If the worst-case scenario for Germany hits, BMW AG, Mercedes-Benz AG and Volkswagen AG would struggle to paint their cars and the air across the country would get dirtier. Europe’s largest economy is bracing for the prospect that Russian natural gas gets cut off suddenly, a shock that would trigger a form of martial law for energy and affect 80 million residents and businesses from bakers to chemical producers. Auto factories may be forced to switch to more expensive propane or butane to generate the steam and heat for paint shops. Utilities will likely generate more electricity from lignite -- an even dirtier form ... (full story)