The U.S. Department of Justice is suing German automaker Volkswagen for falsifying the emissions on 600,000 diesel vehicles in the U.S.
A civil complaint filed in Detroit Monday does not include criminal charges but would involve additional monetary penalties for Volkswagen, which admitted in September that it had installed software on 11 million vehicles worldwide designed to beat emissions tests.
The company is negotiating a massive mandatory recall withthe EPA and potentially faces more than $18 billion in fines for violations of the federal Clean Air Act.
The company could also still face separate criminal charges, while a raft of private class-action lawsuits filed by angry VW owners are pending.
"Car manufacturers that fail to properly certify their cars and that defeat emission control systems breach the public trust, endanger public health and disadvantage competitors," assistant attorney general John C. Cruden with the Justice Department's Environment and Natural Resources Division said.