I remember the adverts for vehicles running “clean diesel.” My first reaction was “Whaaat?” My second reaction was, “Seriously?” I guess the U.S. Environmental Protection Agency should have done a double check on the emissions tests of Volkswagen 2009-2015 models powered by the German car maker’s 2.0-liter diesel engines.

On Friday the EPA found “irregularities” in the world’s No. 1 car maker’s diesel engine, which runs cleaner during testing than on the road. On Wednesday VW’s CEO, Martin Winterkorn, resigned after admitting the company rigged diesel emissions to pass U.S. tests.

VW could be subject to $18 billion in fines for violating the Clean Air Act. But the fines may pale in comparison to the drumming of the company’s stock price. In the first days since the EPA found “irregularities” in VW’s diesel engine, the stock lost nearly $28 billion (25 billion euros).

Winterkorn’s resignation, VW’s stock loss and the PR hit are only the initial salvo of response. Assuming criminal liability inside VW, the company itself may file a criminal complaint into its use of stealth software to trick the EPA, German prosecutors are weighing the launch of an investigation, law firms have filed class-action litigation, and other national governments are investigating VW’s diesel-powered car imports.

U.S. regulators questioned VW about its diesel emissions in March 2014. The EPA accused VW of installing its smog-defeating software in 482,000 cars sold in the U.S.

Looking beyond the current history of the trick smog-test code, the news will not bode well for an industry looking to automate cars with more software. And there will be no easy exit for VW as the German Chancellor, Angela Merkel, has called for complete transparency.

Now. About that “clean coal”?