software installed on diesel vehicles to manipulate emissions levels.
The complaint, filed on behalf of the Environmental Protection Agency in Detroit federal court, alleged that the German automaker equipped nearly 600,000 vehicles with "illegal defeat devices" in violation of the Clean Air Act.
Prosecutors argued that although the software enabled VW cars to meet emissions standards during official tests, those vehicles emitted nitrogen oxides at levels up to 40 times greater than the EPA threshold during normal driving.
The filing asks the court to ban VW's use of the software and impose civil penalties.
“The alleged misrepresentations allowed almost 600,000 diesel engines to emit excessive air pollution across the country, harming our health and cheating consumers," said Barbara McQuade, U.S. attorney for Michigan's Eastern District.
The EPA first announced VW's use of emissions software in September. The scandal — which involved about 11 million vehicles worldwide — led to plummeting VW sales and significant departures from its executive ranks.
The company pulled the affected vehicles from sales lots last fall and is preparing to implement a massive recall to fix the issue.
A federal investigation — which could include criminal charges and billions in fines — remains ongoing.