The Wall Street Journal [sub] reports that Indiana diesel engine supplier Cummins will pay $2.1m in civil penalties for violations of the Clean Air Act. The EPA and the Justice Department complaint alleges that Cummins shipped 570k heavy-duty diesel engines to OEM customers between 1998 and 2006 without the emissions-control systems that make them Clean Air Act-compliant. It’s not even clear clear that the crud-controlling gear is missing. The paperwork is.  Cummins spokesfolks admit that 405 (or about .7 percent) of those engines never received documentation that shows they were fitted with the appropriate emissions-control systems. This is particularly embarrassing for Energy Secretary Steven Chu, who recently gave Cummins $54m in Recovery Act grants intended to improve truck efficiency and emissions, and called the firm “the leader in clean-diesel manufacturing.”